New guy - building a forge

[DavidF]

Hi guys,

I am new to the forum and also new to building a forge. I have done some research and tried to incorporate best practices, etc. I am sure I have even used ideas/designs/concepts from some of you. So thanks for all of your knowledge sharing. Nothing I am doing is original, nor do I want it to be. My goal is to build a good first forge for myself and I intend to do that through known and best practice. However, I wanted to share what I am doing and see if I can gain some feedback.

I have used a 20# propane tank for my shell. I did not want to be concerned about gas in the cylinder, so I purchased a new tank (inside the Home Depot vs outside). I have removed the top and bottom brackets/guards, cut out front and back pass through, made a hinged door for front access, and placed a base on the bottom. This is where the projects stands today. It has been a lot of planning, grinding, welding, etc. I will be adding a latch to the door, a handle on top, and a pipe through the top for the burner to conduct heat. After this, I will spray it with a paint just to make it look a little better. Then I am finished with the metal work and will move on to lining.

For the lining, I plan to use 2” of insulated wool, 1” of refractory. The refractory will be close to 1” of cement and then as small of an amount of a coating as possible (since this is very expensive and from my reading, only a small layer is needed to radiate the heat back). On the lining, I have seen others use glass cement as an adhesive. Is that the best route? Or is an adhesive needed for the wool to the door? Couldn’t a small layer of refractory cement be used between the door and wool? Would rigidizer provide any adhesive and bonding between the door and wool?

I have struggled with finding the right burner design. I had settled on the burner design attached, until I saw a burner design by Mike on this forum. I will reduce the nipple toward the burner end to ~6-8”. I welcome any feedback on simplifying the plan for the burner design. I have listed a small incomplete calculation that shows the volume of the cylinder less the volume of a firebrick (there is some additional space that will be filled in), but based on just those areas, I know I am below 700 cubic inches. Based on what I have heard and read, a 3/4” burner will heat up to 350 cubic inches of a forge to welding temperatures or above. I knew I would be north of 350 so I had to go to 2 burners and I wanted to ensure I was south of 700. Based on my burner image, I may be overkill on my design. I planned this prior to today when I found this forum and I will definitely incorporate some of the things I have seen here for the burner. But I will take any input on the burner as well.

Thanks a ton for your time and invaluable feedback. I hope to pay this back down the road as I gain experience and newer users need similar help as I do today.

 

Edited December 7, 2017 by DavidF
Spell check

[WayneCoeArtistBlacksmith]

Check out the Build a Gas Forge on the Forge Supplies page of my web-site.

You can get the url and my contact info from my profiles page.  I prefer e-mail over PMs.

Let me know if I can help you.

Wayne

[Frosty]

Welcome aboard David, glad to have you.  Wayne's site has good forge plans and he sells small amounts of what you need for reasonable so you don't have to buy large quantities.

However, you asked. Use two 1" layers of 8 lb. ceramic blanket refractory for the insulating outer liner. YES you want to rigidize it! Not as an adhesive, cut it a little oversize and it'll hold itself in position due to compression. You need to rigidize it to encapsulate the ceramic fibers, forget what the MSDS says they're breathing hazards, see: silicosis, mesotheleoma, asbestosis, etc. It's a bad way to die. Second reason for rigidizing is to make it less compressible in place the hard inner liner or (flame face) has all the flexibility of set concrete and laying it over something that can be smooshed under it will cause it to break up. 

Lose the brick, it's just a heat sink you don't need and is vulnerable to thermal cycling and welding flux. It's easy to make a good working floor in a forge. Two methods. First strip down some blanket and feather the edges so it makes a level floor the width you like. Rigidize and plaster with the hard refractory and kiln wash as described below. The other is again strip and rigidize some blanket  and lay in a piece of high alumina kiln shelf. The blanket under the shelf is to support it and make it last longer. Be sure you actually get HIGH ALUMINA kiln shelf there are shelf material that aren't and they won't last long in a forge. 

