Anti seize and aluminum mold disaster

[kevin c]

I decided to try an anti seize compound on a couple MP aluminum molds, specifically on the sprue plate pivot bolt and the two handle bolts. This was the Permatex version in a tube, containing aluminum, copper and graphite. It’s rated to 1600°. I put just a thin layer on the bearing surfaces, specifically avoiding the threads.

BIG mistake.

After a single casting session, all the bolts seized up, jamming after maybe a quarter turn. I could only get the sprue plate bolt out, and found part of the threads full of hardened silver material (the same color as the anti seize) that is very difficult to remove.

The molds had been taken apart and reassembled a few times before without problem, and I’m sure I didn’t cross thread them.

I tried putting a dab of the Permatex on the mold preheater: a piece of steel on a coil hot plate whose surface gets to ~500°. It sizzled as it liquefied and ran before smoking and drying into a crumbly cakey silver powder. I’m guessing the compound migrated into the threads and decomposed from the heat in the blocks, though it never got near the upper limit of the operating range.

The molds still cast fine. It’s just that now the handles are permanently mounted, and I’m not sure how long the threads in the sprue plate bolt holes will stand future use.

Anybody want a barely used tube of Permatex anti seize?

[imashooter2]

I use a bottle of Permatex 133K that I bought in the 80s on Lee molds with complete satisfaction. Eliminates galling at the pivots and doesn’t migrate into the bolt threads at all. Not sure why my results are so different than yours.

[deces]

Did you use the Silver or Copper colored anti-seize?

[OS OK]

Been using Permatex anti seize since the late 70's, never heard of such a thing as you describe.

Maybe you got one of your other tubes of Permatex 'stuff' mixed up and used it?

https://i.imgur.com/Y54uZHVl.jpg

[Rickf1985]

What you are describing is thread galling. The aluminum threads have galled against the steel bolts. If you heat the aluminum molds and quick freeze the bolts with Freon or Co2 (Eco nazi alert!!!!) then quickly unthread them before the bolt heats or mold cools you should be able to get them out. I would run a rethreading tap through the mold but be aware that the threads are probably going to be loose from now on. You will need to put in a steel insert to repair them. Be sure to rethread the bolt also. If the bolt is Stainless steel you are screwed!!! THAT will be what galled and it ain't coming out!

[JSnover]

We had a stuck bolt in an extruder at work the other day. I can't remember the max temperatures but they're easily as high as casting temps. In spite of applying anti-sieze we still get stuck bolts on a regular basis.
One of the guys heat-cycled it by heating with a torch and then spraying it with "dust-off" (made for cleaning keyboards, etc.); holding the can upside down so it came out as a cold liquid. I can't comment on how safe it was but it worked.

[243winxb]

Should work for all aluminum moulds? https://www.thehighroad.org/index.php?media/casting-with-lee-molds.4127/full

[kevin c]

Deuces and OS OK:

It was the silver anti seize, product number 81343 that comes in a blister packed tube, that I bought specifically to try out. I have no idea why it failed so spectacularly.

Rickf1985 and JSnover:

I have never had galling on any bolt on any of my aluminum molds before, and the only change was the application of the anti seize. Maybe the extra material initiated the galling? Regardless I certainly will try your suggested removal technique and repairs.

243winxb:

I just wanted to try something that I’d read here. I certainly didn’t expect such a bad outcome. I’ll probably talk to Permatex to get their insights, but, unless they can explain convincingly that I didn’t use their product right, I doubt I’ll give it another go. MP molds are too nice for me to risk again.

[farmerjim]

I have aluminum anti seize on all of ( about 50 ) my aluminum molds. I have never had a problem with them.

[Carrier]

That Permatex you used is the same stuff I use at home and work. it is used on studs, nuts, bolts are items that see temps well over 1200 degrees F and I’ve never experienced what you did. I use it on sprue and handle bolts on all my molds. Only difference is we get it in tubs instead of tubes.

[uscra112]

You say you specifically AVOIDED putting the anti-seize on the threads. Why? Preventing thread galling is what it's FOR.

[Carrier]

You say you specifically AVOIDED putting the anti-seize on the threads. Why? Preventing thread galling is what it's FOR.


I have to quit trying to read things on this iPad without my glasses as I missing the OP saying he avoided the threads part. That makes no sense at all.

[imashooter2]

You say you specifically AVOIDED putting the anti-seize on the threads. Why? Preventing thread galling is what it's FOR.

I won’t speak for the OP, but I don’t put it on the threads because I have no issue with thread galling and I don’t want them lubricated so they loosen easier in use. I use it only to avoid galling and wear on the pivot points and alignment pins.

[nicholst55]

I always thought that nickel-based anti-seize is recommended for high temps - then silver, and then copper (as you decrease in temp). IIRC, nickel is rated to around 1100 degrees F. Applying it to the threads would be useful, however.

[kevin c]

I had read here about using this as a a lubricant so I thought it worked like a non migrating grease. One aim I had was to reduce what looked like galling on the block top around the sprue plate pivot (circular scoring), another was to have a bit more long lasting lubricant at certain points. I never had an issue with thread galling before; the bolts on all my other aluminum molds turn in and out easily despite much use.

As far as preventing thread galling and “assuring easy disassembly” (straight from Permatex’s website), whether I put it on the threads or not, I had the opposite effect after using it (again, I’m sure I didn’t cross thread the bolts, and even if I’m wrong in one case, it’s beyond imagining that I’d cross thread three bolts all at once), so forgive me if I seem just a little reluctant to CORRECTLY apply it to the bolt threads on any other mold.

Nicholst55:

The product I got, per Permatex, contains aluminum, copper and graphite, and is rated to 1600°. No mention of nickel or silver. I described it as silvery in color, I didn’t mean to say it had a silver content.

[Mk42gunner]

I don't know what the problem was caused by, unless you got hold of a bad batch. But then I have never used anti-seize from a tube either.

Forty years ago we used the heck out of spray type aluminum anti seize on truck lug nuts, when I worked in a tire shop. Now I use copper based brush on anti seize on my vehicles and farm equipment.

For use on aluminum molds I use the brush on aluminum stuff. I don't know what is in it nor the temperature rating, but the approximately one pint bottle should last for centuries.

Robert

[JimB..]

I wonder if it separated in the tube. Maybe squirt the whole thing into an old medicine bottle to see, not a waste since you won’t be using it again anyway.

For the mold, I’d try kroil. I might even put the mold in a bag of kroil in an ultrasonic cleaner.

[imashooter2]

I wonder if it separated in the tube. Maybe squirt the whole thing into an old medicine bottle to see, not a waste since you won’t be using it again anyway.

For the mold, I’d try kroil. I might even put the mold in a bag of kroil in an ultrasonic cleaner.

My big jar with the brush lid definitely separates. Oil (for lack of a better term) floats on the solids and has to be mixed back in before use.

[deces]

I think it's glycerin that separates.

[JimB..]

I think it's glycerin that separates.

MSDS suggests to me that it’s mineral oil.

[uscra112]

Glycerin is hygroscopic. You wouldn't want it in anything that is in contact with steel.