Question about how to heat cycle a brass mold

[stubert]

I just got a new NOE 4 cav. mold. The break in instructions say to heat it up 3-4 times to 350 deg. on a hot plate and let it cool down between cycles. I did have it drilled for a probe. Should I heat it with the mold closed or open? Does it matter? I emailed NOE but have not gotten a response. Thanks, Stu

[oldhenry]

I heat mine closed. Either way would work. I like closed to protect the cavities from any minor mishap.

[USSR]

The exact temperature and position of the mold is not critical. Just heat it up and cool it down a couple of times.

Don

[FLINTNFIRE]

I do it in oven closed first then cool completely then open for at least 2 more cycles at 400 f , you can do it on your hotplate also , get it up to temp and cool repeat a few times , clean cavities first , though sometimes I do not I just run them and dump straight into sprue pan , if you clean them good and have heat cycled they should start right off throwing good bullets .

[gwpercle]

If the instructions say to "smoke" the cavities with the flame of a Bic lighter ... DON'T !!!
Brass moulds , heat cycled 3 times and then do some casting ... should need no soot / smoke .
Preheat the mould is good advice .

I have always heat cycled and pre-heated all my moulds closed ... just seemed the right way to do it !
Gary

[ddixie884]

Sounds right to me.......

[winelover]

I don't bother with the heat cycling. Just spray new mould with brake cleaner, air dry. Preheat mold on hot plate, while waiting for alloy to melt. Cast away, with a ladle. BTW, I also don't advise putting sprue plate lube on the alignment pins. I have had both pins on a 4 cavity NOE brass mould, walk out, binding up mould. Had to reseat them in my bench vise with copper jaw inserts.

Winelover

[GregLaROCHE]

I agree with what Winelover just said. I have always cleaned molds and then cast until they started dropping good boolits, even without heating on a hot plate, because I didn’t have one. That was with aluminum and steel molds. I don’t have any brass molds yet.

You may want to follow the directions given. I don’t see any harm in it. I would keep the mold open, so the heat gets to the inside surface first, as in casting.

[Chill Wills]

What is the heat cycling do? I have had no problems to date, so what am I missing?

[stubert]

The heat cycling puts a patina on the mold, it seasons it, it also helps to keep it from tinning. You can achieve the same results by just casting when it is new, however it takes longer.