Warming Shelf vs Hot Plate

[Mike W1]

Years back I made the little shelf for my Lee 10# to use to preheat my Lyman moulds and have always been satisfied with the results. By the time alloy is up to temperature so is the mould. First bullets out are always visually good if I pour em' right. Shelf temperature is in the 300° range which apparently is adequate for a Lyman mould.

That wasn't enough for a Lee that I purchased! The hot plate takes care of this one though. Also PID controlled, first bullets out are good. Little extension on the shelf was made adjustable so I could lay the mould flat on the shelf but I've removed it since determining I wasn't going to get the Lee hot enough.
Will continue using the shelf on the iron ones. Don't have any brass moulds so cannot say how the shelf would work on them.

 

[Brad]

I use a hotplate. Mostly because it was a quick, cheap solution. I use the same hotplate for lube making so it does double duty.
I am the odd man out here, I don't use any sort of an oven or steel plate on mine. The mould sits right on the coils. I keep it on medium heat while the pot melts then crank it up to high while I flux and get things ready. It might take a pour or two to get the mould fully to temp but that doesn't bother me any.

In the end I do it this way because I'm too lazy to make an oven!

 

[Mike W1]

I made an oven and think they're a waste of time. The hot plate is what does the job not the air around the mould!

 

[Rick]

I use an oven but I didn't make one, I went to Home Depot and bought an electrical box that was open on one side and one end and big enough to encompass an NOE 5 cavity. Just set it over the mold. Why? If your casting in cool or cold temp it helps keep air currents off the mold. I also use a 5/8 inch thick aluminum plate between the coils and the mold. Why? The aluminum will distribute the heat evenly across it's surface eliminating hot spots from sitting on the coils. I also use NOE's digital thermometer with the probe in the side of the aluminum plate and pre-heat to 400 degrees.

 

[Missionary]

Greetings Mike
I like that shelf. Normally I sit the next mold to be added to the rotation on the pot lip but I have knocked then off onto the table. Next time north it will be shelf time.
Down here I use a Propane burner for casting. Use a sheet metal "collar" around the pot to retain more heat around pot outside. Next in line molds sit next to the collar on the burner grill getting pre-heated.
Mike in Peru

 

[Mike W1]

I use an oven but I didn't make one, I went to Home Depot and bought an electrical box that was open on one side and one end and big enough to encompass an NOE 5 cavity. Just set it over the mold. Why? If your casting in cool or cold temp it helps keep air currents off the mold. I also use a 5/8 inch thick aluminum plate between the coils and the mold. Why? The aluminum will distribute the heat evenly across it's surface eliminating hot spots from sitting on the coils. I also use NOE's digital thermometer with the probe in the side of the aluminum plate and pre-heat to 400 degrees.

My plate is only 1/4" aluminum cause that's what I had on hand. Plate is PID controlled so the temp stays pretty constant. One thing I haven't done is verified the mould temperature sitting on the plate so that will give me something to do but I'm betting if the plate temperature is hot enough the mould will be too.

 

[Ian]

I made an oven and think they're a waste of time. The hot plate is what does the job not the air around the mould!

You might change your mind if you ever buy a brass mould, particularly a small-caliber one.

 

[Dale53]

I have used a hot plate for years with excellent results. I have the same results whether the mould is of iron (including six cavity iron), brass, or aluminum. The top of my burners are solid metal (no calrod open coils for me)!
Dale53

 

[Mike W1]

You might change your mind if you ever buy a brass mould, particularly a small-caliber one.

You could very well be right but I just turned 73 the other day and it's highly unlikely I'll be in the market for any new moulds.

 

[Dale53]

Mike;
Never say never...
I'm 80, and I have two molds ordered as we speak (and I have over 80 molds).

Dale53

 

[Mike W1]

I have used a hot plate for years with excellent results. I have the same results whether the mould is of iron (including six cavity iron), brass, or aluminum. The top of my burners are solid metal (no calrod open coils for me)!
Dale53

Actually mine has a solid top, not the open coils, but was glad I had the aluminum on top recently. Had sent a PID back and forgot to turn the hot plate down. Melted those ingots pretty fast! Cleanup was easy though.

 

[Mike W1]

Mike;
Never say never...
I'm 80, and I have two molds ordered as we speak (and I have over 80 molds).

Dale53

Already got more bullets than time to shoot em' and I'm retired with a range and heated shed. Sold the moulds I didn't use long ago so I'm probably down to about 6 now.

