New melting pot almost complete... where do I put the temp gauge?

[oregonshooter]

Got done welding 90% of the pot tonight, but need to install the bottom pour screw and was thinking of welding a 1/2NPT coupling at a 45deg to install (THIS THERM (http://www.surpluscenter.com/item.asp?UID=2009050200202714&item=21-1617-I&catname=)) into into the pot.

Questions is... how far off the bottom should the end of the therm be?

The pot is 8"dia X 8" tall and the bottom pour is flush with the bottom plate. I was thinking of putting it 2" off the bottom, but don't know if I will get the most consistant reading there?

Does it matter that much?

[imashooter2]

If it's a bottom pour pot the spout temperature is most important. The closer you can get to that the better.

[oregonshooter]

So if the spout is at 650deg, the rest of the tank should be melted enough to pour smoothly correct?

I'll post pics of the tank tonight. I copied a design on this board by having the spout under a shroud to keep heat on it. Now I wonder if there will be too much heat on the spout, but I think I'm over thinking this stuff.

[imashooter2]

I can't say that for sure, it depends on the heating elements, where they are positioned and more. I can say that the temperature at the spout reflects what is going into the mold. That is the temperature that affects your casting the most directly, so that is the temperature you want to monitor.

[oregonshooter]

The spout temp will be a little higher than the bottom of the tank I would think since it is inside the flame and in thinner metal.


THE SETUP:
I have a homemade single jet burner that uses a dispersion plate that will be regulated with an inline tank regulator. The spout is offset though so it is going to be getting radiant heat and not direct flame.

Decided to use a trough to reach the muffin pans. Hoping this will not be an issue. The bench is made of Aluminum Alloy (hard stuff we use to press particle board at work with) bolted to a steel frame and sits on studs welded to the cross angle on the burner stand.

Pot is 12"tall and 8"dia with an 8"x8" reservoir and 4" false bottom made from remnant 3/8" steel pipe. The bottom pour is made from a 45deg chamfered insert I made on the lathe and uses a ball bearing to seal (reason why the stem does not need to be centered) the tank. 3/4 turn on the handle and you get full flow with water (haven't done lead yet) and 1/4 turn gives 1/2 flow.

The valve was made from turning down an old piece of ACME thread, leaving only 3 inches of thread at top. I tapped the end and put an old hydraulic flow control handle on it also.

Tank should hold 1.5 gallons in it. All said I have $20.00 in the stand (bought from guy at work) will need another $25.00 for adj. regulator, $10.00 for cast iron muffin pan and with the 200-1000deg therm ($20.00) coming it will be a total of $75.00 as it sits.

http://oregonshooter.com/share/smelter_pot_01.jpg

http://oregonshooter.com/share/smelter_pot_02.jpg

http://oregonshooter.com/share/smelter_pot_03.jpg

http://oregonshooter.com/share/smelter_pot_04.jpg

[oregonshooter]

Bump for pics

[imashooter2]

I thought this was a casting pot. For a smelting pot, I would hang the thermometer off the top edge with a simple clip to make it easily removable.

[oregonshooter]

Sorry, not up to snuff on the terminology yet. :)

Welding the coupling to the side will allow it to be unscrewed out when not in use and a plug can fill the hole, but not sure why I would want to remove it?

I was thinking hanging something from the side would get need it to be lowered (adjustable, simple mechanics wire would work probably) to what ever level of lead I had to melt at the time of that particular session.

I want to stay under 650deg, so I was thinking to closer to the bottom without getting transfer from metal bottom, the better the accuracy of the lead temp near the spout?

[imashooter2]

When I smelt, I flux liberally and stir vigorously, scraping the bottom and sides quite a bit to ensure that all the dirt is dislodged and floats to the top for removal. The thermometer stem would be in the way and subject to damage. Pour temperature isn't of much consequence for ingots. A low temperature smelt is good to avoid problems from zinc weights, but that is all. Frankly, a thermometer is not nearly as handy for this task as a watchful eye.

[oregonshooter]

imashooter2,

Got ya! I'm not really up on the fluxing part yet, but didn't realize it involved scrapping the sides. I thought it was just adding organic and mixing.

I think I will try mounting the therm in the side but at an angle so that the bottom pour valve will provide the protection needed for it. I can always remove it later if its an issue.

Thank for the suggestions guys.