hbmasa Posted November 25, 2024 Posted November 25, 2024 (edited) Is there set plans to put bricks in a propane tank so I can skip kaowool? I know you can make one out of angle iron and bricks but like the durability of it closed in a shell. The "bottom" of the tanke has been smashed flat to an 8," bottom. I will use a venturi and am tired of replacing lining after every two forgings because the heavy weight makes my cable bend, making it scrape top or bottom everytime. In two years I've kastolited, kaowooled and buttered about 9 times. I need no info on kaowool, I will not use it. I'd hoped to soft brick. Then hard brick bottom and coat it all with plastic. Will the exposed opening around the entry and exit melt? Thanks all, hope yal are all OK. Forges was colored blue so I couldn't get it to add this question there. NO KAOWOOL. Take care **This is for any poster/advisor who knows. It is not limited to any 1 poster Edited November 25, 2024 by Mod34 Moved to proper section. Quote
JHCC Posted November 25, 2024 Posted November 25, 2024 Hi, hbmasa. Can you clarify something for me? When you say you're "tired of replacing lining after every two forgings because the heavy weight makes my cable bend, making it scrape top or bottom everytime", what cable are you talking about? Is it your workpiece, and how heavy is it that its bending (presumably under its own weight) that it doesn't fit properly in the forge? Also, I assume "coat it all with plastic" means "coat it all with Plistex". Coating with plastic would be ... interesting. And dramatic. Apart from that, I expect you could trim soft bricks to fit inside a propane tank rather like how a mason trims the stones to form an archway: I'd suggest turning the tank upside-down, layering in the bricks for what will be the top of the arch (trimming as you go; this may take some fiddling), and then giving them a good layer of kastolite both as a flame face and to hold them in place. Then turn the tank right-side-up, install the soft brick and hard brick layers of the floor, and coat everything with Plistex. Does that make sense? Regarding the tank melting around the openings, I had this problem with the original version of my D-tunnel forge. I recently cut the burned metal away, trimmed back the damaged kastolite around the openings, rebuilt those edges with Greenpatch 421, and haven't had any trouble since. If the metal is at least 3/4"-1" back from the opening of the refractory (especially if the refractory extends beyond the opening in the metal), you should be fine. Quote
Shainarue Posted November 26, 2024 Posted November 26, 2024 The first forge I used was at a class in a maker space and their forge was a propane brick forge. Basically angle iron frame held the outer bricks in place. Then kaowool sandwiched with more bricks on the inside. Holes drilled into the brick for the burners. Metal flaps on either end so it can close up if needed. Quote
hbmasa Posted December 1, 2024 Author Posted December 1, 2024 sorry for delayed response. Thank yal. My weight is often only 15-20 lbs but it can be up to about 18". Honestly. I have trouble with13" pieces if they're hot. It has to be pretty perfect in and out to not hit plistex kastolite and eventually the evil kaowool. I'm pretty darn sure my chamber could be 11wide at bottom, 9" tall and 13" long. I don't want to use kaowool. It's literally my only fear in this life. I guess this will also cause problems w edges. The longer length of 13" will make heat stay in longer, thus being hotter. I can cut the tank however I need to. Like the handle on it design for easy carrying. Wanted to show an illustrative picture. I wouldn't be near as offended to occasionally scratch plistex on soft brick on the sides and roof as long as it's not gonna go through to a kaowool layer. Thanks again And why unpaint in something if your gonna bring it up to 2200 degrees ? And shouldn't forge be room temp to touch if it's got 3000 degree insulation. I'm know it get alot hotter. Poorly sealed intervals? Quote
Frosty Posted December 1, 2024 Posted December 1, 2024 You should do some reading in the forges 101 section, you're operating under a lot of false assumptions. A longer forge can't be hotter than a shorter forge with the same number of burners. One properly tuned 3/4" naturally aspirated propane burner will reliably bring 300-350 cu/in to welding temperature. You'll need one 3/4" burner for every 350 cu/in of chamber volume. PERIOD. Building long forges is rarely useful, you can only realistically work about 4-6" at a time before losing heat and bringing steel to or above forging temperatures without refining the crystal structure damages it internally and decarbs the surface. If you actually Need to heat a length, say to twist fence pickets, drawing the stock back and forth through a HOT forge works nicely and you're still only burning 1/2 - 1/3 the fuel. Adding another inch of Kaowool or equivalent refractory wool will NOT make a hotter forge, the point of diminishing returns falls at about 2". About 95% of heat loss for a propane forge is the exhaust gasses exiting the openings. No, you can't "close" the ends NA burners need to breath free, back pressure impairs their ability to induce combustion air. The visible flames escaping the openings is commonly called "Dragon's Breath" and it can be minimized but not eliminated and maintain a high temp forge. The outside of my forge runs about the same temp as a fresh cup of coffee. No, paint won't burn off at that temp but it sure will within a few inches of the openings, bare steal is better and you might as well do the hole tank while you're at it. Not necessary of course, it's your forge. You won't damage the hard flame face unless you just jam work in and jerk it out, nothing is safe from careless abuse. Properly installed and cured Kastolite 30 is about as delicate at welding temps as a sidewalk. People who damage forges with Kastolite flame face either applied way too little or are ham handed in the extreme. I have experience with guys who if told something is really tough will do their best to damage it. What happened to the end of that propane tank? I know it's become popular to use a cut off disk in an angle grinder instead of a reciprocating saw but holly COW take a little time and stay within the line. LOTS of short cuts works where a few great long hacks makes for sloppy ugly circles and that uneven an opening will be a devil to line and finish. Stick around, we'll get you up and smithing. Frosty The Lucky. Quote
