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View Full Version : 3rd grade math, I need help !



Papa Jack
08-03-2010, 07:53 PM
Hello Guys, I'm kinda new here, but been casting and loading for quite a while. I'm having a little trouble with my 3rd grade math ( No, I'm NOT smarter than a 3rd grader !)...But my boolits seem to shoot OK...

Lets say I want to make some 30 -1 alloy....(Lead-Tin).
I weigh out 30 lbs of lead and add 1 lb of Tin ?
Same with say, 15-1 ?

Seems like when I am reading my casting books, something doesn't seem right in my math. Some times they have a little different answer.
I won't get into percentages yet, thats WAY over my head......Trying to figger out how many ounces in those percentages is confusing .

Thank's for the slap upside the head ! :veryconfu "Papa Jack"

SciFiJim
08-03-2010, 08:52 PM
Papa Jack,

30-1 alloy is 30 lbs of lead to 1 lb of tin or
30 lbs of lead and 2 lbs of 50/50 solder (radiator shop drippings)



30-1 is about 3% tin (100 divided by 30)
15-1 is about 6% tin (100 divided by 15)

Unless you are starting out with pure lead (or close) to start with, your percentages will be off a point or two because of whats already mixed in.

What are you using it for? Maybe we can get at it from that angle.

giz189
08-03-2010, 09:04 PM
See, that is what happens when you breathe up all those lead fumes.

Papa Jack
08-03-2010, 09:48 PM
Papa Jack,

30-1 alloy is 30 lbs of lead to 1 lb of tin or
30 lbs of lead and 2 lbs of 50/50 solder (radiator shop drippings)



30-1 is about 3% tin (100 divided by 30)
15-1 is about 6% tin (100 divided by 15)

Unless you are starting out with pure lead (or close) to start with, your percentages will be off a point or two because of whats already mixed in.

What are you using it for? Maybe we can get at it from that angle.

Thank's for the info. .I thought I had it right, but seemed like some of the reading I was doing made me unsure....

Here is the plan: I have LOTS of 63/37 (lead-tin) industrial solder, I'd like to use it as the "TIN" in my batches. I have "pure " tin, but hate to use it with all this other alloy laying around.
I'm just plinking with the Boolits, mostly .30-30, .45-70,.450marlin, 44 mag rifle, 357 mag.rifle, some 38 spcl/mag hangun. Thank's !! "papa Jack"

Papa Jack
08-03-2010, 09:51 PM
See, that is what happens when you breathe up all those lead fumes.

Your Right, I gotta quit pickin my nose when I'm casting, that lead goes right to the brain![smilie=s: "Papa Jack"

sagacious
08-03-2010, 09:57 PM
Here is the plan: I have LOTS of 63/37 (lead-tin) industrial solder, I'd like to use it as the "TIN" in my batches.
Just so your math is right, note that 63/37 solder is 63% tin, and 37% lead, and not the other way around. Good luck.

Papa Jack
08-03-2010, 10:09 PM
Just so your math is right, note that 63/37 solder is 63% tin, and 37% lead, and not the other way around. Good luck.

Thank's for that INFO, I thought the first number was always the LEAD, I guess after all these years, thats what I get for thinkin....Now I gotta re-stamp all those dang little ingots...."PJ"

southpaw
08-04-2010, 01:08 AM
x/y = z

x= total amount of tin added to batch
y= batch size in pounds
z= % of tin in batch

So say we want to make a batch of lead with a total of 3% tin in it. Lets start with pure lead and add tin to it for a total of 100 pounds. It would look like this:

x/100= 3

Multiple both sides by 100 and we get x (the total amount of tin we want to add to each batch) = 300. Now dived that number (300) by the amount of tin in each one pound bar that you have (in your case 63%). 300/63= ~4.76 (pounds of 63/37 solder to add).

Subtract this number from the total weight that you want the batch to way. 100-4.76=95.24. So to make a batch of 100 pounds with 3% tin in it you will need to add 4.76 pounds of 63% tin to 95.24 pounds of pure lead.

Hope this is as clear as mud.

Jerry Jr.

sagacious
08-04-2010, 01:26 AM
x/y = z
That just might be 4th grade math! ;)

Reminds me of the time I asked my physics professor, "Hey, what's new?"

And he replied, "c/λ."






Sorry for the physics joke-- couldn't stop myself!

Papa Jack
08-04-2010, 10:58 AM
x/y = z

x= total amount of tin added to batch
y= batch size in pounds
z= % of tin in batch

So say we want to make a batch of lead with a total of 3% tin in it. Lets start with pure lead and add tin to it for a total of 100 pounds. It would look like this:

x/100= 3

Multiple both sides by 100 and we get x (the total amount of tin we want to add to each batch) = 300. Now dived that number (300) by the amount of tin in each one pound bar that you have (in your case 63%). 300/63= ~4.76 (pounds of 63/37 solder to add).

Subtract this number from the total weight that you want the batch to way. 100-4.76=95.24. So to make a batch of 100 pounds with 3% tin in it you will need to add 4.76 pounds of 63% tin to 95.24 pounds of pure lead.

Hope this is as clear as mud.

Jerry Jr.
Thank's South Paw !! Thats what I have been looking for, trying to figger this percentage and ratio stuff out...
"Papa Jack"

southpaw
08-04-2010, 01:22 PM
No problem Papa Jack. If you have any more questions don't be shy. There are lots here that can explain things clearer mud. I have trouble getting in from between my ears to the puter screen, heck I am happy if I get it as clear as swamp water after a rain storm.

Jerry Jr.

Echo
08-04-2010, 01:57 PM
And let's not get too anal about this effort. Seldom will we have PURE stuff to deal with. That which I call lino >should< be 4% Sn, 12% Sb, and the rest Pb. And I treat it that way. But it might be somewhat depleted and so only have 3.5% Sn, and that's about a 15% error. When I mix Lead-free solder in with WW's to get WW+2%, I might end up with 2.3% Sn - or 2.5% - or 2.1% - depending on the WW's and the accuracy of my weighing effort. By keeping an alloying session as a lot, at least all alloy in that lot is dang near the same.

I prefer to convert to ounces, and figure from there, when using alloys like lino- or mono-, and realize that the result will be CLOSE to what I expect, but probably NOT dead on. To reduce variability, I date ingots, and use from one batch when casting.

Papa Jack
08-04-2010, 03:19 PM
Weighing alloys.... All I been using is an old baby scale i found at a garage sale. I don't get too picky about the mixes, long as I am close to what I want, or think I want, I can adjust it in the pot. I really need to find a lead hardness tester so I know where I'm at.
I have a lot of sheet lead, up to 3/8" thick, lots of lead sheathed telephone cable, so I use that to alloy with the 63/37 solder. I also have brand new Lino-Type, still wrapped in the packages from the factory, but I want to keep that just for "special" needs, but I think I will melt it down and put it into 1 lb ingots so it's easier to store..... "PJ"

DGV
08-04-2010, 11:02 PM
29 lbs of lead and 2 lbs of 50/50 solder = 30-1

7of7
08-07-2010, 12:22 AM
29 lbs of lead and 2 lbs of 50/50 solder = 30-1

I was wondering if someone would pick up on that equation... especially with the 50/50 part...