reefera4m

I'm re-working a forge I built many years ago. It's been great for general forging, but I want to start welding and it's just not hot enough here at altitude. (Salt Lake area)

The forge body is 8" pipe, 17" long. Two layers of 1" Kaowool all the way around, and a piece of kiln shelf on the bottom. Net inside diameter is, taking into account the non-round shape, about 5.5". So we're looking at around 404 in3. I made a little movable wall out of satanite-and-itc100'd kaowool. Oh, and ITC-100 on the Kaowool, though that needs to be re-coated.

Single 3/4 "Reil EZ burner dead center, i.e. 8.5" from each end at about 10:00 pointed in so the flame hits the wall and swirls. If I were doing this over, I'd place it closer to the front - that's where all the heat goes. The back stays pretty toasty.

I am looking at two improvements: adding a second burner, Porter-type, and upgrading the old burner to a Porter-type.

My burner holder is 1.5" pipe welded into the forge body. Really not looking to cut it off and move it. I am thinking of adding another burner between the existing burner and the front - maybe 4" OC from the existing burner. Is that too close? Can I go closer? I really don't want the additional burner right in my lap... Or should I bite the bullet and move them both? Or just weld up a new forge body - I think I have the cutoff from that 8" pipe around here somewhere...

I've already plumbed ball valves for each burner, so I can run them individually. Same pressure to both, though.

Any advice welcome!

Thanks,
Dave

 I don't know any place in Spokeane, but if you ever get over to the Seattle area you can work on it in my shop - no charge!  Just PM me in advance. 

just finished a blade i have been working on for a while. I am very pleased with it made from a HC r/r spike it measures 11 1/2 inches long, blade 6 1/2, handle 5.Deer antler handle brass pins and polished to an almost mirror finish. I tried to stay away from the grinder and did most of the work w/a file and sand paper but the buffer w/a little emory compound went a long way. When tempering the edge got an almost perfect straw yellow and this blade actually holds a pretty good edge unlike a lot of my spike knives but recently aquired some leaf springs out of a big rig and we did some banging on some this weekend. Oh boy what a difference! we used twice as much coal and got half the work done not sure the carbon content but i'm told its pretty high.Can't wait to get a little further on them. Any and all comments appreciated.

THANKS GUYS

scott

thanks a lot! I will take your advise on the rivets, what would you recommend on wooden handles? like the types of wood? I'm looking forward on taking local wood, we have oak/maple/white cedar/black cherry/ash/beech and black walnut... again, thanks for the advice and all, it's encouraging! off to the forge!

I visited the best hardware store that I know of, about 15 minutes from my house. They have a large fastener selection. We were unable to find a compatible nut. The pitch is 24 threads per inch; that is what I measured, and they confirmed it. We tried metric sizes, as well as #12-24. Nothing fit. I measured the OD of the threads with a digital caliper, and came up with 0.230 inches, a little less than 1/4 inch. The manager of the fastener department said that it had to be a special thread, and I am inclined to agree with him. He said that anything 1/4-24 was probably pre world war II, but that the railroads still used it because they have some lights that were made that way.

I may order a special tap, size 1/4-24, knowing that it will be a little large. It may not work too well, but maybe better than the 1/4-20 that I tapped the hole for the first time. (For quarter inch, the standard threads are UNF 1/4-28, and UNC 1/4-20.)

Richard

Bought one ......didn't last but two hours, finally bought a metabo just need to get a couple more.

As for clamping slabs to tang while using epoxy - tight is relative. You certainly don't want to use an 8" 'C' clamp and really screw it down. On the other hand using a couple of small spring clamps works well as does several strong rubber bands. I like to use rubber bands as they allow for easy positioning of the slabs and can easily be adjusted looser or tighter just by adding or subtracting a wrap or two.

Regardless of the glue you use, pins are alway a good idea. I've had two knives that I've used the Home Depot 2 ton epoxy on whose handles have come off in normal usage but they didn't have pins. After I added pins they seemed to hold a lot better, thought not as well as the high performance Hysol epoxies from Loctitie. Once epoxied in, you couldn't remove the pins without destroying the entire handle - whether you peen the pins or not. I stopped peeding small pins (1/8" or less) altogether - less chance of damaging the handle for little or no benefit.

