Ross Jones Posted September 10, 2017 Share Posted September 10, 2017 I'm making my new forge and I'm thinking of using insboard as a sacrificial floor on top of 2" thick inswool. The typical hard firebricks I find that I used for the floor of my last forge aren't long enough for this one. Would insboard make a good replaceable floor, should it be coated, or is this a bunk idea entirely? Thanks for any help you can give. Link to comment Share on other sites More sharing options...
timgunn Posted September 10, 2017 Share Posted September 10, 2017 Yes, it eats it. Fast. Link to comment Share on other sites More sharing options...
Joël Mercier Posted September 10, 2017 Share Posted September 10, 2017 What if you line your insboard with refractory cement? You could make high borders to prevent drips. Just my 2 cents Link to comment Share on other sites More sharing options...
Alan Longmire Posted September 10, 2017 Share Posted September 10, 2017 The only refractories that stand up to borax for long are the castables, bubble alumina, and hard brick. Satanite holds up okay as long as it's at least half an inch thick, but any cracks allow the molten borax through to the wool or insboard, which will then disappear like cotton candy in hot water. I have known people to use a pan made of heavy stainless, but you have to rake out the flux puddle while it's hot. And even 10 gauge stainless warps and eventually goes away after enough firings. Link to comment Share on other sites More sharing options...
Justin Mercier Posted September 10, 2017 Share Posted September 10, 2017 I use hard fire brick floors with kaolin 'dams' on the sides, but when enough borax has built up it starts to run over the edges and eat the wool lining. Eventually you just gota suck it up and re-line the forge =P 1 --- Justin "Tharkis" Mercier www.tharkis.com Link to comment Share on other sites More sharing options...
Ross Jones Posted September 11, 2017 Author Share Posted September 11, 2017 I'm thinking of coating the floor of the forge with bubble alumina and putting a hard fire brick down on top of it. I'll get the that dam effect while hopefully minimizing damage to the lining. I was doing some googling today and saw some people posting about a refractory called "Pyramid Super air set" that reportedly is completely flux resistant and is rated for 4000f. I did my poking around through google and found out that the company that makes it went under. Is anyone still making a refractory similar to this? Link to comment Share on other sites More sharing options...
Ross Jones Posted September 11, 2017 Author Share Posted September 11, 2017 I'm not completely opposed to using a hard fire brick on the floor, but the bricks I find are typically 9" and the steel tool box I'm re purposing for the forge body is 15" long. I would just cut another brick to meet the missing 6", but I'd rather just have an insboard shelf I can slide in and out. I'm thinking the best way would be to coat the board in bubble alumina and replace it when necessary. Link to comment Share on other sites More sharing options...
GEzell Posted September 11, 2017 Share Posted September 11, 2017 Kiln shelves is an option I'm looking into, they are cheap enough to be replaced occasionally and should be immune to flux. Now if someone just made some with raised edges.... George Ezell, bladesmith" How much useful knowledge is lost by the scattered forms in which it is ushered to the world! How many solitary students spend half their lives in making discoveries which had been perfected a century before their time, for want of a condensed exhibition of what is known."Buffonview some of my work RelicForge on facebook Link to comment Share on other sites More sharing options...
Wes Detrick Posted September 11, 2017 Share Posted September 11, 2017 A buddy of mine casts a welding tray out of Mizzou for his forge. He has a mold set up, and puts a rectangular box in the middle so that there will be raised sides. Whenever he welds, the tray goes in. When it starts to wear out, he casts another. Mizzou is cheap. 1 “In the midst of winter, I found there was, within me, an invincible summer." -Albert Camus http://www.krakenforge.net/ Link to comment Share on other sites More sharing options...
Don Abbott Posted September 11, 2017 Share Posted September 11, 2017 That tray idea sounds really good. I put a hard brick forge in mine before I coated it. Then I went over the brick with satanite and a coat of ITC. I thought at the time I should leave it low in the center. Now I have a lake of flux standing in the forge every time I fire it up. If you want something that will hold the liquid flux, make sure it is removable. Link to comment Share on other sites More sharing options...
Wes Detrick Posted September 11, 2017 Share Posted September 11, 2017 3 hours ago, Don Abbott said: That tray idea sounds really good. I put a hard brick forge in mine before I coated it. Then I went over the brick with satanite and a coat of ITC. I thought at the time I should leave it low in the center. Now I have a lake of flux standing in the forge every time I fire it up. If you want something that will hold the liquid flux, make sure it is removable. Ya, that tray works pretty well. The only bad part is that it takes the forge a little longer to come up to heat because of the added thermal mass. But, he never has a problem with flux in his forge since he takes the tray out for regular forging. “In the midst of winter, I found there was, within me, an invincible summer." -Albert Camus http://www.krakenforge.net/ Link to comment Share on other sites More sharing options...
Ross Jones Posted September 14, 2017 Author Share Posted September 14, 2017 After looking through all my options, I've decided to use bubble alumina for the floor along with coated fire bricks as a sacrificial floor. All of these options were really insightful and definitely things I'll be looking into, but my best personal option is to just suck it up and cut firebricks to fill that 6" gap. Thanks for all of your suggestions, it's amazing how much I learn from this forum! Link to comment Share on other sites More sharing options...
Jerrod Miller Posted September 14, 2017 Share Posted September 14, 2017 I feel that it should also be said: there is also always the option of not using borax. Fluxless welding is a thing, and it does work if you can run your system right (as demonstrated by numerous people). Link to comment Share on other sites More sharing options...
Craig Rice Posted September 18, 2017 Share Posted September 18, 2017 On 9/10/2017 at 6:37 PM, Justin Mercier said: I use hard fire brick floors with kaolin 'dams' on the sides, but when enough borax has built up it starts to run over the edges and eat the wool lining. Eventually you just gota suck it up and re-line the forge =P what is the borax for? is it the flux Link to comment Share on other sites More sharing options...
Ross Jones Posted September 18, 2017 Author Share Posted September 18, 2017 5 minutes ago, Craig Rice said: what is the borax for? is it the flux Yes. It's commonly used for laundry, but smiths found a better use for it Link to comment Share on other sites More sharing options...
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