New, old mould

Spindrift

Spindrift

Well-Known Member
Just picked up this Lachmiller 429-240GC. With Lyman handles, maybe? If I have got it right, Lachmiller made moulds in the late sixties and seventies, before RCBS bought their business. I got it at a bargain price, feels like I paid for no more than the handles. It has seen a bit of use, but no abuse it seems. Things that should move, moves smoothly. Things that shouldn’t move, is rock solid. No rust or defects.

This is actually my first iron mould (!), and I have a newbie question.

Would two-stroke oil be a suitable preservant to prevent rust?

Ok, time to fire up the pot (lead pot, that is)

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Pistolero

Pistolero

Well-Known Member
I'd call that one pretty much excellent condition. I'm not much of a GC fan for handguns, but I bet that
will be a good one if you don't mind the bother of the GCs.

Someone took very good care of it. And any sort of oil that will exclude air and moisture will work fine.
Many of the better synthetic 2 stroke oils leave almost zero residue when they burn away, so you may not
have to even clean it much after storage.
 
Spindrift

Spindrift

Well-Known Member
Thanks, everyone!
Just cast with it for the first time, after cleaning it with acetone. Still was a little oil to purge, but after a little while nice bullets started jumping out of the mould. The bullets are .431 on the driving bands, and weigh 265grs with GC, in my BHN15 alloy. Will enjoy this mould and bullet, I think!
50EACEA3-8B9E-4B60-A2FA-F77285ADBED7.jpeg
 
Ian

Ian

Notorious member
You may have noticed the mould retains heat a lot better than brass or aluminum, so you might need to slow your casting speed down considerably to match the results you get with other mould materials. To counteract having to slow down so much and wait for the sprue to cool and/or pausing before refilling the mould with alloy, I tend to run the alloy temperature as cool as I can. Mould temperature = bullet quality, cooler alloy just means you can cast faster with nearly the same results. An added benefit of the cooler alloy is it is less fluid and has less tendency to flow into the vent lines and give you "whiskers" like in the photo. Those whiskers end up stuck to the block faces and throw off your weights and diameters if you don't watch really closely for them. I saw the mould had some lead stuck to the faces already, before you ever cast with it and those whiskers is likely the source. It could be that the vent lines are just too big, though, in which case cooler alloy and less tin will definitely help prevent metal from clogging them.
 
Ben

Ben

Moderator
Staff member
I have several " carpenter's pencils " on my casting table.
If I have a mould that wants to fin, I rub & fill the vent lines with a carpenter's pencil.
It can totally stop the finning.
If your goal is to stop finning, these three are NOT your friend.

  1. High heat alloy
  2. Tin in your alloy
  3. Pressure pour with your alloy

Ben
 
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fiver

fiver

Well-Known Member
I have the RCBS counterpart, it has to be in the top 5 of my easiest casting molds ever.
when I need a batch I just set the mold on top of the pot and when my other mold needs a break I just make 4-5 pours with it, put it back up there, and resume with the other mold.

I don't put any oil on my molds or do anything special with them to keep the rust off.
maybe if I lived in the east or south I'd need to.
2 stroke oil would work as good as anything and should clean off with some acetone, I'd also put the mold in a baggie or dollar store container with a snap on lid to keep the oil from drying out.
 
Ian

Ian

Notorious member
Ditto fluid film, it's the only thing that keeps my lathe from rusting out in the shop where everything rusts from condensation. For a mould, vavujm seling with a dessicant pack or a sealed container with dessicant will keep rust away. If you have a temperature-contolled gun safe that is also a good place for iron moulds.
 
Spindrift

Spindrift

Well-Known Member
Thank you all, for excellent advice!
For a while, I have done pressure casting with a spouted ladle, and a relatively hot alloy with 2% tin (just like Ben`s list above). Pressure casting solved the problem with rounded bases, but created other problems.

My casting sessions are typically a bit hurried, squeezed in between other chores, and focused on quantity. I have realized I need to refine my casting technique, if I am to get better results. This is something I am working on these days.
Will try casting at lower alloy temp/higher pace, and will definately try the pencil trick. Thanks, again!
 
Ian

Ian

Notorious member
Rounded bases are from not filling the mould quickly enough from a stream (non-contact), sprue plate too cool, or more likely sprue plate too tight causing venting issues. Still, I think a mould should be able to stand the modest pressure of a ladle-contact pour and not make whiskers, perhaps the vent lines are too robust and Ben's trick of filling them with a little graphite may help.
 
Ben

Ben

Moderator
Staff member
Ian said:
Ben's trick of filling them with a little graphite may help.
Click to expand...


Yes, it " MAY " help.
Sometimes with vent lines that are too deep, I find that there isn't a lot I can do to totally stop whiskers.
I once heard of a fellow who used a small artist brush and brushed into the vent lines aerosol mold release ( I hate the stuff ! ! ). Might work if you did that and took a clean cloth and wiped off the excess to allow for proper mould closure. Might take more than 1 treatment ? ?

Ben
 
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CZ93X62

CZ93X62

Official forum enigma
Graphite can be "Magic Powder" when dealing with balky moulds or generous venting. I am none too fond of those mould release sprays, but small amounts of that graphite in suspension (sprayed onto a Q-Tip) can do good things to a mould top/sprue plate interface--ESPECIALLY to the pivot surface on the bolt. Synthetic 2-stroke oils have superseded a lot of the graphite for me, but I am not above trying whatever it takes to make moulds behave themselves.

Yes, Lee Bullet Molds--I am referring to YOU. The price break on Lee moulds is given because the buyer usually has to finish their fabrication. Rugers have similar quirks, minus the price relief. Heck, anybody can make good bullets with iron/steel/Meehanite RCBS or Lachmiller bullet moulds. It takes a purist--a skilled caster--an artiste--to get castings from a Lee mould block. Some newer Lyman blocks have similar poetry in their dimensioning and utility, but like the Ruger products delete the price-break advantages.

Small wonder that makers like Accurate Molds, NOE, and Mountain Molds are thriving.
 
Pistolero

Pistolero

Well-Known Member
IMO, current Lee 6 cavs are right up there in quality and functionality. My newest one drops all 6 with a smart opening,
and occasionally rapping the hinge pin once. No special treatment, no "Lee menting", just wash and cast, traces of
MP mold lube on the sprue plate bottom and mold top.

Agree totally on RCBS molds, they are right up there with old H&Gs.
 
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