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DO-IT MOLD Casting Problems Guide
11-06-2010, 02:03 PM,
#1
DO-IT MOLD Casting Problems Guide
This might be helpful with some of the questions someone new to lead casting may experience.

Casting Problem Diagnosis Guide


PROBLEM.................................. SOLUTION
Casting Incomplete............... 1,2,3,4,5,6,7,11,12,or 13
Flash Around Castings....................... 6,8
Inserts Do Not Fit.............................. 6
Pull Pin Rod Difficult to Remove........... 9,10
Castings Look Wrinkled.............. 1,2,3,4,7,12,or 13

1. Allow lead to heat longer before using.
2. Pre-heat mold by making several castings without inserts.
3. Pour a fine stream of lead directly into the cavity gate. Do not flood the sprue or fail to pour directly into the gate.
4. Some electric units will not heat lead to maximum temperature when completely full. Try with only 1/2 full.
5. Spinner-jig wire form and hook eye must be in the cavity center to fill properly.
6. Wrong insert - check specifications.
7. Try a different lead alloy. Wheel weight or tire weight metal is the cause of many molding problems.
8. Foreign object on the surface of the mold prevents it from closing tightly. Look for small specks of lead or other particles. Remove by carefully scraping away with a knife. Just remove the particle, not the surface of the mold.
9. Oil pin lightly or smoke with carbon soot before first use.
10. Remove rod quickly before the solidifying lead shrinks and grips the pin.
11. Air trapped inside cavity. This can occur with a new, very tight mold. Test by placing a small piece of paper between the surfaces of the mold. A small corner of an adhesive label or gummed paper, like the seal on an envelope or corner of a postage stamp, will serve very well for this purpose by temporarily adhering to the molds’ surface. The paper will not allow the mold to close absolutely tight, and this small gap will permit air to escape from the cavity. If complete castings are obtained, leave the paper in place until the mold is broken in (usually 100-200 castings) and then remove it.
12. Lead is not entering the cavity fast enough and lead is cooling too soon. Clean pour spout on bottom pour furnace. Large cavities may require ladle pouring to fill fast enough. Pour quickly.
13. Smoke the mold cavities by positioning them just above a candle’s flame. A thin coat of black carbon soot will form which will help the flow of molten lead into the cavities and also make it easier to remove the cast lead parts.

These are taken from DO-IT MOLDS websight.
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11-07-2010, 01:58 AM,
#2
RE: DO-IT MOLD Casting Problems Guide
Sometimes you can smooth a mold cavity with a tooth paste like pearl drops or make a paste from powder comet . scrub it real good with a tooth brush.
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