cleaning aluminum bullet mold with electrolysis

[Joe S]

I have an aluminum bullet mold which will no longer cast good bullets, for some reason. I have cleaned it with boiling water, boiling water and Dawn for Dishes, acetone, denatured alcohol, isopropyl alcohol and Methylethylketone. so far, nothing works.
I suspect the problem started with some zinc contamination in my lead supply. So I am thinking perhaps there is some zinc or zinc oxide that has gotten stuck to the mold, even though I cannot see it even with magnification.
At any rate, has anyone tried cleaning an aluminim mold with electrolysis?
Thanks!
Joe S

[Rcmaveric]

What do the bullets look like?

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[DougGuy]

I don't think you can put aluminum in an e-tank it will eat it.

[Traffer]

As far as I know, electrolysis will completely destroy aluminum.
If you cant see a problem even with a magnifying glass... Have you tried smoking it?

[country gent]

I would start with a good solvent and tooth brush remove all you can then dish soap and hot water scrubbing and working up a good lather, rinse in hoy water and inspect it as best you can,

You don't say what the issues are with the bullets so a shot in the dark. If the mould has vent lines make sure they are clean and not plugged. Make sure pins are seating correctly and mould closes and is alighned.

[longbow]

If you haven't already, try pre-heating the mould almost to the melting point of lead then cast. The boolits will take a few seconds to freeze but go slow and see how they come out. After a few pours the mould will cool and stay at the right temperature if you keep casting steady.

As mentioned, smoking the mould or trying a mould release or maybe graphite spray should coat over anything that is on the mould but I doubt any contamination would "stick" to the mould and cause you grief. My opinion.

Try pre-heating and maybe a mould release before going drastic.

Whose mould is it (brand)? If a Lee then it is easily and economically replaceable. If an NOE, Accurate, Mihec or other high end or group buy mould that is not cheaply or easily replaceable then think hard about doing things that may ruin it.

My thoughts anyway.

Longbow

[Joe S]

Thanks everyone for your comments. The bullets look good superficially, with excellent bases, but the bands consistently fail to fill out. I have tried smoking the cavities, scrubbing with hot water as suggested above, and I do use a hot plate to pre-heat the mold. Have also pre-heated it to the point of almost being too hot.
I suspect there is some blocking of the vent lines. It is an Accurate Molds product, and the vent lines are very fine.
I have another one on order, this time in iron, so as of now, the problem mold is basically worthless to me, I might as well try opening up the vent lines. I have a number of small files, not sure exactly what I should use.
Joe

[redhawk0]

If its Al...try a needle first before you go too aggressive with a file.

redhawk

[Traffer]

I would investigate the lead and the temperature of the lead. You may need a bit of tin in your alloy OR MORE LIKELY, your lead needs to be hotter when you pour.
I wouldn't use a file on the vent lines. With Aluminum, you can just scribe the lines with a sharp point. They should not be very deep at all.

[country gent]

A needle will work but is on the fine side. AN Awl does good, Scribe is good, Ice pick. A bamboo skewers point will do it also. These are easier to hold and contro than the needle or pin. A file will cut a wide line and may cause some finning. Work slowly and carefully you want to remove any build up or dings but not any actual metal.

Have you cast with this mould alloy combination in the past, what were the results. It may be a temp issue or need a little more tin added. Some times an ounce or so to a 10 lb pot makes a big difference. Another place to look is if your using a bottom pour pot is the stream up to full strength. A restricted nozzle can cause issues with fill out also. Ideally you want to fill the cavity fast so all the metal is still liquid. In very small or large long bullets this can be tricky.

[Traffer]

I bought some "steel gravers tools" on eBay from China to try my hand at a little engraving. No good for engraving steel BUT with a good straight edge they may be good for making vent lines in aluminum molds. I will take a chance on sharing the listing on eBay cuz it's cheap and I'm just showing it to help...

[Mitch]

Just a shot in the dark here.Sounds like you have the mold clean all the things you used on it shoud do the job with any **** that may get in the mold.So if you ae not getting good fill ad the mold is clean.I bet you up the temp of the melt to try and get fill out?and it does nothing or gets worse?So try going the other way do not clean the mold anymore you likely have all the oxidation off it and it needs to build a little back up.you said the mold no longer casts good bullets.This tells me it did at one time.What temp did you run the mold befor when you got good bullets?Or try running the mold at around 700 to 720.Do this for several sessions casting enough to get the mold up to temp.you can call it reseasoning the mold .this will build up a bit of the oxidation you cleaned off.this may be the problem to clean and to hot of melt.after a few short sessions it may come right out of it and cast great.This sounds like some of the problems i have had in the past.hope this helps.

