Date: Fri, 16 Oct 2009 08:31:19 -0700
Reply-To: Don Hanson <dhanson928@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Don Hanson <dhanson928@GMAIL.COM>
Subject: Re: is primer/sealer weathertight?
In-Reply-To: <82769c7e0910160738l42ac49eep417a800cf705ec18@mail.gmail.com>
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On Fri, Oct 16, 2009 at 7:38 AM, Jim Lieb <jlieberie@gmail.com> wrote:
> I agree Frank POR is great. I have also used Rust Bullet, it's not bad
> either and like POR don't get it on your skin. lol.
>
> Jim
>
The main thing for effective coating over bare metal is to get the paint
on there quickly without leaving bare metal exposed for long. Even a few
minutes exposure to air will allow rust or oxidation to get a start and then
you will have issues with the paints not sticking or getting a good bond.
Epoxy based primers can be impervious..But primers have no UV inhibitors
so in the weather, they will not endure.
Painting, especially in tough environments like autos or boats, takes a
systematic approach. The success of the whole paint job depends on all the
steps being done properly and all the products used being compatible. Mess
up any step of the way and you will get less favorable or sometimes
downright awful results. The closer you get to the end of the process, the
more time you have invested, the more time to 'lose' if you mess up.
Friday OFF Topic story about paint:
Worked as a boatbuilder for a while and we did an R&R cosmetic repair of a
42' Erickson sailboat. Hauled it and re-worked the hull surface to remove
blisters where water had invaded the finish causing blisters under the gel
coat. Many many man-hours, grinding the blisters and filling them with
epoxy putty, sanding the whole hull and coating it with an impervious layer
of Epoxy. Then a complete re-sand and some sprayed-on epoxy primer.
Another re-sand and some linear polyurethane two part primer...After almost
3 weeks of 2-3 guys, under that boat sanding above your head with long
boards and air sanders, then wet sanding with water running down and into
your sleeves (winter in Puget Sound, too) it was Finish Coat Time...
We had the boat inside the big shop, up on the railway, with a curtain
closed..semi-controlled environment. Well, the painter started squirting
and he was really pleased with the finish. The whole shop was stoked! We
all went inside the joinery shop, gathered around the woodstove for
celebratory donuts and coffee and patted ourselves on the back for a long
tedious job, well done. Then we went back out to the main bay to check, and
found all the paint hanging off the boat from the turn of the bilges..!! It
seems the temp had dropped and caused the mixture of the paint to be
slightly wrong....We all had to jump to with Acetone-soaked rags to try to
wipe off as much paint as we could, to try to save as much of our previous
work as possible...
Then we had to start back at 150gr wet and dry and work the whole hull
again down to 400 gr wet and dry..Another primer coat before we could try
the spray job again...
Got it right the second time around...PS...we wiped about $1500 worth of
fancy Awl Grip paint off that morning and ended up with awful headaches from
the poisons we all inhaled and absorbed through our skins.. and the owner
chose an awful bright Orange color...We workers called the boat "the Great
Pumpkin" when he wasn't around.
Don Hanson