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I have a 4 cavity Murphy OR #503 H&G that is starting to misbehave.
The first two cavities' bullets fall right out when you open the mould. The third one falls out after a tap. The fourth one (the one farthest away) sometimes just doesn't want to let go.
Solid raps...and I mean SOLID will make it let go.
It casts beautiful 44 bullets but man this is driving me crazy.
There are no obvious signs of any finning, sharp corners, etc.
Any thoughts?
Maybe a rough surface or grooves with slight back angle creating a mechanical lock. With out some real magnification and good light this can be hard to see. I checked this on a optical comparator at 100X . That .030 deep edge then became 3" long on the screen and the squareness stood out.
On the 2 problem cavities fluff up a q-tip and rub edges and rub cavity itself down looking for pulled fibers. Look at it under good light for tough surfaces dings burred edges.
Has anything changed with the casting when this problem started, different alloy, different furnace, new handles. Look at the procedure for changes or something new or different.
On the 2 problem cavities a rubber pencil eraser rub in the cavities and mould cleaned may help with release by lightly polishing the surface and removing any hard deposits. You may need to trim an eraser to fit in for best results. An Exacto knife with a light coat of oil works here. Clean mould good after this. The push on eraser caps and a dowel work pretty good for this. The last is to cot the problem cavities with a pencil ( Graphite) start with the sides of the grease grooves and any sharp corners. then add in the nose, last the driving bands and bottoms of the grease grooves. When bullets start releasing you have found your problem area, and know where to really look.
It seems that temperature makes a little difference, but hardly even enough to notice.
Run the pot hot and there seems to be a point that it sticks just a tiny bit less.
When the mould is cooler it seems to stick less.
Mid range heat lots of sticking,
Hot (frosted bullets) it sticks less.....but still sticks.
Alloy is 5lbs ww to 1lb lino. That is my standard alloy for all handgun and submachinegun loads
I can't really say that there is a definable pattern to it.
Have you tried switching sides you fill from to keep all of the mold the same temp?
That method has worked for me on occasion. I like to pour from near to far, but switching the order for a few passes has proven useful to equalize heat.Quote:
Originally Posted by oger
I would suggest coating the cavities with the lead from a #2 pencil. Sharpen the pencil to a fine point to get into the bands then just color the cavities with the pencil/graphite. If the problem persists, you may have a tiny buildup of alloy at the edge of the cavity. I would use the pencil eraser dipped in a 50/50 mix of white vinegar and hydrogen peroxide and rub the outside edge of the cavity to loosen and dissolve any buildup. A sharpened lead point is also good for cleaning out the vent lines. The mix will also tend to make any alloy buildup more visible as sometimes these spots are very small and hard to see.
Treat the cavities with a coat of any dry lube like Liquid Wrench Dry Lube ( L512 ).
I read about this , didn't think it would work but had a 4 oz. bottle of the liquid in the garage , coated the cavities with a Q-Tip , and on the first cast they jumped out the mould. After that a tap on the hinge pin was all it took for them to fall out. I coat each cavity, top of blocks and underside of sprue plate before each casting session now....the stuff doesn't contaminate the cavities and helps stop smearing. It does work !
Gary
Those H&G molds will hold the heat. I cast my 50/50 +1% tin alloy at 675degF. It takes about 20-25 seconds from pouring the last cavity to cutting the sprue in my #45 mold. No lead smear or finning. If I see either start, I slow my casting pace.
You been casting plenty long so I'm sure it wasn't acting up before. Check your alignment pins. Maybe the mould needs to be a little tighter on closing.
Many thanks to all for their insights. I just cast about 2000 #503's and lubed/sized them in the Star. I'll load them into 44 specials and light 44 mags.....that should hold me for a while.
I printed out all the suggestions and kept them with the mould.
I added it to my list of things to do in the reloading room.
Winters are long and hard here in NH and I will get to it sometime this winter.
The alignment pin was one that never occurred to me.
Thanks again to all for the suggestions.
Donald
Wish you well with the mould & the long winter ahead.