Plugging threaded holes while galvanizing

[rlangdon]

I am trying to find a way to plug or protect threaded holes while galvanizing to eliminate chasing the threads. This would also eliminate a set up and tap process. I have heard that Liquid Nails works with limited success, but there has to be a cleaner way out there. Thanks.

 

[israelkk]

The correct way is to use oversized taps and gages.

 

[Tmoose]

Hot dip or electro ?

 

[rlangdon]

hot dipped.

 

[BillPSU]

israekk
Galvanizing is not a plating process. The part is cleaned in a acid tank and flushed allowed to dry and then dipped in molten zinc. The molten zinc will fill the threads, not just change the size.

rlangdon
If you can accept the threads not being coated silicone plugs can be used or slicone RTV can also be used. Make sure if you plug a hole there is no water trapped behind the plug.

 

[rlangdon]

BillPSU,

Are silicone plugs readily available, or would I have to fill the threaded holes with some sort of sealant. Also, are the plugs reusable/ or cheap. Thanks.

 

[BillPSU]

They are not reusable and they are relatively inexpensive. They will be cheaper than retapping the holes. I believe the plugs are installed after cleaning thus the galvanizer must do the work. Call your local galvanizer and talk with him.

If you are looking for a galvanizer use the following link.
This website has tecnical data available both on line and CD format.

http://www.galvanizeit.org/

 

[Vonmagnuson]

We have a similar problem. Our galvanizer's suggestions didn't work so well so we started experimenting. We found that a plain bolt with the threads coated liberaly with "Magnalube" worked best. The screw is removed and scrapped after the galv. and any residuals around the hole is hit with a sanding wheel. The hole is generally clean enough to pass a new screw through without re-tapping.