kraythe

Pressure in a 1/8" supply line will be much higher than the orifice needs. No need for big lines.

No. See my thread Brick Pile Forge post for an easy way to get a good forge up. The benzomatic torches just dont put out enough heat to do the job. They are, however, handy for starting the forge and finishing up your creme brule.

. Author's Note: This thread talks about activities and techniques that are DANGEROUS. You use this information at your own risk. I suggest you read the entire thread before embarking on the build. It should be noted that is not a project for a beginner. Look into brick pile forges and building venturi burners to get some experience before tackling something like this. In my previous thread "Ribbon Burner Build" I created a square ribbon burner and learned a lot of things about what makes these things work. One thing that I neglected to include in my calculations was Bernouli's Principle; which states that a gas exiting a small tube into a large tube results in a larger pressure in the bigger tube but slower velocity. When we consider a ribbon burner, this means that the plenum doesn't need to be pressurized by back pressure building in the burner but rather its a natural result of the principle. What it also explains is the performance of the final burner. The numerous 5/16" holes on the exit of the burner are essentially one exit pipe since all will be backed by the same plenum pressure. So applying the principle we see that our 14 holes 5/16" wide comprise an exit pipe about a third of the input pipe. Applying Bernouli's principle it is clear that this means that the exit from the plenum will be three times the velocity (and a third of the pressure) of the gas inflow. Thus the reason that the burner has such a high velocity and hard time staying lit. Furthermore, since each jet is a flat casted tube, the burner lacks the dynamics of the traditional burner's flare to slow down the gas and balance flame front velocity. Another lesson learned is the cumbersome nature of a square burner. With the square burner, the forge dimensions must be accurate on all four sides to accommodate the burner. This leaves us with precious little tolerance for fitting. A perfectly round burner would work better. Additionally the structure of burner requires that there is little contact surface between the castable and the burner itself, only a small ridge and ¾" of metal around the edge. This will weaken the burner's ability to handle thermal shock. Also with the way it is cast, the square burner is prone to error in the depth and efficiency it is set in the castable; if a builder makes a small adjustment or the castable doesn't flow and resettle over the burner properly, it won't work properly and could break. A potential castable failure is another problem of that design. With the manner in which it is cast, a catastrophic castable failure would result in a complete failure of the plenum enclosure and thus a very bad result. as propane is dumped in at high pressure. The forge could suddenly burst in propane resulting in bad consequences. So clearly we need to work on a superior design. Thus is the Three Inch Round Pressurized Plenum Multi-Jet Burner (Ribbon Burner) Born. I started on my cad system planning the Burner. I planned to use a 3" inside diameter pipe (3.5" outside) as the size. The burner would be fed by a 1" feed tube and would be built to learn all the past lessons. The burner will have 9 jets that are ⅜" in diameter with ½" flares for each jet. The reason for the calculation of size results from the calculation of feed pipe input to burner jet output pipe size. So I wanted to make sure the jets comprised at least the same area in sum as the feed pipe. The calculation is fairly simply derived from the formula for the area of a circle. Area = πr2. So we want to know how many pipes of diameter x will take to equal a feed pipe of diameter y so: π(y/2)2 / π(x/2)2 ==> (y/2)2 / (x/2)2 ==> (y2/4) / (x2/4) ==> (y2/4) * (4/x2) ==> y2 / x2. From the complex we derive a simple equation courtesy of a little algebra. Putting the numbers in for a 1" feed pipe and a ⅜" output pipe, we get 12 / (⅜)2 ==> 1 / (9/64) ==> 1 * 64/9 ==> 7.111111 jets. So we would need 8 jets to accomplish a jet total diameter equivalent to the feed pipe. Wow. Is Everyone's brain hurting now? Stuffing all of this into my CAD system you have the following Burner. You may note that I included not 8 but 9 jets. The reason is that I wanted to make sure I really had enough output flow to slow it down. In retrospect I might have gone with 8 or even 7. Although the burner works good with 9, as you see later it seems to lack a little velocity. This is a pretty spiffy model but how do we construct it in real life? Well those that use CAD systems know that the easiest way to do a model like this is to whip up a cross section, create a single object from it and then extrude that cross section for the 3d model. I did exactly that and here are the cross sections for the Baffle, Flare and metering