what paint to go over cold galvenized on a triler

[sandy...@gmail.com]

I thought I was doing therightthing by coating my trailer with cold galvenized paint, thinking it would look lke newish hot galvenize shee finish. ? I am now faced with a dull unfinished look. what can I re coat with to get something better.


Thanks to anybody that can advise

Gerald Hosking

[sandy...@gmail.com]

[Jim Wilkins]

<sandy...@gmail.com> wrote in message
news:c2868e7e-4cf4-4ee1...@googlegroups.com...

Talk to an experienced clerk in a paint store. Automotive spray paint
didn't stay on cold galvanizing very well for me.

[David Billington]

IIRC Rustoleum do a bright cold galvanising paint as well as dull
versions so maybe try some of the bright paint over what you have
applied. I've used it myself and while not a perfect match for hot dip
the bright cold galvanise paint looks much better than the dull stuff.

[Clare Snyder]

On Sat, 7 Apr 2018 18:59:21 +0100, David Billington <d...@invalid.com>
wrote:

And you can topcoat the cold galvanize paint with regular rustoleum
(or just about any other enamel or acrylic) paint.

[Ed Huntress]

"Cold galvanizing" refers to several different materials. The common
one, from Rust-Oleum and others, is a reggular organic paint binder
with up to 95% zinc powder. It's the least protective because it
generally hresults in poor electrical contact among the zinc
particles. It's often recommended to top-coat it and I'd just check
with the company that made it for recommendations on preparing it for
a top coat.

Another material, one that I haven't seen for about ten years but
which was popular for a while for coating boat trailers, is two-part
epoxy paint with the same zinc powder. Top-coating epoxy is always
tricky. It develops an "amine blush" on the surface from the amine
curing agent. You can't sand it off; it just smears around. Acetone
won't help, nor will other paint thinners.

However, thankfully it's water soluble and the blush can easily be
washed off with soap or detergent and water. My favorite is TSP, for
the same reason that it's used for prepping walls for painting: it
doesn't leave a residue.

The third material is harder to get in ordinary consumer products but
it's the best, and you'll find it from commercial sources. It's
INORGANIC binder (usually ethyl silicate) with 90 - 95% zinc powder.
The reason it's best is that it has good electrical conductivity with
the surface and with the particles themselves. That's essential to get
a true "galvanizing" effect, which is a sacrificial electrolytic
phenomenon in which the zinc is the sacrificial anode.

If you happened to get that, you'd better check with the supplier
about coating it. It's the one that least needs top coating.

Whatever you use, keep stirring or shaking the hell out of it as you
use it, or you'll get wildly different percentages of zinc as you
spray, roll or brush.

--
Ed Huntress

[Neon John]

On Sat, 7 Apr 2018 18:59:21 +0100, David Billington <d...@invalid.com>
wrote:

>On 07/04/18 18:05, sandy...@gmail.com wrote:
>> I thought I was doing therightthing by coating my trailer with cold galvenized paint, thinking it would look lke newish hot galvenize shee finish. ? I am now faced with a dull unfinished look. what can I re coat with to get something better.

the cold galvanize paint (at least CRC brand) is an excellent primer
so you can spray just about anything over it.

Another option if you live anywhere near TN is to have the whole
trailer re-dipped. There's a company near South Pittsburgh that
maintains a zinc pond about 100 ft long and about 75 ft wide.

About 30 years ago I built an especially fine trailer and hauled it
over to be dipped. Cost was modest. Still looks like the day it was
dipped. This place is still there because I've sent people over that
way in recent times.

He will not dip anything with ANY rust on it. So the procedure is to
have the entire trailer frame sandblasted, as quick as possible wipe
on a coating of light lube oil (which burns off in the dip) and whisk
it over there for dipping.

John



John DeArmond
http://www.neon-john.com
http://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address

[David Billington]

I had many things galvanised and always found it an excellent process
and cheap for the protection provided, IIRC about 70 years + in normal
environment and around 25 years + in a marine environment but that can
be extended with additional surface prep such as grit blasting to get a
thicker deposit. My local place isn't bothered about rust or mill scale
as the first part is an acid dip to remove that followed by a flux dip,
salammoniac IIRC, then the zinc dip. My neighbour priced it up against
paint and the industrial plant he designed and the galvanise came out
cheaper overall compared to paint as the paint required blasting and
repainting from time to time. The main thing with galvanising is to make
sure the bits are designed for it so the can drain and vent, interesting
video of a non vented section failing in the dip tank here at 1:15
https://www.youtube.com/watch?v=C8EGUlerwVg

[Bob La Londe]

Metal Etching Primer