Cold galvanizing

[markdoane]

I am reattaching the floor channel on my '59 Tradewind, using hot dipped galvanized bolts.
I found some cold galvanizing spray (LPS cold galvanizing paint) that is very high in zinc. I think spraying the bolt heads and washers where they contact the aluminum channel should provide some corrosion protection.
Is this a good idea? Has anyone tried this? Comments? Alternatives (other than stainless steel)?
Thanks.

[john hd]

don

cold galv is good stuff, the lps brand is very good imho.

been using for years, it does stop the rust. i sprayed my fresh water tank housing with it last year when replacing the drains, it is holding up quite well as expected.

john

[raebaker06]

Originally Posted by markdoane

I am reattaching the floor channel on my '59 Tradewind, using hot dipped galvanized bolts.
I found some cold galvanizing spray (LPS cold galvanizing paint) that is very high in zinc. I think spraying the bolt heads and washers where they contact the aluminum channel should provide some corrosion protection.
Is this a good idea? Has anyone tried this? Comments? Alternatives (other than stainless steel)?
Thanks.

I have applied Cold zinc Spray on many Items and found it to be excellent.
I would be careful in that It will not stop Galvanic action between different metals.

Explaination. metal have a different atomic level and like in a battery if you apply a solution such as salt water in will become a battery and material will move from the one to the other...Hense corrosion. and the same fro electrical currents in the trailer body.

Rae

[nickcrowhurst]

Don, to prevent electrolytic corrosion you need to electrically isolate the dissimilar metals. One way is to use non-metallic washers under the head and the nut. I have used Tufnol. A perfect job also sleeves the hidden part of the bolt in plastic tube. A compromise, which we use when fixing stainless steel fittings to aluminium masts on yachts, is to bed the bolt heads and washers in a layer of zinc chromate paste. This thick yellow paste is available from specialist yacht spar stores, but a pharmacist would probably supply it. It acts as an insulator between the dissimilar metals. Nick.

[markdoane]

Originally Posted by nickcrowhurst

Don, to prevent electrolytic corrosion you need to electrically isolate the dissimilar metals. One way is to use non-metallic washers under the head and the nut. I have used Tufnol. A perfect job also sleeves the hidden part of the bolt in plastic tube. A compromise, which we use when fixing stainless steel fittings to aluminium masts on yachts, is to bed the bolt heads and washers in a layer of zinc chromate paste. This thick yellow paste is available from specialist yacht spar stores, but a pharmacist would probably supply it. It acts as an insulator between the dissimilar metals. Nick.

Thanks!

I've looked all over for zinc chromate paste. It's hard to find since the movie "Erin Brockovich", all about hexavalent chromium (Cr++++++).

I think one function of the zinc chromate (and the now popular zinc molybdate) is that the zinc oxidizes preferentially to the aluminum, since it is more anodic than either aluminum or steel. That's why I wanted to try it.

The isolating bushings are equally scarce here in the midwest, away from the coast and salt air. Not many sail lofts or chandlers.

Again, thanks for the help.