plate respectively. The fuel/air mixture enters through the feed pipe in the back then passes through the baffle which is designed to cause turbulence in the stream and make sure the mix is as complete as possible. The fuel/air is then forced through the metering tubes and is forced out into the flare. The flare jets are half inch in diameter, which is the outside diameter of each metering tube. The casted flare will now grip the metering plate, and the edge of the plenum as well as the wall of each of the metering tubes. The metal metering tubes also are a safety mechanism. If the flare were to crack catastrophically and drop into the forge, the metering tubes would still be working as jets and give you time to shut down the burner safely rather than a whole mess of pressurized propane bursting into the forge. To build this burner I selected 3" inside diameter ¼" wall mild steel pipe with ¼" x 4" wide plate to use for the baffle, metering and back plates. The metering tubes are ⅜" inside diameter by 1/16" wall tubing equaling ½" outside diameter. The very heavy materials will let us repeatedly recast the flare as needed. We can even hit a damaged flare with a hammer to break it off due to the plenum's strength. Now its time to build it. We start by cutting 4" of the pipe to serve as the plenum and 12" of the ¼" x 4" flat stock. For the baffle and metering plates we trace the inside of the pipe on the flat stock with the welding pencil. For the back plate we trace the outside of the pipe. Now we take a center punch and clearly mark the drawn circles with push marks. Later when working with the plates, we will be putting the metal under a lot of heat and the pencil or chalk lines could rub off. The punch marks will endure despite OA torch work or anything short of grinding them off. Also note that if you don't have a welding pencil, a permanent marker will do the trick. I have marked over my welding pencil lines in the images with the marker to demonstrate. Use a thin marker or your lines will be erratic. Now the task is to find the middle of the circle and then draw the 45º angle lines which will help us align the punch marks for drilling the holes. At this time I was estimating the best I could for how to do the center so it was slightly off. A day after I had drilled everything I found a geometric and easy way way to find the exact center of any circle. I will talk about that method later so don't start marking yet. My marks were reasonably accurate though I can see them a tiny bit off. I chose the best marked plate to punch for the metering tubes. I measured in along each line from the outside circle one half an inch and punched a mark. For the metering plate, I punched a mark in the middle as well. Now its time to drill the holes for the metering tubes and baffle. You might notice that i haven't cut apart the plates yet. You shouldn't either. The long plate makes it easy to clamp to the drill press securely. Clamping the individual circles would be very difficult. Drill first, then cut. When it comes to drilling I have put a piece of scrap plywood under the plate and adjusted the drill press to stop halfway through the plywood. That way I can make sure I get all the way through the metal as well as not hit my drill press table. I am using Dewalt Titanium drill bits because, frankly, they are awesome. You could theoretically do this with a hand drill but your accuracy will suffer badly. If you don't have a drill press, borrow one. Now its time to cut the hole for the feed pipe in the back plate. A bimetal saw will do this as long as you have a good lead drill bit to guide the hole saw. This will generate a TON of noise and vibration and so I recommend you put on as many clamps as you can and put them on tight. Unfortunately my hole saw rig was damaged and I couldn't use a lead bit. As a result the hole saw wandered off center and skipped a bit. The result would still be acceptable as the burner doesn't have to be centered. However, I am something of a perfectionist for this and I will correct it later. Now we can separate the plates first with a chop saw and then with an OA torch we rough cut out the outer circle of each plate. After that we use an angle grinder and clamp each plate in a vise and then grind down to the dots we punched for the circle (all welder's pencil and ink marks will be long gone). We just keep grinding down and turning the plates in the vise until they are right. To make sure they fit, test fit them in the pipe and grind down as needed. Don't forget to grind a slot for the seam inside the pipe. Then grind the plates clean and shiny for better welding. Now we can install the metering tubes. Cut off a 1 inch piece of tubing for each metering tube and then use a round file to clean off any metal burrs and grind a small bevel in one end of each of the tubes. Then take a hammer and set the beveled end in the metering plate and tap them down with the hammer but don't crush them. If they won't go, file out the hole a bit to make it work. It should