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Devils Advocate
Firing on two.
Joined: July 26th, 2009, 3:36 pm Posts: 1019
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 Zinc-rich primer.
Milder weather at last, so I can think about getting around to spraying the front of my Blue Celeste Special.
I bought a few aerosols of 'galvanising' primer, a very zinc-rich stuff which seem to work well (I coated the cut ends of steel fencing bolts, and it seems to be holding out well.)
I haven't seen this stuff in larger quantities, tho', such as the 5L cans you get cellulose primer and top coat in. Strikes me it would be a useful thing to coat the whole of my Charlie's bodyshell in when I get around to doing that car later on - I could buy lots more aerosols, but would prefer to use my gun.
Anyone seen this stuff sold in bulk? Anyone tried it?! Any good?!!
Ta.
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February 24th, 2011, 9:56 pm |
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twofifty AZU
Firing on two.
Joined: May 16th, 2010, 5:04 pm Posts: 835
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 Re: Zinc-rich primer.
It works really well, but the proper "cold galvanising" paint like galvafroid etc isn't particularly suited for use under paint that is there for aesthetic reasons. The reason being is that it is a sacrificial coating, the zinc in the paint corrodes rather than the steel.
On the outer surface of a wing you're better off cleaning backto bbare metal and using an epoxy primer.
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February 24th, 2011, 10:01 pm |
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Devils Advocate
Firing on two.
Joined: July 26th, 2009, 3:36 pm Posts: 1019
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 Re: Zinc-rich primer.
That's interesting, AZU. I'd have thought it would then be useful in the event of a stone chip - really slow down its spread. But you're suggesting it might start to degrade underneath the paint layer?
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February 25th, 2011, 12:04 pm |
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twofifty AZU
Firing on two.
Joined: May 16th, 2010, 5:04 pm Posts: 835
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 Re: Zinc-rich primer.
Devils Advocate wrote: That's interesting, AZU. I'd have thought it would then be useful in the event of a stone chip - really slow down its spread. But you're suggesting it might start to degrade underneath the paint layer? The high zinc content stuff will tend to cause paint adhesion problems in the long term. It isn't an issue on something like a chassis, but it is on a wing. If you think about it corrosion prevention is in essence extremely simple. If ozygen and an electrolyte can't get to the steel it will last pretty much indefinitely. That is what makes epoxy primers so highly effective on clean steel. Galvanising protects steel in a different way, the corrosion resistance of zinc is considerably less than that of iron or steel. Consequently the zinc is consumed before the steel as a sacrificial anode. Don't get me wrong, high zinc content paint is brilliant stuff, but not when used used under shiny top coat. The ubderside of your wing is a whole different story. To stop corrosion you need a number of different solutions, the other thing that'll make a huge difference is diligently spraying anti rust wax in all the box sections and crevices, Bilt Hamber Dynax is excellent. http://www.bilthamber.com/search-produc ... =Corrosion Prevention
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February 25th, 2011, 12:19 pm |
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samfieldhouse
Firing on two.
Joined: February 11th, 2009, 12:32 am Posts: 3324 Location: Chichester, West Sussex
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 Re: Zinc-rich primer.
Can you tell me a good epoxy primer please?
Also, what's a generally good bare metal primer to use?
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February 25th, 2011, 12:53 pm |
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Old-Nail
Firing on two.
Joined: October 7th, 2009, 12:10 pm Posts: 2192 Location: NWUK
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 Re: Zinc-rich primer.
_________________
 'Democracy my Arse'
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February 25th, 2011, 1:44 pm |
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Devils Advocate
Firing on two.
Joined: July 26th, 2009, 3:36 pm Posts: 1019
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 Re: Zinc-rich primer.
Thanks, all.
I doubt I'll be using 2-pack for the usual reasons - tho' maybe it ain't as bad as the top-coat 2-pack? But I also don't like the idea of it 'setting' in the delicate parts of the gun - ok, that shouldn't happen with good cleaning, of course, but I'd rather stick with one cleaner and 'base' type, and that'll have to be cellulose.
So, zinc-rich primer followed by standard grey hi-build cellulose primer and then cellu top coat might be planting future problems? All the inner and under panels will be thoroughly covered in the usual products - Waxoyl an 'at - but I want to give the outer 'cosmetic' surfaces the best protection possible too, but within my DIYing resources.
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February 25th, 2011, 3:52 pm |
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