Old Lee Mold Sprue Plate Problem

[LenH]

In need of a bit of help. I have an old Lee 6 cavity .452 190 grain SWC mold. I don't know the actual mold number but it was discontinued several years ago.
As far as I can remember I bought this mold back in 03 or 04. I used this boolit to replace some 200 gr boolits that were store bought. The mold has 2 shallow lube grooves
and shoots lights out from a wad gun.

I got the mold our last night to cast some boolits for my brother. I cleaned it with break fluid and a toothbrush and then sprayed it again and put it on the hot plate.
It was casting great boolits and then kind of fell apart and the sprue plate got loose and there was some finning at the base of the boolit, I tightened the bolt on the
sprue plate and that fixed the problem for a while but as the casting session went on and I guess the mold got too hot the finning at the base back and the bolt was tight.
It was also taking a while, maybe 20 or 30 seconds before the sprue solidified. Possibly too hot.

This is the only Lee mold I have and it cast some pretty good boolits but the sprue plate problem got bothersome. Any Suggestions.

[sdcitizen]

Definitely too hot. Cool it down till it takes 5-10 sec to solidify the sprue. I use a damp cloth in a shallow pan to set the mold on to cool it periodically. The sprue plate may also be warped, almost every lee 6 cavity mold I have has needed the sprue plate flattened out. I use wet sandpaper on a granite plate to lap them flat again. Start with 320 and work up to 800 or 1,000 grit doing figure 8's.

[Boolit_Head]

Might also check for a speck of lead keeping the block apart and causing that fining.

[Echo]

I believe the base finning is not on the side of the base, but finning off the flat base of the boolit - Right? If so, too hot is definitely one possibility. Another possibility is that you may have too much Sn in your alloy - I have been unintentionally in that situation, and the solution was to dilute the alloy 3/1 w/Pb.
And Roger on the wet cloth next to the furnace - not damp, WET! Sopping, as a matter of fact. See the picture - I made a little tray out of HD Al foil, folded up a ragged old chunk of towel, and doused it thoroughly with distilled water. Regular faucet water has minerals in it that will discolor the mold, and Life Is Too Short to use discolored molds!

If the sprue runs off the plate like water, the sprue plate is TOO HOT, and needs to be cooled by turning the mold upside down and setting it on the sopping pad and letting it steam for a few seconds. No harm to any equipment...

[LenH]

Thanks for the comments, the alloy was WW/PL mix. PID set at 700 and the pot was a Pro Melt. The PID held true. This mold just got too hot, I really needed the damp rag or sponge,
and will for the next batch. I went through the batch and only had about 10 or 15 rejects out of about 250. The bullets were nice and frosty, the way I like them. I applied a damp Q-Tip
of sprue plate lube to the hinge, the leading edge & to the alignment pins. I'm going to dismantle the mold later and go over it with a curry comb.

This is the only mold I have ever had do this. I have 2 new NOE and several old H & G molds. The sprue plates on those are a no brainer but this one has me a bit stumped.

[leadman]

Around that time Lee was producing a sprue plate that is not flat, has a curve that peaks at the holes. So check that along with cleaning any lead off the top of the blocks and sprue plate. Make sure you lube the pivot bolt. I recommend Bull plate lube which is 2 cycle engine oil. Just a dab will do ya.

I have a piece of emery paper taped down to a chunk of granite counter top I use for sanding things like this. Run the sprue plate in a figure 8 on the paper as this will keep it removing metal the same all over the plate.
Use something to align the mold halves when closing them. I have a piece of flat steel I place the mold on to cool and it is also used to align the mold.
Lee molds tend to be delicate and need to be treated gently to get any life out of them.

[tazman]

When I am casting hot and fast with my Lee 6 cavity molds, I will sometimes get a small smear of lead building up around the cavity nearest the hinge bolt. Sometimes this will build up and migrate till it is under the sprue plat around the bolt. When the bolt gets just a bit loose, the lead can build up, holding the sprue plate up slightly and allow the last cavity to flash between the mold and plate. The bolt will feel tight but is actually held up by the lead.
At that point I have to take the mold apart and clean off the built up lead so the plate fits properly. Fortunately it doesn't happen often. I usually can avoid this by casting a bit more slowly and keeping the mold cooler.

[LenH]

leadman, I am using Randyrat's zip lube. I bought a lube kit from him 3 or 4 years ago to make boolit lube. It was to make his Tac lube.
I have been using the little bit in the bottom of the bottles from making the boolit lube. It don't take much but it sure do make a difference.


Tazman, the more I think about it, the lead got under the sprue plate and caused problems, it will be taken apart and cleaned and the sprue plate sanded.


Thanks guys.