be tight and take a hammer to set them but they should go in. Tap each tube down til it hits the metal underneath. All tubes should be flush with the back of the plate. Now using a MIG welder carefully weld around the outside of the metering tubes on the back of the plate. Try not to fill in the tubes too much or you will be filing for a while. Make good welds. Although they don't absolutely need to be gas tight, if you can weld them that way, all the better. Once welded, use a grinder to smooth off the back of the metering plate flat. The picture shows this in progress. Next take a round file and file out the inside of each tube to round again to get rid of any weld material. Now the metering plate is done. You can see the basic "Gatling Gun" structure and the lights from behind show the metering tubes are smooth inside and not obstructed. Now we put the plenum on a flat piece of metal that is at least as wide as the plenum and drop in the metering plate facing down and make sure it is sitting flat. Then we gently tack weld the metering plate in place. Now flip over the plenum and inspect it. The metering tubes should all be in flat with all tubes flush with the edge of the plenum. If it all is good then weld around the side of the plate to permanently mount it in the plenum. Take care to make good welds as gas tight would be beneficial. Try not to obstruct a tube with weld material or you will have to file that out with the round file. Its hard to brush off welds down in the pipe to make it look good but the principles of the weld are important, not its appearance. Now we are back to the problem of the back plate. Recall earlier I had a problem cutting the feed tube hole. I decided to redo it and this time i used my new method to find the center of a circle. It seems that geometrically any chord of a circle can be used to help find its center. A line passing through the halfway point of any chord and perpendicular to the chord must pass through the circle. So once you have pushed the circle, take a ruler and draw a chord exactly two inches long. Mark the 1" center of that chord. Then using a right angle draw a line passing clear through the circle. I used a cheap $5 adjustable metal protractor from Home Depot. Repeat this process and where the two perpendicular lines intersect is the exact center of the circle. Neat huh? I punch a mark at the center and drill a half inch hole (largest drill bit I have) in the middle. Then I draw out a one inch circle centered on the drilled hole. If you have a locking compass this should be easier to do before you drill out the center. Finally I punch the center circle with a center punch and then use the OA torch to cut it out. I file it as smooth as I can get it and then use the OA torch to cut the outside, and then grind it as before. in retrospect a Dremel might have made better work of the center but it doesn't have to be precise as turbulence is actually desired. I could have, of course, just bought another hole saw but now you have two ways to do it. Now its time to install the baffle plate. We measure down 1" into the plenum and mark it with a welding pencil. Then my helper (my son) holds the plate with some needle nose vise grips at the lines and flat so I can tack it in. We check the fit and then weld it in permanently. Next I weld the feed tube to the back plate. For the tube we used a 1" black pipe connector. Do not use a nipple or you will not have much material to weld to. Its better to use a straight connector for its greater metal mass. This weld MUST be gas tight and we will insure that later. Once this is done, we fit it on the plenum and then weld the back plate to the plenum. For this weld make sure you use high heat and probably two passes. Next I pass over the back plate and feed tube welds with an OA torch with a number 3 welding tip. The goal here is just to walk the weld puddle around the plenum and tube. If there are pinholes, they will be filled. If there are voids they will collapse and can be filled from welding rod in your hand. We dipped it in the water to cool it off after it was black again. The dead cricket in the water seems to help. Now I did something a bit boneheaded. Or rather ill timed. We decided to paint the plenum to resist rusting. Good idea to use an engine approved paint for 500º as the plenum shouldn't ever get that hot. So we crafted a box and painted it nicely. It looks great. Except we forgot later we will have to shove the thing in a forge and that will burn off our paint job. Oh well, live and learn. We will paint it again later when it is done. And now the plenum is done! Time to work on the flare. The flare will be cast out of Kastolyte 30 reinforced with stainless steel needles. In retrospect I might have used something a bit more dense but with the same rating. I don't know if a base of kastolyte with a Mizzou last inch would hold together. It might be worth a try. The problem is the kastolyte is an insulating refractory that is soft and the jets at the flare end might be prone to