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I Forge Iron

Planning my first gas forge


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this is my first post here. 

First of all, thank you for an impressive amount of information. I have been reading through  most of the pinned threads here and am deligted to find so much good information.

For those of you who don't care to read a long post, please skip to the text in bold below. This is what I really want to get input on.

I have started a rather slow process of getting started with blacksmithing. I am not in a rush as it is winter and I am yet to build a new workshop since we moved. Most things are clear to me by now, but getting the materials is a real pain in the neck here in Noway. We have a very small domestic market, and since we're outside the EU many products are expensive to ship. I have located reasonable sources of most of the things I need. Some I will order from Wayne here at the forum and some I have found on ebay. But the refractory I would like to get here. I have not been able to find anyone selling Cast-O-Lite 30, but there is a local producer that makes a product called Borgcast 85. It compares well to Cast-O-lite 30 in most aspects apart from the thermal conductivity:

1.9 W/m*K at 1000C for Borgcast 85 vs 0.65 W/m*K for Kast-o-lite 30. Can anyone comment on whether this will be an issue? I am planning to insulate with 2" Kaowool, but am worried about the liner becoming a heat sink if I use Borgcast 85.

For those curius, here are the rest of the numbers: (Borgcast 85 vs Cast-O-lite 30)

-Alumina content: 83% vs 56.6% for for Kast-o-lite 30.
-Maximum recommended temperature 1700C/3092F.   vs 1650°C/3000F 
-Permanent Linear Change 
Borgcast 85:
- after firing at 110C:       0%
- after firing at 1200C:         -0.3%
- after firing at 1400C         -0,4%
- after firing at 1600C:         -0,4%
 After 220°F (105°C)         Nil
 After 1500°F (815°C)         -0.2
 After 2000°F (1095°C)     -0.2
 After 2500°F (1370°C)     +2.0
 After 2910°F (1599°C)     +1.0 
-Modulus of Rupture and Cold crushing strength 
CCS: 130MPa vs 17.2MPa for Kast-O-Lite 30
MoR: 16-20 vs 5.5MPa

For the rest of the forge the plan is as follows:

Helium tank or other empty vessel I can get hold of. Gas tanks are expensive here (>$100), so that is not an option.

Kaowool from WAYNE COE

Fumed silica from ebay (Cab-O-Sil M5). Dissolved in water with food coloring and spritzed on the insulation. Then fire with the burner to set.

Kiln wash:
Plistix IR reflective from Wayne, or Zirconium silicate (Zirkosil) from a domestic provider.

Black pipe and fittings are not easy to get here. We use plastic for water pipes and there is no residential gas. In an eager moment I bought a 1" burner from Alec Steele. Yada yada! But I found his site first, and it was his enthusiasm that eventually brought me here! I later realized that I could probably buy stainless pipes and fittings from china and make one myself for much cheaper, but done is done... 

Propane regulator from local gas supplier. Using 11L barbecue tanks it will supply up to 30 psi and a bit more than 2kg per hour. Using industrial tanks is as far as I understand not practical/possible for private persons here. I am in any case limited in tank size, as the tanks have to be carried up steep stairs from the road. If I get trouble with freezing I can connect two tanks in parallel. I have verified that parts for that are available here.


Hoping I have done my homework well, and looking forward to your input!




Borgcast 85.pdf

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Welcome aboard, glad to have you. The Borgcast sounds fine, you can buy evacuated glass spheres and add them to the refractory if you want the extra insulation. A concrete supply should carry them it's commonly used to make light weight concrete.

You sound like you have done your reading, the forge plan sounds pretty good. Remember the hard refractory only needs to be abut 1/2" or 12.7 mm. thick to make a good durable inner liner. It's not much of a heat sink at that thickness so it won't waste fuel. It WILL provide both thermal and physical armor for the Kaowool.

I think I"m looking forward to seeing pictures of your forge at welding temperature. Give a shout if you have questions.

Frosty The Lucky.

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I have 2 of the 1" burners you're talking about on my BIG (18" X 9" D shape) forge I made for larger projects (axes, twisting long cable) and I love them, they work very well.  I still have and mainly use my first smaller (5" X 11" D shape) forge with a 3/4 home-made pos burner. Both easily reach welding temperatures, but for me the Alec Steele burner is a GAS HOG, I hope you have some good sized tanks!


Good plan, look forward to seeing some pictures and some nice work come out of it.

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We were a little concerned about using a GACO-750 kiln burner that we had on hand and several of our club members said it was way too big. It worked out very well after some tweaking though. It brings the forge up to welding temp without burning the steel and can be idled down to 3 psi to conserve fuel.


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Thanks for the feedback, and I'll be sure to get plenty of pictures. Both of the building and the heat when we get that far.

As for door I will certainly try to cast one, but to keep it simple I'll probably go for sliding blocks as in the picture above.

So far I have not had any luck in finding an empty helium tank, but I'll keep looking for some time. Irondragon Forge & Clay (what a mouthful), are you happy with that solution?

If I'm out of luck: does anyone have experience/know of a build using sheet metal and pop rivets?  Welding sheet metal is not an option as I only have access to a stick welder. I'm generally fairly accomplished at making things, but my only experience with welding was 15 years ago Back then I made a rebar and oil drum barbecue while the guests and the lamb were waiting. It wasn't pretty, but no one got hurt.

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3 hours ago, EspenL said:

Irondragon Forge & Clay (what a mouthful), are you happy with that solution?

Not sure which solution, but yes we are very happy with the forge. The burner is working very well, after the right orifice size was found and the soft fire brick doors are plentiful at our place so the cracking is no problem as they are considered consumable. They are a heat sink though but work after it gets to temperature.

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Thanks, yes I was referring to the doors. Particularly the way you hold them in place. Cast refractory doors wouldn't be much better with regards to being a heat sink, so soft fire bricks might be just as well. 

Sewer pipes we have. Thanks for the tip Binesman.

Bluesman7: Thanks. Sheet metal may be a viable alternative then.

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That's a good idea coops1911.

Further: I found a suplier of ceramic insulation blanket in china. I don't ask you to vouch for this particular seller or his country, but if anyone had any experience with ordering ceramic insulation from China it would be great to know.


I noticed that the title says 2600F/1426C while the text below says 2400F/1315C. Not too trustworthy, but I have contacted the seller anyway to see if I can get the data sheet.

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