gas forges

[leroyk]

This is my problem. I built a forge out of 2" fire brick just big enough for damascus billets. It is about 4 by 4 " in side I do not think it is getting hot enough. would raping the out side with inswool help.
thanks for any help I appericate it Leroy

[teenylittlemetalguy]

If you are using hard brick no reasonable amout of wrapping will help.
If you already built it from insulating brick, then you have a burner problem.
I built my little forge from 2 insulating bricks and then coated with ITC. with a tiny 1/2" burner I can melt steel. if I had that same burner in hard brick I wouldn't get enough heat to even bend steel, let alone weld.

[Borntoolate]

If you are using hard brick no reasonable amout of wrapping will help.
If you already built it from insulating brick, then you have a burner problem.
I built my little forge from 2 insulating bricks and then coated with ITC. with a tiny 1/2" burner I can melt steel. if I had that same burner in hard brick I wouldn't get enough heat to even bend steel, let alone weld.

What is the diff between "Hard" brick and Insulating brick. I have firebrick in the bottom of my gas forge and is it hard. I have Kaowool and ITC for the bulk of the inside. BUt I may rework this forge and am curious of the difference above.

[leroyk]

If you are using hard brick no reasonable amout of wrapping will help.
If you already built it from insulating brick, then you have a burner problem.
I built my little forge from 2 insulating bricks and then coated with ITC. with a tiny 1/2" burner I can melt steel. if I had that same burner in hard brick I wouldn't get enough heat to even bend steel, let alone weld.

I am not sure but I think they are probably the hard brick. I just went to the brick yard and asked for fire brick and they are quite hard. Is there any soft brick less than i inch thick I could line the inside with? anything more would make the inside to small.
I did notice that my propand presure droped form 15 lbs to only eight when I shut it off and the tank haad a lot of frost on it, maybe the loss of pressure was part of my problem

[teenylittlemetalguy]

LeroyK- Yeah, you have hard brick, the issue here is not if the bricks can take the heat but can they insulate and keep the heat inside your forge while they take the heat. Soft bricks are similar to drywall or whipped up plaster in weight and consistency. try "refractory " in the yellow pages.
I buy mine locally from a refractory contractor that keeps them on hand for industrial jobs. they are about $3/e.
I would start over with over construction if it were me. If you want some help with a small welding forge let me know, I have some pixtures I just posted of mine in another thread on the issue.
But if you want to modify what you have there is Kaoboard that would probably help and it is 3/4 inch or so. welding in there you will have to protect it with something like ITC or a sacrificial pan to catch the flux as the good soft insulation is delicate when it comes to flux.
Gas pressure can sure have an effect, but realistically if you are using hard fire bricks that is a huge issue.

Borntolate- My large forge is built like yours and has a hard brick bottom I can weld in it, but the side that contacts the hard brick will not get hot enough, if you prop your piece up it will work fine. I would not rebuld it if I were you as the hard brick is durable, where soft bricks are a bit delicate.
But that being said, I love my small soft brick forge (picture attached) and use it for 90% of what I do. Welds like a champ, but they do require a bit more care and maintenance to keep the flux away from the insulation.

[John B]

I love my small soft brick forge (picture attached) and use it for 90% of what I do. Welds like a champ, but they do require a bit more care and maintenance to keep the flux away from the insulation.

Nice neat little forge,

Could you tell us does it have a flare on the end of the burner or not? And what is the clearance around where it goes in the firebrick?

Thanks

[Borntoolate]

Teeny, thanks for the thought.

My rebuild plan includes putting the burners in to create swirl. Mine point pretty much straight down/across and hit the firebrick. There is no rotation like I would expect to get from yours. Plus one burner is smaller than the second larger one and has a huffing problem. My kaowool is a bit messed up and so forth. So this was my initial first time gas forge where I learned and now need to tweak. Tidbits like yours help as well as pictures... like yours. Thanks

[teenylittlemetalguy]

JohnB- I think I used a 6 inch nipple for the down tube, no flare in the metal, but the insulation flares away inside with good effect and much easier to build. the clearance on mine is about 1/8" on any given side. The critical idea is to not touch as heat could build and shortens the downtube lifespan. a tiny bit of flame comes back up that hole which means I have a little back pressue (good thing) if the air was sucking in around the tube it will mess with the effciency, cool the forge and create a lot of scale.

Borntolate- These burners that frosty designed are excellent for the price, there is not a noticable swirl, but I figure if it can melt steel it must be running good. Again if you need help with them just ask.
I have $9.00 total in my 1/2" burner as you see it. A 3/4" would set you back about $15.00 in parts.
With the huffing problem you have are you sure you are not getting exhaust swirling around into the intake? I have one burner on my big forge that does that, but it runs good if I blow a fan across it.

[John B]

JohnB- I think I used a 6 inch nipple for the down tube, no flare in the metal, but the insulation flares away inside with good effect and much easier to build. the clearance on mine is about 1/8" on any given side. The critical idea is to not touch as heat could build and shortens the downtube lifespan. a tiny bit of flame comes back up that hole which means I have a little back pressue (good thing) if the air was sucking in around the tube it will mess with the effciency, cool the forge and create a lot of scale.

Thanks for that,I found it useful.