Protecting threaded holes during anodizing

A. Absolutely....

If the Anodizer you are using is etching the parts to long or at too high of a temperature the etch will most certainly remove enough material to oversize a hole on a part.

You should speak with your plater about the necessity of the tight tolerance of the holes and arrange to either plug the holes, mask, or reduce/eliminate the etch time completely..

A. On first glance the first two answers might look confusing and appear to contradict each other -- so, to clear up the confusion... When I said "yes" I was interpreting "anodizing" to mean "I sent this to a shop to get anodized" and inherently include the pre-process steps. James Watts' answer is completely correct - the material loss is due to the etch, not the actual anodizing step -- but the problem would be occurring during the anodizing process as a whole.

Sorry for the confusion.

Good luck!

A. Hi Matt. Nylon is not acid-proof, unlike some other plastics such as polyethylene, polypropylene, and PVC. But the simple silicone plugs mentioned by Jim will probably do a more effective job than plastic screws.

Regards,

A. Pay attention to your plastic screws, what worked for me is to reduce amount of thread on the scew, so that when you screw your plastic screw into the hole, it will form a seal at the end of last thread - if you use continuous thread, there is always some space between the threads, and it turns into a tight spiral "hole", the air behind it acts as a pump, and on every temperature change you will have fluids going in and out of the spiral, and some will get trapped there, which in a warm dye will leach out, and will definitely leach out during sealing, which sometimes leads problems as well.

I usually make my own plugs for such cases, I use teflon, it is soft enough and springy, so it can act as a cork to plug the spiral "hole", cut just a diameters length of threads on the plug [b]in most cases[/b] the hole will have more threads in it, so this solution should work.