Thread: Kiln/Furnace for knife making heat treatment, who built one?

Hi,
was just wondering if anyone has build a simple gas fired firebrick furnace for heat treatment of knife blades?
Any advise on how to build, what to look out for (brick, gas unit) and where to get fire bricks or make yourself?
Who build one and wants to share some knowledge/ pictures?
Cheers

Check YouTube.

Check out https://www.nzhuntingandshooting.co.nz/f53/forge-51432/

You can build one out of an old LPG cylinder, or using refractory bricks - there is heaps of info on youtube.
If you are going to use a LPG cylinder, follow the safety instructions when it comes of cutting the tank otherwise you will kill yourself.
If you are going the brick route, spend the money and buy proper refractory bricks. Shinagawa in Huntly is your best bet for refractory bricks. I used them in my pizza oven and for the floor in my LPG forge.

Shinagawa contact details - https://yellow.co.nz/y/shinagawa-ref...ralasia-rayner

For the forge burner, I can recommend artisan supplies. I put a double burner into a double length LPG tank forge. Most of the time I only run one small burner. https://www.artisansupplies.com.au/p...c=dab83b10fbbe

@Teggy

I made a basic brick one. Super easy. Just use a hole saw to drill through a bunch of fire bricks to make a chamber then I used refractory cement/mortar to glue together and line the hole. Couple holes drill in from the side for the heat source. I just use the little gas torches you get from bunnings or whatever. Ill take a pic later

Theres a way of doing it in an oven as well , google it up

Not so much for knife making but I have a DIY furnace for melting/casting.

Rammed DIY castable refractory and a waste-motor-oil burner. Cheap to build and to burn. Not too particular on temp control but I do anneal and temper with it. You can add a thermo couple and a bit more precise controls (mine basically has three settings, Off, hot, and f@ckin hot) if you needed to.
Can be run on charcoal as well, which is a bit more traditional for knife making.

Hi mimms do you have a picture or two?

Originally Posted by diana2

[FONT=arial]Hi mimms do you have a picture or two?

As a matter of fact, I do. These are all old pics, it's slightly more refined now, with less to trip over.

Pic 1 Is the shell, an old oil drum, top cut off, tuyere cut into the side down low and a drain-former in the middle bottom.
Pic 2 is half way through a melt with the burner off, you can see the crucible/melt inside
Pic 3 is after I had melted some cast iron, way, way hot, looks like I actually melted the sand out of the walls/lining and made glass.
Pic 4 is what happens when you over fuel it, and that was my old undersized lid. Can't remember why I drew on that pic.
Pic 5 is the refractory ingredients. Grog (crushed firebrick), sand, bentonite, cement, and perlite.
Pic 6 is something aluminium I was casting in greensand and a couple of muffin-tin ingots

Sorry for the huge photos... I'd think forum software should sort that out, but err..

Good resources to be found at https://alloyavenue.com/vb/forum.php and https://www.backyardmetalcasting.com/

I made one of these for quickly heat treating small parts that wernt worth starting up my electric furnace for.
Super cheap and easy to make. The bricks are the lightweight porous type. Kind of similar to pumice. You can shape the hole in the middle using a spoon (yes a spoon) thats how soft the bricks are.
Power with a propane/butane torch or for more power, a map gas torch. I have heat treated blades up to around 90mm long with it. They are very efficient and effective.
I would not use one of these for forging.

Search google for 2 brick forge and you will have all the info you need.

Bricks are called K23 or Type 23 Firebricks. I bought mine from Certec in Auckland. They were $10 per brick, comes in a box of 8.

@diana2 If you can find a copy of the July/August edition of The Shed magazine, it has a detailed write up of making a simple brick forge.