reefera4m

I posted a thread of my venturi forges a while back that had some photos on two different burner placements. Both forges are 12" long & 8" in diameter, and insulated with ceramic wool, refractory cement and ITC-100. On my first forge I placed the two burners on top of the forge equal distance apart. They tend to create twe distinct 'hot spots'. On my second forge I kept the same distance between the burners but mounted them on the sides of the forge (one on each side 1/3 of the way down the side). This arrangement causes the flame and heat to 'swirl' around the inside of the forge and heats it much more evenly. However, I must admit that although the 2nd forge heats more evenly the heat doesn't necessarily get transfered to a blade evenly. Blade geometry plays an role in how the steel heats, the tip and edge will always get hotter faster - just due to the lower mass. So I still have to move the blade around in the forge occasionally to get the blade to heat evenly. Bottom line - offset/canted burners help even the heat but you still have to pay attention. The real key to burner placement is the lenth of the steel you'll be heating. For an small billet it makes more sense to concentrate the heat near the billet. Heating the back of the forge is inefficient to some degree. For longer blades/billets it is better to distribute the heat as evenly as possible throughout the forge. I find concentrating the heat is even more useful in welding as I don't try and weld very large billets and it is much easier to get to and sustain welding heat in a small concentrated area. Just my .$02 cents worth.

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.

Leaf spring is commonly 5160 (.6% carbon compared to 1095 which is .95% carbon), However 5160 also has .8% chromium, which makes it considerably harder. You did well to get half the work with only twice as much coal compared to a RR Spike. It took me 5 times as much coal and I only got 1/3 as much work done forging 5160 , which is why I switched to using my propane forge for leaf spring steel!

Harder wood is usually better than soft wood for handles. A relative ranking of the wood you have available, fro softest to hardest: cedar, cherry, walnut, ash, beech, oak (depending on oak variety). Maple varies even more in hardness,so without a species I wouldn't hazard a quess. All but the cedar, with some stabilizing, with make good handles. Ranke Wood hardness A lot of knife makers would highly recommend 'stabilized' wood, i.e. wood that has been treated to increase hardness and protect against moisture. This can get expensive and if you want to do it yourself you can to one of two ways. First, Google 'stabilizing wood'. There are concoctions that you can make that will do some real good with or without the use of a vacuum. Second, you can use a commercially available product from Minwax - Minwax® High Performance Wood Hardener. Admittedly, it's not as good as professional stabilizing but it WILL vastly improve the durabality of wood handles (and it works just as well on antler). If you chhose not to stabilize at all you should at least apply a coat of protective finish. Birchwood-Casey Tru-Oil Gunstock Finish works well and looks good.

That's exactly the approach and outcome I got - it looked line 1/4" 24 thread. It turned out tips were indeed metric. 6mm to be exact which requires #5 drill bit.

I don't have any experience with Kawasaki Grinders but I bought one of their cordless drills - it started smoking the first time I used it. I returned it for a full refund an bought a Makita. :D

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.

When I use the siphon sandblast gun I do it outdoors and use a dust mask, indoors I use my sandblast cabinet. However, most small, inexpensive sand blast cabinets specifically advise against using sand (silica sand). Even without a mask (though well advised) sandblasting one tang outdoors doesn't create much of a serious risk of silicosis. And using a siphon gun is by far the least expensive method to get the best results.

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.

I know you're discouraged but don't give up! When I first built my '$20 Forge capable of welding heat' one burner did not work - at all! I played around with it for several days then discovered that when I tapped the threads for the MIG nozzle into the propane feed line (3/8" steel plug) I use a standard tap and that MIG nozzle had metric threads. This caused a leak with prevented the nozzle from generating enough pressure. When I fixed the problem - voila! Forging Heat! Then I experimented with a couple of coatings, furnace cement and ITC-100 - again voila! Welding Heat! My $20 forge was now a $25 dollar forge (and the 2nd one cost $30 - I ran out of some scrap). I could build 10 of these forges @ $50 for the cost of 1 $500 commercial forge. Even if only half of them worked for forging and only 1 in ten got to welding heat I'm still way ahead! Step back, take a deep breath and think about the problem - sometimes it the simple things that make a BIG difference.

Ceiling joists, roof rafters, plywood sheathing, anywhere the chimney passes through a ceiling or roof is at risk. Creosote and carbon that builds up in a chimney pipe will ignite at 400 degrees under the right (or wrong) conditions, adding additional heat to the chimney pipe. If my shop wasn't worth much I wouldn't loose any sleep over it but........

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.

These two attachements might help.

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.

A masonry cut-off wheel on a 4" grinder makes cutting firebrick a breeze (just make sure you do it outdoors as it creates a lot of dust). If you don't have a grinder (HF for about $20 would suffice), the try a masonry hack-saw blade or a mas0nry blade for a sawsall (reciprocating saw) or even a radial hand saw - they all work on firebrick though the hacksaw take a little longer but gets the job done more precisely than a chisel.

ITC-100 is a refractory clay that you thin with water and spray or brush on. I coated my ceramic wool with furnace cement (to protect the wool) and then coated the cement with several brushed on layers of ITC-100 (available at most large pottery supply stores). ITC-100 reflects heat back into the forge increasing both the maximum temperature possible and decreasing the time it takes to get to temp. I saw a thread on another forum where Ed Caffrey, aka The Montana Bladesmith, said he saw an increase in top temperature of 500 - 700 degrees. I didn't get that much with my 'venturi' forge but it does get hot enough to weld with. I also have incorporated removeable rear covers for my forge - they seem to help quite a bit as well. One cover has a slit it it just big enoug for a blade to fit through. When I'm working on smaller blades I just stuff some ceramic wool in the slit.

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!