hbmasa Posted December 1, 2024 Author Posted December 1, 2024 Kastolite 30 isn't cheap and I did guesstimate about 6 '10 bs to fill it minimum. Plus , I thought kastolite only worked if it had kaowool under it and i dont wznt that.. The old forge only had about a 9x6 openings( pre wool kol and plis, I can't keep gloves usable, get torn up or lubed up (from cable), so I've been trying long pieces but a few inches off doesn't fit and hot metal rushes my accuracy You've gotta be really exact with 18" x 2" going in a small toaster. And sliding piece over floor. My castolite breaks out in chunks. It was rigidized, buttered, high humidity period Burn in, followed by full plistexand burned. The kol was very sticky in a good way but applied w texture I didn't smooth out. I can't be the first yahoo to try this Thanks Quote
hbmasa Posted December 2, 2024 Author Posted December 2, 2024 On 11/25/2024 at 11:32 AM, JHCC said: Hi, hbmasa. Can you clarify something for me? When you say you're "tired of replacing lining after every two forgings because the heavy weight makes my cable bend, making it scrape top or bottom everytime", what cable are you talking about? Is it your workpiece, and how heavy is it that its bending (presumably under its own weight) that it doesn't fit properly in the forge? Also, I assume "coat it all with plastic" means "coat it all with Plistex". Coating with plastic would be ... interesting. And dramatic. Apart from that, I expect you could trim soft bricks to fit inside a propane tank rather like how a mason trims the stones to form an archway: I'd suggest turning the tank upside-down, layering in the bricks for what will be the top of the arch (trimming as you go; this may take some fiddling), and then giving them a good layer of kastolite both as a flame face and to hold them in place. Then turn the tank right-side-up, install the soft brick and hard brick layers of the floor, and coat everything with Plistex. Does that make sense? Regarding the tank melting around the openings, I had this problem with the original version of my D-tunnel forge. I recently cut the burned metal away, trimmed back the damaged kastolite around the openings, rebuilt those edges with Greenpatch 421, and haven't had any trouble since. If the metal is at least 3/4"-1" back from the opening of the refractory (especially if the refractory extends beyond the opening in the metal), you should be fine. One of the things I was looking forward to was having the ends start to get smaller to keep more heat it. And everytime I use kol over the outside lip it's broken quickly. My op was an exaggeration, I usually get about only 6-8 months with stock to big to be comfortably fit. Kol isn't disappearing, it falls out In chunks. Sorry for misleading anyone. Tx Quote
JHCC Posted December 2, 2024 Posted December 2, 2024 23 hours ago, Frosty said: About 95% of heat loss for a propane forge is the exhaust gasses exiting the openings. No, you can't "close" the ends NA burners need to breath free, back pressure impairs their ability to induce combustion air. The visible flames escaping the openings is commonly called "Dragon's Breath" and it can be minimized but not eliminated and maintain a high temp forge. This is generally true for NA (naturally aspirated) burners, but less applicable to forced-air ribbon burners and gun burners. It is possible to have doors (hinged or sliding) that cover the openings on a forge with NA burners so long as they don't fit tightly. My own forge runs on a NARB (naturally aspirated ribbon burner) powered by a 3/4" Frosty T-burner; closing the front and back doors does allow it to heat up faster, but there's a lot of leakage around their edges. Here's a dramatic nighttime shot that shows what I mean: Quote
Frosty Posted December 2, 2024 Posted December 2, 2024 Beautiful pic John! A perfect illustration of Mikey's thermal baffle forge closures. One minor correction, even gun (blown) burners need an exhaust port though smaller. There are tricks you can play with gun fired furnaces you can't with NA. Say mount the floor above the forge chamber's bottom with the exhaust port through the forge's bottom under the raised working floor. This directs the flame so the working floor is heated from both sides, inside and outside. That's a brief example of what's known as a recuperative wall and can encompass the entire furnace flame face chamber. It's pretty industry standard for large commercial furnaces. Frosty The Lucky. Quote
JHCC Posted December 2, 2024 Posted December 2, 2024 34 minutes ago, Frosty said: One minor correction, even gun (blown) burners need an exhaust port though smaller. Very true; thanks for clarifying. Quote
hbmasa Posted December 3, 2024 Author Posted December 3, 2024 That's a fire! Mine only has orange breath. That looks like an ai drawing Quote
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