fracturing. Perhaps less jets and more space between jets would help. At any rate, to cast the flare we have to keep castable from getting inside the plenum and also cast ½" jets centered right over the metering tubes. We accomplished this by first trying to epoxy in ⅜" dowels into the plenum and then epoxying ½" dowels on top of the metering tubes. This is shown below but it didn't work well because it was nearly impossible to get the top dowels centered properly and remain perfectly vertical. Back to the drawing board. We took our half inch dowels and sanded them off and drilled out or pressed out the ⅜" dowels inserted in the metering tubes. If they go inside that is ok because they will burn out later. We then throw the plenum in the forge and burn it clean, burning epoxy as well as wood. This is NASTY so have a good ventilation fan! Oh yeah, the paint didn't hold up to the forge. We then decided to glue the ⅜" inserts to the dowel rods first and let them cure 24 hours first. In the meantime we experimented with making a tool out of the tubing used on metering tubes and a drill press. We also tried using sandpaper like a lathe since we only had to take off 1/16". These didn't work as well. I am sure there is a better way to do this to keep the tube perfectly straight but I haven't found one. At any rate our glued dowels worked. One thing we would have done is to sharpen the "up" points of the dowels so the castable would fall easier in between the dowels later. Make sure your dowels clear the top of the flare by at least 3.5". We glue them into the metering tubes with two part epoxy and let cure at least 24 hours. In retrospect would have also made a top plate out of thin wood with holes cut for the dowels for perfect alignment fit after the castable is poured. The pattern for the metering plate would have worked nicely with a larger outside diameter; for materials use the thin wood that you can get from the hardware store with a shiny side. To create the form for the outside of the flare we will use poster board and duct tape. We cut a 5" long slice out of poster board and roll it around the flare so the shiny side is inside. It should roll around several times. Get it nice and tight and tape the roll end. Now slide the new poster board tube up the plenum to make a depth of exactly 3 inches from the plenum pipe edge to the top of the poster board. Its possible you might be able to use a shorter cast but this looked good for insulation reasons. We duct tape the form in place on the plenum then later duct tape to reinforce the poster board all the way up the form. Now its time to mix the castable. We put on respirators (this stuff is bad for you to be breathing) and then my son opens the can we store Kastolyte 30 in and scoops it out into a drywall mud pan for mixing. We then get a couple of handfuls of stainless steel needles that will help reinforce the castable and put them in the dry castable. Now we add water VERY SLOWLY to the pan using a small plastic cup. You will be astonished at how a few drops can change the mix. Put a very small amount in, mix it up like crazy and then very slowly add a thimble full of water at a time. The final consistency should be like thick peanut butter. Now its time to pour. Scoop out the castable and put it right on top of the dowels. If I had sanded them into cones like pencils on top, this would have been easier. Fill the form until its full. Periodically you will have to pick up the burner and rap it solidly against the table repeatedly. This will force the castable mix to settle and fill all gaps. The vibration tamping is important. Without this you could end up with large voids. Just pick it up, keep it upright and rap it against the table several times and add more castable until it is full and even a bit overflowing. Once the form is full you can put on the top alignment form (not shown) tap down the form until its flush against the top of the poster board tube (some castable may squish out but that is ok). Then rap the whole thing against the table a few more times to settle the castable around any rods you have moved. Now you have to wait three days; if its cold where you live, bring it inside where temperature is constant. After three days you can peel off the duct tape and unroll the poster board off the flare. This will let the bottom parts of the flare cure faster. Leave the top plate of the form in place as removing it now could crack the cast. After another day drying its time to bake it. Put the whole thing in a forge you have currently operating or a brick pile quick forge. It doesn't have to be that efficient of a forge. Put the flare in the forge when the forge is cold. Light the forge and let the thing bake. The wood dowels, top plate and epoxy will burn out. This will be NASTY so have good powered ventilation. Now we let it cool in the forge a couple of minutes and use a shop vac in blower mode to blow out ash and charcoal. Keep an eye on where embers go and put them out quickly. A friend helps for this part. Make