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I Forge Iron

Advice for Making a Propane Forge


Mad Dawg

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Hello guys,

At the moment I have been forging in a broken chiminea I had, but this is temporary at best. I picked up an old craftsman 5 gal airtank at the junkyard for a buck and I want to turn it into my new forge. The tank has a pretty substantial dent in one side. It doesn't go in more than an inch so I was thinking it shouldn't be a problem. Anyhow is there any way to get this dent out. I was thinking of putting a small hydraulic car jack inside the tank once I cut off the end and tray to pop it back close to original shape. I am not worried bout aesthetics at all, I just don't want the dent to affect performance. My second question is simple but after an hour of reading old posts I haven't found an answer. Do I need to put a firebrick on the floor of the forge, or will a Plistix coating over the ceramic blanket work just as well. The only reason I'm asking is alot of the pics I see of small cylindrical forges don't have firebricks bottoms.

I am gonna try to post a pic w/ the dent and my first tomahawk I made for my son...

Later Mark
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Mark,
The tomahawk looks great for a first one ! Once you cut the end off the tank you will find that dent is easy to knock out with a hammer. If you place the tank with the dent facing a hard flat surface you can knock it out to that point easily then if you want to get closer to original shape hold a good size piece of stock inside behind the dent and hit the edges down being careful not to make it high on the outside.
Firebrick will go a long way to saving the floor from flux.

Hope this helps,
Dick

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Assuming that you use some sort of ceramic fiber for insulation, covered by Plistix or ITC100, you'll have a very serviceable forge, but the firebrick will protect the bottom (a) from physical trauma (ceramic fiber is not all that tough) and (B) if you intend to do any forge welding, the borax eats through the ceramic fiber with gusto, which means that you'll need to do some repairs.

My propane forge is made from soft firebrick (the insulating type) and has a thin super-duty firebrick (the hard type) on the floor, which takes the beating from the direct blast from the burner.

Lots of fun!

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Thanks for the nice comment about my tomahawk. :) It was my third blacksmithing project. I made a knife first, then tongs, then that tomahawk. The knife turned out decent, but I have too many deep grooves to grind it out nice. If I ground them out the metal would be too thin to make the knife servicable. I am happy with the knife and I learned quite a bit making it. The tongs turned out great as well. Anyhow I digress, since I asked for advice I figured it'd be easiest to just outline my forge plans...

The tank you've seen... I was gonna line it with 2 running feet of ceramic blanket then coat it w/ plistix 900F. I was gonna put an insulated firebrick for the floor. The burner I was gonna buy the side arm burner kit from zoeller's site, as well as all the materials for the forge. The forge will be perfectly sized for one burner. I priced it out at $164 plus shipping.. does this sound bout right? There is a pic of a 5 gal craftsman tank forge just like mine on his site and I didn't plan on copying it at first, but after I got the tank and realized it was the exact same one I see no reason not to copy that one exactly. It seems to be just what I had in mind and I really like the way the guy did the doors at the ends.

Also thanks for the advice on getting the dent out. As I stated I am much more concerned about performance than looks. The main reason I wanted to get the dent out was cuz it goes into where I am gonna cut the end and I didn't want it to affect the door. But if I can cut the one end out, then hammer the dent mostly out then cut the other end I should be fine.

I had pretty much gathered that I would need a firebrick floor to the forge for forge welding, but I tend to ask a lot of questions before I start a project. Sorta along the lines of measure twice, cut once sort of thinking. And after perusing a buncha sites I noticed that alot of people didn't have firebrick floors in their forges.


I am gonna include pic of my first two projects... mostly cuz I am happy I figured out how to post pics and want to do a couple more :)

Later,
Mark

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The plan sounds good. The price seems about right. The dent doesn't matter much but knocking it back out is a good idea. What are the dimensions of the tank? I like to put at least two inches of kaowool in the liner. What size burner are you going to use?

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Ok, I just measured it. It is 16 inches long from the furtherest points out. The diameter is 9 1/2 inches. I was planning on cutting it at the original weld seams, which would give me a workspace of 10 inches. I was then gonna hinge the cut pieces and make doors with smaller opening when they are closed. I had one more question. I plan on lining the interior with ceramic blankest and plistix.. two one inch layers then coated.. 8lb density. I had originally intended to line the caps or end pieces w/ the the leftover blanket and plistix them as well, though I am worried about them staying in place. Would it be better to cast the end caps with a home made refractory? I was thinking it may stay in place better and since only the ends are casted refractory it shouldn't take too long to heat it up... though I am not sure 'bout that. It's why I'm asking for the best route. I was also gonna use a thin firebrick for the bottom. For a burner I was gonna buy Zoeller's side arm burner kit. That's 'bout it. I am hoping this configuration will give me a nice little forge that won't take up too much room :).

Thanks for all the replies, this is a great forum.

Mark

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Mark, if you have a local ceramic supply house somewhat close get a piece of kiln shelf for the floor. Wrap the first layer of insulation all the way around the shell with the seam at the bottom. Then cut and place the kiln shelf and put the second layer of insulation in. And then coat with itc100. I use refractory board for the doors.

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  • 2 weeks later...

Hey Guys,

I fabricated the propane forge yesterday and after a full day of using it I must say I'm 100% pleased w/ my results. I didn't make doors for the forge, it's just a tube lined with 2 inches of ceramic blanket. I put a piece of kiln shelving between the layers for a floor, then coated the entire thing with alumina silicate rigidizer I bought from ellis knifeworks. I ended up making my own burner and am glad I did. Works great. I am tired, but when I get some time I am gonna post pics of the entire setup. I ended up using a .035 wire feed welding tip which screws into a brass plug that I drilled and tapped to hold it. Don't really know how a burner is supposed to perform... but I can take mine down to no reading on the gauge and keep a flame. Just the smallest trickle of gas will keep it going. I have only forge welded once, but it took, and from my limited experience I'd say 8-10psi would reach welding temps just fine. When the propane tank got down to about 1/4 it started to freeze up, I will definately have to fabricate a system to piggy back two tanks. Once harbor freight put's there cheapie steel cart on a good sale I am gonna buy it and bolt the forge to it. Then use the bottom to hold the tanks. I took video of the who process so I'll post it sometime once I figure out how to do so.

Again, thanks for the help. Without your kindness and support I'm not sure I'd of had the confidence to attempt the project at all. :)

Mark

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  • 2 years later...

Randy, I like that you can adjust the height of you forge. that is neat!

 

Thanks.. I designed it to be adjustable because I haul the forge to hammer-ins. I take everything from the floor flange up and mount it to a similar surface, plywood covered with concrete backerboard held by my Workmate bench. The bench height is  lower therefore the need to raise/lower the forge.  Spring and fall is a good time to look for dead grills appearing on the side of the road.

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  • 2 weeks later...

Gents,

Brand new to the forum and I am thinking of building a propane forge. 

One question I have that I can't seem to find an answer to is in regards to air flow and sealing the forge.  Do I need to have some sort of hole, vent or opening in either end of the forge?  I was planning on having a sealed back and closable front, as I deal mostly with small pieces.  I figured this would be more efficient in terms of heat production, but then I started thinking about pressure and fuel/air etc.  Thoughts? Advice?

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