Lead Build-up on Sprue plate

[wv109323]

I have a 2 cavity NEI mold in a .358- 158 gn. SWC. The last two times I have cast with it lead accumulates on the sprue plate and the mold. The lead builds up and starts to lift the sprue plate up and varies the bullet base. I can get 2-300 bullets before the buildup is so bad I need to stop casting with the mold.
Am I cutting the sprue too quick or is there a solution? It is an aluminum mold.

[Butchman205]

I always smoke mine with a Bic lighter before I start casting, and smoke it occasionally while I'm casting. The carbon buildup keeps lead from sticking.


-Butchman

[Ben]

Once you get the underside of the sprue plate clean, a VERY THIN film of 2 cycle oil applied to the underside of the plate and then wipped off with a paper towel will keep lead from building up.

I re-coat mine about every 300 bullets or so.

Ben

[DerekP Houston]

if the 2-cycle/sprue lube doesn't help. Try liquid dry wrench spray, worked like a champ for me. Might be cutting it a tad soon and smearing the lead?

[gwpercle]

The reason for the build up is you are opening the mould before the sprue has fully hardened, the not hard metal gets smeared across the block top and underside of sprue plate.
Stop , clean it off....it will just get worse. Count to 5 , 6 or 7 before opening.
Coat the block top (with bullets still in cavities) and underside of sprue plate , with 2 stroke oil on a Q-tip and wipe off with a cloth. Thinnest of films will do. Too much will contaminate the next few boolits...they will be wrinkly .
Liquid Wrench Dry Lube on a Q-tip works also and will not contaminate ....it is a great mould release ...I treat my moulds with it before storage and before casting.
Gary

[10x]

I use synthetic 2 stroke oil on the sprue plate applied with a Q tip and wiped with a paper towel every 300 casts or so
I do wait until I see the sprue harden then count 8 seconds. Then open with my thumb. There should be light resistance to the sprue plate cutting. Light resistance means a pound or so of force. I will also look at the bottom of the sprue plate for lead smear. Any sign of lead and the sprue plate gets a wipe with the Q tip

[Butchman205]

Sometimes I'll cut the sprue with a flick of my finger (I always wear gloves), and sometimes I'll cut the sprue off with a wooden "knocker". The knocker is basically a cut off piece of a broken shovel or sledgehammer handle.

When I'm flicking off the sprue with gloved hand, I get more lead smearing. When let the lead cool longer and cut the sprue with a wooden knocker, the lead smearing is waaaaay less.

Smoking the sprue cutter with a Bic lighter every so often helps a heap.


-Butchman

[JonB_in_Glencoe]

If you choose to use synth two cycle oil, there is a sticky with instructions.
http://castboolits.gunloads.com/showthread.php?137982-Mould-Lube-Instructions-(works-with-BullPlate-too)

[Dimner]

I have the same problem. The 2 cycle lube doesn't seem to do the trick. Well it helps for about 50 bullets, but then the problem is back. I'm counting till about 10 or more most of the times. My lead is about 725. And my mold is preheated and everything.

The only way I have been able to combat it is to try and cool down my sprue plate every third cast by pressing it on a damp cloth. It's so odd because I don't get how the sprue is so hot because I'm casting so slow.

[JonB_in_Glencoe]

Yep, many times, depending on the mold, I am re-applying/wiping the bottom of the sprue plate every 50 to 100 boolits, with the same q-tip that was treated w/2 cyc oil at the begining of the casting session. Most of my casting sessions are 400 to 500 boolits, so rubbing the q-tip on the sprue plate 8 to 10 times is no biggie.

[Hogdaddy]

I use Johnsons paste wax, Works for me ; )
H/D

[ncbearman]

gw post #5 hit it on the head. Let your sprue cool longer. I soak my (steel) moulds in kroil after each session. And use no lube on the next session and have no issues casting 100's per session. It will be the same for aluminum. If casting with one mould the aluminum a will get very hot.