Noob needs some help getting a new old mold casting

[jld_in_IA]

Hi all,

As I am new to casting, I've been reading everything I can find about the process and trying to educate myself, but still have some questions.

I have an old Lyman 358091 that I picked up inexpensively several years ago. Not really knowing what to look for, I didn't see any signs of abuse - no clear wear marks, the mold blocks fit closely so I can't see light through them, spru plate looks clean and not showing any lead. To tell the truth, I'm not entirely certain if it was ever used.

When I got a new set of Lyman 4c handles for it, I was very surprised to find the mold fits loosely on the handles and that the handle joint was loose with a lot of play in it. Is this right? I could understand some adjustment so you can put the mold halves together, and then tighten down the adjustments, but this is just sloppy to the point that I'm a little concerned about battering the alignment features.

Second, I warmed up the mold for a while on the edge of my pot, then cast about 50 bullets just to see what the size and weight looks like. I find that the size is .358 +0.001 / - 0.000. They are a little out of round as well because the diameter varies about 0.0008 depending on where I take the measurement - some cavities better, some worse.

All this leads me to believe that there is some basic setup and mold prep that needs to be done here. I'm not sure if Beagling or lapping really applies to this mold as it is iron instead of aluminum.

Any help appreciated.

John

[AggieEE]

Hi John; If it was me I think I would just go with the flow. You are already at +.001" so size to .358" and you're go to go. I would probably take out some of the play if it is real bad just remember you are going from room temp to a couple of hundred degrees and things move in that kind of temp shift. Alot of the guys here use Bullplate for sprue plate and aliginment pin lube. I never used bullplate but I'm thinking about it. Load the bullets and see how they shoot after all that is the only thing that really matters. I hope this helps and good luck.
AggieEE

[462]

You don't say how many cavities the mould has. If it's a two-cavity mould, the four-cavity handles are too thin, and you will need either Lyman two-cavity or Lee six-cavity handles.

The out-of-round and possible non-sufficient fillout issues could be due to a mould not hot enough. In my experience, a hotplate is substantially more efficient, at pre-heating a mould, than setting it on the edge of the pot.

[stubshaft]

You don't mention the alloy either.

[blackthorn]

You don't say how many cavities the mould has. If it's a two-cavity mould, the four-cavity handles are too thin, and you will need either Lyman two-cavity or Lee six-cavity handles.

Or a couple of size appropriate shims

[runfiverun]

did you clean the mold?
the handle issue has been adressed.
you can close the mold while it is sitting on the bench.

[Sonnypie]

And you don't say if you are in the basement, or the garage.
The elevation change may be important....

:kidding:



I believe in sizing every thing I cast. That way I know what is going into my cases and guns.
And it makes it much less critical what the molds are dropping. Because everybody gets squished round.
(Sometimes I go along sizing just fine, then hit one a bit tougher to size. Ahh-HAH! That's why I go to the trouble.) ;)

[Max Brand]

Yep, just spend <$20 on a Lee sizing die and call it a day. I'm with Sonnypie, I size everything I load and it sure makes the boolits fit the brass a whole lot better.

[jld_in_IA]

You don't say how many cavities the mould has. If it's a two-cavity mould, the four-cavity handles are too thin, and you will need either Lyman two-cavity or Lee six-cavity handles.

The out-of-round and possible non-sufficient fillout issues could be due to a mould not hot enough. In my experience, a hotplate is substantially more efficient, at pre-heating a mould, than setting it on the edge of the pot.

Sorry - some of the important details were left out. The mold is a 4 cavity and I am using the Lyman 4 cavity handles. I just thought the fit was unusually poor for a company with a reputation for not producing garbage.

I started this adventure by cleaning the mold with isopropyl alcohol and a soft cloth. When dry I smoked the cavities with a match. Release is not as nice as I would like, so I'm thinking to do it again. The mold had been stored with a liberal coat of WD-40 to prevent rusting, so think I got it all, but may have missed some.

The alloy I've been using so far is smelted roof flashing, so nearly pure Pb. Figured with a WC design, the lack of tin would be only a minimal issue. Also, I wanted to have dead soft bullets to use in slugging my revolver.

The revolver slugs at 0.358 for the barrel, so I have a 0.359 die on order, but that won't help much if the bullets are coming out under sized. Thought I could try bumping them or adjusting the mold to deal with this. On the other hand, if the pure Pb alloy is the issue, I have a supply of WW that I can alloy with.

As for the mold not being up to temperature, that is certainly a possibility. I pre-heat the mold on top of the casting pot while it is melting. Still, casting in the garage with temperatures in the 25-30 range, the mold will cool quickly. I don't have a mold thermometer yet, but figure that and a lead thermometer will be my next purchases. I'm sure Swede Nelson can hear me coming! How hot do the rest of you normally run your iron molds?

BTW, I haven't seen any post of a lab test done on content of stick on WW. Thought was that this might be almost as good as solder for Sn, but probably very little Sb. I understand that the content will vary with manufacturer, and so likely with geographic location, but does anyone have a guess, about their content?

[462]

Okay, you have the correct handles, good. There needs to be horizontal play of the mould blocks to help in alignment upon mould closing, but there shouldn't be any vertical play.

Pure lead will cast smaller than a wheel weight alloy, and smoking may contribute to a skinnier boolit, too. I don't smoke moulds, but some have reported that doing so made for skinnier boolits, so I'll take their word for it.

Wheel weight content has varied, over the years. Seems that a 12 to 15 BHN is/has been most common. You can use the lead and wheel weights to make your own alloys, to meet your various needs. As an example, for .357 wadcutter boolits, I use an alloy of 50/50 lead/wheel weights, and for all other .357 Magnum loads a 1:2 lead:wheel weight alloy. Experimentation will uncover what works best for your gun.

By the way, don't forget to slug the cylinder throats.

[Iron Mike Golf]

I cast in my garage, near the door, with the door opened a couple of feet in sub-freezing temps. I use a hotplate with an old circular saw blade on it and that has been a big help in getting me making good boolits with fewer casts and better boolits overall.

When I cast with my Lyman or SAECO 4 cav molds, I have no problem getting the molds hot enough on a hotplate. I never could get them hot enough on the edge of the pot. Once you get the mold hot enough, maintaining that temp depends on alloy temp and casting cadence.

[happy7]

Pure lead is hard to cast with for a newbie. I would definitely add some WW. Pure lead needs a hotter mold and you really need to cut the sprue before it has solidified. This is different from WW.

A four cavity lyman mold is going to take a while to get up to temperature in a cold garage with 150 grain bullets. You may need to make 20-30 drops before you get it up to temp, maybe more since you are using pure lead. Just setting it on top the pot is not going to be sufficient, but is a start. A hot plate is a really good idea, but you can also dip the corner of the mold in the melt. Depending on how much you dip in about 1.5-2 mins should be about right. Casting with a cold four cavity lyman is always going to be an exercise in frustration.

If you are getting .358 with pure lead, WW should get you .359.

If you ever have a mold that fits a handle tight, you will see that it is undesireable. However, too loose is also not good. Without being able to see just how loose your mold is, it is hard to say, but if you are using unaltered Lyman handles and mold, then I think we can assume the handle fit is correct. But do be careful closing the mold. Wallowing out of alignment holes is a common problem on Lyman molds, and is entirely due to misuse.