Leaving boolit in mould

[texas tenring]

I bought some used single cavity Lee moulds and the previous user had left a cast boolit and uncut sprue in the mould. I assume he did this to keep the mould cavity from being contaminated and ready for the next casting session.

So is this a good or bad practice?:???:

[montana_charlie]

I leave a bullet in the cavity (although I do cut off the sprue) if I am going to spray the mould exterior with graphite to prevent lead from sticking.

In your case, it kept the mould halves from vibrating against each other during shipping.

I sometimes leave the last bullet in the mould (with sprue intact) for much the same reason...if I don't plan to use it for a while...just to prevent 'handling damage' during storage. But, I have never done it with an iron mould.
CM

[Bullshop Junior]

I vote bad. reason #1 very hard to cut sprue. #2 The casting does not seal off the block from oxidation. The boolit can oxidize and excelerate the rust/corrosion process. #3 you cant see it when its happening.
I learned the hard way by causing damage to a nice 4 cav Veral mold.
BIC/BS

[floodgate]

I don't think leaving a bullet - uh, "boolit" - in the mould would have much effect with an aluminum (or brass/bronze) mould, but I do have some recent observations regarding iron (Lyman) moulds that may be pertinent here. I used to leave the last bullet and sprue in place, wipe down the outside with a slightly oily cloth, and put the mould blocks away, in that condition. I was checking the details on some moulds that had not been used for at least twenty years, and found light "blushes" of rust in the cavities on some of them, and not in others (it wiped out easily, BUT...). I THINK the difference depended on whether I had cracked the mould open at all and let air in (= eventual rust) or not (= no rust), but I am NOT going to run another 20-year experiment just to find out. From here on out, I will NOT be leaving the last bullet in iron moulds, and - now living 12 miles from the Pacific instead of the Upper Mojave Desert - I WILL add a bit of protective oil to moulds I plan to put away for any length of time; it's a LOT easier to remove oil than rust!

floodgate

[Jon K]

Me too, I vote leaving the boolit in is a NO_NO. Aluminum or steel/iron. The boolit draws moisture, and the aluminum will oxidize, steel/iron or any ferrous metal will rust. I have bought both that have been stored for years, couldn't hardly get them open, and guess what? Sorry I ever bought them. Most keep the molds in the garage - Lots of moisture in the garage.

Want to protect them, spray w/WD40 put a tie wrap or rubber band to keep it closed, bag it and put it back in the box. Wanna take extra measures, put a dessicant packet in the box.

Jon
:castmine:

[Bullshop]

My aluminum LBT mold was damaged by leaving the boolit in. After several months of storage perhaps a year or more I found the boolit badly oxidized and the cavities badly corroded. It is usable but each of the four cavities is dotted with shallow pitts. Never again!
BIC/BS

[Hunter]

I have been told by a few folks who cast not to leave the bullet in but be sure to coat the mold with a quality gun oil.

[Lloyd Smale]

use to dont anymore.

[Bret4207]

I gave up on that idea when I got a rusted mould. I do live in a humid area and that contributed no doubt. I now use ammo cans and dessicant boxes for storage. No problems at all.

[keeper89]

My long term storage method consists of leaving the molds in a sealed container filled with Marvel Mystery Oil. Have had molds in storage for 15 years or more in this condition, pulled them out and sprayed down with carb or brake cleaner. Never a speck of rust.......Don't know if that's a proper method but it has worked well for me.....[smilie=1:

[montana_charlie]

In my earlier post, I said 'sometimes' I leave a bullet in an aluminum mould. I admitted to that because I have a mould made by Shiloh (remember that company?) which still has a .45 Maxi-Ball in it with sprue intact.
The bullet was cast in 1975.

I discovered this when I was searching out all of my old casting stuff...in preparation for re-entering the casting arena.

After reading the comments of those who have participated, I decided to open that mould...stored in a cardboard box for thirty-plus years in a multitude of climates (including 5 years in Mississippi)...to see what condition my condition is in.

