trouble with a new mold

[Shadow9mm]

Got a new mold in today, a Lee C309-170F, and I am struggling to cast clean bullets.

I put lead in the pot and the mold on top to warm up for about 30min.

Started casting at 700F, super wrinkly.

Worked my way up in temps in 50F increments.

Stopped at 950F as I did not feel comfortable continuing up in the temps.

At 950F the bullets all have a frosty appearance. Many do not have good fill out on the grooves. Of the 100 or so I cast I only got 4 total that were clean.

What am I doing wrong? Is the mold not hot enough? I have several lee pistol bullet molds for handgun bullets that cast well at 750-800 F. I kept the mold on the pot to keep it warm between casting while letting the pot heat. I let the first couple castings at each temp sit in the mold a few extra seconds to help make sure the mold was at a good temp. Or with the long rifle bullets do I just have to push the temps up?

[Winger Ed.]

Sounds like you might need a little bump of Tin in the alloy. That should help with the fill out.
Also make sure the mold is really clean and there isn't any oil left in the vent grooves.

I don't have a thermometer,
but I run the pot up pretty hot until I get a little bit of frosting, then ease it back until it stops.

[atr]

I agree with Winger Ed. I bit more tin might help it flow better.
atr

[GregLaROCHE]

I go along with Winger Ed’s advice too. Also make sure you have an adequate flow rate. I normally don’t have a problem with mold temperature too low. After I get in the groove, I often need to cool down my mold on a wet rag or switch to another mold and let it cool.

[rintinglen]

New LEE molds tend to be full of cutting oil. I don't know if its the alloy they use or what, but a new LEE mold needs to boil in soapy water for 15 minutes to get the oil out. Except perhaps for single cavity, small, boolit molds (I'm looking at you 225-438,) 750° is plenty for good bullets. If that doesn't get you where you want to be, you need to look at other things.

[Shadow9mm]

Got good flow rate. I did forget to clean her out, I'm hoping that's the issue, its been too long since I got a new mold. Got the pot and mold warming up, will see how she casts now.

[gwpercle]

The Lee moulds have cutting oils deep into the pores .
Clean with acetone and a tooth brush . Heat up mould and cast a few ...let cool .
The heat will bring out more oil ...heat and cast
Third time will usually result with all oils driven out , acetone removes it completely and the third session has the aluminum seasoned and broken in .

Not likeing the repeated cleaning and casting ... I started soaking Lee blocks in a jar filled with acetone ... 24 hour soak and those blocks are oil free !
Gary

[Shadow9mm]

so seems to have worked, cast around 100. got 42 clean bullets. the first 58 has some very light wrinkles in small areas and it cleared up. was able to cast clear and got good fill out right around 750F

[Wally]

Spray the mold with either Carb Cleaner or Brake Cleaner; let it air dry. I have numerous Lee rifle & pistol molds--never had an issue.

[gwpercle]

so seems to have worked, cast around 100. got 42 clean bullets. the first 58 has some very light wrinkles in small areas and it cleared up. was able to cast clear and got good fill out right around 750F

Good ... sounds like the oils have been driven out ... clean with acetone , Carb. or Brake cleaner another time or two after cool down . When the cavities are broke in and seasoned it will cast without any problems ... the aluminum likes to hold oil deep and heat brings a little more out ...three heatings and cleanings will usually get it all out .
Gary

[El Bibliotecario]

I've found this thread informative because I am having a similar experience. Would adding linotype to my wheelweights make any difference? I don't need to harden the alloy, but it is a lot cheaper to use something which I have rather than something I have to buy--providing of course, it works.

[kevin c]

EB:

I think the follow up posts in the thread point to cutting oil in the new mold as the cause of the wrinkles.

That being said, straight clip on wheel weights are short on tin, which, as suggested in the first replies, helps fill out, as does raising the temp of the mold blocks and/or alloy.

If your mold is clean, I’d start with raising alloy temp or speeding up your casting cadence first. Also try preheating the blocks. Adding up to 2% by weight of tin would be next.

If you already have the linotype you’re not out of pocket using it, but it’ll cost you $2.50 to $3.00 a pound to replace it. Getting 2% in your presumably tin free COWW needs Lino at a 1:1 ratio, so your alloy is now worth at least another $1.25 per pound (the value of the lino in a pound of the new alloy). As an alternative, pewter, even at $10.00 per pound, would only add ~22 cents a pound cost to the alloy, and saves the Lino for harder alloys if you ever need them.

[G. Freeman]

Shadow,
I think you may have an issue with your mold not being up to temp--at least 400 degrees IIRC. Your lead only needs to be in the 700-750 degree make good bullets. At 900 degrees, you will get frosted and undersized bullets (happened to me).

I had the same problems and my Lee or RCBS molds would take almost an hour to reach proper temp to eliminate wrinkled bullets. Laying the mold on top of the pot to warm up did not do the trick for me.

What worked for me:
Purchased a 1000w hotplate.
Turned all the way to high.
Covered the mold with a modified bread pan (with holes cut for the handles)
After 20-30 min my mold is the proper temp, all residual oil in the cavities are burned off. I only need 3 pours in order to get well-filled, wrinkle-free bullets.

Good luck. (from a newbie caster)

[243winxb]

Looks like a good cleaning fixed it. Good job.


https://support.leeprecision.net/en/knowledgebase

[rustyshooter]

Almost always wrinkles = cold mould. Tin, solder and pewter will help with mold fill out and flow. Kroil or preservatives used on the mold for storage will burn off with the first pour or two. An inexpensive hot plate from Walmart or 2nd hand store will cure any mold temperature/wrinkle problems. It brings the mold up to temperature faster at the beginning of your casting session. It also helps to maintain correct mold temperature during casting. I always cast with at least two molds during my sessions. Rotating them and leaving them on the hot plate in between each pour. Just have to find the particular sweet spot for the hot plate that you purchase. Once I mastered that Lyman #2 recipe I haven’t had to change my temperature on my pot in 12 years. 720° give or take a degree or two.