Smelting Question

[Casting Timmy]

I have a flat bottom dutch oven that I use for smelting and I was thinking about putting an old brake drum between my dutch oven and fish fryer so that the drum would catch the heat and hopefully heat everything up faster.

Anyone ever tried this before?

[lwknight]

I think that anything between the fire and the what you want heated will just slow things down.
When I used to work for a boiler manufacturer that made 2-4 mega btu heaters , we learned that putting the fire directly into the water was the most efficient way to heat the water.

This of course is not practical but we could put fire through copper tubes that ran through the water. We achieved 98% efficiency but learned that the flu gas had to be hotter that 210 degrees or condensation would be a problem.
Copper is a great heat conductor and steel is not so impressive.
Also any discontinuity between the fire and what gets heated is a resistance like insulation. Multiple layers of metal can actually reflect heat the wrong way.

[RP]

I have found some fish fryer burners direct the heat outwards and not as much upwards. Changing the distance closer to the flame may help or hurt at diff settings. I have changed my burner to one that directs the flame up not to the side and run it lower so the heat is not rushing to the outside of the pot. Also the pot shape and size effects the heat transfer a lot along with the type of metal and thickness. The biggest thing I have found is a wind break around the flame keeping the heat where you want it. I am a big fan of trying to make something work better and easier. So trial and error you should fines something to help you out but either way you will learn something.

[thegreatdane]

I'd just make a wind-shield or other wind blocking contraption, if you're looking for better efficiency.

[mdi]

Open side of the drum up or down?

[Casting Timmy]

I was thinking about putting the open side of the drum down.

When I worked in an aluminum foundry we had "flamers" for heating up the molds, just 1/2" pipe system with a lot of holes with gas and compressed air giong through it. I made one with angle iron to try and direct the heat towards the mold cavities by having the angle iron with the tip pointed down to heat the mold. One of the inmates turned it upside down so the angle iron looked like the roof of a house. That flamer woudl always have the angle iron glowing red and heated up a mold faster than anything could. It was actually the only one we had to watch as it could overheat a mold, the rest could never do that. (It would get the mold so hot that the steel wool used to clean them before spraying would catch on fire.)

That's why I think I'm going to try and use the brake drum upside down, hopefully it will catch a lot of that heat.

[Mk42gunner]

I think that if you cut a hole for the pot to sit inside the brake drum, it would work better. Still set the pot on the burner support, but use the brake drum as a shield with the open end down, to trap the heat.

Robert

[Casting Timmy]

If I can find one big enough that's exactly what I want to do. I might have to stop by a semi repair center to find one big enough.