CTaylorJr
Well-Known Member
OK, a LOT of folks come on here asking about using MAPP gas for a forge. well, below, you'll find out what all I've learned thus far...
When I first got back into knife making I made a small forge out of sheet metal and 2" kaowool. The forge body is 14" long, has an outside diameter of 7", and has a full size fire brick in the bottom; it is also fed with mapp gas...
I built this little mapp gas fed forge so that I could heat metal up to beat on, and to heat it up to non magnetic for heat treat. It has also been handy for making a few tools out of O1 and such, but it was NEVER intended to be used for welding.
Over the last year that I've been a member of this forum I've seen a lot of folks come on and ask if they could forge weld, make Damascus, etc., with a mapp gas forge. Well, the answer is yes and no. Mostly no.
I've since moved up to a propane forge and have found it to be perfect for what I want to do, but tonight I decided to do a little test with the mapp gas forge to see if it would do anything that a lot of folks are asking about.
Tonight I decided that 2 pieces of 1018 and a piece of O1 needed to be married, joined, welded up... So I cut them and stuck them into the mapp gas forge with a full bottle.
I cut the 3/16" 1018 long enough that I could use some of it for a grab bar for the tongs, ground off the scale, and stuck it into the pre-heated forge. While the 1018 was heating I cut off a piece of 3/16" O1 3" long to sandwich between the 1018 after heating.
the 1018 finally got to where I felt I could fold it over on the anvil, so I did and then sandwiched the O1 in the middle of the fold. I brought everything to a "red hot" temp and then fluxed with anhydrous borax.
Then came the wait... I waited and waited for the END of the metal to get hot enough to beat on. The end with the fold finally got to where I thought it was good so I pulled it out, medium tapped upon it, and then stuck it back into the forge since the "right color" didn't last long. I brushed and fluxed again first...
After a few more MINUTES I was able to pull out the almost billet and hit it a couple of more times before I had to put it back into the forge to heat back up... Critical temp for forge welding is short lived to say the least.
OK, long story made short.... I WAS able to make a san mai billet ~4" long and 1/2" thick before I ran out of mapp gas. BUT, it took a FULL canister of mapp gas to do it, AND it took a LONG time! From the looks of the billet so far, I'm ok, but I have NO CLUE if it welded through.
My thoughts on a mapp gas forge are this, it costs WAY too much in gas to weld one billet, even if it is a good weld. For the price of the canister of mapp gas one could buy all of the parts to make a propane burner and use that instead. Propane is a LOT cheaper than mapp gas for sure.
"But I don't have a forge, only some bricks"... Well, if you can get a 5 -gallon bucket and some kaowool you'll have a forge in no time! Then you can build the burner and be on the road to forging in a short time.
Mapp gas is NOT the way to go with this if you are wanting to forge weld and/or make Damascus, laminated steel, etc... It's too expensive and too unpredictable...
Now, on the bright side, the forge has been good for making mokume, heating some metals to forging temps, and heat treating small knife blades and tools. It's a forge I'll keep on the bench, but NOT my go to forge for knife making...
Just my 2 cents...
I'll post pics in the next day or so of the 1018/O1 billet I made... I have to get more mapp gas first, I plan to finish it with the same thing I made it with... Should be a lot of fun for me, and possibly educational as well...
Charlie
When I first got back into knife making I made a small forge out of sheet metal and 2" kaowool. The forge body is 14" long, has an outside diameter of 7", and has a full size fire brick in the bottom; it is also fed with mapp gas...
I built this little mapp gas fed forge so that I could heat metal up to beat on, and to heat it up to non magnetic for heat treat. It has also been handy for making a few tools out of O1 and such, but it was NEVER intended to be used for welding.
Over the last year that I've been a member of this forum I've seen a lot of folks come on and ask if they could forge weld, make Damascus, etc., with a mapp gas forge. Well, the answer is yes and no. Mostly no.
I've since moved up to a propane forge and have found it to be perfect for what I want to do, but tonight I decided to do a little test with the mapp gas forge to see if it would do anything that a lot of folks are asking about.
Tonight I decided that 2 pieces of 1018 and a piece of O1 needed to be married, joined, welded up... So I cut them and stuck them into the mapp gas forge with a full bottle.
I cut the 3/16" 1018 long enough that I could use some of it for a grab bar for the tongs, ground off the scale, and stuck it into the pre-heated forge. While the 1018 was heating I cut off a piece of 3/16" O1 3" long to sandwich between the 1018 after heating.
the 1018 finally got to where I felt I could fold it over on the anvil, so I did and then sandwiched the O1 in the middle of the fold. I brought everything to a "red hot" temp and then fluxed with anhydrous borax.
Then came the wait... I waited and waited for the END of the metal to get hot enough to beat on. The end with the fold finally got to where I thought it was good so I pulled it out, medium tapped upon it, and then stuck it back into the forge since the "right color" didn't last long. I brushed and fluxed again first...
After a few more MINUTES I was able to pull out the almost billet and hit it a couple of more times before I had to put it back into the forge to heat back up... Critical temp for forge welding is short lived to say the least.
OK, long story made short.... I WAS able to make a san mai billet ~4" long and 1/2" thick before I ran out of mapp gas. BUT, it took a FULL canister of mapp gas to do it, AND it took a LONG time! From the looks of the billet so far, I'm ok, but I have NO CLUE if it welded through.
My thoughts on a mapp gas forge are this, it costs WAY too much in gas to weld one billet, even if it is a good weld. For the price of the canister of mapp gas one could buy all of the parts to make a propane burner and use that instead. Propane is a LOT cheaper than mapp gas for sure.
"But I don't have a forge, only some bricks"... Well, if you can get a 5 -gallon bucket and some kaowool you'll have a forge in no time! Then you can build the burner and be on the road to forging in a short time.
Mapp gas is NOT the way to go with this if you are wanting to forge weld and/or make Damascus, laminated steel, etc... It's too expensive and too unpredictable...
Now, on the bright side, the forge has been good for making mokume, heating some metals to forging temps, and heat treating small knife blades and tools. It's a forge I'll keep on the bench, but NOT my go to forge for knife making...
Just my 2 cents...
I'll post pics in the next day or so of the 1018/O1 billet I made... I have to get more mapp gas first, I plan to finish it with the same thing I made it with... Should be a lot of fun for me, and possibly educational as well...
Charlie