[DocSavage]

As others have said either a bit more tin or jack up your heat. I run my aluminium molds between 650 and 700 degrees F.

[Dragonheart]

I would clean the mold with toothbrush soap & water then with a 50/50 mix of white vinegar & peroxide, which should remove minute lead deposits. If you can see anything use a pencil eraser to rub with the mix. Then using the lead of a #2 pencil, color the bullet cavities. Use the sharpened pencil lead to run into the vent lines. Preheat your mold and bring your alloy up to approximately 750 and you should be dropping frosted bullets, but they should be completely filled out. Slowly reduce the alloy about 25 degrees at a time until you find a good spot to stay.

[Joe S]

Thanks Dragonheart, peroxide and vinegar is something I have not yet tried. To address some of the comments made above, I normally cast at 850 degrees, which is where I usually get consistently good bullets. I normally cast with 30-1 but tried 25-1 and 20-1 with no improvement.
Also tried casting a around 700 degrees with no luck.
I assume that hydrogen peroxide which is commonly available is what you are recommending, am I correct?
Thanks!
Joe

[rwadley]

Hydrogen peroxide and vinegar is reportedly corrosive to aluminum.

[KenH]

What usually works for me (assuming the vent lines are clear) is take a bullet from the mold, take a dry wall type screw and screw into base of bullet (I use a lathe to be sure its centered, but not necessary), load bullet with a fine grit (5,000 or so) paste (polishing toothpaste?) and spin bullet in mold. Doesn't take a lot, and it won't increase diameter any to speak of when just cleaning. Bullets drop nicely then.

[Traffer]

Seems like you have tried about everything. So you may as well send it to me. I will either get it to work correctly or not. Either way you won't have to worry about it anymore because I will have it.
Is this not the perfect solution?
:bigsmyl2:

[Stephen Cohen]

Seems like you have tried about everything. So you may as well send it to me. I will either get it to work correctly or not. Either way you won't have to worry about it anymore because I will have it.
Is this not the perfect solution?
:bigsmyl2:

This is why I like this group, members who will take on and weather the hardship for others, with no regard to self preservation. Regards Stephen

[Dragonheart]

Hydrogen peroxide and vinegar is reportedly corrosive to aluminum.

And it will rust and pit steel if left for a long soak, so care needs to be given if used to remove lead from a barrel. However it does not effect stainless.

But if you are using it for the purpose intended to remove those difficult to remove lead deposits there should not be a problem on aluminum, at least I haven't had one in the last 30+ years of using the stuff to clean aluminum, steel & brass molds. I just finished cleaning my RCBS Pro Melt to where it is working like a new one. I know of no other way to get all the buildup out of the pot and especially the spout without damage.

BTW: It will patina a new brass mold without that long break in time.

[Dragonheart]

Thanks Dragonheart, peroxide and vinegar is something I have not yet tried. To address some of the comments made above, I normally cast at 850 degrees, which is where I usually get consistently good bullets. I normally cast with 30-1 but tried 25-1 and 20-1 with no improvement.
Also tried casting a around 700 degrees with no luck.
I assume that hydrogen peroxide which is commonly available is what you are recommending, am I correct?
Thanks!
Joe

Yes, Hydrogen Peroxide the same stuff you can buy at Costco, Sams or any drug store. You probably already have some in your medical supplies as it is a mild antiseptic. It is usually 3%, but strong enough to make the vinegar a super oxidizer that will dissolve lead or break it's bond to the underlying metal.

850 does seem a little too hot, but whatever works. Have you checked your pot with a thermometer to see if it is really at that temp? 700 doesn't work for me either, since I run two molds simultaneously. I typically need it in the 725-750 range to keep the alloy flowing. I also don't worry about the alloy mix as I shoot range scrap, typically is in the 10-12 BHN range, but since it is powder coated I could shoot pure lead at handgun velocities without worry. Hope some of the suggestions work for you.

BTW: I have used electrolysis for removing rust from steel/cast iron and that works quite well, but I am not aware of a process for aluminum. I wouldn't recommend ultrasonic cleaning on aluminum either or at least not for any duration.

