How do you know when a mold dies?

[jayjay1]

Hey guys,
how do you know, when a mold is kind of breaking down?

How does this normally happen and how do you realise that?

I´m having a six-cav. aluminium mold where the BT on the top of it is fouling in two cavs.
Have took a closer look under the magnifying glass and saw some more bad spots.
It´s the first time, that this happens to me, so.

How many throws will a aluminium mold do?
And how many a brass or an iron mold?

[DeanWinchester]

With proper care and maintenance it should never "break down". Wear comes from inexperienced or sloppy users who do not care about their equipment. Pin, hinge and sprue plate must be lubed regularly. A mold must be stored in the dry and not exposed to humidity or moisture.

I've seen old Hensley & Gibbs molds that I KNOW FOR A FACT have run hundreds of thousands of casts. An old guy I knew years ago shot competition and used a H&G for his .45. He has worn out barrels but never the mold.
Aluminum can be more prone to wear but will last all but indefinitely as well, they just need a little extra attention as they are not very forgiving should they gall or get dropped.

A mold is no different than any other tool. Buy quality and have a care when use and store them. There are tools used daily that are older than any of us on this board. As a machinist, I ran many pre-war machines that would chew through steel like butter {better than any new machine made}. They were well built and well maintained.

[masscaster]

Check the Sprue Cutter edge that goes across the top of the mould to see if it's sharp. This is usually the cause, other than not using a Sprue Lube.
If it is sharp get some light sand paper and break the edge of the cutter, especially the corner of the cutter. On a flat surface hold the cutter at 30 degrees, rolling it toward the top as you pull it towards you. Stay away from the hold down hole.
This will allow it to glide over the mould instead of digging in.
Once you've broke the cutter edge, and if possible, rotate the cutter 180 degrees so the first hole you usually pour is the last. ; )
My aluminum moulds have ran countless rounds, but the surface will eventually wear irregardless. Rotating the cutter will help wear the surface evenly.

Hope this helps,
Jeff
P.S.
Always check these edges before using ANY new mould. Some makers do this for you, but it's still a good idea to check for burrs/edges.

[jayjay1]

...

Thanks for your clear words.
Well, I did all what you´ve said, but bullets began to stick.
So I took a closer look and found two points (at the top of the cavities, at the edge of the boat tails where the two mold halfs meet) who had imperfections.
The boat tails ends were crimped downwards somehow, no dropping the mold or anything.

I tried it with a rubber stick, then with a carpenter´s pencil, but that didn´t work.
Having no other alternatives, I´ve cut those two with a cutter knife as careful as I could.
I know that I shouldn´t, but didn´t know what else to do.

It worked, the mold dropped all six cavs flawlessly again.
Two or three sessions later it came back again.
And again I was trying to do it smooth, but had to use the cutter in the end.

Now it works again, more or less.

I have no idea, where this comes from, it´s like if the aluminium grows some fins there.

[jayjay1]

Check the Sprue Cutter edge that goes across the top of the mould to see if it's sharp. ... Always check these edges before using ANY new mould. Some makers do this for you, but it's still a good idea to check for burrs/edges.

Thanks, that´s a good advice.
Will do with new molds then.

[Char-Gar]

I agree that a mold should never break down or wear out, but all molds are not created equal. The aluminium used in Lee molds is much cheaper/inferior to that used by other makers. This inferior metal won't take much abuse for it to roll snake eyes.

I am very careful with my molds and some have been used 50 years by me without a problem. But, I have had to trash two lee molds. This is why I avoid buying them.

[MGnoob]

I seem to be the only dissenter, Like everything else in the world molds can wear out even without abuse...
I am hoping to get 1,000,000 before they wear out....with 2 cavity 4 mold sets like i use that's 8,000,000 projectiles..
i've got about 60,000 on my 9mm 4 mold set. which is 7,500 per cavity...I hope someday i can post here and say "i've worn my mold out" but at that point the mold will have paid for itself so many times over... I've probibly brutally crashed jammed between 5-10 projectiles. resulting in no damage.

Molds can remain serviceable for a long time, They can also be ruined by dropping them, improper cleaning and storage. They can also be repaired depening on the type and cause of damage.

[jayjay1]

Ok, so would you please tell me how you are doing it?

How do you clean a mold and with what?

And how can a mold be repaired, if it has those damages I have written?

[MGnoob]

Post a photo if you have a camera that can take a pic of such a small area.
I have no experience with that style projectile...you can remove the highspots causing the issue...
Having the mold repaired may cost more than this particular mold is worth. IDK what you have into the mold.

The good repair work i have seen from looking on the web has mostly been on iron molds..The damaged spots are welded in and either hand finnished or redone with the original tooling that cut the mold.I'm a pretty good welder and i wouldn't even try to fix an aluminium mold..I've had only a few good experience welding aluminium and it wasn't like the brain surgery that would be needed to properly fix an aluminium mold cavity. I've done some welding repairs on many things people have said..you can weld that...I fix alot of harden keyed shafts that are blown out..one off the top of my head one is the keyed shaft on the transmission of my Harley. Or haudralic fittings, and many small repaires on punch press tool and die sets.

IDK anyone off hand that does this with aluminium molds, maybe someone else can suggest a place.

I'm probably not the best person for clean storage procedure. while i am happy with how i do it, i don't have decades of experience to be able to say what works for the long hall, just don't use anything other than a pencil, toothpick or eraser to remove any build-ups on the mold faces cavities



*edit* i've kind of rethought what i posted here, i guess my 8 million is a pipe dream.This thread below shows so damage to my molds.http://castboolits.gunloads.com/show...-What-did-i-do
I hate to say they where insufficiently lubed, but it may be the case

[Hardcast416taylor]

I always seem to know when 1 of my molds finally gives up and dies. All my other molds are gathered around the deceased mold on my bench and are burying it in the slag pail. Seriously, I have molds that date back to the `40`s and are still turning out excellent products. Treat `em right and they will last a looong time.Robert

[masscaster]

If the edges/corner of the cutter are not sharp, check the actual Sprue Cutter pouring holes.
Laying the cutter on a flat piece of glass will let you see if cutter has burrs on the underside. Getting at eye level with a light behind it will show you.
I've seen this before. The chamfer burrs are not completely removed at the final stage of surfacing the cutter.
Lay a piece of emery cloth, or a bit coarser on the glass or tile taught. With the whole cutter on the flat working surface do small circles, clockwise and counter clockwise. Make sure the cutter remains flat!

Jeff

[jayjay1]

Thanks Jeff,
I will try this.

[MT Chambers]

The only molds that i have ever worn out were Lee 6 cav. .....they wear out where the cavity edge meets the mold parting line, and bullets drop with more than flashing in those spots, prolly cast too many in a semi-production set-up, all wore the same way and were discarded. Most of the wear was before we heard of "BullPlate" or similar lube.