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Thread: Hot plate temp

  1. #1
    Boolit Mold
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    Hot plate temp

    I'm casting pure lead round balls and .45 bullets for my BP revolvers and want to use a hot plate to pre-heat the molds. Question is: what´s the best temp setting to achieve the optimal temps for the molds?

  2. #2
    Boolit Buddy glockfan's Avatar
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    good question.bought one recently,still have to use it.

  3. #3
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    350-400° for me

    get a 3/8 inch steel plate the set on the hotplate to distribute the heat evenly. Some sort of (heat proof) cover helps also

  4. #4
    Boolit Buddy fralic76's Avatar
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    I have a PID controller to keep the temperature at 450°. Most times it will pour good boolits the first time.

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  5. #5
    Boolit Grand Master
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    Seat-o-the-pants for me. But I have measured it in the past and it is at least 550F. Just under the temp where my feed ingots start to melt. I don’t ever worry about reading exact temps even though I have all the industrial test eqipment to do it to NIST accuracies. Mine is an industrial lab digital controlled hig wattage hotplate and the knob setting is very accurate and repeatable. Flat aluminum top...no need for old saw blades or electrical boxes or other junk on the top.

    I listen to the sizzle of the dropped boolits in the water to know if my mix and molds are at the right temp. Years of experience is worth a lot.

    I also use it to preheat feed ingots as said......just turn the temp down! Or you will get running ingots down the sides of your hot plates.

    Just do it. Experience will be your best teacher, not reading how someone else does it.

    Banger

  6. #6
    Boolit Mold
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    Yes, of course personal experience is a necessity, but learning of the sucesses-and failures-of those who have gone before is not necessarily a bad starting point, like reading the instruction manual before using a new piece of equipment! Thanks for the tips from you all so far.

  7. #7
    Boolit Master


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    I can't help with a temp reading, but on my hotplate I set the temp knob between "medium", and "medium-high".

    Really, I simply tried different settings, raising the temp until I got a good pour within the first few tries. I don't want to overheat the mould, but I also don't want to waste time.

    I made an oven out of a #10 can, it fits perfectly over the burner on the hotplate. I put the mould(s) inside the "oven", and set ingots on top to preheat. The ingots get too hot to grab with bare hands, but I have no idea the temp.

  8. #8
    Boolit Master daloper's Avatar
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    I set a circular saw blade on my hot plate and set the knob half way between the med and hi setting. I set the mold on while the pot is getting ready and it will cycle off and on while waiting for the melt. When the pot is ready so is the mold.

  9. #9
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    400°...

  10. #10
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    Good decision to add the hot-plate! I bought a General Electric oldie at a garage sale for $3.00, and -- from a suggestion of a smarter person than me on this site -- put an inverted large soup can from local high school's kitchen, with an opening for mould insertion and removal, atop it. I have an oven thermometer with a stem epoxied down from can bottom -- now, the top -- and for iron moulds (e.g., Lyman, H&G, RCBS) I maintain 350*. For pretty much all BRASS moulds (MP, NOE, MM) I run at 375*, 'cept for mould with pins -- where an extra 25 degrees (400*) seems to improve these moulds' operation. Another factor is the mix/alloy of your "lead". I'd ASSUME for BP round balls, you are using an alloy close to pure lead, or similar softness, in iron moulds? If so, i'd almost wager cooler/lower temps than I use will work dandily! Sadly, vis my response, I have/use no aluminum moulds for bullet casting (albeit I have MANY Do-It Moulds for fishing sinkers and jigs), so I cannot afford knowledgeable suggestions re using aluminum moulds. In any case -- as stated -- I do know when I graduated to the hot plate with inverted soup-can top -- I was, and am still very much impressed by the positive difference using these has made!
    geo

  11. #11
    Boolit Bub D-RIG's Avatar
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    Been looking at getting a hot plate , this is all good info . Thanks

