MaxwellB

I have a 2 burner devil's forge with a door on the butt. I relined it because I was pretty much throwing whatever I could to the wall and see if it stuck. Here's the nitty gritty: The "refractory" they give you, in my opinion, is garbage. There's no mention of what it is, what it's content is, etc. You're better off getting yourself some hydroPHILIC fumed silica off ebay or amazon (I'll link the one I bought if it's allowed) and mixing that with water and food coloring, and rigidizing the blanket on your own. Then you should coat with a known refractory, like kast-o-lite or satanite or any of the others mentioned throughout here and elsewhere on the interwebs. You can probably go about 1/2" thick on it and you'll be fine. Then when it's all set and cured and you're almost ready to go, coat the top of the refractory with an IR reflective coating like Plistix. This is a thin coating, like coating the surface with a layer of paint. This should get you to where you need to be. It sounds daunting, but it's really not that difficult if you can follow directions. The worst part is mixing up the kast-o-lite (if you go with that particular one) because to me it felt like it was too dry, but it held well. There are a few other members here who have the same brand of forge, and I'm sure they'll chime in shortly with their experiences. I actually haven't had time to forge much, settling into a new job and all. But hopefully I'll pick the hammer back up soon. One more thing, and it's something I'll be doing soon... Look into getting a 40lb tank or bigger for your propane. I find that the 20lb grill tanks just don't last me as long as I'd like them too. And since you said you have access to big box stores, you should be able to find propane refill places, which will always come out cheaper than an exchange. IFI sells refractories at Gas Forge Refractories and Supplies

Perhaps "traditional" was the wrong choice of words. A lot of things I've been reading have pointed towards a general shift in using air supply coming from the bottom. Also part of the reason I was inquiring about the use of drums. Seems many designs these days favor air supply coming up from underneath everything. I figure if I'm going to build this, might as well pick a few brains before I commit.

I've browsed the solid fuel section and read the BP on the 55 Forge. I'm planning on putting one together, so I can see if I prefer propane or solid fuel. So my question is simple... Have there been any NECESSARY/NEEDED changes done to a 55 that should be noted, or are they all "operator preference" types of changes? For example, would it be considered a must to go with side-blast over traditional "up from under"? Does a brake drum make things easier/more efficient or does it make things cumbersome? Things like that are questions I have. I have 2 55 steel drums left out of 4 I bought a few seasons ago to turn into burn barrels, and I really don't need 4 burn barrels in the yard. So I figured I would cannibalize one of them and take a shot at the 55.

The reason the floor is thicker is because of the abuse it takes. You're going to be "stabbing" it with stock as you put it in, regardless of how gentle you are. You don't want to chip or gouge that refractory to the point you're having to reline it. Also, depending on the refractory that you're using, it'll hold up to flux to a certain extent. Thinner refractory will get eaten through faster, and then once you get flux on wool it's game over, like water on cotton candy. So you're giving up some thermal efficiency in exchange for durability. As for the ceiling/walls, they're going to heat/cool faster than the floor, and you're going to experience thermal cycle shock to the refractory and cracking will be catastrophic if you're running a thin coat. Just like the floor, thicker is designed for durability. And keep in mind too that the castable doesn't go as far as you think it will. 10lbs of castable seems like a lot, but it's really not.

Late to the party, but I agree with Event... The coating they ship you falls fully into the "no bueno" side of things. I mean, it's probably ok to rigidize the wool, but in no way shape or form should it be classified as a refractory. I have a 2 burner square DF that I actually relined not too far back. And I'm tweaking that lining further. It's kaowool, kast-o-lite 30, and a topcoat of IR reflective. I made it a little too small, so I ripped out the sides (and most of the top came with... c'est la vie) and re-rigidized the exposed wool. Tomorrow I'll slap on the KOL and let it do it's thing. It's functional, but it's just too narrow. So now I eat my crow when I said I didn't see myself working with anything wider than 4"... My bolt tongs are wider than 4". But back on track... Get yourself some real refractory and you'll be solid. A little extra on top of your investment already, but this will be a few steps closer to optimized.

I have 2" of kaowool coated with about 3/8" of KOL. 1/2" should be sufficient since you're covering 2.5" of brick. And since you're going to be coating the KOL, 1/2" should be fine. But definitely take some advice and get an extra bag just to be safe. I ordered 2 bags for when I relined my forge, and I'm glad I did. I didn't have to dip into the second bag, because I went thin on the roof of the forge, but I would have been SOL had I needed to up my thickness at all.

