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michaelmartin
5th March 2010, 04:54
I'm looking to pick up a trailer fender from Tractor Supply Co. and it seems the size I'm looking for comes in galvanized. Is that any problem for paint or powdercoat? Once it's sandblasted, does it even matter?

derailedbus
5th March 2010, 04:59
I'm sure someone who knows more will chime in, but as far as I know, galvanization is a type of surface coating, and there shouldn't be a problem after it's sandblasted.

steelworker
5th March 2010, 11:21
Paint will not adhere well to newly galvanised surfaces. There are three main methods of preparing galvanised surfaces for painting:

Treatment with "T-wash" (a modified zinc phosphate solution), which blackens (chemically alters) the shiny galvanised surface and allows paint to adhere. Personally, I've never liked this method, as it's difficult to control and obtain a constant reaction across large surfaces, and the surface has to be thoroughly washed and dried before painting, or the paint still won't adhere. I've seen paint falling off in sheets from surfaces which were not adequately treated, several months after painting.

Etch primer. My preferred method, but the etch primers we use in industry are mostly discontinued due to environmental protection legislation.

Sweep blasting at low pressure to roughen the surface. Not something we do very often, but sand blasting should give a decent surface for paint adhesion, and for your fender I doubt you'd be as concerned about compromising the zinc coating as we would for steel structures.

jguynn
5th March 2010, 17:45
The last thing I painted that was galvanized was over 20 years ago. I remember using an etching primer that turned a kinda puke yellow-green color, but the paint stuck really well.

IF you can find an etching primer I think that will be the way to go.

michaelmartin
6th March 2010, 01:53
I think it's best I just look further for regular steel instead of just settling for what I can go pick up right now.

Thanks for the input.

atlantaallen
6th March 2010, 04:11
I'm looking to pick up a trailer fender from Tractor Supply Co. and it seems the size I'm looking for comes in galvanized. Is that any problem for paint or powdercoat? Once it's sandblasted, does it even matter?

I've owned a steel building business (www.arcosteel.com) for 30 years and galvanized itself is not so much a problem with paint as is the lubricant on new galvanizing thay allows it to be formed more easily.

Good trisodium phosphate wash prior to priming should let you treat it like any other bare metal. That's all galvanized is - zinc coating...just another metal. Nothing special or anything to be wary of painting as long as it's clean. Treat it like any other metal.

michaelmartin
6th March 2010, 12:06
I've owned a steel building business (www.arcosteel.com) for 30 years and galvanized itself is not so much a problem with paint as is the lubricant on new galvanizing thay allows it to be formed more easily.


Thanks Allen, but like I said, it was just a matter of convenience for me to pick up a galvanized piece. I can wait a little longer for non-galvanized to be ordered.

Nice webisite, by the way...

But I'm not looking through your Erection Slideshow. :doh

steelworker
6th March 2010, 19:45
I've owned a steel building business (www.arcosteel.com) for 30 years...

Excellent!! :clap:clap Here's my company (http://www.apexstructures.co.uk/home/home.htm)(which I don't own) - the other side of the pond!

colonelangus
6th March 2010, 19:49
I'm looking to pick up a trailer fender from Tractor Supply Co. and it seems the size I'm looking for comes in galvanized. Is that any problem for paint or powdercoat? Once it's sandblasted, does it even matter?

ive always pickled the metal first.just wash it with an etching agent or wash it with viniger let dry and paint.i always use viniger myself.i was building rc roll cages out of galvanized brake line when finished id use viniger and paint.
:smoke