Preheating mold

[bazzer485]

I’m interested in finding out the best method for preheating both aluminum and brass molds. NOE recommend using a hotplate but I find this very slow and nearly impossible to get my molds to the required 400 degrees F. So how do you do it?
Thanks
Barry

[bmortell]

aluminum conducts heat so fast you can just stick the end in the pot for a moment.

[JM7.7x58]

I use a cheap electric Panini sandwich press. It has a heating plate/element both top and bottom. I paid like $7.00 for it at the thrift store.

I start heating my molds at the same time as I turn on my Lee 20# pot. By the time the lead is melted the molds are preheated and ready to go.

JM

[poppy42]

Walmart cheep hot plate with an old circular saw blade on the coils. I don’t know what kind you are using but it must not be working right. I put 3 or 4 molds on mine, set it on 3 or 4 ( about the middle temperature) and my molds heat up long before my Lee 4/20 melts a full pot of lead!

[TjB101]

Edge of slightly open mold in pot. When the lead stops sticking to the mold I’m ready to start.

[toallmy]

Like poppy42 - I preheat on a electric burner with a piece of steel plate on it , turned on about 15 minutes before my lee pot is ready .

[r6487]

sit mine atop Lee pot when I turn it on.

[lightman]

Walmart cheep hot plate with an old circular saw blade on the coils. I don’t know what kind you are using but it must not be working right. I put 3 or 4 molds on mine, set it on 3 or 4 ( about the middle temperature) and my molds heat up long before my Lee 4/20 melts a full pot of lead!

I do the same thing. Back when I was using an older Lyman pot with the cast iron liner I would set the mold on the edge of the pot. But my Promelt has a thinner stainless liner that doesn't heat as well.

[georgerkahn]

How I do it? I have a G E Electric hot plate with its thermostat contacts shorted across, plugged in to a PID unit. A small galvanized pot with a grommet-ed hole in rear for the PDF temp sensor; a probe-type oven thermometer epoxied in a hole at top; and, a "door" cut in front for insertion/removal in this "mould-heating-garage" sits atop it. I have the PID set at 375*F, and -- using a RCBS Pro-melt -- the mould in this heats to ~350* -- hot enough except for one or two moulds with pins, which like to be warmer -- at almost the same, exact time my alloy is fluxed and ready to begin my casting session. I rarely use aluminum moulds ('cept for fishing jigs, sinkers, & similar moulds) -- my bullet makers are mostly brass and steel.
geo

[trixter]

I use a GE hot plate that has a solid plate cooking surface adjusted to the farthest extent of the MED setting towards maximum heat setting. I turn it on and set the mold on it as soon as I fire up the pot. The pot takes about 28 minutes to come up temp, so I know that the mold is hot enough.

[LenH]

I use the solid top hot plate and set it to right at a little less than medium when I get the melt started and they are ready at the same time.

I have an 8 cavity H&G and have gotten it too hot twice. That beast takes a while to cool down. When I say too hot it took the sprue about a minute to solidify and the bullets were
very frosty looking almost pitted looking. It took several minutes of sitting on a wood block to get the temp right.

[bangerjim]

After trying a bunch of methods, I use an industrial variable heat hotplate. I goes from warm to lead-melting temps and beyond. It is flat so molds lay nice and flat. If you are lucky you can find one like it (1200-1500W element) in a junk store. They can sell for over $300 new and are lab quality.

But a hotplate (the RIGHT ONE) is the only way to go!
banger

[Ed_Shot]

Walmart cheep hot plate with an old circular saw blade on the coils. I don’t know what kind you are using but it must not be working right. I put 3 or 4 molds on mine, set it on 3 or 4 ( about the middle temperature) and my molds heat up long before my Lee 4/20 melts a full pot of lead!

Also, exactly what I do.

[Conditor22]

Sounds like you have a bad hotplate.

I have a piece of 1/4 steel on top of mine and like previously mentioned a little less than Medium is 400°

https://www.amazon.com/gp/product/B0007QCRNU/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

It was a lot cheaper when I bought mine. since then I've seen many for 3 - 5 $ in thrift stores.

[rockydoc]

You can get one of those inexpensive laser thermometers from Harbor Freight to check the temp of the moulds and then adjust the hot plate temp accordingly. The hot plates with the solid tops are better than the ones with the coil top. Cheap from Walmart, cheaper from thrift shop.

[robg]

i just fill the molds im using and let them sit for a couple of mins .seems to work with ally and iron molds

[bigjake]

IMHO, dipping the mold into the lead pot takes forever. like so many have suggested; some kind of cooking heat source. a propane or mapp gas torch would be my second choice. to measure the temp. you can buy these sticks called; "temp sticks" they melt at a given temp.

[Rizzo]

I use a cheap Walmart hotplate set just below Medium and put an an aluminum lasagna pan over the mold to speed up the mold heating.
I also use a Lee pot with a PID set at 710 Deg. F.

[daloper]

I have a piece of copper flat that I mounted an square electrical box with the end cut out of it sit on my hot plate and it acts as an oven. I have it under the exhaust fan so I don't have to worry about the galvanized box giving off any fumes.

[Muddydogs]

Walmart cheep hot plate with an old circular saw blade on the coils. I don’t know what kind you are using but it must not be working right. I put 3 or 4 molds on mine, set it on 3 or 4 ( about the middle temperature) and my molds heat up long before my Lee 4/20 melts a full pot of lead!

I do the same, heats up the mold in no time.

OP I would say your hot plate is having problems as any old cheap hot plate shouldn't have any trouble heating a mold. I think I paid $5 for mine a few years ago.