 

[Rick]

My plate is only 1/4" aluminum cause that's what I had on hand. Plate is PID controlled so the temp stays pretty constant. One thing I haven't done is verified the mould temperature sitting on the plate so that will give me something to do but I'm betting if the plate temperature is hot enough the mould will be too.

Yeah that's my thinking also. Your PID control and my NOE probe give us both the same thing, if the mold sits there long enough it will be at the set temp. I set it at 400 and that's pretty close for most molds, some may take a few pours to get "right" and larger bullets in small blocks may be a tad to hot but most will be close.

 

[freebullet]

I use a 1980's vintage electric skillet to preheat ingots and molds. I set it around 375 for aluminum solids and 400 for hp molds. Thankfully it was free.

 

[Dale53]

>>>Already got more bullets than time to shoot em' and I'm retired with a range and heated shed. Sold the moulds I didn't use long ago so I'm probably down to about 6 now.<<<

I should do the same, no doubt, but find it difficult to get rid of "old friends". Sentimental crap, no doubt, but lots of memories tied up in those molds (got that nice ten point buck with that one, took three snowshoe rabbits in one day while grouse hunting with another, you get the idea). Cleaned that IPSC match with that one beating all of the big boys, memories, memories, memories...

At any rate, I have a new project for the two multicavity molds coming for my .32's and can't wait to get started.

FWIW
Dale53

 

[Rally Hess]

Like Ian mentioned for brass. I was having fits with a 4 cavity brass RG mould getting to temp. Used a hotplate from the secondhand store. What a difference getting the HP pins up to temp. I had a steel 6" knockout plate that fit the grille perfectly and am now a happy camper. Those HP pins just don't seem to get hot enough laying the mould across the top of the pot, and I'm reluctant to take a torch to the pins. I can also preheat an additional mould and switch mid pot to get a couple different bullets out of the same pot.

Dale53,
80 moulds!!! It isn't like they are shotguns or S&W pistols. LOL At the rate these have gone up in value, probably a good investment. Way better than spending it at the bar.

 

[Mike W1]

Been keeping myself entertained lately mostly experimenting with PIDs and temperatures. The mould I have drilled for a TC seems to always cast good bullets with this particular alloy when it's in the 306-310° F range. Have decided that my warming shelf will get it into the 260-280° range easily enough but you still need to run 6-10 cycles to get it up in that 300° range. So I've been switching PIDs and looking for the spot on the hot plate that'll get and maintain that 306-310° range. One observation has been even after a PID has finished ATing it'll still likely take a few up/down cycles before it really settles into where you want it. And though I'm happy with my REX PID's on the lead pots they don't control my hot plate nearly as well as my Auber unit. Around 40° C variation on the REX and about 8° Fon the Auber unit. That settled that for me, it'll be the Auber hooked to the hot plate.

360° on the hot plate maintains 308-314° F on that mould, right about where I want it. Kept me busier watching the temperatures than it did actual casting but I definitely noticed this mould releases it's bullets much easier when the mould temperature was upwards of 320°. Not what I would have expected to see and wouldn't have thought much about it had I not been monitoring mould temperature.

Another thing I noticed while standing around was there does seem to be some pattern of relationship in the P, I, & D setting that autotune comes up with. Not that it makes any real difference but of interest to me at least. Gonna check out a bunch of them and see if it holds true on all that I've recorded over the last couple years.

So far it appears that P will be around 4.5% of I and D will be around 17.5% of I. I have noted in the past if you AT and record the figure and turn around and AT again, the figures will change but still seems to be some sort of relative relationship between. Downloaded a paper once on setting values for these thing manually and it's way beyond anything I have enough time left on earth to figure out. Thank goodness for the AT feature!

When I get at it going to examine all those previous recordings and see if it holds true or not and then I'll bore you all with whatever I find out.

 

[NAGANT]

I put a cast iron pan on the hot plate, i only have aluminum 2 cav Lee molds. Works great when fluxing and adding alloy.

 

[Mike W1]

Ran a few of those PID setting through the calculator and there's no pattern there that I can see. Varies by PID model as much as anything and I'm convinced that was a useless observation on my part. First couple just "happened" to fit a pattern, the rest do not.

 

[KHornet]

I just use the hot plate, doesn't matter to me if the mold(s) are iron or alum.