The aluminum blocks were anodized (I guess) so they have a dark copper color on all internal and external surfaces. Whether this treatment has a protective quality, or not, is something I don't know.
The (probably pure lead) sprue cut with normal hand pressure.
The top of the sprue is oxidized to an even grey, but the bottom is bright.
The bullet shines like chrome, and the cavity is perfect.
Even the steel sprue plate shows no rust, on top or bottom.

I'm not advocating anything...just reporting.
CM

[Uncle R.]

I doubt very much that leaving a bullet in the blocks will reliably prevent corrosion - although I've seen it done many times and I've never seen it cause corrosion. I wouldn't trust my own moulds to that method.
It just grates on me to oil a set of cast-iron blocks that are cured and broken in and throwing good bullets. No matter what I use to clean them for the next casting session, they'll throw a dozen or more bad drops before they start working again - at least for me.
:(
I keep my most often used cast-iron blocks in sealed ammo cans with a generous pack of dessicant to protect them. I use a cardboard divider to keep the dessicant away from the iron. It's worked well for years even when stored in a cold and damp garage. The best part is that you can preheat those non-oily blocks with a propane torch (Watch out for water!) and be casting good bullets in one or two drops.
Oiling will protect cast iron moulds but be careful what you use. I had one set of blocks get rusty after spraying them with WD-40 and putting them on the shelf for over a year. I learned my lesson - Beware - WD-40 doesn't protect long-term.
:roll:

[ARKANSAS PACKRAT]

I got in the habit of leaving a ball in the mold not so much for corrosion, but to stop the bee's from filling the cavities (sometimes overnight) in a mold left out. Hard to clean one up after that.

[STP]

I`ve seen too many used moulds that were left with the last boolit cast in it that showed the ravages of rust in the cavity. A few showed no evidence of being "oiled up" before they were placed back in the mould box...paper or plastic. My show locations include Elmira, Syracuse, and Rochester, as well as many small shows in-between.. Who knows how far they traveled prior to my encountering them?
I`ve used a local creation to protect my moulds between use as the humidty in this locale tends to run the full spectrum of N.A. map. (Ray`s Gunwax)
I know that if I pick up a used mould at a show and see a boolit left inside, I get a bit nervous. Even had a few exhibitors complain when I ask if I can remove said boolit to inspect the cavities...!

[Marshal Kane]

I now use ammo cans and dessicant boxes for storage. No problems at all.

That's how I store my moulds too. NEVER leave a cast bullet in the mould, PERIOD.

[texas tenring]

What about just leaving last boolit in for just a short period of time, say a week or maybe a month? A mould that is being used on a regular basis. Is it possible you could drop that boolit and heat mould to tempeture and get back to casting good boolits again without cleaning or smoking mould cavities again? Obviously keeping mould in a good enviroment in between, does anybody have any experiance with that!

[waksupi]

The environment here is dry enough that I never have rust in a mold. However, when I recieve a new mold with oil on it, I spray it with carburator or brake cleaner. It dries almost immediately, is squeeky clean, and the mold can easily be smoked if needed.

[dwtim]

Sorry for necroposting, but I wanted to provide a visual example.

Here's a chance find that I picked up now that I'm looking to start casting with my own equipment. It came with a bullet inside and a puddle of lead on top of the sprue plate:

http://img57.imageshack.us/img57/2646/ly358rustnh8.jpg (http://imageshack.us)

[lathesmith]

Interesting posts here, a few items mirror my experience. As Uncle R points out, WD-40 is not long term stuff--I won't use it on ANYTHING as a rust preventative. Its "secret" formula includes alcohol and vegetable oil, two things that can accelerate, not prevent, rust.
Like waksupi, I have found carb cleaner and compressed air is great for cleaning all traces of lube from my molds. A little shot of graphite--i.e. mold drop--if needed, and I am ready to cast.
lathesmith

[Le Loup Solitaire]

I do not have any molds made of aluminum, but tried a couple of times many years ago to leave a cast bullet in an iron mold. In each instance I got rust even though the area was of low humidity. Fortunately I checked and caught the process in time to avoid damage and had to clean the cavities with the tip of a lead pencil. From that time on I wiped the empty cavity and all surfaces of the blocks with a product called "Clenzoil" which is still around and can also be used to effectively clean guns and preserve/protect them as well as other items made of metal. I also pulled the retaining screws after casting and put some on those before running them bak into the blocks. Never had a problem with rust after that, but of course I had to get the stuff out of the blocks in order to resume casting. Did that without a problem by soaking the blocks overnight or even shorter lengths of time in a can containing paint thinner and then wiping dry with a couple of cleaning patches and running a hair dryer on the blocks for a few minutes prior to prewarming. Acetone works fine too as a solvent as does lacquer thinner, but both aren't good for breathing even for a short period of time. In sum, iron molds need to be protected against rust and for me that Clenzoil did a good job.