I think one of the best things I've seen here is the willingness to post mistakes, flaws, imperfect items, etc. all without the fear of that BS that others throw around. I recommend this place to everyone I come across who needs info because I know they'll get what they need AND they won't be branded a newb or a moron or anything along those lines.

Oh yeah Frosty, I know about the mockery and good natured "abuse"... But there's a lot of forums that will ridicule and hound someone for honestly not knowing an answer, or doing something other than the "established way" or the way they think it should have been done. Here it's all in the effort of marching forward. Nobody here thinks of themselves as high and mighty, and so far it looks like even there advanced Crafters remember their early projects. I enjoy it here, even if I don't understand half of the conversations.

Everyone makes mistakes the first time. It's what makes this forum great. There's no pointing and giggling when someone (like me) confesses to wasting time and money on things. It just doesn't work out sometimes. Hydrophilic is the fumed silica you want. Remember to spray water on the wool BEFORE the rigidizier so it can penetrate better.

Most everything I'm seeing has the port in the door open for exhaust. If you think you're losing too much heat through that you could probably make a plug to take up 1/3 or 1/2 of the open space, just to experiment. Make sure you rigidize the wool before you fire the forge back up. You really don't want silicosis.

Outstanding. Thank you all for your feedback. It's very very much appreciated!

I had put the stuff they sent with first, then when I Greenpatch'd the forge I put it on there. Right now it's just rigidized wool, and I might keep it that way. Or if I find where I put that Greenpatch bucket, I'll put a bit on there just to protect the wool.

Latt - Oh yeah... There was plenty of steam. EVERYWHERE. It was coming out of both ends and looked like a Cheech & Chong video. I was worried at first because it kept coming. But then I thought of all the water in the refractory and the water on the wool I buttered with, and the humid conditions of the day. Event - I had the front choke open a bit more than the back, simply because I wanted to try and bring in more air to negate the hot exhaust getting drawn in. I don't have a welder, so I can't tack a heat shield around the choke like I would like to, or even tack a plate over the top of the front to keep exhaust/dragon's breath diverted. I've gotta see how low the burners are sitting inside and see if I need to bring them down further. Everything I've read say they should be flush with the refractory or recessed slightly, up to 1/8". That might be the ticket. I'd still like to see about that cold spot in the middle. The obvious first troubleshooting step is to turn the burner assembly around and see if the front gets hotter than the back. Then there's an issue with the burner assembly not diverting evenly. If the back still stays hotter, then it's an issue with the design or the reline and I go from there.

Is that cold spot between the burners normal then?

So, even though Mother Nature seems to have a chip on her shoulder for good ol' Chicago, I was able to fire the forge today and see if I messed anything up. So, for your review. Burners right after being lit: Burning on low pressure: Higher pressure burn, about 7 or 8 PSI: Back burner seems to be running more efficiently than front. Perhaps the door? Perhaps better placement (lower/higher, angle, etc). Not sure: And after forge is off and cooled down. No apparent cracks or deformation in the KOL layer: So, wiser smiths of the world, what would you say about this... Would you say that the interior is too small, causing the heat to not be able to distribute properly, causing the cold spot in the middle of the forge? What could be causing the rear burner to be hotter than the front? Could it be the door is there, trapping more heat? Could it again be the heat isn't circulating as efficiently so it's just essentially a blast zone? Tips to correct any deficiencies noticed would be appreciated as well.

The flares are 1". I thought that's the measurement you were referring to. After checking again, the flares are 1" with 1/8" wall. So assuming the mixing tube is 1/8" wall as well, I would assume they're 3/4". They fit into the flare with just a sliver of daylight between the exterior of the mixing tube and the interior of the flare "coupler".

Just checked the burners, they're 1". Weather permitting I'll be putting the burners in the forge tomorrow afternoon when I get off work and test firing everything, seeing how that goes. Worse case scenario is I rip out the KOL and the second layer of wool, and just put up a thicker KOL coating over the first layer. But I'll definitely have more info (hopefully) tomorrow after the burn.

Hmm... blood bait. Now that brings back memories. That's pretty bad. Roadkill skunk outside the house. That's one of those that just lingers even after it's removed and the area is sprayed down. Went through a four gallon backpack sprayer filled with vinegar and some dish soap spraying down a 20' x 10' box where the skunk was smished. Still could smell it every time it rained.

Aww c'mon!!! Let's scare the kiddies! I worked at a gas station and was tasked with clearing out the garbage cans by the pumps in August. Like, change the bags and wash the insides.

I've run bear carcasses to a dump hole in the middle of the woods surrounded by fish guts in northern Minnesota. I think I can handle your moose toots.

