Protecting threads when Galvanizing

[Maxakarudy]

As the title states, how do I protect threads & rods from being galvanized when dipped

 

[WorkshopChris]

The only real practical way is to used sacrificial threaded parts that you remove afterwards if you do not want the threaded portion of a job to be coated.

 

[8ob]

Internal threads are best drilled and tapped after galvanising, if thats not practical a bolt with a smear of copperslip on the thread with a copper washer under the head and done up tight works well. Just make sure that the bolt is only as long as the hole is deep.

Bob

 

[Maxakarudy]

They would be external threads, someone told me several layers of masking tape, but not sure if it works

 

[brightspark]

They would be external threads, someone told me several layers of masking tape, but not sure if it works

on hot dip galvanising wouldn't have thought so its only paper

 

[Revs1972]

How many have you got to do ?
We've just recut the threads after galvanising in the past . (Access dependent obviously)

 

[nickk]

Years ago I had a galv job done loads of 30 mm studs in a fabricated frame,the galv staff told me to smear them in heavy grease,so I did,all was fine.
Few years later they installed filtration systems in the works as an environmental procedure & then wouldn't accept anything like that ,especially paint residue.

 

[8ob]

This is just an idea so make of it what you will. I made up a load of belt adjusters for some machines out of tube which I internally threaded, you dont mention the thread size you are trying to protect but 1/4" black pipe will take a 10mm thread internally. You could do the same and squash the end in a vice, then grease and run them over your thread. Just thoughts.

Bob

 

[dan.taylor.1]

Surely just recut / clean the thread with a die after galv.

 

[Maxakarudy]

The job is for my Lotus Elan chassis, the studs are approx 12mm dia by 70mm long, the threaded part is 20mm long, this for the top & bottom wisbones, the rod goes through the chassis uprights, the wishbone bushes are too size, so galvanizing on the rod won't do.
My chassis is original non-galvanized, but new galvanized chassis' seem to have these parts installed before they are dipped, so they are protected in some way.
This is a picture of the type of thing