There's no good reason to put 1" of hard refractory in it, 1/2" is plenty if you use the right stuff. Recently a consensus has developed for Kast-O-Lite 30 Li being the best reasonable refractory. It's a water set, high alumina castable bubble refractory. That mouthful means. It comes dry, you add water and  mix, it then sets and cures like concrete does. It's made from a high alumina material so it's resistant to forge welding fluxes. Silica based refractories are dissolved by molten borax and it goes through Kaowool like hot water through cotton candy. The last bit is why you want to completely cover the ceramic blanket, to keep the nasty caustic molten borax off it. The last bit of goodness brought to you by Kast-O-Lite 30 are the bubbles, they're evacuated silica spheres that reduce the physical weight and provide some insulation.

Lastly is a good "kiln wash," ITC-100 was the #1 material to coat the inside of forges for a long time but our type furnace isn't what it was designed for and it's NOT the best product. The stuff is basically zirconium silicate in a kaolin clay binder. Unfortunately out forges don't stay hot enough long enough to fire the kaolin into porcelain so it stays chalky and your EXPENSIVE ITC-100 rubs off. Wayne carries Metrikote and Plistex both contain zirconium silicate but in a different kind of binder. A water set binder so it paints or spritzes on, dries and stays then when you fire the forge it cures into a hard, tough, chemically resistant coating. It re-radiates IR not relfects it. IR reflector is a common misunderstanding of what the stuff does, basically it gets REALLY hot and radiates it back. 

We talk about building forges a lot, check out "Forges 101" and "Burners 101" for the ongoing discussions.

About the burners. As drawn it looks like you're using T burners, they're easy to build and tune, the plans are available here, ask me if you have problems. Mike Porter burners are no question more efficient but they're more demanding to build. Check out his plans and make your decision based on how good YOUR shop skills are. 

Lose all that plumbing on top of your burners all those long pieces of plumbing make your burners very vulnerable to bending and breaking. Long lengths mean lots of leverage so WHEN someone trips over or something drops on the hose something WILL give. If you're lucky it'll just knock your jets out of alignment ad you'll be shut down till you get them straightened out again. Done this one, got T shirts. The worse bad thing is breaking a fitting in which case you now have an uncontrolled blast of propane shooting Probably at the outside of your forge. 

I put a 1/4 turn ball valve directly after the regulator on my propane tank I run a 100 lb. tank, 20 lb tanks tend to freeze quickly running ONE 3/4" burner let alone two. The 1/4 turn valve is your FAST shut off, in an emergency turning the tank valve off takes too long. The hose then runs to a manifold at the forge, I put it away from or below the forge itself to protect the RUBBER hose from excess heat. The tank, hose and manifold are on a side of the hose nobody has any need to or interest in going to keep folks from tripping o the hose or setting stuff near it. The manifold is just 3/8" pipe nipple, the female fitting on American made propane hoses is 3/8" pipe so you don't need an adapter. The 3/8" manifold has enough volume to provide all the fuel two or even four burners need at working psi. With a 2 burner system you could just use a short 3/8" nipple to a T, then to adapters to the copper tubing but I like a little volume to equalize psi to the burners, I may change that opinion as I reduce the number of burners in my shop forge.  My personal preference for the final gas supply is through 1/4" copper tubing. Use FLARE fittings to adapt from plumbing to copper! NOT the other type, don't let the guy at the plumbing supply talk you into something else, they don't do this. 

That's it, if you follow the T burner instructions you'll be using the copper adapter fitting to mount the mig contact tip jet in the T fitting and can just hook it directly to the copper tubing. 

Copper final supply lines do a couple things for you. First it isolates your rubber hose and tank from the fire, if someone trips over the hose they might jerk the forge a ways on the floor or table top but they won't snap off a fitting and spew burning propane around or mes up the gas jet alignments. Copper tubing doesn't care how hot the outside of your forge gets, even if it's directly above one of the forge doors it can't burn. Copper will also help support your burners, it keeps mine from falling over.

Okay, that's it for now. Nice drawings for not knowing what you're trying to design, you got it pretty close.

Frosty The Lucky.