I purchased this forge: At the beginning of 2019, figuring I needed a hobby. Making knives and small things like that seemed like a good idea. Who doesn't love fire and hitting things with a hammer? I received the forge fairly quickly from the middle of Eastern Europe, and I went about getting it action-ready according to various posts I've seen here, and information I've sniffed out from other interweb sites. After putting a bunch of stuff inside of it to see if I could increase the efficiency, I came to the conclusion that there just wasn't enough of the right stuff in there. So I set about tearing out the old, and putting in the new. I started with ripping out the old kaowool and coatings I had on there, and putting in 2" of wool instead of the stock 1" that the forge came with. Exhibit A, post rigidizing and test burning: Next, I purchased some Kast-o-Lite 30 and lined the sides with about 1/4" on the sides and 3/8" on the floor. Enough to provide ample protection for the wool on the floor of the forge, as well as increase the efficiency of the forge. This also reduced the interior dimensions significantly. Exhibit B, forgive the perspective: The "stock" interior dimensions were, according to the original sale listing, 5.6" x 5.6" x 16". The new (approximate) dimensions after the layering of the wool and the KOL is about 4" x 4" x 16". This means the "stock" interior volume would be about 501.76 cubic inches. The new volume is approximately 256 cubic inches. So a hair over half the original space was taken up. In theory this will make the two burners (small in comparison to homemade burners) the unit came with more efficiently heat up the interior, and allow higher temperatures to be reached with less PSI resulting in greater fuel efficiency. In theory. I hope. The forge and it's new guts are now in it's bag o' humidity, where it'll remain for the next few days (until Saturday at the earliest). Exhibit C: The new dimensions will undoubtedly make it more difficult to work certain stock sizes in it, but I really don't foresee myself working with anything that's going to be wider than 4" and longer than 16". The only thing I can see happening is that trying to straighten coil springs (like the one see in exhibit c) will mean I have to cut off a length first instead of unraveling into a long piece of stock. But that's why man invented angle grinders. I will update this post again when the "cure" is done and take a picture or two of the test fire, as well as any issues I came across. I used about 5lbs of Kast-o-lite to do this. I probably could have used 6, just to make sure I wasn't spreading anything too thin. But that's why I left the roof of the cavity until last, as I had the burner holes to dance around and could spread out the product a little thinner.

The whole thing with this is that with all the reading I've been doing during colder days and downtime and things like that (essentially non-workshop time) I've come to the realization that we got kinda screwed on lining for the forges. It's 1" of wool, and everything I read is two. Now granted, I've compressed the wool when I relined it. The two inches are maybe more like 1.5" or slightly less. But it's definitely smaller on the inside. Which should by rights make it more fuel efficient to get the space up to temp and keep it there. With a test fire as just bare rigidized wool it did heat up to orange inside the forge much faster. Also, I'm thinking I'm going to have to cut the cross-arm on the burner assembly in order to drop the burner flares further down after the KOL treatment. Right now the bar is sitting across the top of the "stems" on the top of the forge, preventing me from bringing the burners any lower. And the flares are recessed a bit into the wool after the second layer. So after adding another 1/4 - 3/8" (I might not go as thick on the ceiling of the forge due to burner placement and weight distribution) I'll definitely need an extra 3/8" to 1/2" out of those burners. So this type of forge seems to be, on a scale of 1 - 10, about a 5 or so out of the box. After this little project of mine is finished, I'm hoping it'll be a solid 7. Of course, it'll probably never get above that due to what I feel are undersized burners, but if it gets up to welding heat without needing the PSI cranked higher than my blood pressure after a day in traffic, I'll consider it a win. Just one of the drawbacks to a budget commercial forge I guess. But hey!! I'm learning, and I'm fine with that.

Event, you're actually someone I had in mind as I was undertaking this. The forge works well for what we paid for them, but I'm seeing that a bit of added investment at the beginning would bring it up a notch or two. I didn't take any pictures of the tear out and reline of wool, because it's the same across the board. If anyone isn't sure what that looks like, cut open a pillow filled with poly stuffing, or look at the fill tank at a Build-a-Bear. Only this stuff will pooch your lungs. Tomorrow I plan to line with KOL30 and I'll definitely before/after that. As well as what the end result is, if it's noticably hotter.

Frosty, have I ever told you that you're awesomeness personified? Cause you are. Thanks for your continued knowledge sharing!

What's the best way to cure it? I've read wrapping it in a garbage bag with a wet towel, and then baking it in an oven. Is it possible to skip the oven baking and just maybe use a hand torch to pull the water out, then use the burners to fully cure? I'm not sure the rest of the family would be impressed with the oven bake method.