View Full Version : Improving the Heating Efficiency of a Turkey Cooker

04-20-2006, 05:55 PM
Converting a Turkey Cooker to an Efficient Lead Smelter. By DaveInFloweryBranchGA

I read several posts and other gentlemen on cast boolits who had a plumber's pots with apparently significantly fast melt times than most other heat sources. I checked into it and the only source I could find for a modern propane driven plumber's pot ran around 300 dollars without a few things, such as a propane tank. I decided to buy a turkey cooker as a heat source instead.

Here’s the one I bought (I paid $35.00 or so.):


I performed my first smelting session using my turkey cooker with a small Dutch oven (approximately a five quart one, taller and about 8” wide, not the one in the link above) on top as my heat source and produced 66 approximately 4-pound ingots in about 4 hours. I was happy with the quantity, but I wasn't satisfied with the amount of time necessary to bring the wheel weights to a molten state or the waste propane gas due to heat loss. I felt some improvements in my heat source were in order, especially if I wanted to be a volume cast like BruceB and Goatlip’s.

I remembered the outfit that offered the plumber's pot also offered a version called the "industrial" smelter with a venturi very similar to my turkey cooker. Looking at pictures of this device, I felt I could modify my turkey cooker to give if not matching performance, at least significantly improved performance. I decided it was worthwhile to give it a try.

I had seen a picture of a heat shield on Goatlip's website (a truly excellent tutorial, I highly recommend anyone new to casting read it) on his smelting pot, which I believe was mounted on a turkey cooker. Here’s a link:


I went online and did a search for articles about plumber's pots, hoping to
find a line diagram or illustrative drawing and a description allowing me to
see construction details. I was successful and found this article with a nice drawing and used this as a basis for modifying my turkey cooker. Here’s a link:


The modifications I made were as follows:

1. I measured the diameter of the venturi of my turkey cooker and
determined a 4" wide steel pipe would be sufficient to limit airflow around
the exit area of the venturi as well as holding the heat created "in." I
had a section of 4" pipe welded onto the bottom of the support section of my
turkey cooker even with the top of the venturi. There is a small gap between the venturi and the pipe. This allowed some minimal airflow around the venturi to prevent it's overheating and prevent any potential compression explosion issues, while keeping the heat source underneath the pot tightly contained and focused. Here are a couple pictures of the modification:



2. I had a 1/8" thick section of sheet steel formed into a circular shield
to contain heat around my smelting pot. There was about an inch of air left
between the pot wall and the shield. This should act somewhat like
insulation, helping to contain the heat. This also blocked most of the air
flowing around the pot and venturi from the top side, leaving only enough to
keep the area cool enough to prevent any potential overheating. Here’s two pictures of the shield:



The two modifications cost a total of $25.00 at my local welder’s and were very effective. The lead smelter (formerly a turkey cooker) heating up much faster, allowing me to cut my smelting time of a single pot (My pot holds about a gallon of wheel weights.) down definitely below 15 minutes, perhaps as low as five to ten from 30 minutes. It was hard to tell, because I wasn't timing it. What I did see what I barely had time to organize everything else and to sort through my wheel weights, getting the last of them ready to go in the pot. I didn't have a full small bucket (1 gallon) left, but if I had, I would not have been able to prep it before the melt was ready.

When a second pot of lead was started, the pot held temperature from the previous melt and very quickly melted the lead down. Also noticeable was the much higher temperature the lead reached, over 800 degrees as it became molten, so I’m going to have to reduce the propane fuel input to keep the temperature at 650 degrees. This shows major improvement fuel efficiency wise, allowing one to do many more pots of lead smelt without having to buy another 20-gallon tank of propane.

I am satisfied I've reached a level of smelting efficiency suitable for my
purposes. I haven't tested it, but I'm reasonably sure I can smelt a bucket
of wheel weights in about an hour to an hour and a half now. This is assuming I’ll work and do my part. If I’m lazy, well, the equipment can only do so much….

Total cost for the turkey cooker with efficiency modifications: $60.00

04-20-2006, 06:16 PM
Those appear to be VERY worthwhile additions to your smelter. I will probably copy some of your work (sincerest form of flattery). Mine already had a heat shield but the 4" pipe may work well with mine, also.

Thanks for sharing with us.


04-20-2006, 06:20 PM
Good job on the entire project, Dave.

Blacktail 8541
04-20-2006, 07:00 PM
Dave I am very impressed with your modifications, and your takeing the time to post the links and pictures. GOOD JOB!

04-21-2006, 06:21 AM
Hmmmmm.......got a buddy who has been a welder for 25 years or so......looks like I nay have to grease him up for some freelance work......:roll:

04-21-2006, 06:27 AM

Thank you for the compliments.

Dale53 and rbstern,

I thought my posting this was the least thing I could do as some token payback for the huge amount of help you guys and others like you who posted answering my myriad of questions so far (and more to come, of course) over the last few weeks.