Hi All,

What's the collective thinking on covering male and female threads when powdercoating?

I was thinking about putting some cheap bolts with plumbers' tape into tapped holes and wasn't sure whether to cover male threads with insulation tape or nuts.

Any views?

Thanks

yes, cover them up. it galls inside the thread otherwise and makes it difficult to screw in and out.

ETA: if youre curing it with a heat gun, youll need high temperature masking tape.

[Edited on 11-12-12, by MakeEverything]

using bolts in the holes means you have to break the powdercoat as you take them out
use silicone bungs

quick search found this site (as an example)
http://www.bpfittings.co.uk/pc/High-Temperature-Silicone-Rubber-Caps-Plugs-c3146.htm

Can't you just run a tap/die down them afterwards?

quote:

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Originally posted by adithorp
Can't you just run a tap/die down them afterwards?

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I also screw tight wads of blue tissue into the holes to protect the threads, or when it is (say) a hole not a thread, then the tissue will protect it. It does tend to set rock-solid but a little wetting and it will come out.

Do not use gaffer/duck tape. the heat sets it solid and it takes some getting off.

I often just use a sacrificial bolt if it's not a hole.

I've seen masking tape used on studs when powdercoating. Suprise me that it worked.

glad it works for something

Duck tape has hods of adhesive, which runs then sets under the heat. I suppose that's the only thing in the universe it's not good for.

I'll probably just ask the guy doing it eh?

My experience of powder coaters is that they just get stuck in, and if it's not masked it should be coated.

Further tips - if you're doing something like a chassis best be sure you block every hole with something like a self tapper else the blasting material will get in there, and there's no way to get it out.

another one for tap & die.........

Hi Tim,
Masking tape is fine but I expect they will know that all threads need masking. Worth just checking with them first. Depends if they are putting the powder on whilst the metal is hot or cold. If cold they can use an air-gun to blow the excess off

quote:

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Originally posted by fullpint
Hi Tim,
Masking tape is fine but I expect they will know that all threads need masking. Worth just checking with them first. Depends if they are putting the powder on whilst the metal is hot or cold. If cold they can use an air-gun to blow the excess off

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Tin foil for external threads and rolled-up newspaper for internal threads and holes.

+1 Re-tap every hole, i think considering the time involved, it'll be quicker to retap all the holes.

The pro's use masking tape for external and silicon bugs for internal. Well the companies i use do.

If its a company they should automatically cover all threads as practice. Again, the ones we use do. We dont even tell them to.

If they miss one the tap and die it. You should not have to prep it. If its a company they will be dipping it and asserts anyway.

I picked up a rad to fan cowl that I made for an Austin Healey this week from
Internations in Sible Hedingham and had forgotten to ask them to block the M4 threadserts.

No worries, as they did it anyway. They made a nice job of it. Highly recommended.

The powder coat hid all my rough hammer marks a treat.

Cheers,
Paul G


Rad to Fan transformation cowl