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Gas Forge on the super cheap ideas


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This is a topic to see if I am on a decent track or if I am simply insane.

I have just been getting started and have been getting more and more frustrated with my solid fuel forge.  I just don't seem to be getting the kinds of temps I want with any consistency.  I also can't seem to figure out how to build things with what I have in order to be able to heat different parts of the metal when the piece is long or oddly shaped.  I'm also frustrated that wind and the weather keeps me from lighting the forge as often as I'd like.  I do understand that this mostly speaks to my impatience and inexperience, but....

I'd like to build a gas forge for as little monetary investment as I can, using mostly what I have lying around.  There are several things I know I will have to buy and I do not want to skimp on safety.  So here is what I have in mind.

The forge body, I think I have an old party Helium tank in the basement.  It's a bit smaller than a propane tank used with most common gas grills, and the metal is substantially thinner.  It's empty, or nearly so and I can bleed it off before cutting.  I think I will leave it standing upright as a forge, unless there is a benefit to turning it on it's side.  I will line it with rigidized kaowool, probably 2 layers of 1" according to the instructions I have seen pinned on this thread.  I'll have to buy the liner materials, obviously.  For the shelf, I have some soft firebrick on hand.

For the Burner, I am thinking one of two things.  The Frosty t-burner is one option, though I will have to buy the bits and bobs to make one, or two, according to the final volume of the forge body.  I need to do a lot more reading on this subject.  The other Idea that just recently occurred to me would be to create a naturally aspirated ribbon burner.  I might be able to carve out an existing firebrick or two.  Another Idea that may or may not be possible, feasible, or advisable would be to use the rigidizer material to cast it.  Depending on the cost of the needed casting material, I may just do that instead.  In short, use existing firebrick, cast with stuff I'll have on had from lining the forge, or buy actual casting material.  Or just go with the tried and true T-burner.

Here is where the main sanity check is:  The regulator.  I have the connections and hoses from 2 different gas grills already on hand.  the Hoses are not cracked or anything.  the connection to the propane tank is in good working order.  Is this a decent kind of regulator, or do I need to spend the cash to get one with dial so I can tell how much pressure I am getting.  I just don't know enough about these things to be able to judge for myself.  Can I use what I have or is it plain and simple safer to buy new stuff.

It's going to be a long process, probably taking most of the summer to get there as I buy the bits a little at the time.  And yes, In the mean time I'll keep practicing with the charcoal forge.

I have also thought of using firebrick to build the whole body of the forge, but I have zero welding skills to make a framework

What do you guys think?  Am I missing something and is the proposed reuse of the existing connection materials from the gas grill nuts.

Edited by Paul TIKI
added something I forgot
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Not to rain on your parade or anything, but you might want to consider the following:

Gas grill regulators are not adjustable and not adequate.  A NARB will still need a burner to be made, the perforated section is just the head of the burner.  Soft firebrick needs to be rated for at least 2600 deg F to survive for long in a gas forge that is operating at typical forging temperatures.  It won't survive regular thermal shocks well, will get eaten by flux, and won't tolerate direct flame from the burner.  Helium tanks make fine forge skins (you could even use chicken wire in a pinch), properly constructed the forge skin should have minimal loading and not get too hot.  Gas forges are typically more difficult to design suitable for spot heating of things that are long or oddly shaped than solid fuel forges.  Wind and weather also affect naturally aspirated gas forges.

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First off.  The party size helium tank is fine.  There is more than one size, but if it's comparable to a disposable refrigerant (freon) tank then it's a good size for a first propane forge.   I used one for a while with a single 1/2" Frosty T burner and was able to forge weld in it.   However, if you think you are frustrated with getting odd-shaped pieces placed properly to heat a specific section now, that will only be magnified with a gas forge.  Small gas forges do quite well with straight or nearly straight pieces that need less than 12 inches heated at one time, but when you are dealing with a chamber opening which is typically between about 4 and 8 inches in the largest dimension, that does create some additional challenges for irregular stock shapes.

Breezes also tend to be an issue for a lot of naturally aspirated burners.  However, the NARBs I have built don't seem to be quite as sensitive to wind as the single port burners were.

If by "shelf" you mean the floor then soft insulating firebrick is not a particularly good choice.  Between the thermal shock of repeated heating and cooling and the mechanical abuse of dragging hot steel across the forge floor an IFB will not last long.  If you use flux you could destroy it in a single forge welding session.  You're better off with a castable refractory floor or even a split hard fire brick.   High alumina kiln shelf is better yet.

Regulators designed for gas grills only operate at a couple psi usually and are not adjustable.  That's barely enough pressure to make some naturally aspirated burners function, and not enough for others.  If you want to build it right then you want an adjustable regulator.  If possible you want to get one that can go from 0 psi to at least 20 psi. It's not so much about the "dial" (I assume you mean gauge here) as it is about being able to change the pressure of the fuel going to your burner.  That pressure will be a major factor in the temperature achieved inside the forge, and while we caution people not to fixate on specific numbers, you probably won't be able to achieve the temperatures you want using a regulator from a gas grill.

You do not need welding skills to build a brick pile forge.  Many people have built them with a few pieces of angle iron and some all-thread rods for the main components.  Frosty has shown pictures several times of forges built that way at his local club and they clearly work well as they are built.

The best advice I can probably give you is this: pick one plan known to function well and strictly follow that plan.  Don't substitute or change anything unless/until you ask the designer or a knowledgeable person who has used that design if it will matter.  Once you build and understand your gas forge you will be in a position to incorporate changes/improvements into your next one - and there will be a next one.

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OK, thanks so much for the benefit of your experience!

So I think I may stick with the helium tank.  As is, I think I will have some more options in design.  I'm thinking a front opening and a closable back door in case I have a longer piece that I need to pass through to get the heat where I want it.  I do know I'd have to buy more bricks for a brick pile, so I'd have to compare that cost with the cost of Kaowool and rigidizer.

As to the wind problem I'm currently dealing with, It doesn't so much give me problems with the metal or heat or anything.  The big problem is that I don't want ash and firefleas going everywhere.  Local farmers frown on people setting the crops on fire.  Also, when local authorities say "no Burn", they mean it.  Even grilling is frowned upon.  I don't think I'd set anything on fire, but polite behavior means happy neighbors.  With some basic shop plans running in parallel with a propane forge build I think I'll have a more weatherproof solution.  The shop will be some 4x4's sunk in to the ground with corrugated metal walls and roof.  Super easy and cheap.

It's good to know I'll need a decent regulator.  I suspected as much, but I just really wanted to make use of what I have.

so, I guess I need to do some cost comparisons and start gathering supplies.

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For your regulator and hose check eBay/Craig's list used for weed burners. I bought one for $20 U.S. and free shipping. The burner part is not applicable for a forge but the savings on the regulator and hose is worth it. Mine came with 20 ft of propane rated hose and a regulator that would cost twice what I paid. I can also use the weed burner when needed by disconnecting the forge and hooking it up.

I would build the forge horizontal, I tried a friends vertical forge and getting the steel in & out was a chore and it didn't heat the steel as well as our horizontal forge also the long stock couldn't be passed through.  Soft firebrick will work for sliding doors although they will deteriorate faster than hard K26 IFB. We used the soft bricks we had on hand because we have a lot of them from the Kilns. When they are used up we will buy Morgan K26 bricks but so far they are holding up just fine.

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