sprue tearing on linotype

[sneared]

I'm a new old newbie who hasn't cast a boolit for 30+ years. You could say I've forgotten more than I ever learned about casting.

I cast a bunch of boolits with a Lyman 311316 mould using linotype. I was working without a thermometer, but I got good fill out.

I allowed the sprue to cool at least 10 sec. Most if not all the bullets tore at the sprue. There was no lead smearing.

I have read that linotype is susceptible to tearing of the sprue. Is this true or do I just have to get more heat into the mould or cast at a higher temperature? Or do I need to allow more cooling time before I cut the sprue?

Also, what is the correct adjustment for the sprue plate? I have seen varying opinions. I read that the sprue plate should swing by it's own weight when properly adjusted.

Glad to see a bunch of folks who like to sling hot toxic metal!

[jhalcott]

I don't usually cast with linotype as it's harder than I need. When I do use lino I get a lot of torn sprues. I think it is from allowing the sprue to get to cold. It might also be a symptom of a bad alloy. When lino is reused a lot, the tin seems to get burned out. The result appears to be a more brittle (high antimony) mix. As for the sprue plate, I like it just tight enough not to move on it's own.

[44man]

I get torn sprues with WW metal too if I cut at the point the metal is still chyrstalline. Cut too soon and it smears and leads the plate and mold, don't wait enough and it tears.
Try waiting longer before cutting and make sure the plate is SHARP.
I never used linotype so I don't know how it acts.

[DLCTEX]

Using Bullplate lube on the sprue plate, I watch the sprue and when it is no longer molten I blow on the sprue for 2-3 seconds, then cut. This is with WW. as I don't use lino, but I would guess you are letting the sprue get too hard. Vary the time and see what happens. I do find that the Bullplate makes cutting easier and helps prevent smearing if the lead is wet. DALE

[grumpy one]

I used to cast bullets from stereotype a few years ago, before I learned it wasn't a good idea. It tested at around 6.5% tin, 14.5% antimony. With that alloy I never achieved cut sprues - hitting the sprue plate hard and often with a block of wood I'd end up with, on average, about a third of the sprue area cut, and two-thirds fractured. The fracture plane was always very fine-grained and flat, never hollowed out. This alloy is extremely brittle.

I finally concluded this was an unsuitable alloy for making bullets: it wouldn't obturate, it seemed to have about the same effect on the barrel throat as a file, and getting it through a Lyman 45 sizer was very destructive - to the sizing machine.

[Morgan Astorbilt]

Check your sprue plate and make sure the countersink is all the way down to the bottom, creating a sharp edge. If not, you'll have to cut it down deeper on a drill press, or send it back to Lyman for them to do it. Just a thought, I've had a few that needed to be cut deeper.
Morgan

[Papa smurf]

Hay sneared ----- All my sprues tear or break rather than cut clean. I use ww metal in both Lyman and Lee molds. I cant tell any difference once I put a gas check on them. I cant shoot a handgun well enough to judge a plain base,but I'm ok with the long guns.

[joeb33050]

I've cast a lot of linotype bullets, some harder. My experience is that those holes in the bullet base are caused by opening the sprue plate too soon. I can cast with essentially perfect bases. I don't know what happens when a lino bullet is cooled to room temp., then sprue plate is opened.
joe.b

[sneared]

Thanks for all the suggestions.

I'll order some bullplate lube since I see lots of good reports.

I did inspect the sprue plate and it is properly countersunk.

Linotype may not be the alloy I need. I just happened to have a bunch on hand. I've only seen a few people using it in .357 mag and .44 mag.

I'm trying to make up a load for a 5 in. barreled Ruger Blackhawk that was converted to 32-20 from .357 mag.

So far, I haven't found a suitable powder since most have been on the slow burning side. Just not enough barrel to burn all the powder. AA1680, which works well in TC Contenders was a miserable failure. 4227 worked OK. I figure I should be using AA #9 or #7. Maybe unique.

I have been pretty unhappy with the accuracy and the gunsmith who did the conversion suggested using lead boolits. The gun performs well with cowboy loads. Unfortunately, his source of lead boolits disappeared. The cylinder has .312 throats and the barrel is .308. He recommended boolits sized to .312

I figure I may be pushing velocities up to the 1400 fps neighborhood.

What alloy would you recommend, seeing as how this is also a gas check mould?

Dang! Just what I needed. Another addiction.

[grouch]

I used lots of linotype when it was available, and got good accuracy with it. I can't think of any reason it won't work for you if you've got it and it's not prohibitively expensive.
It sounds to me like you're not letting the sprue cool enough. Linotype is very hard and you need to cast at pretty high temp, so to speed things up you can cool your sprues by touching them to a damp rag for a second or so, then if more time is needed, count off seconds until you hit a point where it cuts off both smooth and relatively easily.
You can feel this better and get better bullet bases if you twist the sprue plate with a gloved hand instead of beating it with a stick.
Good luck. Grouch

[John Boy]

I was working without a thermometer
sneared - Buy one. They are an essential tool for casting bullets


... Most if not all the bullets tore at the sprue.
what is the correct adjustment for the sprue plate?

Linotype has a Bhn of 22 - it's hard. The base of the bullet could be being "torn" because the the sprue plate is too loose.
Possible suggestions:
1. Tighten the plate. Make sure it is not gauling the top of the mold. When you cut the sprue - due it slowly after the sprue puddle has only hardened for approx 5 seconds.
2. If this doesn't work - increase the temperature of you melt so the mold is hotter too.
3. Make a bigger sprue puddle
4. All of the above
If the above don't work - may want to consider a heavier sprue plate

If you meant by tearing that there is a hole in the base of the bullet - this is an air hole and has nothing to do with the sprue working correctly

[mto7464]

Hey grouch, I cast with Lino at a lower temp, then WW's, since it melts at a lower temp. my boolits turn out great. Why the higher temp?

[sneared]

Got a thermometer a few days ago.

Is there a preferred temperature range for casting or is it all trial and error? I've read 750-850 F

Where do you buy the thicker sprue plates for Lyman moulds?

[grouch]

Well, mto7464, maybe it"s because it's been a long time and I'd forgotten that detail. If you're casting now and it's working for you, I must be mistaken about the temperature. I'm sure I remember the great bullets, though, and stand by what I said about cooling the sprue(although it may not be necessary if you're casting in cold conditions) and about twisting the sprue off with a gloved hand giving a feel for time to cut and better bullet bases. Thanks for pointing out the error.
Grouch

[mto7464]

No problem, wasn't trying to sound like a smart ass just thought maybe I was doing something wrong.

Sneared, with Lino try running it cooler then with WW's. It also is nice because you can speed up your pace since the mold won't get as hot.