Problems in casting & sizing

[Yooper003]

I ran into several problems yesterday in my casting & sizing & thought I would run it by the folks here. First I just got a new .225 - 62 gr. Mold from Noe, they make great molds ,I have several but, I cast for a couple hours & still had a 50% rejection ( wrinkled boolits).I was using a hot plate & run lead temp. All the way up to 800 & still lots of wrinkles.only thing I can figure is the large blocks that Noe uses with just 62 hrs of lead just not enough heat into mold. Next I started installing gas checks & was happy that they seemed to be going on very nicely. But, when I was sizing them I seen it was shearing the check & leaving a sharp edge at the bottom,enough to cause problems. My fix for this ,after several tries was to run them through .225 die check first , which leaves a domed check. This I fixed by running them through a .224 die nose first. This was the size I wanted them as I powder coat then size to .225 after. Ideas?

[Cosmic_Charlie]

Preheat your mold till it's too hot to touch. Skip the .224 die and install the checks with the .225. Powder coat and size again.

[mdi]

A very minor "hint" of oil in a new mold will produce wrinkled bullets. Most of the time I will soak a new mold in clean mineral spirits andsquirt with cholorinated brake clean.

I'd have to see a checked bullet and watch you apply one before I can comment on that. I haven't had any problems seating checks as you describe using my Lee bullet sizing dies...

[Dusty Bannister]

Perhaps you are using thin aluminum gas checks? Those can fold back over the push rod if you are using a Lee type push through size die. Polish the entry into the die to make a gentle taper and smooth the surface to reduce resistance may also help.

[Yooper003]

A very minor "hint" of oil in a new mold will produce wrinkled bullets. Most of the time I will soak a new mold in clean mineral spirits andsquirt with cholorinated brake clean.

I'd have to see a checked bullet and watch you apply one before I can comment on that. I haven't had any problems seating checks as you describe using my Lee bullet sizing dies...

I think you are right about the hint. I think I got a little oil when I tried to get lube on the sprue cutter pivot. I recleaned & smoked the cavity’s today and had a much better day.
As to the checks,I think I will keep on doing the first pass check first , then reverse & run them through 2nd time 1 size smaller. It is more work but they seem to be set very well.

[gwpercle]

Check your .224 sizing die for a sharp inside edge .
Older dies came with a more pronounced radius / chamfer and a polished surface than the new ones .
The sharp edges like to shear off metal .
Round it over and polish it nicely ... if you have an old sizing die look at how the edge is done .
I guess they save 2 cents by not chamfering and polishing this edge ... but it sure does help sizing and especially when using gas checks .

3 casting sessions or 3 heat cycles will drive the cutting oils out from the pores of the aluminum blocks , clean with brake cleaner or acetone after each heat cycle .
Gary

[WHITETAIL]

I +1 on recleaning the mold.
Every time I get the mold out that I want,
I spray it down with carb cleaner.
Never had a problem with oil in a mold when I
spray it first.:holysheep

[AlHunt]

I'll add that I've recently been casting 38 grain bullets in a new 3 cavity NOE mold.

It very definitely took longer for the mold to come to casting temp due to the very low ratio of cavity space to the amount of mass in the blocks.