sure you have a fire extinguisher handy if needed. DO NOT VACCUM THE EMBERS INTO YOUR SHOP VAC. If you do, you are courting a bad fire later. Eventually you might have one or two holes plugged. Use a spare welding rod or metal or whatever to clean it out. At the end you should be able to see smooth bores for the flare and the top of the metering tubes. Now we let the burner cool and very carefully, very gently touch any extraneous ridges with an angle grinder. The grinder will eat through the castable like it is air so be very gentle and quick. There may be some stainless steel needles on top of the flare but they will burn away later so don't stress over them. Now it is time to build the supply pipe. We take a ⅛" brass pipe plug and chuck it in the drill with the dimple side up. Make sure to get the ones with the centered dimple. It will save you some time. We drill a small hole for the propane jet. As will all blown burners the exact size isn't that important. Then we screw that plug into a straight connector, that into a pipe nipple, pass the pipe nipple through a 1" to ½" black or galvanized reducer and through a ½" inch brass plug that has been drilled out to be almost exactly the outside diameter of the brass pipe nipple. We attach the other end of the nipple to a ¼" to ⅛" reducer and an elbow. This assembly we attach to the supply assembly. This consists of a propane hose to the regulator attached to a propane flashback suppressor, then a fuel to pipe thread converter than a ball valve and finally a ¼" brass nipple to the jet assembly. Use propane sealant on all brass connections and check for leaks with child's bubble solution while pressurized. Now we attach our blower (clamp it) to the a pipe to feed the air in. The feed plate is a 2" black iron pip nipple welded to a plate with a 2" hole in it. Then attach the blower feed to a bell reducer then to a gate valve using some pipe nipples and then to an elbow and then another long nipple. The propane feed assembly is attached to the top of a T fitting, the pipe from the blower enters on the leg of the T and the nipple leading to the plenum is on the other leg. This setup allows you to adjust the position of the jet, though I haven't really noticed a difference so I will probably go down to a shorter brass pipe nipple in the jet assembly. Any space around the pipe nipple will leak fuel /air unless you seal it off with duct tape or something else. I am working on a better config that isn't so leaky. Now we attach another elbow and then another nipple and then finally the plenum with its cast flare. We are now ready to test. We start a plumber's torch, set propane to 5 psi, turn on the blower and open the ball valve with the plumber's torch in front of the flare and WHOOSH, it lights. My son is waiting with his hand on the bottle valve, ready to cut the propane if anything bad happens. The flare really roars, all 9 jets are firing. We end up feeling like we aren't getting enough air velocity but even as imperfect as it is, its awesome in its functionality. It totally blows the normal blown burners to heck. I might try plugging one or two jets and seeing what the result is in velocity. The video is sort of on it's side so I hope you will pardon the roughness. I should have filmed it in landscape. Oops. Next we go to test it in a brick pile forge. We rig up a support arm, use hose clamps to attach the feed tube to the arm, mount the blower and move our brick pile to center up the burner. This is not the optimal forge for this burner but it will make a nice test. We close up the forge and shove pieces of insulating block to accommodate the roundness of the burner in the square forge. The burner is a bit low in the forge but for now its fine. We put the plumber's torch flame in the forge and open the ball valve (with the blower on). The burner really rocks the forge. You can see the blue jets in the picture. This forge was running hotter than it ever has and heating up very quick with only 2.5 to 3 psi of propane! After we play around and run it a bout 20 minutes, we see that it heats awesomely. We cut the propane, waited for all to cool, and the took apart the forge to examine the flare. There is some minor breaking around one jet but nothing serious. This is the reason I was thinking of a denser castable next time. When running we heard a couple of times a thump and then a low rumbling. I am not entirely sure what is causing it and I will investigate it. It was a low pitched ruble. This flare could be covered with ITC-100 and used. The extra stainless wires will degrade quickly. I might experiment with fewer jets and tinker with the castable process but the burner performs magnificently. The burner is easy to build, low cost and very durable. If you drop it and break it or the castable cracks due to wear, you can recast it easily. It uses a fraction of the propane of my old blown and venturi burner and the increased surface area of flame allows much better heat transfer into the forge. It is a resounding success.

