OMG I saw the light and it was a hot plate
- Thread starter bruce381
- Start date
Mitty38
Well-Known Member
So a little late to the game.
Just got a hot plate.
Is 400 degrees the general target for most moulds before casting is started, or does this tend to vary?
Do you leave the hot plate on while casting and rest the mould on there while resting the mould?
Any thing else I need to know about hot plate use?.
Will be using mine for . 223, hopefully get the wrinkles out a little sooner without cranking the heat on the pot.
Just got a hot plate.
Is 400 degrees the general target for most moulds before casting is started, or does this tend to vary?
Do you leave the hot plate on while casting and rest the mould on there while resting the mould?
Any thing else I need to know about hot plate use?.
Will be using mine for . 223, hopefully get the wrinkles out a little sooner without cranking the heat on the pot.
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I too use a cast iron diffuser plate on my hot plate. I crank it up to "5" it reads 395degrees, Close enough. Molds go on the D plate same time I turn on the pot. I only cast from one pot these days so I "hang" ingots off the edge of the HP to get them pre-warmed for refilling the pot. Depending on the mold style/make I stand them up on the front or lay down on their sides to warm them. As long as the sprue plate makes contact with the HP. Often as not I get "keepers" from the first pour.
And while the pot is being refilled and coming up to temp, the molds go back on the HP.
Cadillac Jeff
Well-Known Member
Yup I got my first one last weekend at a yard sale for a buck bran new in box !! will look tho my pile of scrap for a D plate.
For me, it "tends to vary." Not by a lot, but it's not a hard and fast XXF.
I know it doesn't sound like much and may just be part of my personal superstition, but MOST of my moulds seem to hit their happy place just under 400 - like 370 to 390.
I have one 4C NOE 360-180 which seems to do its best with the alloy hotter than usual (800F) and the mould cooler (350F) than usual, but the important thing to remember is that..........
Any of these discussions is based on RELATIVE terms among members/members' sensors. Not everyone's thermocouples (TCs), analog thermometers, non-contact thermometers, etc. are calibrated to "agree," and even among the several sensors I personally employ, I can't guarantee that they are all within 10% of one another. It's all relative.
I know you all know that, but I wanted to throw that in for anyone "new" or just lurking so they had a more realistic perspective.
Now that someone's brought this up again, I still think my cheap hot plate is the one (embarrassingly) best/biggest help in casting for me. Not that I couldn't without it, but it sure makes life easier. If I have to stop and load clothes from the washer to the dryer, take the dog out, fix lunch, take a leak, etc. I can turn on the hot plate, set the mould on it and walk away (not too far, mind you) and come back and roll right back into the original pace. It's also nice to let the mould slowly come up to temp while the alloy melts or you dink with adding some magical component.
quicksylver
Well-Known Member
Just to break the norm, I tried all thesteel plate table saw blades etc. , IMOthey took too long to heat up and did not transfer the heat well, so I went back to setting mine at the mid range setting placing the mold directly on the plate, SPURE SIDE DOWN. with a block of wood supporting the handles. I used to use a NOE probe to get the mold up to 350 degs and then start pouring. I no longer use the probe ,as I have done it so many times I leave it on and place the mold back on when I take a break.
I use a square aluminum plate just a little bigger than the coils about 3/8" thick. Heats up quickly & transfers the heat evenly. Picked it up from a metals supplier scrap bin as cut offs for about a buck many years a ago. It's thick enough drill to a hole in the edge to hold the NOE probe & read the plate temp.
Mitty38
Well-Known Member
I have dug for one of those, no luck. So I got what I got, I guess. $12 at Wally world.
My saw blade is a little thick, so maybe a tall pie pan? Then I can use the edge to rest the handles on.
The thermometer I am using is a Klein handheld heat sensor gun.
It is +or- .95 degrees. Course I understand that is surface temp.
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Herb in pa
Member
I found a lab grade hot plate on EBay for about 35 bucks. It's got a porcelain / ceramic top. It's 600 watt and adjustable (quoting factory specs from 100 to 500 degrees C.) Seems to do the job...........Model is Corning PC-35.
That's OK. Let it "soak" for ten minutes once it hits the temp you are shooting for. If it stays the same (or close), then you got the setting right on the hot-plate. Whether that setting is "right" or not doesn't matter if the bullets are coming out nice. Just write down what your dial setting is and what your thermometer tells you and accept that as your reference point using THAT thermometer.
I'm pretty confident that a ten minute soak time on most any mould up to 6C (especially aluminum) will be enough to balance the surface temp with the internal temp. I wouldn't be surprised if five minutes were enough.
For a while, you want to keep an eye on how hot "low, medium and high" on the hot plate dial get the mould so you don't get it TOO hot. I don't actually KNOW how hot TOO hot is, I just don't like taking mine past 400F. Set just a tic above "MED" on mine does the trick.
L Ross
Well-Known Member
Like most things I do I just kind of wing it. Walk into the shack, plug the old two prong hot plate into the two prong outlet with the 15 amp fuse. There's a 1/4" thick piece of rusty steel plate about 5" square sitting on top of the coils. I lay the mould sprue side up and use anything layin' around to block up the handles so the mould blocks sit flat against the plate for maximum contact.
Then I go turn on whatever pot I'm using. When the lead is melted and fluxed and seems hot enough, I walk over to the mould and wave my hand over it, yup hotter'n I'd want to touch and go to castin'. Just a couple of reject cycles in the sprue can and the bullets start to take on the right sheen with crispy edges and go!
Then I go turn on whatever pot I'm using. When the lead is melted and fluxed and seems hot enough, I walk over to the mould and wave my hand over it, yup hotter'n I'd want to touch and go to castin'. Just a couple of reject cycles in the sprue can and the bullets start to take on the right sheen with crispy edges and go!
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It's a lot more fun that way.
My methods are much less scientific than they may sound when I try to explain it.
Mitty38
Well-Known Member
@Cherokee @L Ross You guys kinda got me thinking, I am overthinking this.
There is one thought that just crossed me. Aluminum draws heat. It is used in electronics, as heat sink material. When I used to play with soldering a lot, way back when you could buy components and fix circuit boards, used aluminum heat sinks to keep the heat from burning out the new transistor, ect.
Why would not laying an aluminum mold directly on the coils be ok? It is a diffuser, so their should be no need for a diffuser. Maybe with steel but not aluminum.
There is one thought that just crossed me. Aluminum draws heat. It is used in electronics, as heat sink material. When I used to play with soldering a lot, way back when you could buy components and fix circuit boards, used aluminum heat sinks to keep the heat from burning out the new transistor, ect.
Why would not laying an aluminum mold directly on the coils be ok? It is a diffuser, so their should be no need for a diffuser. Maybe with steel but not aluminum.
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