Heating Up Moulds???

[Grump]

Okay, I haven't been reading the gunzines and cast boolit manuals every year and old stuff to some here is kinda new to me.

References come and go here to heating up moulds on a hot plate to get them up to temp. The old stuff I remember said to NEVER apply high heat lest the iron blocks warp. And NEVER just dip the corner of a block into the melt to heat them up, same reason, might warp the blocks. The 70s vintage then-new Lee moulds touted their advantages as including just dipping the blocks in the melt, since their aluminum moulds won't warp.

So is the modern doctrine that it's okay to put lotsa heat on iron mould blocks? I see no other way to get them hot enough to melt lead smears (before wiping with burlap or brass wool and such), as some recommend doing in the "Lead Adhearing to Mould" thread.

Was messing with a single-cavity mould the other day and it sure would be nice to get 'em up to temp in less than 30 pours...

[Stonecrusher]

I use a hotplate set on medium to med-hi and it works like a charm. Just the other day I wanted to see how a new wadcutter mold I acquired cast so I heated up the pot and put the mold on the hotplate. I heat them up to about 350-400F. First pour left bases a little rounded, from sprue plate not getting up to full temp as I wasn't using a cover. Second pour all four were keepers, and so on.

The hot plate idea is the single best I have gleaned from this treasure trove. It saves untold aggravation getting molds up to usable temp.

[JSnover]

Hot plates are popular. So is resting your molds on the top of the pot or dipping a corner into the melt. None of this will hurt your mold.

[Grump]

The old school method I have always used was to put the mould(s) on the lip of the pot. That surface gets to about 350 F or a little more, which helps but doesn't get them all the way up. Lost patience a few months ago and dipped the impact surface of the sprue plate of one mould in the melt, helped a LOT for that part but I didn't trust anything other than rapid pours to get the blocks hot.

The other night, the blocks read about 450 F when things were humming along, but the short time I had (was just pouring to check alloy hardness tomorrow) was ALL used up getting the last of the A/C oil dissipated even after wiping the blocks and the sprue plate. That mould had just come out of storage.

THANKS!!! My life is about to get even better.

[Shooter6br]

124665124666Make a box for top of hot plate

[dale2242]

I use a hotplate set to a medium temp.
I put a piece of 1/4" steel plate on top of the hotplate and set the mold on that.
I use the hotplate with both steel and aluminum molds. I don`t have a brass mold so can`t say about them.
It sure speeds up the casting process and keeps my molds hot while bringing the temp of the pot up when adding alloy.
I use a small electric fan to cool the molds down when I am casting too fast....dale

[Shooter6br]

Make 124667124668a box for top of hot plate (double box) SORRY DOUBLE POST

[Grump]

Aw, the backup button took me back to the input window and I thought I forgot to hit "post". Double deleted.

[paul h]

I've yet to warp an aluminum, brass, iron or steel mold by dipping the corner in the pot to get it up to temp, and that's for 1, 2, 4 and 6 cavity molds, and those machined in the past few years or over 30 years ago.

I'm sure it can happen, but I haven't experienced it personally and I plan to continue dipping my molds to get good casts as quickly as possible.

[Yodogsandman]

Grump, I found a hot plate at a yard sale for $2 this summer. I set my mold right on it, where the heating surface is solid (not a coil). I set it on "high" and cover the mold with a #10 peach can with a cut-out and a little wood handle on it. I turn the pot on and in 20 minutes, I'm casting frosted boolits. I have to drop about 2-3 sets before it cools enough to throw nice shiny boolits. Wow, it's nice! With the pot hooked up to a PID, we're just raining boolits here! Both are new additions this year and make quite a difference.

I've also used the hot plate with an old pan to boil lube from my sizer dies. Works for boiling the lube out of boolit grooves, too. You can also keep some extra ingots warmed up on it, ready to go.

[georgerkahn]

One of the many things I've learned &/or picked up on this site was the concept of taking a large can (free from a local diner), cutting a hole in it the size of your mould, and placing it ON the hot plate. Voila! The oven has been invented. I believe Beagle333 came up with this concept and I tried it: IT WORKS! He posted a photo if you go back to November 1st of this year, under his thread, "Out of Necessity". I copied it here. Kudos again to Beagle333 -- it surely is a winner!
http://i613.photobucket.com/albums/tt214/shutupandjump/PID/Moldoven1_zpsa4ea8bcb.jpg

[Bullwolf]

I haven't managed to warp an aluminum or iron boolit mould yet using my hotplate.

http://castboolits.gunloads.com/attachment.php?attachmentid=114714&d=1409027142

The cover on the hotplate, or mould oven really makes it a joy to cast with on windy days. Acknowledgements go out to Gearnasher for the original idea, and to JohnB_in_Glencoe for the super convenient top handle idea which I shamelessly borrowed.

