Never had this happen!

JWFilips

JWFilips

Well-Known Member
I always store my moulds in a temperature and humidly controlled room and After a casting session I always leave the last bullets cast in the moulds to store them.
I wanted to cast with a Lee 2 cavity 30 cal soup can today and when I opened it to tap out the bullets, one bullets stuck into half it's cavity.
when i finally got it out I could see that the was a white oxidation on the top two bands of that 1/2 cavity!
the rest of the cavities have a nice patina ( including the half in question) except for the top 2 bands on that half! Definitely Aluminum oxidation! I brushed it out with soft copper bristle brush and got it back down to bare metal but it etched the mould enough to cast that half of the bullet rough!
Never had this happen wonder what went wrong?
 
Missionary

Missionary

Well-Known Member
The only thing we leave in our molds is a liquid lube that smells like 30 weight motor oil. Been doing so for 40 years. Plus our molds sit unused for 2-4 years a wack wrapped in wax paper in cardboard boxes in some ones basement.
 
RicinYakima

RicinYakima

High Steppes of Eastern Washington
Lead, tin, antimony and aluminum all have different electro-valances. The electrode potential between aluminum and the other metals is far enough apart that with oxygen from the air and moisture, the aluminum will oxidize. Normally the "patina" layer will be enough, but it this case it didn't provide enough previously oxidized thickness.

I never leave bullets in the mould, and aluminum is worse than iron.
 
462

462

California's Central Coast Amid The Insanity
My take on leaving bullets in moulds is, if it's to prevent air from entering and causing rust, it won't, because the bullet shrinks as it cools and there is no longer an airtight seal. I don't subscribe to the practice.

The outside of iron moulds get an application of mould lube, then wrapped in a baggie along with a of VPI paper, then placed in its box with another piece of VPI paper. Living on the coast, I've never had an iron mould show any signs of rust.
Aluminum moulds just get hung on a pegboard hook.
 
Rick

Rick

Moderator
Staff member
Me either, never once in all my decades of casting have I left a bullet in the cavities for storage. That is another old wives tale and as you discovered one that can be harmful.
 
S Mac

S Mac

Sept. 10, 2021 Steve left us. You are missed.
I never leave them in the blocks, I bought a mould or two that did have, took some persuasion to remove.
 
fiver

fiver

Well-Known Member
you got rust.

a couple of years back Ranch dog had basically the same thing happen to a bullet in one of his rifles.
he leaves it sitting next to his back door in the kitchen area as a just in case rifle, and the bullet in the chamber done basically the same thing, even though it was coated in alox.
none of the ones in the magazine done it though.

we went through every scenario we could both think of to try and figure it out.
I still think the bullet/round was slightly jiggling in the chamber [from people walking on the floor/the door being opened and closed eyc.] causing a little electrolysis.
 
RBHarter

RBHarter

West Central AR
The advice does appear in the Lyman #43 to leave the last pour in .

The H&G I bought looking like it had been in the cowl of a John Deere for about 10 years in a barn had the last pour left in it . No problem for getting the bullets out but cutting the sprue was a bear .

I bought an RCBS 7mm-168 from brass magnet , I think , that still had the last pour in it also , same deal with the sprue cut .

I have off and on , in the desert it doesn't seem to matter . Here I don't think it's a really good idea steel against lead,tin , and copper seems like a good way to get things ate up and stuck together .
 
Ian

Ian

Notorious member
fiver said:
I still think the bullet/round was slightly jiggling in the chamber [from people walking on the floor/the door being opened and closed...
Click to expand...

I remember that. He lives near Cuero and it is an abolute forest-swamp there, besides movement and frequent air currents by the door.

RBHarter said:
The advice does appear in the Lyman #43 to leave the last pour in .
Click to expand...

I knew I'd read that in one of the Lyman or old Ideal manuals, right along with keeping your alloy stirred so the tin doesn't separate. :rolleyes:
 
Missionary

Missionary

Well-Known Member
Only issue I find up here in our desert is the nasty volcano dust gets into everything... Even molds wrapped in wax paper. That stuff sticks like glue to oiled metal. But brake cleaner defeats most anything.
 
RBHarter

RBHarter

West Central AR
I think it is probably a sound suggestion to minimize air change inside the cavity . If you have only 2-3 moulds and use them even once a month how much could they rust even if they got wet ?
Here we sit , I bet the low man here has over a dozen , I have 60+ and half maybe more are iron and I know good and well I have more than a few that were cast to check size , weight , and 100 bullets and got wrapped up 3 yr ago before the big move . I'm not alone in that I'm sure . So we oil and bag or some variation there of and call it good .
 
Creeker

Creeker

Well-Known Member
I leave my molds bare unless I'm going to store them & then I spray the cavities with Drop Out.
 
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