ambient temp or forge temp making forge run rich?

[BattleBoar]

I have just completed my first Propane forge.

It's made from an expired air tank (because that's what everyone does, eh Frosty?)

It is a 2 burner using the "Frosty T" burners.

I built it too big for my needs (because that's what everyone does)

Build details are, two one inch layers of ceramic fiber covered with  1/8" refractory cement. Kiln shelf for floor.

I fired the forge and trimmed the tips to tune it as it was a very yellow flame in the dragons breath. It worked great, nice blue cones and hardly any dragons breath from 5-10 PSI.

Got forge up to operating temp and used it a bit, still nice flame. Ambient temp in my shop was -18F

Brought the forge into the garage and gave it a few coats of ITC-100 let it cure for 3 days.

Last night I went out and the temp in my shop the ambient temp is up to about 14F.

I fired up the forge and got it to temp. Dragons breath showing  bit of orange. As I went on forging the dragons breath had more and more yellow in it.

This was the Hottest I had gotten this forge.

The problem with diagnosis is that I changed three different variables when tis happened. ITC-100, ambient temp,foge internal temp.

Any guess on which one is the culprit?

Here are a few pics of forge, Its only running one burner @ 3 PSI in the pics because I was freezing up before switching t the 100lb bottle.

Also, the side pic of the forge it isn't hooked up or running, incase anyone noticed the lighter and hose hanging by the forge.

 

 

 

[Frozenforge]

Running 2 burners off 1 20lb propane bottle at low temperatures is problematic. Don't know what kind of regulation you are using but maintaining consistent pressure under those conditions is difficult. The itc was still curing as well but should be completed now.

A tub of hot water to set the propane tank in will help with the fuel delivery issue.

[BattleBoar]

The 20lb tank was just for first test burn. Everything after has been done on a full 100lb tank maintaining constant 7 PSI at the manifold.

[Mikey98118]

It's hard to tell what its potential is, until you finish the forge with a pass through door slot for smaller parts and to provide a view of what is going on in there. I can see you are in good shape to do metal work, so a swinging door, with hinges featuring multiple holes, which can allow the door to set at various distances from 1/4" to 1-1/2" away from the forge shell should present no problem to you. Make a square frame that is 2" wider and higher than the exhaust opening, and fill it with a high alumina kiln shelf, or cast refractory to allow the hot gas to leave, while the radiant heat gets bounced back into the forge interior, and let us see that puppy raise to heat yellow incandescence inside. There are other things you can do to help performance, but you should begin there.

[Mikey98118]

As to the color change in your forge's ""dragon's breath"; I would expect that with the ITC-100. Another coating like this has to settle in (burn off consumables in the ceramic formula", but more importantly, it sounds like the heat reflection you spent good money to buy is working; as greater re-radiation of incandescent surfaces occur, forge temperatures will rise, increasingly turning a straightforward combustion oven into a radiant oven; this in turn has a profound effect on the internal gases, which then have to pass through increasing amounts of radiant energy on their was to the exhaust port, which is going to insure ever more of any flammable materials to be consumed, whether they are fuel molecules or refractory chemicals that are destined to burn out.

Thus, the change from orange to yellow in the "dragon's breath" is good, and only to be expected.