Bram

Yes, I meant insolated. Just now chamber is build from roof tiles held by metal welded frame. New construction will be based on light bricks.

Thank's Marc.
So I am back with the question, maybe my problem is too small orifice?
(I am using 1/16" hole). If I'll try the current BBQ regulator with higher flow (bigger orifice), will I have more heat? (I have big enough fan)
Safety: My shop is outdoor. ie, I have only roof and 2 walls so there is less risk of CO ect.

Yes, I am making a forced air burner and what counts is amount of gas flowing into the forge. Now I am thinking that I might play with the orifice size... but first going to have a look at the site you quoted.

Thank's for the advice.
Just talked to my gas supplier. I want to hook up to my bulk tank (much cheaper comparing to 40 kg cylinder) but need him to do that due to our local safety laws. He will install the needed regulator with gauge at cost charge only.

Thank you for the information. A lot of homework to read...

Yes, same as for BBQ. Can you tell what should be the pressure?

Helo,
I am new in the blacksmithing business and just now building my gas forge and need some advice:
I use a standard home gas tank & regulator and fan for forced air but do not get enough heat.
The 1/2" bar I am trying to work with stays black.
Some facts:
- Color of flame is blue.
- The forge chamber is not isolated (working on it...)
- Gas orifice is 1/16"
- I tried all variations of air and gas flow with no success.
Can anybody help?