removing lead smears from mold

[happyhunter]

I was casting with my new MiHec 180 gr 357 mold the other day. I notice there are 4 lines of lead on top of the mold going from each cavity to the edge of the mold. How do I remove that? It is a brass mold.

How do I prevent it from happening? I waited a long time after pouring to cut the sprue (like 25 secs) Many of the bullets have a dent where the lead pulled off the base of the bullet. I guess that is the lead that deposited across the top of the mold? The mold was running pretty hot and my bullets all frosted. I was using 710 deg pot temperature. I was pouting lead from a dipper. I am going to drop that to about 680 deg F and see if I can pick up the pace and get better looking bullets next time.

Thanks,
HH

[Wally]

Next time you use the mold have a cotton rag handy and heat the smears up with a propane torch just a tad--then wipe off with the rag. To prevent wipe thesmears off as soon as they form...then touch the open sprue plate to a damp sponge. This will cool it just enough to prevent. Also try to adjust your cast temperature to as low as possible. Other will recommend Bullpate lube which is not all that easy to obtain.

I use Lee molds and this happens as a matter of course, as one has to use high heat with aluminum molds.

[jethunter]

The smear means you are operating the sprue before the lead is completely hardened. You could add a few more seconds waiting time before opening the sprue to fix this. In some of my aluminum moulds slowing down too much doesn't work because then the mould gets too cold and the quality of the cast starts to suffer. If that's the case you just have to live with the smears and clean them. I use a 3M pot scrubber (plastic material of some kind) to do it on the fly when I'm casting. Don't use a metal pot scrubber on a hot mould.

[Le Loup Solitaire]

If the smears appear on the tops of the blocks under the sprue cutter then they are probably on the bottom side of the cutter/plate as well. Cause; you're moving the plate/cutter before the sprue is fully set/hardened. Wait longer until you see the puddle change culor and go to dull gray. To get the smears off do what Wally said or take an ingot and use one of the corners to rub the smear....the ingot lead will pick up the smear. It takes some pressure and elbow grease, but it works. LLS

[D Crockett]

Happyhunter we used to have a vender hear under the name of Bull plate lube but is no longer here . that is what you need to fix the tears on the base of your bullets . if you woant to get some I have some extra I will send you a small bottle of it enough to treat you moulds for a while . belive me when I say this stuff works . pm me if you would like to try some . all I ask is you pay the postage D Crockett

[bosterr]

Synthetic 2 stroke motor oil works too.

[Forrest r]

+1 with synthetic motor oil

I keep/use a little 4oz bottle of synthetic 2 stroke oil becide me when I cast. During the casting session I'll continuelly lbe the mold, hinge pins, guide pins, the top of the mold & sprue plate with this oil & a q-tip. Any time I see a little lead smear starting on the top of the mold I take 10 seconds out of my casting time & reoil the mold top/sprue plate with a q-tip & light oil. The lead comes right off when the mold is closed & the mold is good for 60 or 70 more pours before I have to do it again.

I don't have the problem with single or double cavity steel molds but I get smearing with the mp 4 cavity molds because I run them hot. The cheap bottle of synthetic 2 stroke oil lasts forever it seems & saves my bacon with my shortcumming in how I cast.

[RobS]

Randyrat here on the forum now sells a sprue plate/mold lube.

[Mal Paso]

Beeswax on a hot Brass mold and scrub with Q-tip or rough cloth is the best I've used. Found in another post here.

[nighthunter]

If the build up is heavy I use a scraper made for removing paint from glass. It holds a single edge razor blade and if used at a very low angle it removes the lead smear and does not damage the mold. Use very light pressure and then apply mold lube and you will be OK.

Nighthunter

[Wally]

If the build up is heavy I use a scraper made for removing paint from glass. It holds a single edge razor blade and if used at a very low angle it removes the lead smear and does not damage the mold. Use very light pressure and then apply mold lube and you will be OK.

Nighthunter

I used to use that method...take a "bad" Brass cartridge case and flatten the mouth--use it as a scrapper (on iron blocks only)..it cannot damage the iron blocks.

[Bob Krack]

I too was frustrated by constant sprue plate smears on the to of of my moulds.

When I changed my methods from using a wooden sprue plate "knocker" to using a gloved hand to open the plate, I got into the habit of wiping the top or the mould and the bottom of the sprue plate every few casts and no more tracks again. Ever.

The rag should work just as well, I think.

Bob

[RU shooter]

I do the same as Bob about does wear a thin leather glove under a thick cotton glove , open the plate and if I see any smear I give it a quick wipe with my thumb . Unless it real heavy deposit it wipes right off.

[Petander]

I will bump this old thread because there is a way to prevent smearing. Sometimes we just go too hot and/or too fast.



Whatever method you use (beeswax/oil/chopsticks work for me, vinegar/H2O2/Q-tips for brass), a clean , degreased mold will then be lightly "painted" with Hi Tek bonding dry lube. It will bond on first session,helps with release but what I really like, no oil is needed anywhere to interfere with coatings later on. And no smearing, not even if you try hard.

An almost cleaned mold. One of my favorite 45-70, RCBS 325 grn FN.



A painted and cured mold. This dry lube will hold for many sessions. Then just paint again. Beautiful brass molds will look ugly when painted but I can cast silky boolits faster and relaxed.

[Petander]

Treated brass molds look like this:



Those boolits are airgun pellet scrap, almost pure lead. I was able to cast fast and hot ,Lyman Big Dipper at max. No smearing at all.

Small ones are for Saeco BHN tester only,never mind the wrinkles.

[zymguy]

Synthetic 2 stroke motor oil works too.

i agree with synthetic 2 smoke oil being the solution.

[Shuz]

A piece of rough leather, like a work glove, will usually remove lead smears from a mould or sprue plate that is hot. As others have said, a minute amount of 2 stroke motor oil on the underside of the sprue plate will prevent those lead smears as long as you don't open the sprue plate before you should! ��