galvanising threads

[mx110]

got some metalwork to go for galv with some captive nuts in, i can run tap through them afterwards if need be but whats best way to keep them clean? will a greased up bolt help? or will the zinc not crack back off the bolt?

 

[tinman]

I sent drinking troughs away a few years ago with 2"bsp drain plugs in them, coated the threads with filler iirc bar one just to see, when they came back the threads weren't coated but they were a bit of a mess aesthetically wise.
The one I didn't coat I just ran a bsp tap through it and it was by far a better job.

Some times if I really needed a thread in Galv I'd send it away as normal and when I get it back I'll heat it up with the hot spanner and blow them clearish with the airline, but safety here as its right n hot when the Galv melts and your blowing the excess about the place, do it on the likes of latches to get them running free again too.

 

[Humding]

I've used fire cement with good success. It hardens well so will have to be punched out. Threads are perfect when cleaned out.

 

[Cowcalf]

would putting a bolt in thread work ?

 

[tomlad]

Greased up bit of threaded bar ?
No head to bother

 

[MickMoor]

Most male threadeditems are spun galvanised. Nut and other female threads are tapped oversize after galvanising to allow for the galvanising. On silo bolts, (1/2" UNC) the nuts are tapped 10 thou oversize. A normal nut on a galvanised thread will be very tight if it actually goes on.

 

[A1an]

Save yourself the hassle and just run a tap through it when you get it back.

 

[Rs chunk]

Just re tap them bolt can be dodgy if it’s screwed into far with threads showing

 

[Shovelhands]

I just re-tap threaded holes or polish out bushes etc.

I have tried painting said items, with an oil based paint, our local galv place advises this was the best way to prevent the galv taking hold in the areas where it wasn’t needed, ie threads and bushes.
Tbh I have had limited success with that method. It sort of works, but everything still needs a tidy up afterwards.

I have tried fitting a bolt or if a threaded pipe boss, a piece of threaded tube with a big nut welded to it for removal after the galvanise has taken place. This works too, but obviously you’ve got to break the galv to get it out.