New member

[PAT303]

I've started having problems with a grey scum contaminating my bullets. I assume it's tin but not sure. The mix is no.2 alloy with some chilled shot added and no amount of fluxing seems to help.Any ideas?. I thought I new about casting before I found this site.

[Pepe Ray]

Pat
Based on the info you've given.
Tin is never a contaminant as it alloys readily w/lead.
Shot ,however, can be a problem if used injudiciously. In order to make shot, Arsinic(sp) is used. Arsinic is helpful in tempering lead alloys, whether by oven or water droop, so a TINY amount is helpful. Too much CAN be a contaminant. Consider this as a HEADS UP only, as there are probably other factors to consider that you may have overlooked.
One oif the things that are apparant when too much Arsinic is used is the rounding of edges in the finished boolets, much like when zink is present.
Anyone else care to chop this up? :-D Pepe Ray

[PAT303]

Thanks for the reply I have had problems with rounded corners and increased the temperature with no luck. By cutting the mix with more w/w help fix the problem?.

[Bigjohn]

Pat303; I am assuming you are using an electric furnace? Some details of the setup would help and the source of the material. Thermostats can be out, way out, there is a thread on this site which discusses this problem.

There are several reasons why a metal will not cast. Has the mold been cleaned as directed in the instructions?
If not, cleaning it again will not hurt, then start again.

Empty the pot and check to see if there is dross etc stuck to the inside of the pot. This can happen and is not easy to remove through fluxing. I empty and cleaning the pot after every second casting session. It is amazing the amount of material I find. There is a thread on this site about cleaning a pot.

Is the material fluxed properly and with sufficient flux (stirred after dropping a pea size piece of wax)?
If not it could be dross or seperatation of the alloy. (Some seperatation can and does happen hence the need to flux/mix.)

The size of the projectile being cast can cause rounded edges; large molds, 500gr weight etc. The air can get trapped in the mold causing the rounded edges. Do not place the spout hard into the sprue plate hole stand off a half inch and aim the 'Silver Stream' through the hole, this helps with trapped air pockets.

Is the furnace reaching casting temperature for that mix?
Invest in a temperature gauge and check the temp. should reach 700 degrees upto approx 850.
If the material will not cast at these temperatures then pour it into ingots and use it for paperweights, or sell it to a fisherman for sinkers. This would be the final indicator that there is a contaminant in the material which is next to impossible to remove.

Zinc, Aresinic and Aluminium can contaminate a mix of metal. Zinc is one of the worst as it takes so little of it to ruin a lot of metal. If you have a zinc problem in the batch you are using, adding more good metal to it will only ruin the additional material.

If you can obtain these two books as I find they have section with photo's of cause and effect.

Cast Bullets, by Col. E. H. Harrison NRA Publications

A B C's of Bullet Casting, from Wolfe Publishing.

I have both and refer to them often.

If you have further questions about this problem you are experiencing just raise then here and someone will help.

John.:drinks:

[PAT303]

I cast with electric pot and i flux with bullet lube normaly but after this problem started i covered the melt with sawdust which raised the temp to over a 1000 degs when set on high. I just started a new shift so in a couple of days i will ladle pour some bullets and see if the problem is in the pot or not.