It could be .035. I try both. It depends on a lot of things. I live at almost 6000 feet of elevation so that might alter things.

They will glow orange in some parts and those areas will be hot. Very hot. Anything near the hot face of the forge will be hot. However, on the outside you can put a gloved hand on the bricks and keep it there. Your copper hose and connections to the burner should NOT get hot. If it does, shut down the burner immediately and find whatever heat leak is allowing them to heat. The flare of the burner, on the other hand, will get red hot.

.035 Works. It depends on the length of the tube. Try both and see which works better.

Read Drawing on the Right Side of the Brain and do the exercises. You will be amazed at your improvement in a short time with minimal expense of the book and materials. I read it and went from stick figures to life like portraits in a couple of weeks.

I am usually not one to post replys like this but Brian, you don't know what the heck you are talking about. Not only is your information inaccurate, it defies the basic laws of physics. The whole reply is rubbish and should be chucked into the "listening to this guy is dangerous" bin. A tank getting cold to the point of accumulating frost is nothing to worry about unless all you have used propane for is barbequing steaks. (And that should be done with charcoal anyway.) Tanks get cold and frost because of a result of the Joule-Thompson effect. As the fuel is drawn out of the tank it is converted from liquid to gas which, as Thomas points out, is an Endothermic process. This causes the temperature of the bottle to go down. Pulling cold propane through lines will potentially cause them to get cold as well. When those lines get cold they cause the air around them to condense on the tank and lines because they are lower than the dew point in the room. Subsequently the condensation may freeze into frost. There is no moisture in the line. Its not even possible in the laws of physics. Anyone putting a cylinder in front of a forge close enough to heat the bottle is asking for a BLEVE. This is a short term for a Boiling Liquid Expanding Vapor Explosion. Youtube that and you will see why it is bad. The proper way to "thaw" frozen tanks is with a warm bath of water if anything. Personally i just have another tank and switch the regulator and that is that. This is just insane ranting. Propane bottles are designed to handle a much higher flow than smiths pull out of them but the result is the cooling of the tanks. Its the same effect as that cold spray paint can you might use in the garage. There is nothing wrong with the pressure flow or anything else. Furthermore you comment about the unburnt propane cooling the forge is patently ridiculous. What do you think happens to superheated propane at 1500º in a reducing atmosphere (lack of sufficient oxygen)? Its simple, it exits the forge out the opening and when it slows enough and combines with enough air, it ignites at its stochiometric mixture. You get yellow "dragon's breath" outside the forge. However since the mixture is uncontrolled you produce more carbon monoxide than you do with a good lean burn. To say the unburnt propane cools the forge is just a violation of the laws of physics. The openings in the forge have a cooling effect on orders of magnitude higher than any unburnt propane of whatever temperature. Furthermore the atmosphere in the forge has nothing to do with the temperature of the propane. When the propane is rich in the forge it means that the burner is not tuned properly. A properly tuned burner will not do this. Propane forges, whether blown or venturi, use a premixed propane at high speed to balance the flame front velocity of the propane. Without premix the forge wouldn't even light. So the adjustment of the burner will change the mix in the forge, not the temperature or even pressure of the forge. Pressure loss (which occurs as tanks freeze) will have no effect whatsoever on a venturi burner as it is designed to suck in the proper amount of oxygen for the given pressure. As for a blown burner, if the pressure drops, the atmosphere will get LEAN not rich. The temperature you would need to get the regulator to to cause the diaphragm to malfunction is so godawful low that you would have so little pressure in the tanks that you couldn't get the forge to light. Those things are rated to perform in arctic environments which is a heck of a lot colder than the freezing point of water. Assuming you could get the diaphragm that cold and assuming you could still run the forge on that pressure you are getting, the most likely thing is the regulator would malfunction til it thawed. And if you have leaks at your fittings, they weren't tight enough to begin with and they weren't sealed with propane rated sealant. Do you really know the temperature you have to get brass to to change the fittings significantly? What are you burning? Liquid nitrogen? First of all commercial forge manufacturers are trying to sell a product and so they are not unbiased sources. Secondly they would say that running propane that cold is bad because mostly you are not getting reasonable pressure out of the tanks and thus the forge wont perform properly. The rest of the rubbish you state is a violation of the laws of physics and so I would avoid any forge manufacturer that pushed that rubbish. I assume you are just trying to help but when you are not an informed source, you should avoid trying to inform others. You can get someone hurt that way and that is the last thing I wish to see happen to anyone on this forum, you included. I'm sorry for being so harsh but I cant in good conscience let your post go unanswered.

Its just a generic metal table. Actually the one I use is one that I welded up one day. Its probably overbuilt but better than underbuilt. :)

Glad to help. I will be adding info on how to add a 3000º hot face to a soft firebrick. Stay tuned.

Oh wow. ... 1) Siica sand ground fine is VERY VERY bad for you. Not even metal casters use it anymore if they can avoid it. You need a real flux like borax. 2) You don't have to hit hard to weld, just QUICK. As soon as you yank it out you have to touch it instantly. If you have to reach for the hammer you are in trouble unless the rod is VERY hot. Once you pull it out, it starts dumping heat fast.

Yeah but its not as bad as the other stuff for creating the forge. And gives you a bit more peace of mind until its coated.

I resolve to not make any new year's resolutions. Doh!!!!

I dont use coal but I would check into your flux and make sure it's a good brand. And I have an adaptation of the old maxim about discipline; spare the flux and you will spoil the weld. Also as Thomas says you can have lines still after welding. The only really good way to tell a good weld without 10k in equipment is to cut through it. Make practice pieces and then cut thin slices with an abrasive cut off wheel and inspect the result with a microscope or at least magnifying glass. And once you get that working you can try welding cable. That's a whole other pain. :)

Sorry man, most of us build our own. That is a huge forge and a huge amount of gas consumption. What are you making? Scrollwork for gates?