Sandblasting that way could get you into a lot of trouble! Silicosis is SCARY! At the least wear a really good dust mask... better yet get a sandblasting booth. The booths are not all terribly expensive and they are quite well suited for knifemakers uses (I have seen them on Craig's List for a hundred or two). I have personally found that Loctite "professional extra time epoxy" from Lowe's serves me well. You can tint it with standard painters tinters (glycol type). Use small amounts of tinters... I often just use raw umber. I don't get into any special prep before gluing but my blades are forged and then I hot brush the scale. The natural scale pitting and forge marks leave a helpful "tooth" to bond to. If you do stock removal only, you'll have to add some work to get the needed "tooth". Further, since the epoxies tend to grab the wood rather well but sometimes have trouble holding onto the metal, try drilling an extra hole or two so that your epoxy can self rivet to the metal (this in addition to your riveted pins). I've not needed to do this so far, but I think it would work well in case I do have problems. A similar technique is to file or grind notches out of the tang edge so that the epoxy makes a through join there. An under sized or hidden tang can also be used allowing for the edges of the scales to glue directly together.

One further note on the use of epoxies in general. The mfr's don't often make this clear but epoxies produce a waxy "blush" as they cure (called Amine Blush). This must be removed with a damp cloth or by sanding or both, before subsequent coats or other finishes will stick to the epoxy surfaces.

I've found the best way to insure a great epoxy bond is to sandblast the tang and then wipe down with denatured alcohol.
If you have access to an air compressor then with a bucket of silica sand and a $19 siphon sandblasting gun makes it real simple.

JB Weld is definitely not something I would use. I've tried it and it doesn't bond wood to metal all that well.

Loctite Hysol, 'E' series epoxies are excellant. In a glue/epoxy comparison on another forum, JB Weld came in near the bottom and specifically not recommended for attaching slabs to handles - too bad for me I didn't find it before I tried JB Weld..

The sandblast tip came from the same forum and was credited with being the best means of prepping the tang - over sanding, grinding, or anything else.

It'll work. It's usually harder to light but will produce more heat. Like all coal it varies in quality. The best way I've found to get the most benefit is to mix it with some bituminus coal. The bituminus is easier to light and keep going and haing some of that in the mix makes maintaining the fire easier. For me at least, without the bituminus, it takes a lot more air from my blower to keep it cooking.

Sam,


Ditto Doug's comments! I hadn't seen the tutorial before and it's taught me a thing or to. Thanks for contributing

First, to answer your question. If you were to make a blade just by grinding/filing/sanding youmight not need to heat treat it at all IF, during the process, you didn't over heat the steel (using bare hands it a good way to make sure you don't over heat it). That said, it is darn difficult to make a knife from hardened high carbon steel (much less good tools steel) just by stock removal without annealing it first. It can be done, it's just very difficult.

You can use a forge, kiln or furnace but if you go that route I'd think you'd want one that goes beyond 1550 degrees. Many good knife steels require higher temperatures (A2 for example requires 1700 degrees and 1600 degrees is recommended for 5160).

Absent of a pyrometer you can use the magnet test. Using any means you have (even a hot wood or charcoal fire) heat the steel up to the point that a magnet won't stick. The difference in normalizing and hardening, for a lot of steel, is just the cooling process. For normalizing you just air cool, for hardening a quick cooling via a quench (quench material vary by steel by vegetable oil work for a number of them - heat the veggie oil to 140 degrees +/- 10 degrees).

Don't forget the tempering.

One other observation. Your forge is a lot larger than mine (and maybe larger that it needs to be). Riel burners are very inexpensive to make wo you might try adding a second burner. I'd put the second one on the opposite side and space the apart a couple of inches if possible. That will distribute the heat more evenly as well as increase the heating potential.

No, I am not offended. I never claimed to be very knowledgeable about blacksmithing. My work is in metal, but my expertise is more in sheet metal, especially copper. If you want to see my work, http://www.fergusonscupture.com Yes, I have taken a blacksmithing class, and attended a couple of blacksmithing conferences, but blacksmithing is not something I do every week or even every month.

There are no shortage of those who say that building a forge is not that big a deal. I hear people talk about getting a white heat from a propane forge. I have never even gotten close to that with this forge.

