Some Math questions

[MikeS]

Hi All.

I had posted a question regarding Dutch Boy 888 solder, but got no answers. Well, I started digging deeper than I had before and finally found a reference to the various Dutch Boy ingots (111, 222, etc.) Some of them had percentages of what they were (all are simple pb/sn), but alas 888 is simply listed as plumber's solder, and so I have no clue what percentages are in it. Well, I melted down 3 of the ingots I had here (7.5lbs) and cast a few boolits with it. I then mixed 5lbs of it with the remaining #2 alloy in my Lee 4-20 pot, and proceeded to cast 50 boolits. When I got them back inside, and everything had cooled down I weighed some of the boolits. Using a mould that cast a boolit weighing exactly 300gr from #2 the boolits that were cast from pure 888 solder weighed 262gr, and the boolits cast from a mix of the 888 and #2 weighed 288gr. So, knowing those numbers is there anyway to figure the percentages of what's in the boolits?

When I did a hardness test with my SAECO tester the solder boolits came in at a BHN of about 13.5, and the solder + #2 were slightly higher. The reference I found listed a BHN of 13.9 so the ones I measured are pretty close. Due to the lighter weight I'm assuming these boolits are high in tin content, probably higher than I should use, but it's what I got, so I'll use them. Another question tho, being high in tin, will these boolits tend to lead the bore any more or less than a boolit cast from #2 might?

Thanks for any answers to these questions!

[southpaw]

Try a specific gravity test. Here is a link that should be helpfull. http://castboolits.gunloads.com/showthread.php?t=124483&highlight=gravity

Here is how to do the specific gravity test. Do this with the boolits that you cast out of the plumbers solder (lead-tin only).

SW= sample weight
DW= dry weight
WW= wet weight

Weigh one of your boolits. This is your SW. Suspend this boolit from a piece of string and weigh it. This is you DW. Bring a cup of room temp water up under the boolit and just submerge it. This is your WW.

The formula is as follows:

SW / (DW-WW) = SG

The SG of pure tin is 7.318
for 50/50 SN/PB it is 8.882
for pure pb it is 11.34

If you get a number that is less than 7.3 or higher than 11.34 there is a math or measuring error. Check your work.

To find the percentage of tin that you have use the following formula.

2049.06 / SG - 180.69= % tin

Of course this only works if there are only PB and SN in the mix.

Hope this helps some.

Jerry Jr.