Uh no. I practically freeze my tanks every time I forge weld. Its a result of Bernouli's Principle. Its normal and I wouldnt worry about it.

Over the time I have been visiting this forge I have seen a lot of people come through and ask about all sorts of designs of forges. Most of the people posting such threads are actually new to using a gas forge and often new to smithing. I have advised many of these newer smiths to first build a brick pile forge, use that a while and then go to something more serious once you figure out how big you will need. So now I wanted to make a definitive post as a guide for these people. The forge will have an internal size of 9" x 4.5" x 6.5", or 263 cubic inches. It is, however, easily reconfigured to be smaller, shorter, wider or whatever you need for your particular tasks in the shop. That is the beauty of a brick pile forge, it can be reconfigured at will and allows the smith to see what size they need in the end. This forge is not the end all-be-all of smithing forges. It is a starter forge and as you work with it, you will learn a ton about how forges work and will grow into more efficient systems. The brick pile forge is so versatile that occasionally I will toss one together just to do some specific task that doesn't work well in my main forge. Forge Materials: About 10 to 15 Soft insulating bricks, rated 2300 degrees farenheit. 3 Hard firebricks. Metal Table Burner Materials:1" to ¾" Black Iron T fitting (1" across the top and 3/4" on the leg of the T) ¾" to to 1" Black Iron reducer ¾" x 6" Black Iron Pipe Nipple High Pressure Propane Regulator Propane Pressure Gage ¼" Propane Rated hose with Fuel Threaded ends (available at welding supply stores) ¼" Propane Rated Flashback Supressor (available at welding supply stores) ¼" Fuel to normal pipe thread converter (available at welding supply stores) ¼" Ball Valve ¼" Brass Pipe Nipple (4") ¼" Brass pipe Nippel (smallest) ¼" Brass Pipe Straight Connector ¼" Brass Pipe to 1/8" Copper Compression Fitting (2) ⅛" Brass Pipe Compression nuts 24" flexible copper pipe ⅛" Compression to normal pipe Nipple .025 MIG Tip Propane rated thread sealant. Tools (Basic):Copper Compression Hose Flare Fitting Tap for your MIG tip thread (varies by the tip brand) Tap for ⅛" pipe thread Couple of Crescent Wrenches Drill 2" Hole Saw Hacksaw Reducer for ¾" to drill bit size for the tap. Plumber's torch with click starter Tools (Best): Drill Press rather than drill Dremmel with Cut-off wheel Propane Supply Assembly First tap the 1/8" compression to normal pipe nipple with the tap for your MIG tip. The right tap to use depends on the tip brand that you are using. If you ask a welding supply store they can supply you (or at lest tell you) the right size. Then cut about ⅛" off of your MIG tip and put propane sealant on the threads and screw it into the tapped fitting securely. Next attach the copper flexible hose to the compression fitting by putting on the compression nut and then flaring the tubing and finally screwing the compression nut on the fitting you tapped. The goal of the flexible copper tip is to get a good nice gas tight seal without constraining yourself with rigid pipe. Next put the compression nut on the other side of the tubing and flare that. Take the ¼" pipe to compression fitting and attach the other end of the flexible copper tubing to this fitting. Then attach the converter fitting to a small pipe nipple then to the straight connector and then to the longer pipe nipple. The extra parts make this assembly easy to use on other burners and other projects in the future. Finally attach the 4" brass pipe nipple to the ball valve, then attach the ball valve to the fuel to pipe thread converter. use propane sealant on all threaded connections. Fuel hoses are backward threaded. You learn "Righty tighty, lefty loosey" to understand normal threads. Fuel threads are the reverse of that and this is a safety feature that you don't want to violate. The converter changes the normal pipe thread into fuel threading. This should be screwed right into a propane rated flashback suppressor. This device will keep a flashback from reaching your bottle if something should go badly wrong. You can potentially skip this device but when it comes to exploding propane bottles, I prefer to play it safe. Attach the flashback suppressor to your propane fuel hose and then the other end of the fuel hose to the regulator. Screw the pressure gage on the regulator and you have the jet assembly done. Again remember to use propane sealant on all threads, if you didn't, go back and take it apart and do it right. Burner The burner is a standard "Frosty" T burner so named after the forum user Frosty who created it and has a propensity for wrestling large trees. To tap the back of the T, get a reducer that will screw into the ¾" side part and reduce it to just barely the size of the drill bit you will use for the pipe thread tap. If it is smaller, that is fine, if larger that isn't optimal. This reducer will serve as a guide to the drill to position the jet exactly in the middle of the T leg. Drill out the burner and then tap it for the ⅛" pipe that the MIG tip is attached to. Next attach the black iron pipe nipple and the ¾" to 1" reducer to act as a flare. If you don't know how to drill and tap, then you should probably research that and practice before embarking on this project. Now screw the burner jet into the burner and then test the burner. Testing the Burner Check for leaks using dishwashing fluid mixed with water or, even better, child's bubble solution. If you see bubbles that is a leak. Twist it tighter, make sure you have a good amount of propane sealant and so on. Light the burner with a plumber's torch (this is the safest way to light your forge). Another great trick for checking leaks is a cheap medicine syringe used for children. Fill it with bubble fluid and squirt on your junctions. Note that while I am testing my son is sitting there with his hand on the bottle valve and watching what is going on. His job is simple, if something goes bad, he cuts the propane at the bottle. Forge When we say brick pile, we aren't kidding, its literally a pile of bricks on the table. Use a metal table and you can fabricate one if need be. Mine is fabricated to hold forges. Start with three bricks in the center of the table configured as shown Add a hard firebrick in the middle. This will heat up in the forge and serve to regulate the forge temperature. Make sure the brick is at least the width of one brick from front, back and sides. Next add vertical bricks to the side of the hard brick. Now we test out the roof bricks. We want to make sure that we have the right width. Now we add some hard bricks to the side to support the vertical bricks from falling. We also set up a couple of bricks to serve as the back door. Now we have to drill out one brick for the flare. These bricks are very soft so be careful or you will shatter them. We use a hole saw to drill the brick. Put plywood under the brick to support it and make sure you can drill all the way through without hitting the table. When you drill, go very slow and steady. Don't press hard or the brick will shatter. Now we place the flare brick on top of the pile, stick the flare through and clamp up a support for the burner. The bricks won't be strong enough to support it. Now we seal up the roof using a brick on edge to serve to give a roof over our front door bricks. Finally turn on the burner to about 5psi and open the ball valve while the plumber's torch is in the forge and enjoy the glow. Enhancements: The bricks can be coated with ITC-100 wherever they are exposed to heat. This will make the forge hold a lot more heat. You can also make a quick form the size of a brick and pour half an inch of castable over the brick (like Kastolyte 30) and then coat that with ITC-100. Make sure the first time you fire the castable you go slow. This will allow a much hotter face. You can put in blown burners, change the configuration and a dozen other enhancements. Comments and questions are welcome.