From my standpoint, I was just disappointed that after reading everything that I could find, then following all the recommendations, experimenting with the burner in free air and tuning it there, my forge did not seem to get much hotter. I have spent a day or two working on the forge in the last week or so, so it is not for lack of effort. It does run better at low propane pressure, so that is an improvement. My blacksmithing friends tell me that I am close, but from my standpoint, I am running low on ideas. I do plan to try smaller MIG tips, probably .030 and .025, maybe that will help. It is unclear to me if my 5800 ft elevation is part of the problem, my guess is that it plays a role.

I am sure that a store bought forge would work better. I need a forge that I can pick up and put on the shelf when I am not using it. I am usually pretty good at figuring things out. I can wear my artist hat or my mechanical engineering hat, usually one or the other will give me what I need. I tend to prefer to build my own tools anyway. But I also know that commercial tools generally work better.

I think that if the ITC-100 and the smaller MIG tips do not help, I will rebuild the forge to include two Reil burners, or perhaps one larger burner.

So for those readers thinking about building their own forge, perhaps this thread will give you some idea of the downsides of doing that. You might be better off buying a propane forge for $500 or so, presumably getting good results out of the box.

It is on my list to visit one of the local gurus and see how he would slit and drift a hammer, that might also help

What is this "wood" you speak of and why does it pertain to your smithy? OK it's a poor joke; but my smithy's original part had *no* wood in it's construction whatsoever and the extension I am working on has only 4 pieces---telephone poles as uprights---and I am thinking of sheathing them with sheetmetal.

If your "code" treats forge chimneys the same as woodstove chimneys then the code needs to be modified; but you better follow it in the meantime to assuage the insurance companies.

Thomas

Cbennett0811,

Nice looking forge. Don't sweat the small stuff - you forge will work just fine. There are countless way to improve any forge - just like you could make a better mousetrap. But I'm sure your will work more that adequately.

Good advice regarding firebrick, specialty masonry stores and some feed stores carry it. A mall concentrated fire will work as well as a large fire and be easier to maintain and control.

As for getting rid of clinkers/ash, your can always sweep it up and out after you're done forging. While my forge has a trap fro this stuff it seems like I usually end up celaning the clenkers and ash from the forge itself more than just dumping the trap - more trouble sweeping the stuff through the tuyere. I've never cleaned clinkers/ash out while forging one particular piece of work. But then again I only do one thing at a time (except maybe a couple of railroad spike knifes when the neighbor kids comer over for lessons).

I've attached the forge plans

Venturi Propane Forge.doc

Next time you see a forge at welding or even forging with a chimney, put you hand on the chimney. I you get burned use at least double-walled insulated pipe through all ceilings and roofs. It doesn't take all that much heat to start a fire in very dry wood.

I've seen a number of forges with chimneys, the last one in W. Wa at a blacksmith school. The chimeny pipes throught the ceiling and roofs were double-walled.

If you don't get burned, ignore this advice, and the heck with the code.

I hope you're on the right track because that's basically what I do. I anneal first (5160 leaf spring is too hard to even cut without annealing), forge, rough grind, normalize, drawfile, and sand (to 200 grit), normalize, sand to 400, normalize twice more, then heat to critial and quench in vegetable oil (heated to 140 degrees) then immediately temper for 1 hour at 400 degrees, let cool and re-temper at 400 degrees for another hour.

Normalizing, i.e., heatng to critical and holding for a few minute, then letting air cool, helps refine the grain (make the grain smaller) in the steel. The finer the grain the better potential for good results with hardening.

I've also heard/read in several forums and other articles, as well as from several bladesmiths that 400 degree is the best temperature for tempering leaf spring steel (5160).

In addition to knife blades, I've made a couple of tools. Here is a photo of a couple of woodworking chisels I made from leaf springs. I used one of the chisels to shape the handles (hickory). After an hour or so the chisel showed no signs of wear and was still as sharp as when I started - and that hickory is HARD.

Does anyone know how to get an idea of the carbon content of a piece of metal? I have all kinds or metal scrap; round stock, hexagonal stock, etc. Is there any way possible to get a ball-park idea???