[Charles R. Stevens]

Welcome to Glenn’s international block party

[DavidF]

Thanks Frosty! Great information that I will use as I progress. I finished some more work today. I will post some pics to share the progress. I built a latching system today to close the door. I am pretty excited. It has been a fun project. I really, REALLY need to spend time practicing welding. This is the first welding I have performed and thank the Lord it is not structural work!

This image shows the latch system I have put on the forge. I used 1/2” tubing and a large bolt

I used 1/2” tubing to create a base for the forge. I also used smaller pieces of the tube for the door to sit on. Please don’t look at the horrible welding, it was literally the first time I have ever welded. I am committed to becoming a better welder. I need to figure out the speed, depth, and most importantly learn to watch the flow as I draw cursive Es.

This is a hinge for the door. I used the same 1/2” tubing, with a brake pin for the hinge.

[Irondragon Forge ClayWorks]

I learned to never weld more in the morning, than you can grind off in the afternoon.

[ThomasPowers]

The better a grinder I became the better a welder I appeared!

[DavidF]

For each hour of welding, I am grinding about 6 hours. Lol!

[Frosty]

You're welcome David, my pleasure. Don't overthink it, you're going to build a few more before you find your daily user. Most all of us have early release gas forges gathering dust. My first double liner T burner powered forge is a trip hazard if I clean that part of the floor.

If you want pretty Tig Stainless.

Frosty The Lucky.

[DavidF]

I completed building the burners, stock shelf on the front, and tubes in the top for the burners.i did end up moving my burners to the top of the forge instead of 2 o’clock position. Have some cleanup and moving on to insulation and refractory

[Frosty]

Pics please, we don't really believe anything unless pics are posted. 

Frosty The Lucky.

[DavidF]

Lol! I will post new pics tomorrow or during the weekend. It is staring to look like it should.

[DavidF]

Lol! I will post new pics tomorrow or during the weekend. It is staring to look like it should.

[DavidF]

Here are four new pics of progress. Excuse the messy workbench. I haven’t cleaned up after this round. You can see the stock shelf, and two ports for the burners. I took Frosty’s feedback on the length of pipe and changed to a much shorter extension. The regulator is in route. I picked up one that goes all the way to 60 psi and has a flow gauge integrated (although I don’t expect from my research that I will ever go beyond 30 psi if I even need to go beyond 15). When I picked up the reducers, they only had galvanized, so I ended up soaking all parts with zinc for more than three days. The acid bath worked extremely well. One thing I wanted to share is that my Dremel lost power, so I picked up a rotary tool from Harbor Freight. The locking pin button has failed on two of those units, so I have returned them and I am now on my third Chicago Electric rotary tool. I also rebuilt the Dremel, so if I continue to have the failures on the Chicago Electric version, I will switch back permanently to my Dremel which is now about 15 years old. Lots of fun, lots of grinding, and my welding skills are getting better, but I have found that I can’t go through a surge protector with the 110v mig welder. I get ok results going straight through an acceptably rated cord directly.

 

I also found that stripping zinc is a pretty caustic environment. I had as much open air as possible and sealed everything in ziploc bags and placed them in a cubby tray. I don’t have a respirator yet, so I was using the masks you can purchase for cheap. But I definitely got hit with fumes and luckily I am young and healthy enough that I was fine the next morning. My biggest lessons from this build has been to respect the need for personal safety. I will be picking up the best respirator I can find, and opening as much air flow as possible. I have also burned through three pairs of mechanics gloves which have saved my skin from sparks, abrasives, and even drill bits. I still have all ten fully functional digits and I always wear two pairs of gloves when welding or grinding. Outer pair is welding gloves.

 

I also always use eye protection and welding masks. When I was 18, I built golf clubs and ended up with a red hot piece of metal in my eye. I don’t know if anyone has had that experience, but I was at the ER within two hours of the accident and the metal had already rusted. They used an optical drill to remove the rust rings and patched my eye. It was one of the worst pains I have experienced. It felt like someone was hammering my eye and brain for the next 24 hours. I now always wear eye protection, even on the sanding belt. My sight fully recovered, but I am thankful that it didn’t end up any worse than a couple of days in an eye patch.

