Sign in to follow this  
toadboy65

First gas forge build

Recommended Posts

I made it out of fairly heavy materials, because that is what I had on hand. The chamber is 3/4" steel. I purchased the burners, and made everything else.  The burners are on a removable stainless plate for ease of re configuring. All the stainless tubing and valves are industrial hydraulic components. I have two inch ceramic blanket everywhere but the bottom, where there is one inch and an inch of firebrick. 

Criticism or suggestions requested

forgesm.jpg.83b38ed374b354dc358e0cb9caa8f50c.jpgforgedoor.thumb.jpg.68ac7838c7e61ac26b52205c00a7acc6.jpgforgeint.thumb.jpg.73b8d5a73efe986beede56aefacdb2f6.jpgC

Share this post


Link to post
Share on other sites

I have done nothing to the wool. One of the experts I talked to discouraged me from using any coatings or rigidizer. I am skeptical of that, but it is beyond my expertise to have an opinion.

I have made a handle for the stainless door, but have not attached it yet. I actually made two doors, but the temporary sliding brick thing seems to be working so far. I have only done a little test work, and the forge is definitely an evolving project. I have a thermocouple to install as well, although I am not sure how useful it will be.

My previous experience is with an old coal forge, which I have used infrequently. Although I have managed to complete some projects successfully, I am still a novice at forging.

So design criticism is welcomed.

Share this post


Link to post
Share on other sites

An "expert"said no ridgidizer.  Cant wait for our "experts"to chim in. Maybe our doctor will have some advice on this. 

Share this post


Link to post
Share on other sites

Rigidize or regret later, your choice.  I've got the lung damage from exposure to unsealed high temperature ceramic wool insulated equipment to substantiate, but only you can decide what you feel is adequate.  Actually as a beginning smith rigidizer and a layer of some kind of high temperature castable for protection of the insulation layer is probably a good idea.

Share this post


Link to post
Share on other sites

I would, and I know many others will agree, at a minimum use ridgidizer on the ceramic blanket and preferable use both ridgidizer and a castable on it. There is a pinned post about the health concerns of uncoated ceramic blanket, but in short it will eventually cause silicosis and possibly mesothelioma, similar to fibrous asbestos.

Another thing of note, I know nothing of industrial hydraulic components but ensure that they are rated for use with lpg, which can cause degradation of components that are not made of the appropriate materials, it is fairly caustic.

Share this post


Link to post
Share on other sites

The "expert" is someone who builds commercial kilns. It is entirely likely that the problems faced by a single smith in a normal shop are different than those faced by industry.  I have had it running, although I have not measured temperatures yet. The burners are from Dempsy's Forge.

Here is an early test:forgelits.jpg.556903b82547e406ab923544793688dc.jpg

I think that was 15 psi. It roars pretty good at 20.

Share this post


Link to post
Share on other sites

I appreciate the info on the danger of ceramic wool. I will try to figure out the next step using the resources at this forum.

As far as the valves go, I disassembled all the valves and rebuilt the pipe connectors, and I am pretty confident that my plumbing system will hold up. Almost everything seems to be stainless steel. I was mostly worried about heat affecting the connections and valves, and I suppose the heat shield is overkill.

But it is all a learning process.

Share this post


Link to post
Share on other sites

As one of those experts who recommend rigidizing, I have no intention of arguing the point one more time, or any other point so utterly well established in favor of safety and common sense.

What I do feel like discussing is his choice of gas tubing; BRAVO! Anything he cares to add about how he went about mounting it, including recommendations--I'm all ears.

Share this post


Link to post
Share on other sites

Looks like stainless tubing with swage lock fittings to me. Very high quality and we'll installed, but certainly not the budget option. 

Share this post


Link to post
Share on other sites

I like Frosty's choice of copper tubing over gas hose; it is the safer bet. But, I don't like copper's ability to heat up the propane, compared to hose. I like incoming propane to be cold, as a further safety margin against flashback; especially in small burners, which are deeply buried in forge insulation. When we add in its physical toughness, stainless steel tube seems well worthwhile--safety first!

Share this post


Link to post
Share on other sites

Mike,

I 100% agree on the quality increase for using stainless gas piping, just know that in the industry it typically isn't done unless in a clean room or pharmacy because of the differential cost (3-5 times copper or standard black malleable iron).

Share this post


Link to post
Share on other sites

200% agree with Latticino and Mikey :D 

Small addition from my side, copper have a thermal conductivity of 380, mild steel 50 and stainless steel or Inconel </= 15. I prefer the material with the lowest λ-value ones the heat crawls up from your burner.

Indeed a expensive solution and well-crafted executed. Another economic and wise option are Frosty’s gas intakes there q……………………...uit long enough ;)

I feel with Latticino and the bad ugly experience hi made and have to suffer on contact with organic mineral ceramic fibers:(. Got some less heavy lessons learned by grinding and hammering 25 years without ear protection witch left an permanent Tinitus on both ears all the time!

Share this post


Link to post
Share on other sites

Thanks for the input. I am planning now on using rigidizer.

I used stainless because I already had quite a bit of it in the shop. I have never used a gas forge before, so I was concerned about heat affecting the plumbing. The swage-lock fittings are 100% stainless, so no o-rings or anything else to be compromised. My first plan was to weld all the joints, but that would make re configuring difficult. I assumed changes would be required, as I am a novice. 

I bent the stainless tubing on an Enerpac bending system, although I had to make a die for the small tubing. The heat shield is spaced from the forge body with a piece of square tubing mounted sideways to minimize heat transfer. I don't know it that is necessary or not.  The gas input at the bottom is a quick release fitting, so I can wheel the forge around to where I want it. I also have some glassworking equipment that uses the same propane source. I have not really figured out where the forge is going to be in the shop, either.

I probably could have fabricated the burners, but it seemed prudent to start with premade ones, until I got some experience. I made the mounts for the burners based on the maker's published dimensions, and found that the burner bodies were not made to as tight a tolerance as I had expected. I turned the mounts out of SS, and welded them to the removable plate on top of the forge. Set screws hold the burners to allow for depth adjustment.

I don't like the idea of just having the burners firing through a hole I cut in the insulation. They are mounted halfway through the two inch ceramic wool. It seems like I should be able to make a rigid nozzle out of titanium or some kind of ceramic.

I made a three burner forge for potential large future projects. I assume I can use only one burner, if I build a firebrick wall to enclose smaller space in the forge, and remove or plug the non-firing burners so they are not killed by exhaust gas.

Share this post


Link to post
Share on other sites

Hi TB, look at this post to,

  from a brother struggles with the same 'challenge' and take care with the other safety items as well. Glad to have you here as an reasonable member and good craftsmen.

Cheers, Hans

Share this post


Link to post
Share on other sites

I agree that stainless tubing is more work and more expense. I have finally brought the subject up for debate (it needs input), because piping and tubing are, like forge doors, hiigh end burners, etc.; what I mentally classify as add-ons; something that can always be upgrades at a later date :)

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this