What have I done to my Accurate Mold

[giz189]

I had one come in from somebody, it wasn't one of Toms that was that way. I pushed the alignment pin in just a hair and that fixed that one. Just my .02.

[geargnasher]

I think the problem is the alinment pin. If i use that pin as the pivot point and rotate one of the two halves 180 degrees The two halves will not mate flush. Did that make sense?

Makes perfect sense to me, that's how I check alignment pin seating depth when adjusting it. Sounds like the pin or socket slipped, but that's hard to imagine because it takes several tons of force to move them. If you're convinced it's the pins on that one end and not burrs or warpage, take my advice and let Tom fix it for you unless you have a shop press and good skills.

Brass warps if you take it way over the temperature that the blocks normally achieve while casting. You cannot get carried away with preheating. No torch, no uneven preheating, no overheated hotplate.

I know, I warped one of your three-bangers (brass) by preheating it on an open-coil hotplate. There was a .003" gap in the middle, I fixed it with pieces of shim stock, a hydraulic press, hardwood blocks, and lots of care and patience. I since made an oven out of an electrical box with a steel heat sink plate underneath to put on top of the hotplate coil so that the mould is heated by air, not direct conduction so no hot spots to cause mould warpage. I also have a BBQ grill thermometer mounted through a small hole on top and never let the moulds get over 420 degrees, less is probably better.

Gear

[tommygirlMT]

I once warped a Mountain Molds brass mold --- I fixed by clamping it tight in small bench vise --- (not attached to bench loose) --- and then carefully and evenly heating both mold and vise together with pre-heater torch nozzle --- basically you "paint" with the flame to keep everything even --- got it very hot but not glowing or nothing --- then dunk in bucket of water --- vise and everything --- Same process as annealing brass cases only much bigger scale and mold blocks clamped against each other not loose so faces form to each other

Annealed the mold twice like that --- then heated it up one more time and let it slow air cool to "set" it --- When I unclamped it --- everything back like supose to be as far as no more warp --- Lee-mented the cavities with toothpaste and it cast good boolits to this day

Not saying it always work out with that method --- or it should be anything other then last thing to try --- but worked for me --- and mine had big bad warp --- gap big enough in center right between cavities (one side cup warped in middle between the two cavities) to slip in a strip of paper when tightly closed and you could clearly see warp with naked eye

[dbarnhart]

The mold is on it's way back to Tom. I'm sure he'll be able to tell me what I did to it.

[Colorado4wheel]

Even on high my hot plate won't get the brass mold to ideal casting temp. It won't even boil water for crying out loud. I don't know why they even sell them to be honest.

[dbarnhart]

Maybe it should be called a 'warm plate'

[Gregger]

Interesting thread. I'm new to casting and have only cast about 600 useable bullets. The first (and only) molds I've purchased were two brass Mihec molds that I got from seperate group buys on this site.
At the end of my last session, I noticed the faint parting lines like dbarnhart describes. After air cooling, I inspected the mold and could see a faint sliver of light shining through the bullet cavities. I've never overheated the mold or done anything else to warp it and can not see anything that would not cause the mold to close completely. The mold was removed from the handles during the inspection.
Just for grins, I decided to check my other Mihec mold in a different caliber, which has not been used at all. I could also see a faint sliver of light through the bullet cavities on this mold. Until I saw this thread I put the faint parting line at the end of the session down to getting tired after about 3 hours of casting. Now I think the molds might be the issue.
Is this "light" test indicative of a faulty mold or is a faint sliver of light acceptable as long as the parting line does not become too bad.
Also should you be squeezing the handles tightly while pouring ( I use a lee bottom pour).
Thanks for all the help. I was happy with the bullets I was able to cast with the info mostly from this site, even if a few of the last ones had the parting lines.

[Iron Mike Golf]

Your eye can detect an incredibly small hairline of light. I don't worry about a parting line unless my thumbnail catches on it. Any slight out of round (on the order of several ten-thousandths) is taken care of by sizing.

[lt250r_86]

Just checked my 2 cavity mould I received from Tom. Zero bullets casted. No light between the mould halves. Mounted the mould to a brand new set of Lee 4 cavity handels and I can see light through the base of one cavity ( inside cavity ), no matter how hard I squeeze I still see light, so maybe its just the handels causing your problem.

[dbarnhart]

The first thing I did was to remove the mold from the handles. The problem exists when the mold is on the handles or not.

[Colorado4wheel]

Just checked my 2 cavity mould I received from Tom. Zero bullets casted. No light between the mould halves. Mounted the mould to a brand new set of Lee 4 cavity handels and I can see light through the base of one cavity ( inside cavity ), no matter how hard I squeeze I still see light, so maybe its just the handels causing your problem.

Take the mold halfs off. Look at how the tips line up. Bend the tips till they line up perfectly. Reinstall and check for light. Nice mold. Sucky handles.

[dbarnhart]

I talked to Tom today and the mold is now on its way back to me. Somehow one of the alignment pins moved and was sticking out too far.

I have no idea how I could have caused that but I surely must have done so.

[Dannix]

I talked to Tom today and the mold is now on its way back to me. Somehow one of the alignment pins moved and was sticking out too far.

I have no idea how I could have caused that but I surely must have done so.

Did you ever whack the mould with a wooden mallet to release the boolits?

[madsenshooter]

Perhaps not fully seated, for example NOE recommends a 3 or 4 heating/cooling cycles to get the pins locked in place. No mold whacking, I found out with one of BaBore's molds. Even a plastic screwdriver handle will deform hot aluminum! Had to sand a bit off the top edge to get the sprue plate back down where it was supposed to be.

[shootinxd]

I had a feeling Tom would take care of it.Best to have the pro do it.Just my .02

[dbarnhart]

The mold is brass, not aluminum. No Whacking needed. One of the benefits of having a fine high quality mold from Accurate Molds is that the sprue plate can easily be opened with a gloved hand.