Polycarbonate - off topic
All;
I know this isn't really a Tormach question, but I don't post on that many forums, and this is about as close as I could get.
I need to place some small magnets ( 3/8") into bores in polycarbonate, and I'm looking for advice as to the best way to do it.
My initial thought is a light press fit, but I have very limited experience with polycarbonate, and I'm concerned that this may cause micro cracks to develop over time and lead to failure.
Is this a valid concern? My next thought was to epoxy the magnets in place.
Any advice would be much appreciated.
Terry
Re: Polycarbonate - off topic
Thanks Gary, I like your approach, think that I will try that first.
I am milling one part that will be held in place magnetically to another one that I had planned to print in PLA. I've never used a polycarbonate filament before. Any advantages over PLA? I assume that the poly filament will work with standard printers, temps, diameter, etc.
Terry
Re: Polycarbonate - off topic
Have you considered epoxy?
Re: Polycarbonate - off topic
I have, that was my second thought after the press fit.
I just finished milling the first piece and the fit of the magnet in the hole is very close, I suspect I will have better luck on this one with the CA, because I don't believe I can get enough epoxy between the magnet and the poly to create a decent bond.
Terry
Re: Polycarbonate - off topic
Quote:
Originally Posted by
MFchief
I have, that was my second thought after the press fit.
I just finished milling the first piece and the fit of the magnet in the hole is very close, I suspect I will have better luck on this one with the CA, because I don't believe I can get enough epoxy between the magnet and the poly to create a decent bond.
Terry
CA does not bond well to smooth surfaces. see this article.
https://www.starbond.com/tutorials/w...dhere-well-to/
Re: Polycarbonate - off topic
Fractures usually start around drilled holes. I use a propane torch to melt the edges of acrylic or plexiglass to head off later fractures. Lexan has a very fine point between melting the edge and burning. I don't know if any type of glue will prevent this.
Rough drilling and boring may give a better surface finish that will not fracture.
Dave
Re: Polycarbonate - off topic
I have read various accounts that most common adhesives don't play well with polycarbonate, CA's and epoxies included. The stress relief of the torching sounds like it could help.
I have room to put a plug behind the magnet, and plan to leave a small thin lip in front of the magnet to keep it from pulling out to the other magnet it faces. I hope that will do the job, it's not a super critical situation, so I think that will work.
Terry
Re: Polycarbonate - off topic
I haven't glu3e to PC, but I have glued to that really-slick stuff: acetal!
The adhesive that works there is "show goo," which is made to waterproof hiking shoes. But ... it also bonds pretty well.
Sounds like you have something that works, but if you need to experiment more, I'd recommend that!
Re: Polycarbonate - off topic
CA will work just fine, just make sure you don't over-do it, as it will make a mess of ANY surface it touches. Gorilla brand "Super Glue" is, by FAR, the best I've found for gluing to Acrylic and PolyCarbonate, and is thick enough to fill any small gaps. Many others will not stick at all. Applied to a machined surface, you will never be able to get the magnets out, without destroying the Poly.
Regards,
Ray L.
Re: Polycarbonate - off topic
Thanks for the tips Gary, I'm going to get some and play around with it.
I have some Gorilla brand CA, that's what I plan to use, I'll let everyone know how it comes out. It will take a few days, Cura says it's going to take 20 hours to do the print I need, and I'm still fiddling with the CAD for the part.
Terry