boolit porn and a question

[jld_in_IA]

Hi all,

Spent some time this afternoon casting my 165gr 452 Lee round nosed bullets with decent results:





Once the mold was warmed up, I got fairly good results, say about 10% rejects (undersized or the base not filled out). Another 25% of my casts showed wrinkles, but were still well formed and functional. Of course, that leaves the 65% that are cherries or very nearly.

Now for the question. I cast this with a mix of 50/50 WW and Pure Pb. Without any sort of assayer's report, I am guessing about 3% Sb content and negligible Sn. Would it help with my wrinkling (or rather my bullet's) to add some tin to the mix? I know it would improve hardness if I added the proper 3% to make a balanced Sb/Sn mix, but I'm not clear on if it would improve casting properties much.

Second, my local scrap yard doesn't really have any good scrap tin. Where to most of you get it to add in with your mixes? Plumber's solder?

Thanks,

[runfiverun]

you cut your ww alloy in half leaving about 1.5% antimony.
and maybe .25% tin.
add the tin to your ww alloy before cutting it.
some tin wouldn't hurt, but mold temp control is really the key to good casting.

[warf73]

Would it help with my wrinkling (or rather my bullet's) to add some tin to the mix? IThanks,

90% of the time wrinkles mean your mold isn’t up to proper casting temp yet. Once the mold is at the right temp the wrinkle go away. Adding tin will help fill out (help make sharp edge) but by the looks of your boolits fill out seems to be good.

Preheat your mold by setting it on top of your casting pot (what I do) while the alloy is coming up to temp. Or get yourself a hot plate (some do this) to place your mold on while your alloy comes up to temp.

Hope this gets you going in the right direction.


Warf

[tomme boy]

Where in Iowa?

[jld_in_IA]

Cedar Rapids., IA

Thanks for the suggestions. My wrinkled bullets are most likely from the early part of the session before the mold was fully up to temperature. I certainly noted that once I got a rythm going, the quality of dropped boolits increased.

So the added tin probably won't make a huge difference to the 25% part of my casting, and if it is a warm up problem, it will be a mostly fixed number of boolits. I just need to cast more and the percentage of flawed casts will decrease. Really I need to make sure the mold is better pre-heated before I try to get much quality out of it. Guess its time to drill that one for Sweede Nelson's temperature probe.

The most likley result of adding some tin will be a reduction in the improperly filled casts, and better feature definition (sharper edges). That will certainly cut in to my 10% rate for poor mold fill out.

Thanks for the suggestions.

jld_in_IA

[captaint]

jld - I often recommend a cheap hot plate for mold warmup. It works really great, you spend less time pouring wrinkled boolits and they cost about 12 bux. Get that mold fully up to temp with the hot plate while your lead is melting and you can literally pour winners from the first cast... enjoy Mike

[Echo]

Sn reduces the surface tension of the melt, allowing complete mold fill-out. I use lead-free solder - bought some on-line a couple of years ago for less than $10/lb, delivered. Twenty-one inches of this wire solder is one ounce, so if I need to add 2% Sn to a 10 lb pot - 10 lbs = 160 ounces, so I add 3.2 ounces of Sn, or 67" of solder.
I also bought some solder ingots on ebay, and use them when smelting.

[Larry Gibson]

Add 2 % tin to the COWWs before cutting it with the lead.

Larry Gibson

[40Super]

If you want to see the difference tin makes get you mold and lead up to temp and cast a few to see how its doing, then add 1 % tin and mix it up good, now cast some more, you'll be impressed with how sharp and detailed the bullets come out. But it doesn't pay to add any more than needed for good fillout.