[Milsurplus] Painting Aluminum - BC-348 in particular

[J. Forster]

Have you tried to apply wrinkle paint to small areas (under dime size)
with a brush or other means to fix an otherwise perfect paint job?

-John

===============


>
> ---- John Hutchins <olegerityincj at austin.rr.com> wrote:
>> Group  -
>> Good evening -
>>
>> The black wrinkle tex paint I applied many years ago never cured it
>> remained soft/slightly sticky.  So I am removing the bad paing job and
>> starting over.
>>
>> That being said I noticed that there is a green chromate primer layer;
>> Is this a paint or a immersion coating?
>
> John,
>   Zinc Chromate paint is available from a retailer called Aircraft Spruce,
> in spray cans, and they will ship UPS at no additional charge. It just
> has the usual ORM-D stickers on the box.
> I make replica shock mounts for the ARC-5 and 274N sets so I have quite a
> bit of experience with wrinkle paint.
> On the subject of cleaning the aluminum:
>  The easiest way I have found is to use an aluminum wheel cleaner in a
> pump spray bottle called DuraGloss 851. It is an etching type cleaner and
> it works very well. You do have to use it very sparingly on nickel plated
> stuff, stick to one quick application on things with nickel plated
> hardware or you'll have copper colored hardware when you're done.
>  It's not really necessary to specifically use Drano, a simple Lye and
> water solution works too. The alloy of the aluminum plays a big role too.
> 6061 is harder to etch than 5052 or 3003 due to its better corrosion
> properties but it will etch, it just takes longer. Don't etch until
> you're ready to prime and do it as soon as possible after etching. I
> etch, rinse well, blow dry with compressed air, and prime. Aluminum will
> oxidized very quickly so the sooner you get the zinc chromate on the
> better. I seem to recall that Zinc Chromate is an etching primer, so the
> cleaner the aluminum is and the less oxidation you have, the better the
> adhesion.
> The DuraGloss just rinses off with water but I recall reading that the lye
> solution needed to be first rinsed with white vinegar, then cold water.
> You may want to research that a little bit cuz it's been a long time since
> I used that method.
> Be very very thorough with your rinse and blow drying, getting all the
> cleaner and water out of the little nooks and crannies and holes. You
> don't want to leave any water and especially the cleaner in those places.
> A front panel is easy, but overlapping riveted parts are tougher.
> Painting:
> I've tried a lot of different paints but the one that has given me the
> most consistent results is Krylon brand. It's harder to find than VHT too.
> The last I bought I had to order from an ACE Hardware
> warehouse/distributer. Krylon gave them as the vendor for their wrinkle
> paint products. Before I used Krylon I used the Black wrinkle paint from
> Harley Davidson. I suspect it was Krylon with a Harley label and a higher
> price tag because it looked and behaved just like Krylon. :-)
> They all will work, but it just seemed like the Krylon best matched the
> older gear's original texture and like I said before, it gave the same
> results every time.
> They all say they will wrinkle without heat and maybe they will most of
> the time, but I've had the same problem you describe when I don't use it.
> I quit trying it without heat long ago. I use heat lamps in a shop that is
> separate from the house because it do cause a really big stink!! The other
> guy wasn't kidding with his line about divorce proceedings. :-) Direct
> sunlight on a good clear hot day works too.
> It takes a while for the wrinkle to appear, maybe 10 minutes tops, but
> then it spreads over the piece very quickly. Once it wrinkles it's done.
> More heat or nothing else will change the pattern you get. Set it aside
> for 24 hours to let it completely dry.
> The wrinkle pattern or texture is determined by three things- Thickness of
> the coats, how even the coats are, and the time between the coats. For a
> fine texture use only one coat. The cans instructions should tell you to
> apply two coats and specify the time between coats. Follow those
> instructions if you want a heavier texture. What they don't tell you is
> that wrinkle paint when wet, looks like a very heavy coat, and it is. It
> seems to go on thicker than most paints look when sprayed. Avoid vertical
> surfaces if at all possible to prevent runs. It will be a very glossy
> finish too until it wrinkles. Bottom line, experiment first and keep track
> of what gave you the texture you wanted.
>
> Last but not least: Wrinkle paint WILL NOT hide flaws, it will amplify
> them!! Anything that changes the way that film pulls when it is trying to
> wrinkle will also change the wrinkle pattern around that change in
> surface. That means any dent, bump, or even the drilled holes in a panel
> will have a different wrinkle pattern around them. That tends to make the
> flaw even more noticeable.
>
> One other ting I've learned from experience is that you can't take a piece
> from an air conditioned home to a humid outdoors. If you do you have to
> give time for the moisture to evaporate before you paint. Pay particular
> attention to that phenomenon when you're about to apply the first coat of
> primer.
>
> Hopefully this and all the other information from the others will make
> your next paint job more successful.
>
> Later,
> Steve
> KB4DMF
>
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