Need advice

[500cadillac]

I recently bought 2 Lee 6 cavity molds: 429-240-2R, and TL452-230-2R.

The problem with them is the base of the boolits would have fins on them.

I returned them to Lee and got 2 new molds back, but they listed the problems as being a defective alignment pin on one, and the other was the sprue plate bolt by the notch was too long. But I never noticed these things as being issues.

So today I tested out one of the new replacement molds, and it does the same thing! I also noticed that the "fins" always are in the direction that the sprue plate opens.

Just to make sure I knew what I was doing, I took out an older 6 cavity .45 Lee mold. Perfect bases on this one

The biggest difference that I found is the molds that don't work well have very dull sprue plates. I don't know if this matters though.

Can I fix this or do I have to bother Pat at Lee again? thanks

[justingrosche]

Something is keeping your mold halves from completely coming together. It could be any # of things from burrs to the mold handles binding, either on the handle bolt or the attachment screws. Considering its on two molds, check the handles first.
Good luck.

[deltaenterprizes]

With the mold halves together and the sprue plate open, hold the blocks up to the light. Looking into the cavities you should see no light between the blocks. I you see no light, try it with the handles on.
Try to see if a piece of aluminum foil will fit between the blocks and release when pulled gently in the area of finning with the blocks on and off the handles.

[onesonek]

I don't know for sure, as I'm new to this. But I believe the first 2 response's missed something. Maybe, it's because the term used as "fins", in the OP. To me fins occur on the side of the boolit, due to a slight gap in the mold halves. The OP is describing, what I would call smear, or more so flashing at the top of the mold on the boolit base. It makes sense to a point, that a dull sprue plate could be the culprit. But I also wouldn't rule out a slight warp in the sprue plate. Nor would I take for granted, that the mold top is completely flat. Whether that is from alignment pins slightly off, or uneveness from milling, or mold warp, would be a guess without seeing the mold in hand.
With the 2 halves together, and the sprue plate closed, I would look between the SP and mold, when cold then hot, first off.
But I could be completely off base here, just guessing on my part

[casterofboolits]

My take on the OP"s original question is the same as onesonek's. Flash around the base of the boolit caused by poor sprue cutter alignment or mould block misalignment.

Ive had this problem occur with Lyman four cavity moulds until I learned to correctly put the right pressure on the pivot screw and the rear sprue plate stop/retention screw. Once adjusted correctly, no more flash.

On Lee two cavity moulds, the problem is caused by the self tapping sprue plate pivot screw which raises a ring of aluminum causing the sprue plate to be cocked at a slight angle. I remove the sprue plate and use a Wilson case chamfering tool to remove the ridge and chamfer the screw hole enough that it will not raise a ridge of metal when the sprue plate is put back on.

I also stone the bottom of the sprue plate flat and chamfer all sharp corners on the mould block and sprue plate. 99% of the time this will cure the problem.

[justingrosche]

Ok, cut me some slack it was 2 in the morning when I posted.LOL
Now that I re-read, yes it sounds like flash. Either to much tension on the sprue plate bolt, or too loose and the hold down is too tight. Aren't Lee molds great!

[500cadillac]

Yes to onesonek and casterofboolits. I also suspected warped sprue plates. Before I sent them back I tried fixing one of them by sanding the SP flatter. That helped some, then I used the conventional SP screw method using a set screw instead of the wavy washer. It was pretty much good at that point. Then i tightened the screw a little more and the mold galled. (6061 Al = ) Yes it was lubed.

I will try swapping sprue plates with the mold that works.

[mroliver77]

Like casterofboolits I make sure plate is flat(I use emery on a flat plate to dress sprue plate and mold tops), holes beveled and everything deburred. I run very little tension on the sprue plate bolt letting the plate swing freely. After stoning flat I rework the sprue hole so edge is clean and sharp. I like a sharp cutting edge. I use Mihecs plate lube and am happy with the results.

Sometimes breaking the top edges of mold face ever so slightly helps with base fill out.

I use JB Weld on handles and they stay on forever and do not split if the void between wood and steel is filled with JB.

A thorough leementing along with these touchups and Lee molds service me well.

Jay

[w5pv]

I have three different Lee moulds<I have to open and close them a couple of times before they match real close and even I watch for this each time before I pour lead.This system gives me good boolites each time.Also look for a little lead or trash around the alignment pins this can cause a problem.

[500cadillac]

Swapping sprue plates helped a bit, sanding the area flat under the SP bolt fixed it. So now i know it is a SP problem.

[myg30]

Its always hit or miss with the 2 cav lee molds. Some are good right out of the box and some you wish you never took out of the box ! Still worth the money and the labor to fix em up. They do cast some good boolits fer cheep !

Mike