When I considered which solid fuel to use a I considered several alternatives, coal/coke, charcoal and wood (I didn't consider corn as it is not readily available here in the PNW and what with ethanol conversion the price is skyrocketing). I compared availability, price and efficiency. Until I found a cheap supply of coal I chose charcoal that I could make myself. I did a little research, talked to a couple of blacksmith who used coal and learned the following:

White pine has 2236 BTU per pound of wood, while white oak has over 4000. By comparison, charcoal burns at 9700 BTU per pound. And corn about 3600 BTUs per pound.
Unlike charcoal (which is charred hardwood) coal is a solid, black, rock-like hydrocarbon. Its stored energy is about 12,000 to 15,000 BTU and thus produces a much hotter fire using much less fuel than even charcoal. On a per pound basis charcoal can approach the lower end of coal BTU output. On a volume basis charcoal takes up 5 - 10 times as much room, coal being 5 - 10 times as dense. In practical terms a cantaloupe size chunk of coal has the same or more BTUs than a 5 gallon bucket of charcoal - first hand experience!

Any coal can be used for blacksmithing (bituminous coal is the most plentiful and usually cheaper, anthracite coal has the highest BTU). The main thing is the cleaner the better - sulfur being the worst contaminent. Most, but not all, coal that is available to blacksmiths is bituminous coal.

On a cost basis I found that it is hard to beat coal when you consider cost AND BTU's. If I don't consider the value of my labor, I can cut firewood the cheapest and make charcoal for just a little more. But when I do consider how much time it takes to cut, split, haul, stack, make charcoal, etc, then coal is by far the cheapest. .

There is also the consideration of the amount of effort it takes to maintain the heat. It takes me much less work to keep the forge fire going and at forging temp with coal than charcoal or wood (wood requires the most work).

I got real lucky and found a ton of coal on Craigslist (another thread). I knew what to look for and when I found out that the coal was being used in a coal stove inside a house I figured it was probably fairly clean. As it turned out it was excellent coal - very clean.

Thanks for all the replies. I knew you guys would steer me in the right direction even if it wasn't what I wanted to hear. I was just hoping to use something I already had laying around. I guess I will either go with the fire bricks or a sheet metal top. I know my local home improvement store has fire bricks for $1.29 - but they will be a pain to cut with a chisel to match the shap of the brake drum.

Jeff

Lots of good comments, let me try to address them.

The floor is refractory, but buried in the refractory is lightweight fire brick, for better insulation. I really don't want to rip the refractory out, I don't have any to replace it.

The firebricks at the end are the soft lightweight type, so not a big thermal mass. I ran the forge for a long time today at high pressure, so I think that the thermal mass had plenty of time to heat up.

I have heard people talk about ITC-100, but I have never seen it, where can I get it? I understand that it is kind of a slurry that I would brush on. I have heard the claim that it increases efficiency 30%, that sounds like a lot.

I think that I set the end of the burner flush with the kaowool. I have the stainless nozzle on it, so I suspect that I could stick it into the chamber a bit further and get away with it.

I can try closing the forge up more with firebricks.

I am thinking that the mixture may be too rich, which might explain the loose and poorly defined flame front. I would have to cut back to .030 or .025, but would have to special order the 14T tips, like I did the .035 tips.

Thanks,
Richard

MONDO Forge!

Great job of fabrication and the weld don't look too bad either.

The doors will come in handy, especially for maintenance - which you'll inevitably have to do.

A couple of suggestions. Coat the ceramic wool with a refractory/furnace cement - several layers to keep the fibers from becomming airborne (and ending up in your lungs) and then coat the refractory cement with ITC-100. The ITC-100 will reflect the heat back into the interior and increase the max temp possible and reduce the time it takes to get to temp - much more efficient. With a forge this large you'll need all the efficiency you can get.

Along those lines, add a cover for the rear slot. With your fabrication skills it should be easy. Stuffing a piece of ceramic wool in the slot and placing a steel cover over it will make a world of difference in how much heat you can retain - more efficiency.

Again - heck of a job, I can't wait to see it in operation!

Man, do I feel lucky! It used to be when I bought coal it was $6/80 lbs (in Utah - they sell it for hunters during hunting season for campfires). Then I saw an advertisement in Craigslist - One ton of coal for FREE - YOU HAUL!

I couldn't get down there fast enough with my pickup - luckily I was the first responder! I took me about an hour to shovel (by hand) the coal from a plywood bin into my Pickup but now I have 2000+ lbs of clean coal!

Pays to shop at Craiglist!