[Le Loup Solitaire]

I do not have any molds made of aluminum, but tried a couple of times many years ago to leave a cast bullet in an iron mold. In each instance I got rust even though the area was of low humidity. Fortunately I checked and caught the process in time to avoid damage and had to clean the cavities with the tip of a lead pencil. From that time on I wiped the empty cavity and all surfaces of the blocks with a product called "Clenzoil" which is still around and can also be used to effectively clean guns and preserve/protect them as well as other items made of metal. I also pulled the retaining screws after casting and put some on those before running them bak into the blocks. Never had a problem with rust after that, but of course I had to get the stuff out of the blocks in order to resume casting. Did that without a problem by soaking the blocks overnight or even shorter lengths of time in a can containing paint thinner and then wiping dry with a couple of cleaning patches and running a hair dryer on the blocks for a few minutes prior to prewarming. Acetone works fine too as a solvent as does lacquer thinner, but both aren't good for breathing even for a short period of time. In sum, iron molds need to be protected against rust and for me that Clenzoil did a good job."Always trusted my Mom, but when we played cards I made her cut the deck".

[montana_charlie]

I have an observation about that picture posted by dwtim.
That mould was obviously kept in some place which was not mould friendly, but...

The only shiny metal left on those blocks is found inside the cavity...which had a bullet left in it.
CM

[Willbird]

The late great Harvey Donaldson said he left a bullet in a mold cavity because he stored them hung on nails in his workshop, and if he did not there was a little paper wasp that would make a nest in the cavities, said nest drew moisture and rusted the mold cavity.


Bill

[longbow]

Well, here's another opinion,

I was taught by a gunsmith about 30 years ago to always leave a cast boolit in place when storing a mould. I think partly to prevent movement between mould halves but also to seal the cavities. Having said that I usualy cut the sprue and open the mould so I can oil the faces and let oil wick into the cavities - sometimes removing the boolit(s) oiling then replacing boolits in cavities. This makes sure the important casting faces of the mould are preserved and capillary action keeps oil all over the casting surfaces. Oil on surfaces = no rust.

I'll take a little time to clean oil off and have a nice mould rather than be worrying about rust. I have never had a problem doing this or when I start casting either. I usually use a light gun oil or 3 in 1. Automatic transmission fluid also works well. Just wipe it off and wipe down with solvent before casting.

I agree with the WD40 comments above - not for long term storage!

[leftiye]

Small zip lock plastic bags you can get at hobby stores. Leave boolit in (or not) and put one of those pieces of dessicant paper in with mold and seal. Walk away. (just don't beat up the bag)

[Ken O]

I don't do anything to the aluminum molds, but the iron ones I spray with any kind of oil I have around like fogging oil, Kroil, ect. I spray carborator cleaner on them just before I use them to clean up the oil.

I wonder if leaving a bullet in could possible cause corrosion from electrolisis since its dissimular metals. I know where I have done some plumbing in the house and had some joints that went from copper to galvanized I had corrosion on the joints. I'm thinking a battery is lead on one pole and a different metal on the other (cant remember what).

[35remington]

Add me to the list of guys who don't worry about it. I oil everything. Carb and brake cleaner gets oil off easily, and very often my first cast or two yields a good bullet after hosing the blocks down and warming them up.

[longbow]

I'm with 35 remington.

I oil whether a boolit is left in or not, clean before use and never have problem.

I preheat and usually get good boolits within the first few cast.

[MtGun44]

Another vote for molds in 50 cal ammo can and surplus dissicant bag -
baked to reactivate. Cheap, easy, no cleanup, no rust.

Bill