How to deal with Forge loading up with ash?

[AmericanLocomotive]

I have a DIY forge made from a semi-truck brake drum (about 16" diameter) and other various pieces of scrap and a blower scavenged from a clothes dryer. There is a large baseplate placed inside that the coal sits on that's removable for service/cleaning. It has approximately 15 ~3/8" holes drilled in it. We primarily fuel it with coal and coke, but lately it's been mostly coke since I got about a half ton of it for free. It has no problem making even heat, and it easily gets up to welding temperatures (and well beyond) if we need it. The problem we're having is after about ~2 hours of use, the forge starts to load up with lots of ash and/or bits of coke that just no longer burn. Once that starts to happen, the forge has a hard time keeping sufficient air moving over the coke to keep it burning. Eventually the burn starts to get uneven with hot spots until it can't maintain heat at all. So I'm looking for some tips on how to manage the ash build it up that keeps occuring, of if its just something that happens with solid fuel forges?

[jeremy k]

Do you have an Ash dump below your firepot? usually A "T" where the blower air goes up into the firepot with a cover or slide cover so you can let the ash fall out so it doesn't block incoming air to the forge.

[Dan C]

Stir it more often and use the dump gate. Since you're not using charcoal you would probably be better with a grate made of a few bars of 1/4" sq spaced a 1/4" apart. You'll still need to stir the pot to clear clinkers and ashes. I turn the air off when doing this. I ran into the same thing with my forge, especially when forge welding after it'd been going for 3-4 hrs

[Candidquality]

easiest way I found to alleviate ash issues.  straight pipe from the bottom of the forge down to a 5 gallon quench bucket(suspended above the bottom a few inches so i can be removed when wanted. "T" into the side of the down pipe to blow in your air.  any ash falls into the bucket, and you don't have to think about it.  water pressure seals off that end of the tube. 

[swedefiddle]

There is a lesson in your statement. Now you know why you need to get/make a forge with an ash dump, and a larger area to work your coke from, and a ..........partridge in a pear tree.  Store bought equipment normally has been thunk through. :) :)

 

Good Luck,

Neil

[Dan C]

Don't need store bought equipment. I have a similar setup, ran into same issue and addressed it as I said above. Who's to say store bought gear won't have issues? I'd rather make my own when I can and be more familiar with it and not afraid to modify it as I learn n see fit.

[forgemaster]

How about you just clean the fire every 1/2 hour, get all the rubbish out of it, maybe also screen or sieve the fuel to get rid of any rubbish/dirt etc before you put it onto the fire.  Dump the ash etc when you give the fire a clean, the bits of coke that are not burning are called clinker, it pays if you get that out of the fire as it forms. Forge fires are a great source of heat, easy to make and simple enough to use, but they do require a bit of house keeping as you go. Another thing that gets my goat is when guys leave their fire roaring away with nothing in it while they go for leak or a drink of water etc, then come back and wonder why their fire is all choked up with clinker and ash.  If you leave it at least turn it down, we were always taught that just before you take your job out you turn the blast back, so as not to waste fuel.

 

Phil

[AmericanLocomotive]

Maybe it'll help if I post a picture of what I'm working with:

 

There is a significant chamber underneath the plate where ash falls, a long with a large air supply pipe that has an ash trap on the bottom - and it does fill and collect with ash that does fall through the holes. We plan to cut around 4-5" heightwise off the drum, and maybe fashsion some kind of table around it as well. Just need to get more cutting discs!

 

So, should I could out the drilled holes all together and just make a grate out of 1/4" stock, or should I make a grate that elevates the coal above the drilled holes? Or do both, and just have a grate above a big opening?

[Frosty]

The picture helps. I'm afraid you've stepped into a trap many of us do when getting into a new craft. You've taken a simple effective piece of equipment that's worked wonderfully for thousands of years and over complicated it. I'd lose the huge drum and just drop a pickup truck brake drum in a sheet steel table with a little rim around it. The air grate is nothing more than some 3/8" - 1/2" round bar with about 3/8" spaces between them and tack them over a hole in a plate blocking the lug holes in the drum. Plumb under it with pipe a T leading off a couple few inches below the air grate for the air supply. Let another 4-5" hang straight down and put a cap on it for the ash dump. I like an exhaust flap cap upside down for the ash dump. I used truck exhaust pipe for mine, tape measure, saber saw and mig welder was about the tool kit necessary for that part.

 

To repair yours I'd lose the plate completely and build a bar air grate in the bottom. cut the plate to just block the lug holes it just lays flat in the bottom, it'll will work a treat.

 

I'm not a fan of semi brake drums, they're generally way too huge for most uses. Unless you're planning on working really large stock, say 4"x4"x8" pattern welded billets you're going to lose smaller projects trying to get them into the sweet spot and long stock will require a huge fuel eating fire to get the sweet spot up to the work.

 

There are lots of brake drum fire pots like I described on the site and Dicky Pitts post today showing the forge he just put together is a good example of a good workable forge. There are a lot of similar designs that look a lot better and no doubt are more user friendly but for a first blush forge it's a solid work horse.

 

simplicity is your friend.

 

Frosty The Lucky.

[AmericanLocomotive]

Remaking it with a truck drum/rotor and a big sheet of plate really isn't in the budget at the moment. All of the stuff we've built this thing out of, including the fuel was free. Based on how the blower feeds in air, I really can't eliminate the plate without rebuilding the entire thing - but I'll see what I can do.

I've ditched the holes in favor of a great made out of a super long bolt I find around - I'm not sure if the spacing between them is wide enough, but it's trivial to change. After discussing it with a few friends I forge with, I decided to also cut off half of the drum - I'm undecided on the other half however.

Also, one thing that makes "cleaning" while running the forge difficult, is that the coke dies extremely quickly (<30 seconds) if you remove it from the air. We had originally burned coal, but I don't remember if it had the same issue or not.





Thanks for all the input though! I'll see how the latest iteration works out, and if it still has issues I guess I'll get to dismantling the whole thing and starting over.

[Dan C]

You could burn a mixture of charcoal with the coke/coal.  That keeps it from dying out when the air is turned off.  Search online for how to make homemade charcoal.