[fcvan]

30+ years ago, I started casting with a 10lb Lee bottom pour. The lead I was getting at the time was from the range at work which was swaged hollow-base wad cutters. To help heat up the melt I cut a tin can lid and placed it over the lead pot. The molds could then be placed on the lid so my the time the melt was up to temp so were the molds. I never saw the need for a hot plate.

I generally smelt into ingots using a SAECO cast ingot mold. When I start casting I place an ingot on the edge of the pot so that it is pre-heated before it could be placed into the pot without affecting the melt temp too much. Having cast for many years before I ever got a thermometer I learned from Dad and other casters to judge temp by watching the sprue cool. If it took to long - it's too hot. I also learned that pouring onto the sprueplate to the left side of the holes the melt would swirl into both and gave good fill. I also learned that if I watch the sprue frost over the mold was good to open. If doing 200 grain or larger boolits use two molds and rotate. Little tiny NOE 225-62 RN I could just fill the mold, blow on the sprue and open when solid.

I finally did get a thermometer and who knew, my pot was at a good range. I learned from others here about speed casting which worked well for me using two molds. BTW, most of my molds are Lee aluminum with a couple SAECO steel molds. I get a good rhythm and I can make a lot of pretty boolits.

[Greg S]

Try putting a cover over your mold on the hotplate made from a modified coffee/tin can.

[Mitch]

I have gone thru several hot plates> some have worked better than others. the 2 i had befor were from Dollar General.they seemd to work a bit better that the one i have now from WM.you have to play with the setting some have been set on Med to hi and work great.the one i have now is about wide open and the cycle time from off to on is to much.so when it hits temp and turns on it is way cooler thatn i want so i end up waiting for the light to turn off then the mold it hot.Sp just keep turning the one you have up will you get it hot enough.if it will not get hot enough try a cover to make a mold oven if that dont work get a new hot plate.i use a tin can to make an oven when i use certain molds that will not set flat on my saw blaed and that works great.

[redhawk0]

I use a hot plate...an old saw blade on top...and a coffee can with a side cut out so its like a small oven.

redhawk

[jlm223]

Has anyone ever tried a heat gun, or is that a bad idea? Just asking.

[fredj338]

Better hot plate? Really you don't need 400deg, 350 is plenty hot & most decent hot plates will easily get that. The ones without the exposed coil are best, flat surface & you can cover with alum foil if you want more heat, but mine heat up nicely with the palte set about 2/3 to high, cheap Target hotplate.

[Walks]

Cheap hot plate witha cast iron heat diffuser plate on top. Turn it to "5" as hot as it will go. By the lead is melted the molds are hot.

[gwpercle]

i just fill the molds im using and let them sit for a couple of mins .seems to work with ally and iron molds

Actually that's the way I do it too , after sitting it on the edge of the hot pot ...and there is always the quick warm...dipping a corner in the melt . Casting a few throw-backs is good for the soul .
But our way doesn't involve any special , fancy or expensive laser powered equipment...
We just aren't technical enough , too simple .
Gary

[fastdadio]

I use a propane torch. Seems to work just fine.

[Rich/WIS]

Cheap WM solid top hot plate set a hair below medium with a cover made from a Danish Butter Cookie tin. Cut a notch out of one side of the tin big enough for the mold handles to stick out. Plug it in when I turn on my Lee 20# pot and in about 20 minutes both are good to go. Frequently get good bullets on the first cast, worst case so far is third pour.

[kmw1954]

Hot plate with an aluminum bike sprocket and then just the top of the Lee Pro IV pot after alloy is melted.

[bazzer485]

I wonder why no one had manufactured a specific heater for Moulds? NOE have a thermometer which can have a probe inserted into one of their Moulds. It would seem a logical next step to design a preheater
Barry

[bangerjim]

I have heard of guys actually warping molds using a "ham-fisted" propane torch approach and getting in a hurry. Just make sure the heat is distributed evenly.

[bangerjim]

Has anyone ever tried a heat gun, or is that a bad idea? Just asking.

It could work.........................if you have all day!

[bangerjim]

Remember, IR thermometers will not read the correct temp off of shiny surfaces like Al molds. I used some "aluminum black" fluid from the gun store to make a 1" black spot on the end of the mold to shoot the LED dot at and the temp is very close to the contact T/C readings I get.

[mehavey]

Simple,
Repeatable,
Use while lead melts in pot.:popcorn:
259123
1st Bullet casts perfectly... even big Minnies.

[OS OK]

https://i.imgur.com/mMA80yC.jpg

https://i.imgur.com/TmqUru1.jpg

[mehavey]

I like the holes in the top (bottom) for pin heating !
:bigsmyl2:

[cwlongshot]

My pop told me to put molds on top of the pot. Takes a good spell to warm that lead. When molten, fill cavities and put back on top Of the pot.

Whole process takes 25-35 minutes. When that time has elapsed usually The Mold is dropping good bullets. Some molds simply have more culls than others. Some Molds will drop good bullets from the get go while others take 10-12 cycles.

Just go with the flow. If ya have wrinkles or voids after all that clean the mold with a couple
Blasts of carb or parts cleaner spray. AWAY FROM THE LEAD! No need to touch mold after spray. It will have gassed off when you fill it with lead.

Good luck

CW

[Walter Laich]

I, too put mine on top of pot--Lee 6-cavities

once lead is at temp I pour one cavity and dump, then pour 2 and dump, all the way up to 6 cavities. Doesn't stress the sprue handle and get good ones from get-go

[bazzer485]

I have bought a new ($17 ) hotplate from Amazon and it’s doing the trick nicely. I’m going to hook up a pid to it to accurately get the temperature to the recommended 400 degrees f. It will be useful to use it with my toaster oven which needs to be the same temp bro bake Hi Tek coating.


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