New Gas Forge (possible edge forge?)

Blacksmithing
#1

Just wondering if it would be possible to get support from either the the Blacksmithing or Metalshop committees to build a small propane forge for DMS; one that would be small enough to wheel outside fairly easily when it needed to be used, and could be hooked up to a standard propane bottle.

I also had an idea for something that i am calling an “edge forge” for knife making. The basic idea is two black iron pipes running parallel, about 1/2" from one another, with a series of small holes drilled in them to create a set of nozzles. In theory, this would create a small line of flame that you could insert the edge of a knife to heat up only the edge for easier beveling. Thoughts?

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#2

The blacksmithing committee is in the process of making a full time gas forge at DMS a reality. There are hurdles to overcome including gas storage, physical space, and suitability for the various processes. We addressing them all and have been making good progress so far. Please feel free to come to the committee meeting to chat about it.

Based on your description, it sounds like a fairly special-use piece of equipment that (I at least) probably wouldn’t recommend allocating really precious storage space to. Based on what I know about forge design, I think your idea has some technical hurdles as well and probably wouldn’t achieve your goals as described, but I may not be interpreting your concept correctly.

#3

Alright! Where can I find the dates and times of the committee meetings?

And here is a rough mock up of what i have been conceiving the edge forge to look like. It’s specced to be made out of standard black iron pipes and fitting and could be either welded together (giving it a dimensions of about 22"x6"x4"), or left unwelded and be able to be taken apart and stored in pieces. What issues can you see with the design? and can the issues be mitigated?

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#4

Our meetings are normally on sunday evening and proceeded by a talk post as well as calendar event. I’ll get the next one posted in the next week, it will likely be third sunday of next month.

As for the forge design the biggest problem is see is the loss of heat because it has no insulation to contain it. It is also possible it will consume a lot of gas to heat a decent sized piece of steel. However it is an interesting concept, I would be interested in seeing it if you were able to get it to work as you desire.

NC Tools, knife makers forge with doors on both ends is the forge I am leaning towards for the space. I’d greatly appreciate any suggestion, however what we get will be premade as volunteer time is our most limited asset and will eliminate the complexity of getting nozzles right

#5

Would encasing the forge in an elongated “U” of refractory cement possibly help hold in the heat? At least enough to get it to work? I’m only trying to heat up the edge of a blade for easier beveling. I got the concept for it from an armoring forge, which only heats up a small portion of the metal at a time for dishing or planishing; i figured a similar concept could apply to knife edges.

Is this the model you were referring to?

#6

Perhaps? I’d ask on a knife making forum, aw I am by no means an expert on forges. However I will say the danger you have with high carbon steels is cracking if you try to work a portion that isn’t hot enough, also uneven heat like that will increase the chance of warping when you quench. Doing multiple normalizing cycles can reduce that risk tho.

Yes we can get it cheaper locally from a farrier supply tho

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#7

This. With insulation I imagine you could probably make that into a workable really long forge. I think it’s gonna run a little cool, because there’s no room on this thing to mix O2 with your gas before it’s on fire. More air= more hotter. So forging temperatures may take time, but it’d probably get there.

Venturi’s are our friends:

And yeah, that sucker’s gonna drink fuel. Might have to go up to a big gas bottle to get around the supply limitations of the home-game BBQ bottles- at least if it had an air intake somewhere.

As to the stress issue, I’m just guessing from your pictures that the way this will make forging operations easier is that only the bevel will be at forging temp and that you can use the differential heat to move the metal away from the “cold zone”. Working the metal under this kind of differential heat is gonna cause a buildup of internal stress- might be fractures, might just cause warpage during heat treating, might be fine; but it’s introducing new variables into a process that doesn’t need them (at least for me). I have seen setups like this used for heat treat on swords and such that are too big to fit in the regular forge all at once, but the idea there is still to evenly heat the whole piece.

Never seen somebody heat during a planishing operation, might work for stuff that doesn’t need heat treatment, dunno, I’m definitely no armorer.

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#8

On your idea for an edge forge, I think you would be much better served by heating the whole piece. This takes marginally longer and you will not be inducing any extra stress by trying to move cold steel. During the beveling process you should be starting with a banana shaped curve with the edge inside the curve. As you bevel the edge the steel will straighten, this removes the need for attempting to deal with the deformation that occurs when trying to bevel a straight piece of steel. This straightening process is occuring due to steel moving in all directions when you impact it with a hammer. Having seen and used this process many times it is my belief that you would be hard pressed to find a better more efficient way to do this.

Thanks

Freddy

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#9

I would love to see you go the route of buying some T-REX burners and building the forge yourself. http://www.hybridburners.com/products.html 3/4 T-REX burner is the one I’m speaking about. The building of the actual forge should take little time and can be completed once all materials are available.

A couple of issues I have noticed both in person and on paper. For normal use I strongly believe that the forge doors will be a serious impediment. They will limit the number of people that can use it effectively. Also the burners on this forge are extremely affected by any wind disturbances.

Lack of coating.
In the interest of efficience, forges built with refractory are not nearly as efficient as those made with ceramic wool. Combine the wool with a coat of ITC100 and ITC296A and you have a very robust surface for the inside. The forge floor should be a silicon carbide kiln shelf for maximum life. Flux and metal will not bother it in the least.

If it is a matter of labor, I am more than happy to assemble a design of the groups approval.

Just my two cents.

Thanks

Freddy