forge question.

[joe9knives]

I have found a local source for insulating firebricks and refractory cement(paragon kiln repairing cement). My question is can I make a small propane forge by coating the firebricks with this type of cement to make it more durable.

 

[Stacy E. Apelt - Bladesmith]

CAN YOU? - Yes.
WILL IT BE A GOOD FORGE? - No.

Brick lined forges require a large heat source, a long warm up, and are not easy to build and maintain.

Check out Darren's site,
http://forgegallery.elliscustomknifeworks.com/

Stacy

 

[crex]

Stacy,
Key word in Joe's post is "insulating". Although he doesn't say what the temp. rating for the bricks are, insulating implies they are the soft bricks. The high temp soft brick make excellent forge liners and can be shaped for a very tight fit with an old hacksaw blade. Not sure about the mortar, depends on it's temp rating as well. With a little forethought and care he can even make a workable welding forge with them. I do reccomend a good coating of ITC 100 or similar to inhance performance. Just needs a flux resistant bottom, say some 20 guage stainless steel sheeting with rolled edges like a mini-cookie sheet filled with some kitty litter.
I actually "core out" the 11 deg flare in the brick itself eliminating the need for a metal one. Much easier than it sounds. Allows you to adjust and/or remove a straight tube venturi torch when ever necessary. And yes, a properly designed venturi burner (1) will get sufficiently hot for welding. Not a guess or a calculation but proven fact (many times over).

 

[bennett]

Just had to chime in here in favor of cast refractory/firebrick forges. I have a cast-body forge I made 2 yrs. ago from AP Green "lightweight" that I got from a local refractory dealer. Like crex pointed out, you can shape the IFB's very easily using old hacksaw blades, but you might also want to go to the local hardware store and get a "currycomb" - looks like a set of sawtoothed concentric circles - they can be had for a few bucks at a Lowe's or Home Depot, and make shaping curves in firebricks an easy chore. If you're going to mortar the bricks together, I'd suggest shaping them into a tube, and rounding out the inside by scraping the bricks with a currycomb. You WILL need to line the inside of the forge with something - fireclay mortar should work if you have enough. I haven't tried ITC100 or Satanite on a firebrick forge, but they should work also. The best option would be to line the inside with Kaowool, and then coat THAT with ITC100 or Satanite - 1" to 2" of kaowool would be ideal. Bldsmth had a point also - a firebrick forge would take a while to heat up. Lining it with Kaowool/Satanite should cut down on that problem. If you're looking for another route to go cheap, I'd reccommend getting some castable and making a large tube and lining it with Kaowool/Satanite. I've had excellent results with mine, and will definitely be making a "new and improved" version soon! If you want detailed info. on making one, PM me or email me, and I'll get you a set of instructions. Either way, good luck with your forging endeavours

 

[Stacy E. Apelt - Bladesmith]

I agree with both of you. A properly made forge which is lined with the right insulating material will make a good forge.
However, just cobbling together some firebricks (Hard won't work,soft would be OK) and mortaring them up will not produce the best forge. A proper burner (venturi or blown,not a bernzomatic torch) and proper design and materials will make a forge that will last and produce good results. That is why I directed him to Darren's site where he could read about forge building and find any materials he would need.
Stacy

 

[fastcamo]

However, just cobbling together some firebricks (Hard won't work,soft would be OK)

and all these years building our small to our large(80,000lb) boilers with all those hard bricks is wrong!

actually just state the extreme here which would far surpass any small forge, the larger ones run 24/7 for 9 months of the year without a minute downtime, the other 3 months are for repairs and touch-ups, during that time ton's of koawool is replaced, Ram90, fiber board, rope and etc that knife makers use, but the firebricks are hardly damaged,(and taking the brunt of the flame) the most damage comes from taking them apart to fix the joints that the heat broke up, so will they work,.. yes, but as bladsmth pointed out, it will take a while to get up to heat, but really there should be a problem with that, even heat throughout is usually the best, from knifemaking to cooking, unless of course your a penny pincher!, but yea do what he recommends and visit Darrens site, theres alot of smart guys on here!!