Newbie casting temperature questions

[jeff423]

While I'm waiting for my Lyman bullet casting manual to arrive I have some newbie questions about temperature. (I apologize in advance if this has been covered many times in the past).
I'm going to start casting with Lyman #2 alloy and wondered what the best temp. was for it? I have also heard about warming the mold. I have an IR thermometer available and could use it to check the mold temp prior to pouring. Are there any guidelines for preheated mold temperature?
Finally I have a PID temperature controller, thermocouple and SCR relay left over from another project that could be used with an electric melting pot to give very good temperature control. Say plus or minus 5 degrees. Would this be of any benefit over the normal temperature control in a Lee Melter?

Thanks in advance,

Jeff

[docone31]

Set it at 8, or 9, set the mold in the melt, go get a cup of coffee.
When the molten lead does not stick to the outside bottom of the mold, it is about ready for casting.
Yesterday, I fired up my pot, soaked the mold, and poured my first set. It took forever for the mold to be cool enough for the sprue to "freeze". I dumped the liquid castings, and set the mold down. In a bit, I poured another set. It slowly froze. I dumped my castings in my water pot, and waited a bit, then poured another set.
In other words, the sprue freeze is an indication of optimum temp, not neccessarilary a thermometer.
I like my castings frosty. I like them filled out even though I paper patch, and size the lube lands off almost.
It will feel clumsy the first few casting sessions. Expect quite a few rejects at first. That is normal.
I have found, to keep the heat, rest the mold with the casting in it. To lose the heat, dump the casting, and rest it on something. Too long, and you will need to heat it up again, too much heat, and the "freeze" takes forever.
Once you get the rythym, it will be second nature. Watch the freeze, the center of the sprue will be pulled into the melt as it freezes. This is the lead contracting as it cools pulling in the sprue material to fill the void. It is fascinating.
You will see a liquid puddle on the sprue plate, then the center gets pulled in just as it turns grey instead of silver. After that event, you cut the sprue, dump the sprues in the pot, dump the castings in the water, and refill the mold.
Get a rythym and it goes real quick. I can cast quite a few in a short time. It takes me longer to load that batch than cast it.
Welcome to the fun.

[Willbird]

The IR thermometer likely will not work, Bill Fergusan who sells a lot of tin and lead tin alloys said he tried several and they did not work because the lead is shiny, you might be able to float a piece of steel in the pot and check it's temp with the IR thermometer.

With the temp controller, if it is a fuzzy logic one which some are it might work very good once the pot was up to temp...typically you have to flip them to manual when your heating up, and maybe when you add alloy.

I run my rcbs promelt wide open when I am casting 6 cavity molds, I premelt my alloy in a saucepan on an $8.95 walmart hotplate and ladle the liquid into the promelt to refill the pot.....I control the mold temp by quenching it on a wet towel (not my idea I got it here on this webpage).

Bill

[atr]

Hi Jeff
I cast with dipper..so bear that in mind when you read this
when the mix pours easily from my dipper then I know Im ready to start...
depending on the mold it may take a few casts to heat up the mold ....you can help by keeping a casting in the mold for a few minutes to let its heat be absorbed by the mold.
As you cast watch your boolits,,,if the boolits are coming out with partial filled castings or with rounded edges or if the spruce is getting hard before you finish the pour then you are probably too cold....if they are coming out frosty then you are probably a bit to hot.
Once I find the optimum temp for casting,,,i.e. molten material and mold at casting temp I try to maintain this my keeping the pot full to the same level....

[catkiller45]

I run my alloy temp. at around 700 degrees..seems to be a pretty good range for me....

[jeff423]

The IR thermometer likely will not work, Bill Fergusan who sells a lot of tin and lead tin alloys said he tried several and they did not work because the lead is shiny, you might be able to float a piece of steel in the pot and check it's temp with the IR thermometer.

With the temp controller, if it is a fuzzy logic one which some are it might work very good once the pot was up to temp...typically you have to flip them to manual when your heating up, and maybe when you add alloy.

I run my rcbs promelt wide open when I am casting 6 cavity molds, I premelt my alloy in a saucepan on an $8.95 walmart hotplate and ladle the liquid into the promelt to refill the pot.....I control the mold temp by quenching it on a wet towel (not my idea I got it here on this webpage).

Bill

Thanks! I was planning on using the IR thermometer on the side of the mold to check it's temp. I agree with Bill, I have never had it work on a shiny surface - flat black works great. My PID controller is Fuzzy logic.

Jeff