  12. #12
    Boolit Mold
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    Quote Originally Posted by georgerkahn View Post
    Good decision to add the hot-plate! I bought a General Electric oldie at a garage sale for $3.00, and -- from a suggestion of a smarter person than me on this site -- put an inverted large soup can from local high school's kitchen, with an opening for mould insertion and removal, atop it. I have an oven thermometer with a stem epoxied down from can bottom -- now, the top -- and for iron moulds (e.g., Lyman, H&G, RCBS) I maintain 350*. For pretty much all BRASS moulds (MP, NOE, MM) I run at 375*, 'cept for mould with pins -- where an extra 25 degrees (400*) seems to improve these moulds' operation. Another factor is the mix/alloy of your "lead". I'd ASSUME for BP round balls, you are using an alloy close to pure lead, or similar softness, in iron moulds? If so, i'd almost wager cooler/lower temps than I use will work dandily! Sadly, vis my response, I have/use no aluminum moulds for bullet casting (albeit I have MANY Do-It Moulds for fishing sinkers and jigs), so I cannot afford knowledgeable suggestions re using aluminum moulds. In any case -- as stated -- I do know when I graduated to the hot plate with inverted soup-can top -- I was, and am still very much impressed by the positive difference using these has made!
    geo
    Yup, iron round-ball moulds and pure lead. That inverted soup-can top idea is great-should help in keeping an even heat chamber around the mould! Thanks for the tip!

  13. #13
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    Most people that use containers around their molds are casting in COLD climates with drafts and winds. That helps (?) to minimize heat loss to the surrounding cold air. The intimate contact of the mold with the hot plate transfers far more heat than the hot air around it in any container.


    Cover you rmold if you think it gains you anything. I have never seen any gains from enclosing it.

  14. #14
    Boolit Master

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    Quote Originally Posted by bangerjim View Post
    Most people that use containers around their molds are casting in COLD climates with drafts and winds. That helps (?) to minimize heat loss to the surrounding cold air. The intimate contact of the mold with the hot plate transfers far more heat than the hot air around it in any container.


    Cover you rmold if you think it gains you anything. I have never seen any gains from enclosing it.
    Ditto. I built one and even insulated the thing. Waste of time and effort other than satisfying myself it didn't gain me anything. 390° on my PID controlled hotplate gets my molds to the desired 320-340° my Lyman DC molds like, while the pots are heating up. The PID and TC's don't let me actually cast better bullets but I did learn a bunch in the process. And it's nice to just hit the switches and know that in about 20 minutes the mold and the alloy are gonna be just where I want them. But I do cast inside a shop I can heat in the winter. FWIW
    Mike

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  15. #15
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    350 degrees according to my BRAND NEW IFR. I've kept the knob turned to #4 (1-5 MAX) for 30yrs, use a cast iron diffuser plate for mold warmup and keeping hot while I fill the empty pot and switch to second pot.

    As far as BALL'S & MINI'S for black powder I have an assortment of 1 & 2 cav iron molds and dipper cast out of a small cast iron pot over a small single propane burner. I drop my lead onto a folded towel as I firmly believe the softer you keep your pure lead projectiles the better.
    I KEEP THE Hotplate at 400degrees when casting pure lead. After I start casting I lay a "ring" of 1lb ingots around the Hotplates edge to make them melt faster to refill the small pot. While that lead melts I put the molds back on the Hotplate with the last bullet still in it to keep it warm. I run that little pot at 625-640 degrees.
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  16. #16
    Boolit Grand Master
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    Quote Originally Posted by Walks View Post
    350 degrees according to my BRAND NEW IFR. I've kept the knob turned to #4 (1-5 MAX) for 30yrs, use a cast iron diffuser plate for mold warmup and keeping hot while I fill the empty pot and switch to second pot.

    As far as BALL'S & MINI'S for black powder I have an assortment of 1 & 2 cav iron molds and dipper cast out of a small cast iron pot over a small single propane burner. I drop my lead onto a folded towel as I firmly believe the softer you keep your pure lead projectiles the better.
    I KEEP THE Hotplate at 400degrees when casting pure lead. After I start casting I lay a "ring" of 1lb ingots around the Hotplates edge to make them melt faster to refill the small pot. While that lead melts I put the molds back on the Hotplate with the last bullet still in it to keep it warm. I run that little pot at 625-640 degrees.
    Just remember IR guns do NOT read shiny surfaces worth a darned. You have to shoot at black or very dark surfaces to get an accurate reading. It's called "black body radiation effect".......from your HS and College physics classes, remember?

    Shooting at a shiny AL or brass mold will yield incorrect temps. Same with melted shiny Pb in your pot. Do not trust IR devices. for what we do unless you have chemically blackened an area on the mold to shoot at.

    Dark Fe-based molds will work with IR.

  17. #17
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    Trial and error found that my thriftstore hotplate needs to be set to "LOW" or maybe one click beyond "LOW"

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  18. #18
    DOR RED BEAR's Avatar
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    could not say for sure i just set it on medium and usually cast good bullets from first ones.

  19. #19
    Boolit Grand Master

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    I just set mine in the middle. I get good bullets after maybe the 2nd or 3rd cast and don't mind that low amount of rejects. I thought about making a dog house for mine but never have.

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BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
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