Painting galvanized tin ?

[BHD]

I have a old barn I use for my shop and I finally got it tined, (I used lightly hail damaged roof sheets) I got for a very good price,

the building is 60 by 65 foot print 10 foot side walls and 40 foot to the peak, so a lot of tin, but I would like to paint it, at least the front of it, and may be one side,

I have been told to use just about every combination of paints and primers by paint sales men, that is out there,

the tin is well weathered, and there is not any factory oil on it any more,

what have you used and what has worked?

As one can see from the pictures the tin is weathered, the front (in the pictures) is what I want to paint,

 

[Stimw]

My dad always wiped new galv with vinegar to etch it before painting.

 

[/pine]

My dad always wiped new galv with vinegar to etch it before painting.

I have always done the same where there could be an oil residue...

you might look at this product
Madison Chemical

 

[BHD]

My dad always wiped new galv with vinegar to etch it before painting.

thank you
like I all ready said it is well weatherd (etched), yes on new tin acid etching is common,

 

[Soundguy]

yep.. an etchant has always wortked for me... fish oil anyone?

 

[BHD]

what paint did you use and how did it last,

I want to paint it RED

 

[kco]

I did the same (reused tin from roof) when I rebuilt my shed 1.5 years ago. I replaced the roof with new steel and reused the galvanized tin on one side with cedar on the other three sides. My tin looks to have the same profile as yours.

I just washed the tin and directly applied the same paint used for the siding. I was not too concerned about looks as that side faces the bush and is not normally seen.

It did an excellent job and appears to have bonded well. There is no flaking.

 

[ray66v]

If it is weathered, the easiest way to paint it is pressure wash it, and spray it with a (DTM), direct to metal paint.

There are lots of other options, depending on exact condition of the siding, the desired budget, and time constraints.

 

[BeezFun]

what have you used and what has worked?

I would first confirm whether you have something that is galvanized or something that is tin. I'm not an expert on this, but I know tin was used as a coating on steel to prevent rust. It had a lot of lead in it, not sure it's made the same way anymore, or if it's even available.
Galvanizing is a different process that applies zinc to steel to prevent rust. I'm not sure what the point of galvanizing tin would be, because they're each designed to prevent rust to the steel underneath. Anyway if you really have something that's galvanized:

From Rustoleum FAQ site:

Q Which product should I use to paint galvanized steel?
A Use a water-based acrylic, including products offered in the Painter痴 Touch and American Accents product lines. You may also use Aluminum Primer.

 

[Frank Surber]

This is going to depend a lot on the quality you are trying to achieve.
You already stated this is weathered metal so acidizing with a weak solution of muratic or a heavy solution of vinegar will not be needed.
But a good pressure washing to clear away any residue dust or dirt is always a good Idea with any paint project.
next for the quickie down and dirty just use a good quality DTM and your done for a few years.
for a little higher quality go with an etching primer to negate the possibility of there still being active contaminants leaching out of the galvanize allow to dry for a couple of days, pressure wash again and spray with a higher quality paint
For a 20 year coating do the above but use 2 or 3 part epoxy assuming you live where High VOCs are not forbidden.
Otherwise you are stuck with water based paints.
Some of the automotive water based paints available now days will rival our old lacquers and epoxies in their quality and appearances but that doesn't mean that I have to like them.