How to insulate a forge door?

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barnett25

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Sep 18, 2008
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I am getting ready to start my first forge build. It will be made from a freon tank, and will be constructed with no welding. I plan to bolt everything together.

I have most of the design figured out. But I am stuck on the doors.
I had planned to hinge both the front and back curved ends of the tanks (so that the forge body is just a straight tube). I would then have a fairly small window in these doors to pass stock through. My problem is how to insulate these doors.

I am afraid insawool would fall out. I thought maybe castable, or bubble alumina, or satinite. If I ran bolts through all around the perimeter to give the refractory something to hold onto would one of these materials work?

If anyone has any ideas or experience in this I could use all the help I can get.
 
I would (and have) used inswool with a coat of Satanite or refractory mortar to make it rigid. You can layer it up, wire it together with high temp. wire, etc. to get the thickness you need, adhering each layer together with mortar. To affix it into the doors you can drill holes and insert bolts (non-galvanized!!!!) into the door so that they protrude into the inswool, put washers and nuts on the ends and pecker the threads up so the nuts dont back themselves off.
 
My recommendation is to NOT have "doors". If you feel you must, then just put a "door" on the back end. Blocking up the front with hard fire brick is much simpler, and your not going to have all the hassles of opening/closing door, and you're not going to have to worry about dealing with holding the insulation in place. Building a forge isn't like building a house....you DO NOT want it sealed up tightly, it operates best when it can "breathe". Remember that when you working with it, it's going to be hot.....if you can't easily work with it when it's hot, then it's only going to cause you grief.

When you build a forge, KISS is the way to go.
 
Ed Caffrey said:
My recommendation is to NOT have "doors". If you feel you must, then just put a "door" on the back end. Blocking up the front with hard fire brick is much simpler, and your not going to have all the hassles of opening/closing door, and you're not going to have to worry about dealing with holding the insulation in place. Building a forge isn't like building a house....you DO NOT want it sealed up tightly, it operates best when it can "breathe". Remember that when you working with it, it's going to be hot.....if you can't easily work with it when it's hot, then it's only going to cause you grief.

When you build a forge, KISS is the way to go.
Click to expand...


I had considered using fire brick, but I'm not sure how to attach a track or shelf for it without welding. I may have to look around the hardware stores and see if anything comes to me.
 
Did you miss the part where Ed said STACK hard fire brick infront of the forge? just stacking loose fire brick give you many more options than having a door or tracks that hold the bricks in one place.
 
Bill Burke said:
Did you miss the part where Ed said STACK hard fire brick infront of the forge? just stacking loose fire brick give you many more options than having a door or tracks that hold the bricks in one place.
Click to expand...

I am going to have to have to wheel the forge outside each time I use it, so I was hoping to keep it a bit more portable.
But it wouldn't be the end of the world to restack some fire brick each time.


I had gotten the impression from my research that people were getting better heat from a more enclosed forge design, which is part of the reason I was going to use doors. I am also trying to make the forge heat up as quick as possible (using highly insulative refractories, and ITC 100). I would think that the hard fire bricks would leak alot of heat.

I should also mention that I am going to use a blown burner.
 
Use insuboard. Ellis sells it. You can cut it to any size, bolt it to an existing door, or hang it on wires. It is perfect for door linings, and temporary doors ( and could be used for permanent doors).
 
Check out these threads. The first one has a forge made from a freon tank and it does not have a door. The door is not necessary however what they were trying to tell you if you felt your opening is to large and you needed to close some of it off. A STACK of firebrick will act as a quick easy door if you feel you need one! The door becomes unneccesary because while heating the steel you will be going in and out the opening. And while you have the steel out pounding on it you will lose only little heat out the opening. Stop and think about coal forging and you see the coal is in an open bin so to speak and the item to be forged is only buried in the coals. The advantage to a modern forge is that it traps some of the heat in and is quicker and cleaner to heat!


http://ronreil.abana.org/minifor1.shtml

http://ronreil.abana.org/design2.shtml

http://fredlyfx.com/large propane.htm

http://forgegallery.elliscustomknifeworks.com/

http://forgegallery.elliscustomknifeworks.com/

http://zoellerforge.com/

http://www.rayrogers.com/blower.htm
 
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When I rearranged my forge shop I located my forge between my press and my hammer. I have a large door for doing large mosaic billets. I usually work two billets at a time. I close the door after retracting my billet or I will get a bunch of radiant heat while I work at the hammer or press.

My door pivots on a stud from the upper right corner of the door frame to cover the 7" by 7" opening. I have framed two firebrick with angle iron and have four angle retainer to keep the brick in place. With out retainers I had to replace the half bricks after two years. I'm hoping for longer service with the retainers.

I have a firebrick extension out the back of my forge which gives me about 28 inch capacity before I remove a couple of bricks. These back door bricks are a fairly tight seal. My front door provides a bit of flow around it perimeter. I'm using a forge blower so how tight the forge is to through put is not as big as issue as an atmospheric burner.

I went to the door because the stacking of bricks is inefficient with a hot billet headed towards the press or hammer. The average drops before breaking with fire bricks is one or two drops before they are half the size that you bought. Building the door has long term cost advantages, and in my case keeps me from radiant burns.

My door is red on the inside and providing refractory heat to the forge, so it is beneficial. I think it will take the steel frame at least three years to oxidize away before having to replace the door....Take Care...Ed
 
Lot's of great information guys, thanks!
Looks like I have some thinking to do before I place my order for materials.
 
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