powder coat over spray galvy

[phabib]

I'm getting ready to powder coat the frame on my Max IV. I had it sandblasted prior to working on it and I'll sandblast the surface rust off it it before I powdercoat it. I am wondering about hitting it with some spray on galvanizing prior to the powdercoating.

The other option would be to hit the frame with some phosphoric acid right after sandblasting and then powdercoating within a day, before surface oxidation can form.

I don't know if the adhesion between the metal and the galvy or the galvy and the powder will make that a worse thing than just powdercoating right onto the bare metal frame.

Does anyone here have first hand knowledge of either approach?

Thank you.

[Tomo]

hi
The powder coater I use sand blasts then chemical prime then powder coats
The galvanizer expects to have reasonably clean product presented to him then it is acid dipped and then the galv process

tomo

[phabib]

I am not planning to have the frame hot dip galvanized. I am trying to choose between powdercoating on bare metal, doing a chemical etch/phosphate coating using a phosphoric acid metal etcher/primer then powdercoat, or a spray out of a can cold galvanizing compound, then powdercoating.

I will be doing the powdercoating myself in each case. I am trying to work out the best way to prep the metal.

[Brock Landers]

I have been powdercoating for years and never found it necessary to prep other than rust removal and smoothing. As long as it is sealed it won't rust.

[Tomo]

hi
The frame operates in a potentially very wet environment .Sand blast steel first . The use of a etch/primer then powder coat is the minimum u should do . There maybe other processes u can do but I am unaware . Investigating this could be a good idea for further corrosion protection treatments etc .
NB the powder coater in my town is a little hit and miss [thin coatings missed areas etc ]
Nb I used the por coating instead over the sand blasted steel [the por product is only good if applied in low humidity and very mild temperatures ]
I did not like it and should have gone with powder coat

tomo