Mould lube disaster

[longcruise]

ok, not really anywhere near "disaster" but it got your attention.

A while back in a casting discussion (can't find it to link) the question of mold lube came up. I have always used the bullet lube solution and it worked well but, being curious like the cat i have to try new things and ideas. Hasn't killed me yet but there's been a few poor outcomes. So, heres one of those poor ones:

It was suggested that high temperature thread treatment would be an excellent mold lube and since it is my go to for nipple threads (for which it serves very well) it was on hand right there in front of me. I decided to try it on a brand new mold. The results were terrible. The mold gradually became more difficult to operate as the session went on. I did a little over 100 balls and that was what I intended to do. By that time the sprue cutter was very stiff.

What happened was the compound made it's way into the thread's of the sprue cutter screw as well as a few other places and there it solidified! There was no turning the screw. I tried a reverse impact driver and it didn't touch it. Finally, I filed flats on the side of the screw head and clamped a vice grip on it. The screw now turned with considerable effort. . . . . Until the head sheared off.

Here's a few pics of the aftermath

Decided to drill the screw out and that was successful except the threads were damaged to unusable.

Here's some of the residue on the inside mating surfaces of the mold.

I can easily rethread the hole but the original screw is a shouldered type to match the sprue plate. I'm not sure if a screw with matching shoulder but larger threads is available.

As to the cause! The only thing I can come up with is that the mold was way overheated. However, I did everything the same as I've been doing for over 40 years of casting. Did I get careless? I'm not sure. Is the thread treatment just unsuited to this use? I don't know.

 

[hawkeye2]

I'm a strong supporter of anti seize products and use them regularly but when I read the recommendation to use them in this application on this forum I shuddered. There are far too many things out there readily available to use as lubes and release agents on bullet molds to try something questionable. You only made one change and this was the result so I would hazard a guess as to what caused the problem. You could oversize the hole, bush it and retap for an original screw. Lee sells all the parts for their molds, they are inexpensive and their customer service is excellent but at the price of a new Lee mold I probably wouldn't put much time in this one.

 

[longcruise]

I agree on the time limitations. In fact, i orxered two molds, a 570 and 575. At least i thought i did. Turns out that i ordere two 575 and that's the perfect size for my tw 58s so i already have a new 575.

Naturally I'll still try to fix it just because!

 

[Jaeger]

I agree on the time limitations. In fact, i orxered two molds, a 570 and 575. At least i thought i did. Turns out that i ordere two 575 and that's the perfect size for my tw 58s so i already have a new 575.

Naturally I'll still try to fix it just because!

I think I agree with Hawkeye on this one. Lee moulds are so reasonably priced that it probably isn't worth working on, but if it were me I would probably be trying to repair it anyway. I've used DuPont Krytox to lube my moulds a little bit, but it really doesn't seem like I need to lube them much. The kind of seizing you experienced is pretty amazing.

 

[Zonie]

longcruise:
You learned something worth telling others and now you have. Thanks for that.

Take it from a person who spent a lot of years designing gas turbine and jet engines (me) there is only one thing that works well for a lube at the 750° - 800°F temperatures of melted lead. MOM. MOM is short for Milk of Magnesia. The stuff people take as a laxative.

I really don't recommend it for use on a bullet mold because it is water based and it can cause corrosion on the steel parts but if care is taken to dry the water out of it after it is applied, it will work.
I also don't recommend applying it to the bullet/ball cavity because it does take up some space so if it is used on those surfaces it will change the size of the finished casting.

 

[longcruise]

Good and interesting tips, Zonie

 

[Maven]

longcruise, By any chance were the threads which hold the sprue cutter in place left-handed as the newer Lee moulds tend to be? Btw, I generally don't use anti-sieze on those bolts as it's messy and migrates: Just a dab of beeswax works for me as long I don't overdo it.

 

[longcruise]

Left hand threads!!!

I shoulda thought about that possibility! I think they might have been.

 

[hawkeye2]

Left hand threads.

.246X.152 PHIL SHLDR

Part FB1112 left hand screw for securing sprue plate on double cavity and single cavity bullet molds.

The good news is they are avaliable for $.50 each.

 

[bang]

I use anti seize but only on surfaces not threads and have poured 100s with no issues. I also clean and reapply after each use. Yes the newer molds are left thread. Most good anti seize is rated in 1000s of degrees and pouring lead generally is half of rating. When turning left doesn't work that says something.

 

[bang]

I agree on the time limitations. In fact, i orxered two molds, a 570 and 575. At least i thought i did. Turns out that i ordere two 575 and that's the perfect size for my tw 58s so i already have a new 575.

Naturally I'll still try to fix it just because!

Have seen same problem fixed by putting a shouldered fastener fashioned to fit in and adding a set screw on the side. Light clamp pressure then tighten set screw.

 

[longcruise]

Have seen same problem fixed by putting a shouldered fastener fashioned to fit in and adding a set screw on the side. Light clamp pressure then tighten set screw.

I like that idea.

 

[user 34300]

Moly Paste

 

[The Crisco Kid]

Is it mentioned anywhere in the poop sheet that comes with Lee moulds that the sprue plate screw is left handed? Did I miss that part before I twisted the screw off since the plate was a little too tight? I thought it was just jammed. Oh well, I tossed it and ordered a Lyman. They're moulds seemed to have improved in quality quite a lot lately.

 

[Tinhorn]

I bought this gynormous tube of Paraffin to lube my bandsaw blade for metal cutting. I use that paraffin to flux my lead, does the vapor lube the mold? The RBs come out nice and shiny and filled out, and the mold and sprue plate work great. My sprue-knocker is a piece of 1" heavy-wall PVC pipe about a foot long, so it won't damage anything, IMO. So is paraffin OK as a lube? I have cast about 2 lbs of .495s with it for my PBR rifle. New Lee mold works great, but I cleaned it with brake cleaner and then boiled it to remove any residue prior to casting for the first time. See my old thread on Lousy Bullets. Tinhorn

 

[hawkeye2]

I don't know if paraffin is OK as a lube but with your results I sure wouldn't change anything. I've used paraffin and old candles when fluxing and they work fine.

 

[TNGhost]

NRA's Beeswax Alox formula bullet lube, as made/sold by just about every purveyor of reloading,and casting gear and many others.

I always have a stick of the LEE brand sitting next to my casting setup. Worked for me for decades. Get the mold hot and a quick touch on the indicated parts is all that is needed. Also works for fluxing. A pea sized piece normally does the job.

Thanks for the heads up longcruise, I am certain you saved more than one of us here some headaches.

 

[mooman76]

2cycle oil works. It's made to withstand hi temp. Use it sparingly of coarse.

 

[longcruise]

Is it mentioned anywhere in the poop sheet that comes with Lee moulds that the sprue plate screw is left handed? Did I miss that part before I twisted the screw off since the plate was a little too tight? I thought it was just jammed. Oh well, I tossed it and ordered a Lyman. They're moulds seemed to have improved in quality quite a lot lately.

Yup, it is mentioned. Too many years of using the Lee molds. Don't need to read the instructions anymore!!

 

[Kno-ie]

I'll second the use of 2cycle oil but would recommend the synthetic style. I've used it for the last 28yrs. I allow the mold to come up to temp then dab a little on the out side joint at the plate screw with a Q-tip. It will then creep through the joints to lube both the top and bottom of the plate and screw. I'll dab again when I refill the pot for a second round. This has work very well for me with Steel and Aluminum molds.