 

I wanted to share some experience with you guys. And I welcome any and all feedback on the build. I have gained invaluable feedback and knowledge from you guys and I look forward to any ideas and/or criticisms. I know I am doing something new to me, but many of you have done this many, many times. So I appreciate being able to incorporate your feedback!

 

Thanks again guys! 

[Irondragon Forge ClayWorks]

I had a similar experience as you with a steel chip in my eye. I worked in an auto machine shop and while turning brake drums on a lathe. Had to have the chip & rust ring removed by an Ophthalmologist. That was 60 or so years ago and I can still remember the pain. Lesson learned the hard way about safety glasses.

Here is a link to our forge building saga. The burner used was one we had on hand from our kiln & pottery days.

 

[DavidF]

Love the build story IronDragon. Went through the thread and enjoyed the adventure and pics. It turned out great.

[Travv801]

Looks like an awesome build, David. Since I'm close by, I might have to steal it ;). I'm looking to build my first forge too. I'll definitely be following your build. 

[DavidF]

Trav, hit me up when you are ready to start. I made a few tweaks, but I would be happy to help you out.

[DavidF]

Ok, updated photos. All that remains is to insulate. Insulation will be from Wayne. Then to paint. I have the regulator and fumed silica in hand. I am at the point where I felt it was “good enough” for finishing. I could grind and beautify more, but I have seen pics of forges once they have been fired and I thought, how much more touching should I do when it will be “seasoned” and looking like a workhorse in a week. One thing I did add was a door for the back pass through. I wanted to be able to allow airflow and also passing of larger materials, but I felt like being able to close it would be helpful for containing heat. I am not a good or even mediocre welder, so it looks rough because, well, it is rough. It is my first project with a welder. Anyway, it has been fun and I will enjoy trying it out soon. Any and all feedback is welcome. I think the next time I build a forge, it will be the Wayne method of cutting the tank in half. The biggest issue I have seen with my project is getting the door flush. I will overlap insulation past the seam, so I am OK with it, but I wish I had seen the Wayne plans before I went with the front door design. It is the difference of a rookie versus someone who has built many of these. But the access to plans I have seen here just shows me that I was creating a new wheel. Simple is best. Last thing, the pass through door is not quite level. If it looks a little skewed, it definitely is. But stock does sit flush, so it will work for a first forge.

[MotoMike]

She looks like a work horse already to me.  Clydesdale!!   one thing I wish I'd done is make sure my arm can fit the mouse hole so that I can apply refractory all the way to the back of the forge.  Mine, turned out to be a bit tight fit for me.  seems I found slathering on the refractory by hand was easier than any of the other methods I tried.  gloved up of course.  that way any touch ups in the interior can be done without having to crack her open.  can't tell if that is an issue for you or not.  

when I get to needing a reline, that will be fixed in mine. 

 

also, on my next update, I will put another few bolts in the burner mount to hold the burner tube on two planes.  a circle of bolts on the same level, holds the burner somewhat feebly.  I leaned this while I let my propane bottle fall and it pulled on the hose and dislodged my burner and cracked my refractory setting me back a bit.  another three bolts an inch higher would have positively located the burner and also allowed burner alignment that is very secure. 

 

 

 

[DavidF]

I agree on the securing bolts. I ended up moving two of mine up 3/8” on one. It was necessary to have clearance because my ports were too close. But it is more secure than the one without the staggering. Definitely a mod for my version 2 as well.

[Jasent]

Looks to me like that back door is going to warp in short order. Other than that I like it

[DavidF]

Thanks for the feedback Jasent. Any recommendations on the rear door? Hinge it? Just eliminate it? Now that you have called that out, I can see it may not be functional. I still like the idea of being able to close it off, but is there value? I could make it hinged and insulate as one option. Looking for input whether it is worthwhile. 

[Jasent]

Just use a fire brick for the back door.  I use a hard FB  for my back door. It sucks a little heat on warm up but once the forge side gets hot it works great. And won't warp and seize up

[MotoMike]

On the back door, I put a porch on that I set bricks on against the opening as needed.