Painting Over New Galvanise

[Nivag]

Painted gate posts today with Vinylast from Rourkes. Goes straight on to galvanise with no primer. Easy to get a nice finish, touch dry in 20 - 30 mins and recoat in 2 hours. Two coats recommended. It is rather smelly so I did the painting outside. I think it might be made by Shipley Paints for Rourkes (the thinners definitely is).
Maybe useful for other forum members.
Nivag.

 

[series2]

The problem with hammerite it that once it is cured it is extremely hard, and tends to chip, then peel as the elements get underneath it. It seems to have quite poor adhesion to smooth surfaces. When applied to pitted rusty metal it seems to work quite well, and I have heard reports of good results over aggresively shot blasted steel and cast iron.

I have used the smooth silver over tetrosyl etch primer to 'restore' the galv trim on my series2 landy, 4 years on still intact! but it doesn't see much mechanical contact. When I originally painted my gates, I used the satin black (because I had it) over an epoxy primer, after about 3 months it started to chip and fall off, but the primer was intact. After I had to have them stripped, i used the epoxy primer again and satin celly topcoat, and they still look good now.

As for painting over galv, if you paint within 24hours of dipping, just abrade 240-360 grit, degrease then etch, prime & topcoat. the same goes for well weathered galv, but if it's been loitering for a few weeks you will need t-wash or similar to artificially 'weather' the galv before etching.

Personally, I would just leave them bare galv, looks great when it develops the nice grey patina & will last 30+ years if it has been done correctly.

Tekaloid coach paint may be an option as it appears to be impossible to remove from anything!

 

[volition82]

Not sure what other peoples experience of galvanizers is but generally I have found that their work can be rough. But if you tell them that what you are having dipped is going to be painted afterwards they do a better job of it.

 

[astro_al]

Series2 - I believe you need to T-wash things that have just been galv'd before painting them, not just if it has been sat around for a while (indeed, the opposite - less important the older it is).

Al.

 

[series2]

Series2 - I believe you need to T-wash things that have just been galv'd before painting them, not just if it has been sat around for a while (indeed, the opposite - less important the older it is).

Al.

The main issue with painting/coating galv is not adhesion to the zinc, but to the oxides that rapidly form on the surface

If you can get the workpiece prep'd and painted before any oxides start to form you will get the best possible adhesion. The oxides that first form on the surface are soft and powdery, it takes about 12 months normal weathering for the harder, molecular bonded, zinc oxides to fully cover the surface.

T-wash forces a rapid formation of the harder oxides, but also strips some of the galvanising from the workpiece in the process.

In industrial painting of galvanised parts, they carefully are shot blasted to remove all oxides and key the surface before a primer or other coating is applied. Sanding is not sufficient on anything otther than flat surfaces to remove the oxides effectively.

t-wash is usually used for articles that can't be easily shot blasted before coating. It is still nesacery to abrade the surface after treatment.

I did quite a lot of research into this when I had a lot of Zintec sheet parts to paint. I also discovered that it is important to etch prime all bare metals before coating.

On another point, galv should never be quenched, controlled cooling is required to prevent distortion of the workpiece.

hope this helps.

 

[series2]

Painted gate posts today with Vinylast from Rourkes. Goes straight on to galvanise with no primer. Easy to get a nice finish, touch dry in 20 - 30 mins and recoat in 2 hours. Two coats recommended. It is rather smelly so I did the painting outside. I think it might be made by Shipley Paints for Rourkes (the thinners definitely is).
Maybe useful for other forum members.
Nivag.

Expensive, but good stuff. It's self etching so will go over pretty much anything. Not sure who makes it, but it's great for painting chassis/axle parts.

 

[brightspark]

Expensive, but good stuff. It's self etching so will go over pretty much anything. Not sure who makes it, but it's great for painting chassis/axle parts.

shipley paints makes it .the local wrought iron gate manafacturers use it single coat strait from the galvanisers no primer needed its called high build vinyl . manor coatings

 

[series2]

It's also flexible, so you can paint things like leaf springs and the such.

good range of colours too.