I also use the hotplate to heat cycle new moulds to season them before casting with them for the first time.

The hot plate allows me to cast nice keeper boolits right from the start without having to cast a pile of cold wrinkled rejects while trying bringing the mould up to temp.

The hotplate really shines if you need to stop during the middle of a casting session and then restart again, or when casting with multiple boolit moulds since they are always at casting temperature.

http://castboolits.gunloads.com/attachment.php?attachmentid=124678&d=1394507737

Using a hotplate as a mould/ingot warmer is one of the best tips that I've read about here on Cast Boolits.





- Bullwolf

[45 2.1]

There are some caveats to this. Dip both sides in the melt.... not just one corner, heat both sides evenly. Try not to flood the alignment holes or any hollow pointing pins or plates. Heat until no lead sticks to the mold, then put the first half inch of the sprue plate in till lead doesn't stick to it..... bull plate the underside of the sprue plate...... then cast. All assuming the lead pot is around 725 degrees unless you're in a cold room.

[too many things]

45 has it right and you don't have the clutter
I have never used a hot plate no need to just more electric to pay for
lead wont stick to mold if you use kroil

[sealer]

i usually heat my mold with a propane torch, but i never stop turning the mold - iron or aluminum.
dennis

[454PB]

I also use a propane torch. I place the mould on the shelf below my casting area with the blocks hanging just past the shelf and place the torch below it with the flame touching the bottom. Within a minute or two it's up to temperature.

I've done this for 40 years and never damaged a mould.

[bangerjim]

Flat top hot plate for me. No fancy ovens or cans or covers needed at all! Just lay your mold(s) on top. You can also use it to heat your feed ingots to save cycle time when refilling your casting pot.

I set my plate to just slightly under the liquidus temp of the alloy I am casting. That gets the mold to casting temp very nicely! Just warm is a waste of time.

Dipping a mold in the melt just leads to extra time later on scraping the stuck lead off the sides and bottom of the mold!

Preheating will not damage a mold that I have ever seen.

bangerjim

[Bullwolf]

Flat top hot plate for me. No fancy ovens or cans or covers needed at all!
bangerjim



The cover on the hotplate, or mould oven really makes it a joy to cast with on windy days.
- Bullwolf

Anyone who has tried to melt lead and pour ingots on a cold and windy day will likely already grasp just how much a simple wind break like aluminum foil, or just plain sheet metal can help to retain heat.

However if you are the type who tends to cast indoors, in your garage, or someplace else where it never snows, is already warm and has a decent wind break - then you probably won't have much use for such things.

You could also likely cook your dinner (or your boolits) with the oven door open as well, but that may not be the most efficient way to get things done.

Not sure how fancy recycling an old coffee can that would have been thrown away is. It is quite easy to try though if you want to improve the efficiency of a smaller hotplate on a cold or windy day, rather than waiting for warmer weather to cast boolits in.

Just relating my experience using an old electric hotplate along with a coffee can, and a worn out skill saw blade to fashion a mould pre-warmer. Try it, or don't.
http://castboolits.gunloads.com/attachment.php?attachmentid=114714&stc=1&thumb=1&d=1409027142
Let me close this with words from another wiser than myself.



This is my .02 and people can use it as they see fit or not. Your choice and I won't hold it against you one way or the other. Everyone finds their own way thru the maze of life. I can only relate my path.
Randy


- Bullwolf

[emrah]

I know I'll get **** for this, but am I the only one who uses a propane torch?

Like all things, you need to be smarter than the inanimate object. Move the flame around and constantly turn the mold so it gets heated evenly. You don't have to directly touch the flame to the mold, just varying degrees of closeness.

Just be careful, but I've never warped a Lyman iron mold not a Lee aluminum one.