Best to run it balanced. Rich means you are wasting fuel that doesn't get burned completely. Lean means you are cooling the flame with too much air and not putting full BTUs into the forge.

http://www.mcmaster.com/#standard-taps/=fl184p McMaster Rocks. :)

You can make one for less than that with an insulating brick pile.

Yeah I considered the pleated option. I don't know if that counts as on edge since it is folded.

Really Phil? I searched and couldn't find the thread. Can you clue me in with a link? And I abandoned the nasty stuff ages ago. I use the safe stuff. I still wear a respirator when working with it.

yeah I agree mat. I figure I have the forge running about 2400 degrees when welding at 20 psi propane. If the bottle doesn't freeze (thats why Im going ribbon now). That will far exceed most wool only solutions. I have found their ratings are a bit optimistic. Thats why I like using castable hot faces.

I considered that phil but couldn't find a really workable solution for the top. Blanket won't be stiff enough, cartable could thermal crack and fall. Its a quandary. If you figure it out, id be interested to see it. Perhaps pleated blanket with a covering of some sort. The problem is I use blown and now going to ribbon burners and so I need the extra rating of the castable as I put a ton of heat into the forge twisting cable damascus and playing with breaker hammer bits.

Well if he is going to be doing blades, the question is whether he is going to be doing damascus which means forge welding. If so then it will become essential to consider the effect of borax. KAO wool gets eaten by borax in seconds. At the very least you should have a borax drip pan and any exposed wool should be coated with castable, refractory mortar and probably ITC-100 to get the temp he needs. Brick pile makes this easier. Now I am going to have to consider a post on building a brick pile forge.