Posted by bruce paul fink on September 10, 1999 at 18:34:49:
In Reply to: Re: Insert molding?... Casting a steel rod in aluminum posted by Don Buchan on September 03, 1999 at 15:03:12:
With aluminum especially... you can do the insert cast system. Other metals will also do it but with more attention needed.
The item being set in place (such as the end of a bolt, a nail or wire or bar etc.)will be a 'chill' but with aluminum it may not make much difference as it will conduct the heat rapidly to normalize and keep flowing.
With bronze it could start to partially cool the flow so the percents of differing masses are important.
Still worth a try and yes, I do it quite often. I am including a figure partially using my son for a model and cast in the studio with stainless steel threaded rods cast in the mold of three the tripod legs (this was so they would nearly float on the final base but really be firmly attached), the one foot that needed to have a bent threaded bar set in and several other spots since I could save metal by using pre bent threaded rods in the paper bag forms at the base. Hope this shows some of the various options.
(The second leg was just drilled and tapped as were places on the slide holder box.)
Not just to save time drilling and tapping later but to make such a thing as a curved or bent bolt attachment if the form could not be drilled and tapped around a curve (such as a turned or twisted ankle on a one legged dancer, etc).
Also this need not be a bolt. More often than not I use stainless steel thin wire or welding rods and set those in with just a bent end to be the locking force. This can get to be more delicately done than you possibly could drill and tap and will be much stronger than any welded 'spot' attachment.
Also do major attachments of stainless steel bar in bronzes for a maximum anchor system with bars of a full inch in diameter (but of course there is a lot of bronze around it also.
Enjoy the challenge and play with it. I used to do a test or more with nearly every casting by having an additional spru in each mold just to try stuff on.
And this is not the limit as you can also do this with other non combinable elements with other potential risks and results. Like locking in copper wire on the surfaces so it combines physically but not melting wise.
Do keep in mind though the long term differences of electrochemical decomposition with the differing combined materials but yes it does work and can actually be a great advantage.
Or can become a battery with moisture and oxygen and corrode outside faster than you might imagine.
Be careful, it's a Universe out here.