[longbow]

Something else you might try is to loosen the sprue plate to allow better venting at the top of the blocks. I usually loosen my sprue plates so they almost swing free. On some moulds I find that I have to bevel the top edges of the mould blocks ever so slightly under the sprue plate. This forms a very small V where the mould blocks meet. it only needs to be a few thou so no files! I use a diamond hone to just break the sharp corner.

Having said that this is usually when bases don't fill out well but the tight sprue plate being loosened and possibly those top corners being just broken will help venting and won't hurt anything so worth a try.

I would not recommend a file for vent lines! I think country gent has it right... try an awl with good point or scriber or fly fishing bodkin. Something with a decently sized shank or handle and nice sharp point then very carefully score the vent lines, but only if you see something in them. I'd try loosening the sprue plate first then breaking sharp corners at the top of the blocks if that doesn't do it. Then if those don't work try clearing vent lines.

Longbow

[yeahbub]

What Doc Savage said. It doesn't sound like your mold has anything in it that would be a problem. I had a mold which cast good looking boolits on the nose and base, but the driving bands were visibly shrunken away from the mold on one side. I added a 3/4" hunk of bar tin to the 20lb pot and left the mold on top of the pot for 15-20 minutes covered with a sheet of aluminum foil. It cast normally after that. I think the temp was a bit low and the alloy benefitted from the tin. The previous casting session gave indications that it could use some.

[HangFireW8]

Thanks everyone for your comments. The bullets look good superficially, with excellent bases, but the bands consistently fail to fill out. I have tried smoking the cavities, scrubbing with hot water as suggested above, and I do use a hot plate to pre-heat the mold. Have also pre-heated it to the point of almost being too hot.
I suspect there is some blocking of the vent lines. It is an Accurate Molds product, and the vent lines are very fine.
I have another one on order, this time in iron, so as of now, the problem mold is basically worthless to me, I might as well try opening up the vent lines. I have a number of small files, not sure exactly what I should use.
Joe

I doubt exploring another dozen ways to clean molds is going to solve this problem. I think you need more pressure. If you are using a bottom pour, either increase the flow rate, or try ladle casting. More tin might also be needed, as has been mentioned.

I'd like to know which mold you're using. I have a 2 cavity Ideal in 458 where pouring the second boolit would push air into the first cavity and flat side the still molten slug there. The two cavities were very, very close together and vents connected them. Waiting between pours, or using only one cavity would fix the problem. Maybe not your situation, but other than cleaning methods we have very little to go on.

[pjh421]

Forgive me if my ignorance on this thread is evident. I'm at lunch and didn't read the whole thing but I did notice that you said your bases are filling out yet you're driving bands are not. To me this indicates a venting problem. I also saw the word file used. You don't need to file. What you need is a carbide scribe with a very fine point. You need to lightly, and I can't emphasize enough that you must do this very carefully, scribe the vent lines. Beginning near the cavities scribe toward the out side of the mold blocks. This can be challenging with Lee moulds given the fly cutter s.tyle vent lines. With other molds that utilize straight vent lines it's a piece of cake. You may need some magnification and a vice to hold your block.

[GRid.1569]

Go back to square one.... clean the mould and get a “controlled” alloy... buy something from rotomeyals and eliminate the concerns about your alloy... if it works then...

[gpidaho]

OP: You stated that you have the same mould, but in iron on the way. It seems you have been very diligent with your cleaning attempts. It's been my experience that for what ever reason, some moulds are just a PITA. Send it off in an Ebay sale and you will have a good start on paying for the new mould. Gp

[uscra112]

What usually works for me (assuming the vent lines are clear) is take a bullet from the mold, take a dry wall type screw and screw into base of bullet (I use a lathe to be sure its centered, but not necessary), load bullet with a fine grit (5,000 or so) paste (polishing toothpaste?) and spin bullet in mold. Doesn't take a lot, and it won't increase diameter any to speak of when just cleaning. Bullets drop nicely then.

I've flat ruined an aluminum mould by using a drywall screw to turn a lap. Screw worked right through, and the tip gouged the mould something awful.

Since then I've drilled a small hole and used a suitably sized Torx bit. Drives well in both directions.

In the '50s we used Colgate toothpaste, which had finely ground feldspar in it as an abrasive. Then I discovered Barkeepers Friend. Mix with a bit of soapy water. Bon Ami also works.