Emrah

[bangerjim]

A torch will definitely work as a heat source, but I prefer to put them on a hotplate and go about other stuff like gathering ingots, tools, safety equipment, etc while the molds and ingots heat on the hotplate. For the few $$ one costs, it is more time-efficient for me than playing a flame over each mold.

banger

[JonB_in_Glencoe]

This has been the easiest way, for me, to pre-heat a mold...and to control the heat so as to NOT over heat it and potentially warp it...and only $1 for the hotplate at a thrift store.

http://i640.photobucket.com/albums/uu127/JonB_in_Glencoe/reduced.jpg (http://s640.photobucket.com/user/JonB_in_Glencoe/media/reduced.jpg.html)

[Blanco]

I picked up a hotplate that was unused and still in the box at an estate sale for $5
I think it was a Montgomery Wards. From the looks of it probably late 60's or early 70's vintage
goes up to 400Deg. I usually have to make 2 casts before the mold comes to temp. Not really an issue, but it has a built in cover over the element
I can put up to 4 molds at one time on there

[mold maker]

At Sams Club and such, they sell a can of chicken that has the same diameter, but is half as tall. It makes a dandy oven for the hotplate.
Besides the wife makes a great chicken pie that is to die for.

[fredj338]

I set mine on top of the pot. piece of alum foil over that, works fine.

[trapper9260]

I learn to use the hot plate on here some time ago and try it and now will not stop usen it.I put the mold right on it , years ago I use to fill the mold till I start to get right boolits now I cut that now just to use the hot plate.

[gwpercle]

Be careful, you can overheat a mould, especially a Lee mould. The first time I hot plated one it took five minutes for the sprue to harden.....WAY too hot!
The Lee moulds can be ruined with too much heat , so be careful.
Gary

[gwpercle]

At Sams Club and such, they sell a can of chicken that has the same diameter, but is half as tall. It makes a dandy oven for the hotplate.
Besides the wife makes a great chicken pie that is to die for.

So post the RECIPE , I love chicken pie!
Gary

[rintinglen]

I know I'll get **** for this, but am I the only one who uses a propane torch?

Like all things, you need to be smarter than the inanimate object. Move the flame around and constantly turn the mold so it gets heated evenly. You don't have to directly touch the flame to the mold, just varying degrees of closeness.

Just be careful, but I've never warped a Lyman iron mold not a Lee aluminum one.

Emrah
What I don't like about the torch is the open flame aspect. I cast outdoors, and in front of my loading shed. I have powder, paint, and assorted petroleum products in there, that could make a nice conflagration if something goes wrong. When I pre-heat my molds on the pot or on a hotplate, there are no open flames. Plus, I don't have to keep my eye fixed on the mold. It simply sets and warms, leaving me free to do other things while waiting for the pot to come up to temperature.

[dromia]

For me aluminium moulds get the bottom front edge dipped in the melt, for iron and brass a blowtorch and keep the mould moving in the flame. Been doing this for over thirty years now and never had a warped mould, yet.

The blow torch is particularly good at getting the sprue plate and HB/HP pins up to temperature as you can apply the heat direct.

[wlc]

This has been the easiest way, for me, to pre-heat a mold...and to control the heat so as to NOT over heat it and potentially warp it...and only $1 for the hotplate at a thrift store.

http://i640.photobucket.com/albums/uu127/JonB_in_Glencoe/reduced.jpg (http://s640.photobucket.com/user/JonB_in_Glencoe/media/reduced.jpg.html)

More or less my set-up. Only I don't have to have the saw blade as my element is solid. I turn the pot on, set the heat on the HP to low and about five or ten minutes after the pot gets turned on I put the mold in the "oven". By the time the pot is ready the mold is as well. Usually only takes one or two casts and things are running nice. Occasionally the first cast turns out right, but most often it takes about two casts for good bullets.

[A pause for the COZ]

I am a hot plate guy. Nothing fancy, I just sit the molds I plan on using that day on the plate at the same time I turn on the pot.
Both are ready to go at the same time.

[RED333]

Old Lee bottom pour, no I do not cast in the kitchen.
http://i896.photobucket.com/albums/ac165/redintn/MiHec%20mold/castingsetup_zps2d97a6e1.jpg (http://s896.photobucket.com/user/redintn/media/MiHec%20mold/castingsetup_zps2d97a6e1.jpg.html)

[454PB]

Uhhhhh....you cook in the casting room?

[RED333]

Uhhhhh....you cook in the casting room?

Yep, powder coat boolits in the oven. [smilie=w: