Temp for preheating ingots

[kevin c]

I'm trying speed casting, and want to preheat the ingots, but there is precious little space on top of the Lee pot I'm using. About what temp should I shoot for with a hot plate?

I'll put the ingots (three to three and a quarter pound gold brick shaped ingots at the moment) in a pan on the element. I can use pliers to pick them up and put them in the pot, but using a gloved hand might be faster and more secure (provided I don't get burned through the glove, of course).

So, hot enough not to lower the pot temp too much but not so hot as to make the ingots hard or hazardous to handle.

Any recommendations?

TIA! kevin c

[Dieselhorses]

Unless someone says differently, this may not speed up your casting I did try this once even with hot plate "hot-wired" for constant high temp and didn't get any quicker results.

[kevin c]

Well I was anticipating leaving a few ingots in the pan on the hot plate while casting. Are you saying that they won't melt even with the element glowing red?

And preheating should cut the wait time, right? The last time I put a cold three pound ingot in a half full 20# pot it froze up what was left. And then there's heating the ingot to drive off moisture - I've had some ominous bubbling from cold ingots in the melt that I wouldn't care to hear again.

[Mike W1]

My hot plate is PID controlled and mainly used to preheat moulds. Have it set for 400° which also seems to be OK for ingots but I use 2 pots, one as a feeder so it's not too critical the way I do it. Feeder pot is set for around 700° and with the warmed up ingot easily keeps me in hot alloy below. It does take around 2 minutes to refill below. Have thought of opening spout on feeder pot but I'm not in that big a hurry when I cast.

[Hossfly]

It does speed up casting, by not cooling down pot. In my case I didn’t watch the ingots on the plate apparently close enough so I had 3 soft puddles ready to run off into the cookie sheet, had to wait for them to cool so I could scrape that up. Since then, stay better on task, works well. Around 350’ pot dips some but continue to cast with ease.

[lightman]

Any temp will help but I would guess around 350-400º would work fine. I can't say that I've ever monitored the temps that I used to preheat the mold or the lead. I use a 1/8th inch steel plate cut to fit the top of my $12 Walmart hot plate and run the temp control about half way. I don't mind a little delay between refills, kinda gives me time to stretch the ole back.

[Leadmad]

Same as Hossfly said, But your ingots are too big, I preheat mine in an electric Skillet set on max, Muffin pan style ingots (12 oz) easy to pick up with multigrips and then place on top of melted alloy where they sort of float and fully melt the temp will drop 15 degree`s or so for 30 seconds +/- and back up again to casting temp.

[rancher1913]

use the double pot method, have a pot setting above your casting pot that pours right into it and use it for melting spews and ingots.

[Idz]

in melting lead about 2/3 of the required energy is heating the lead to melting temperature and 1/3 of the energy changes the lead from solid to liquid.

[owejia]

Preheat my 6" x 2.5" x 1.25 " 7-8 lbs on top of my Lee 20lb pot, have to use slip joint pliers to put them in the pot, to hot for leather gloves, lose very little time bringing pot back to temp.

[wv109323]

Obviously the hotter you can get the ingots, the less heat loss you will have in the pot. I think 400 is a good number the shoot for. I would use a set of tongs or pliers with long handles and gloves.
When I got my PID I was surprised how much temp. was lost and how long it took the melt to get back to casting temp. It explained some of my casting problems.

[kevin c]

I do know my ingots are the wrong weight, size and shape to sit solidly atop the Lee, let alone heat quickly, and I plan on switching to longer and lighter ingots (either angle iron or the 5 and 1/2 inch flat bar ingots that are being discussed in the Group Buy Discussion Forum). In the meantime I have about four hundred pounds of the mini loaf ingots I have to use up first, and was hoping the hot plate would be a solution to the problem.

I am using a feeder pot, and am still having problems cooling it too much by putting in ingots that are not up to temp. I am using up a quarter or slightly more of the alloy in the RCBS casting pot, about six pounds, which takes up a third of the alloy in the Lee feeder to replace it. I put two or even one cold three pound ingot into the Lee and it won't have even completely melted the added alloy by the time I need more in the casting pot, let alone be at 700 degrees or more.

I could feed one ingot after just three pounds of casts, (or after four or five pounds out of the casting pot, if I add back the sprues), but the aluminum 8 cavity molds I'm using need a quick cadence to stay at temp.

OK, shoot for around 400 degrees on the hot plate (good temp for preheating the mold, right?), and use more suitable ingots the next time I make up a batch of casting alloy. Channel lock pliers for handling hot ingots.

Thanks!

[bobthenailer]

about 400 degrees about the same for preheating ingots or bullet moulds

[wlsample]

I use an electric skillet with a notch cut in the lid for the mold handle. Room for 10 to 12 ingots. Set thermostat for 450.

[kevin c]

I use an electric skillet with a notch cut in the lid for the mold handle. Room for 10 to 12 ingots. Set thermostat for 450.

There's an idea! Dime a dozen at the local thrifts.

[Jackpine]

I use a cheap hotplate (about $10 at Walmart) (and have a second hot plate to preheat molds) and a two quart, garage sale, cast iron pot. Will get alloy molten and use a stainless steel gravy ladle to transfer. Put in enough ingots to not fill it much over half way and do not let main pot get below half, so full recovery time is pretty quick. (as above poster said, with PID and electronic thermometer, it is surprising how much temp drops even adding molten alloy to pot, but recovery time is MUCH faster. Also, when stopping session, always leave half inch to one inch in bottom of premelting pot, laying ingots on top of base layer. Greatly decreases startup, vs starting with empty pot and fresh ingots.

[Mxrick55555]

I used to use an old electric skillet set to max temp to preheat ingots and molds it did help but I have since acquired a magma master caster with the 40lb pot and can’t even find the time to cast a quarter of the pot at a time any more. Life gets busy with little ones running around.

[Echo]

I use standard 1-lb ingots and try to keep the pot full. Keep a 'next' ingot on top of the pot to warm, and place and replace as needed, keeping a stack close by. One pound of 300 degree (guess) added to a 9 lb pot won't drop the temp significantly...

[Mike W1]

I use standard 1-lb ingots and try to keep the pot full. Keep a 'next' ingot on top of the pot to warm, and place and replace as needed, keeping a stack close by. One pound of 300 degree (guess) added to a 9 lb pot won't drop the temp significantly...

Just yesterday was doing a bit of casting and measuring. Guessing about 6-7 pounds in the Lee #10 pot. Put a 340° F ingot in. Dropped the pot from 365°C to 335° C. Recovery time was around 5 minutes. It's why I use a 10# feeder pot and feed 365° C to the lower one. That might drop it a degree or two at most.

[squidtamer]

in melting lead about 2/3 of the required energy is heating the lead to melting temperature and 1/3 of the energy changes the lead from solid to liquid.

What in the wide world of sports are you getting at here? Trying to separate phase change or enthalpy of fusion or whatever they're calling it now, and the temp rise of the material? Are you saying just hitting the known melting point of a material still requires additional energy over and above that to melt it??

I'm a bit confused. Never head of this before. Maybe I missed something? Not trying to be rude, just curious.