Forge Brick Question

[IronFist]

My forge is not that old or ' broken in' to say( had it since X-mas), yet ever since I recieved it, a few things I've questioned. It's a 2-burner LP gas forge.

I have fixed the simpler things, but the main concerns I have are the burners themselves and the fire brick.

Burners- I understand that I can adjust/ tune the burners, but the blast, looking through the port windows, doesn't seem to be EXTREMELY strong. I have a good fire and heat( forging temp. reached in about 3-4 minutes), yet the flame on one port is a slighter blue than the other. As if this burner is not pushing as much gas as the other. Is the flame supposed to be more blue or more orange?

Fire Brick- OK, this is the bigger problem, I believe. When I fire my forge up and let it warm up prior to work, it seems to heat up fairly quick and hot, brick and all. Now, when I set my iron in the forge, and it warms to a dull red, upon removal of the iron, there is a cold spot on the brick. And I mean cold, almost shadow black. The windows on my forge are open to where the iron lays on the brick, not suspended above it. I used to work in the boiler systems( refuse recyclers) up and down the eastern seaboard, and inside of the furnace area is lined with refractory brick, which looks alot what is in the floor of my forge. But refractory brick repells heat and is not fire brick in a forge formulated to hold heat?

Thanks for listening and help me out if you can.

[HWooldridge]

You didn't say but this sounds like an atmospheric forge. Some types can get to welding temps but it's usually easier to tune if a small blower is there to provide extra air.

I have a homemade two burner and noticed that the two flames do have different colors at times. I have seen color ranges from blue to turquoise but orange is not right for the flame because that would mean you have too much gas in the mix. You should also hear a good roar when it's right - something like an O/A torch when the mix is correct.

One thing I have found to be very important on smaller forges is that you need to to seal all the holes where heat can leak to atmosphere. It doesn't sound like your forge is reaching forging temps and that may be partly due to the brick acting as a heat sink and/or heat leaks. Reflectivity (like your boiler example) is also critical so the radiant heat is contained.

A good gas forge should be hard to look at when at proper temp, almost an incandescent yellow-white. The best ones will melt a piece of steel.

[skunkriv]

A brick lined gas forge isn't really running right until the bricks get lit up real good. I think if you crank the gas up some and wait a little longer for the forge to warm up both of your "problems" will disappear. Like H says in the post above there is a roar you are listening for. You will get to know running your forge by ear. You will find that you can run your forge over a certain range of pressures depending on what you are doing, how many pieces you have in it and the forging time spent on each heat of your piece(s).

Even in a totally heated forge there will be a dark spot where your piece was laying as you remove it. It is still plenty hot there but your piece is shielding the flame from that spot.

[ThomasPowers]

I tune my forge by looking at the colour of the wall where the flame impinges and adjust the air control until it is brightest.

When knifemaking I will generally then adjust the air to produce a slight plume of burning propane at the door so the fore is a bit more reducing inside.

As the forge heats up the air needs to be adjusted as the "burn" changes a bit.

Thomas