The investment can retain details as subtle as an accidental
fingerprint in the surface of the wax. At least on a good (bad) day.
It sounds like you have a miscommunication with your caster. You’re
talking about the caster returning a “master”…
What, exactly, are you intending to do here? Production? or a one-
The reason this matters:
Yes, investment casting can get every little detail of the wax. Once.
On the original wax.
If you’re trying to make a master that will then be molded and
injected for a production line, that’s a whole 'nother ball of wax.
(pardon the pun.)
If you’re trying for a production piece, you need to take into
account not only the first casting, but also the molding of the
primary metal master, and injecting the mold to make production
waxes. There’s loss of detail & resolution (and shrinkage) with each
of those stages. So you need to make the details deeper if you’re
planning on production. (along with other tweaks to make them work
From what you said, it sounds like your caster thinks this is the
primary cast for a production run, and is trying to help you by
making the details deep enough to work well when cast as production
If you’re just casting one-offs, tell him to just cast them. Clean
the investment, cut the sprues, and bag it up. (That gives you total
control of all polishing operations.)
If you are trying to do a production line, buy him lunch, and pick
his brains about the best way to make these things work the way you
want them to. Don’t be surprised to learn that what you want to do
may not be possible in a production situation, at least not without
recutting the design by hand every time. Or it may not be possible
to do it the way you’re currently trying, but that doesn’t mean there
isn’t another way to get it done, you just have to figure it out.
Talking to the guy who does this for a living will save you both
much time and frustration.