I plan to go propane but to get things going I'm making a coal forge to finish some knives that need to be hardened and tempered. I came across some plans for a break drum forge (and criticisms) but the drum I had fall into my lap is bigger than the ones they seem to show on the youtube videos, where a 2" floor flange fits neatly on the bottom.

This one is bigger and the hole in the middle is large. I found a steel disk that *almost* covers the holes in the bottom. If I drill holes in the middle to make a grate to attach the pipe/flange to, does it matter if those holes on the outside of the disk aren't completely covered? I would think not but would rather find out now than after spending the money and work to put it together. The large circle I drew in the middle of the disk was traced from the hole in the bottom of the drum.

So I'm thinking drill two holes on the outside (where I drew circles at about 4:00 and 5:00) to bolt the disk to the drum. Then drill holes to bolt a 2" floor flange to the disk in the bottom.. then drill holes in the center where the pipe in the flange will be to make a grill to let air through... probably going to get clogged with ashes.

Then like the typical plans say, pipe down to a T, ash drop down the bottom, and a pipe to put a hair dryer in to the side.

That looks like a drum out of a truck and larger than most folk need. However, what you plan will work just fine.

There are a few ways to block lug holes that aren't covered by the plate. Just dropping counter sunk screws in works fine or packing clay around the plate will do it.

Making an air grate by laying round stock across the tuyere hole with spacers between works very well. Holes need to be individually poked to clear junk where a bar grate can be scrape to do same.

Floor flange to nipple to T to another down nipple and a hair drier is pretty standard in this day and age of $5.00 yard sale blow driers. Don't get fancy blocking the ash dump, a screw in plug is way more hassle than necessary. I have an exhaust stack flap cap on mine and it works a treat. It's just clamped on upside down with an extension on the counter weight arm so I can reach it easily under the forge table. The extension keeps it close more securely as well. All my solid fuel forge hardware is welded but plumbing works just fine and you don't have to wear a welding shield.

Frosty The Lucky.

For heat treating knives most folks need a longer forge, alla the Lively wash tub forge. Personally I think the break drum forge is more trouble than it is worth, and would recommend a side blast like Glenn's 55 forge

Shamus, here are a few early pictures when I was making my brake drum forge.  I simply bolted a floor flange to the bottom of the drum.  I built an ash dump similar to Frosty's.  I cutout and welded it from scraps.  The screw on caps are, as Frosty eluded to, a PIA!  I'm using a xxxx fan from HD for air, a blast gate (air gate) for air control.  I only open the gate 1/4 to 1/2 for most forging.  I've since added a hood which I wish I had done from day one.

As for the grating on the tuyere, everyone has a different type.  I started out with some 3/8" rod welded across the drum hole, spaced about 1/4" to 3/8".  They burned through pretty quick, plus welds on cast iron are not strong in this application.  Next, I tried some cast iron drain grates.  They also burned through pretty soon.  Finally, I made a grill out of 1/2" bar stock.  Forged a circle same as the I.D. of the drum, welded the 1/2" bar stock to it, and dropped it in.  Nice snug fit and so far it shows no sign of burning.  If it does, I'll just weld in some replacement bars where it burns out.  Some folks weld their plumbing together, but that's sort of semi-permanent.  I just screwed all my black pipe together and it will come apart very easily if I need to remove it for some reason.

 Nice set up Arkie, almost enough to make me wish I had coal to burn. . . Almost.

About burning through the air grates, If a person uses rectangular stock like Arkies but turns it on edge with  similar gaps, it does two things. First it reduces the area of fire contact so the bar can absorb less heat. Secondly it increases the area in contact with the air blast increasing cooling. On point one, the reduced fire contact area also means there's less mass to distribute heat to so it can actually get hotter. Eg. thin stock heats faster than thick stock.

I've liked the results of standing the bar in grates on edge for andirons, they last longer and warp less. Adding a forced air blast improves it's survivability.

Just food for thought. Call it brain kibble.

Frosty The Lucky.

Edited March 14, 201511 yr by Frosty

Frosty, very good points on turning the bars on the diagonal!  Thanks.

I gave it a brief thought when welding, but thought the corners facing up into the fire might burn up faster.  I like your idea.  When (not if) the middle bars burn up, I'll probably weld the replacements in on the diagonal since they get the most heat.  I might even make another, on the diagonal, and start using it.  The angle of the diagonals might even enhance air flow, not hitting the bars square-on but sorta funneling the air flow better between the bars.

Shamus,

When you are building your forge, no matter what the design, I STRONGLY recommend making a hood for it.  They are worth a fortune to get the smoke and a lot of heat out of your face.  I ran my forge for nearly two years before I got around (lazy, I guess) to putting one on and have never regretted it.  I got so tired of having smoke swirling around and choking or blinding me.  Plus, my wife has stopped complaining when I wash my face and the washcloths are no longer black!

There are a myriad of designs and fabrications out there, from fancy stainless steel to scrap sheet metal.  Whatever you can cob up, go for it.  I found a design for a rectangular one made of sheet metal that I fabbed up and stuck on mine.  I think I got the design drawing/photo from some post on IFI.

 

wow nice forges.  I didn't know break drum forges could be so nice.  can you guys get those hot enough to do forge welding? 

 

Oh yeah, no problem. The coal forge I have doesn't have a fire pot at all and it welds, melts or otherwise gets steel as hot as a boy could want.

Frosty The Lucky.

I can burn metal with the best of 'em!!!   Forge welding, well..............let's say I'm still working on that one.

With the fart fan I'm using, most forging is done with the blast gate open only 1/4, heavy stuff maybe 1/2.

 

Edited March 15, 201511 yr by arkie

I tend to agree with Mr. Stevens. In order to heat treat blades they need to be placed horizontally in the forge in order to get an even heat.

I started with a screw cap on the ash dump but found my blower was so string that I had to leave the cap off to decrease the blast; so I suck a bucket of water under the open ash dump to catch anything that managed to get past the blast and had no issues.

 

Instead of a hood like that could you take a old propane tank and cut a hole in the front and put chimney on top.