Question regarding paint

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hockeyref18
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Joined: 07 Sep 2015, 18:03
Location: Detroit, MI, USA

Question regarding paint

Post by hockeyref18 » 28 May 2019, 08:35

Hello all,

Over the past weekend, I was able to strip my 14 ft aluminum boat and with airplane stripper down to nearly the bare aluminum. Right now, all that remains are a few pesky paint chips and old stickers. It seems at this point, I will be looking to paint within the next couple of weeks. I have been doing some research and have been getting some mixed comments as for what to use on the boat when priming and painting. I know that the first things first, the boat will need to be washed off before putting any primer on. Second, it is to my understanding that zinc chromate primer will be the first coat on followed by the base coat of paint. Now the questions I have are...

1. Is this the correct procedure? To go zinc chromate primer and then the main paint, or is there another method?
2. What type of paint do you recommend for a freshwater only boat?
3. Is one coat sufficient for both the primer and the paint?
4. Is there any part of the procedure that I missed?

I appreciate all the help each and every one of you has been and look forward to hearing your responses soon.

Thanks

Xtremeboats
uttexas
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Joined: 31 Oct 2015, 09:51

Question regarding paint

Post by uttexas » 28 May 2019, 09:01

Yes, there are other, more expensive ways to do it (alumaprep etcher, then alodine, then epoxy primer, etc)

But with a non showroom boat, I'd just go with Rustoleurm self etching primer (light coat), then Rustoleum clean metal primer (light coat), then Rustoleum oil based enamel color(s) of your choice. I would do at least three coats of the Rustoleum oil based enamel.

With the Rustoleum oil based enamal, I thinned 14oz of paint with 1oz mineral spirits; and added 0.5oz of hardener per 14oz of paint

Good technique here (wouldn't do the clear coat last step)

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enwez
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Joined: 05 Apr 2019, 15:44
Location: Connecticut

Question regarding paint

Post by enwez » 28 May 2019, 11:38

uttexas wrote:
28 May 2019, 09:01
Good technique here (wouldn't do the clear coat last step)
just curious, why wouldn't you do the clear coat? Not necessary?

uttexas
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Joined: 31 Oct 2015, 09:51

Question regarding paint

Post by uttexas » 28 May 2019, 11:47

Oil based clear coat might look good for a few weeks, but would start to look hazy and peel.
If you want that shiny finish, wet sanding with 3000 grit and polish would be more effective and long lasting.

With epoxy paints, epoxy clear coats look great and are very durable for a long time.

hockeyref18
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Joined: 07 Sep 2015, 18:03
Location: Detroit, MI, USA

Question regarding paint

Post by hockeyref18 » 28 May 2019, 17:30

uttexas wrote:
28 May 2019, 09:01
Yes, there are other, more expensive ways to do it (alumaprep etcher, then alodine, then epoxy primer, etc)

But with a non showroom boat, I'd just go with Rustoleurm self etching primer (light coat), then Rustoleum clean metal primer (light coat), then Rustoleum oil based enamel color(s) of your choice. I would do at least three coats of the Rustoleum oil based enamel.

With the Rustoleum oil based enamal, I thinned 14oz of paint with 1oz mineral spirits; and added 0.5oz of hardener per 14oz of paint

Good technique here (wouldn't do the clear coat last step)
Thanks a million for the response. Now with the method you listed out, there will be no need for zinc chromate as the self-etching primer and clean metal primer will effectively do the job?

uttexas
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Joined: 31 Oct 2015, 09:51

Question regarding paint

Post by uttexas » 28 May 2019, 19:01

I would only consider zinc chromate if planning on lots of salt water exposure
It is extremely toxic and not worth the risks if primarily using the boat in freshwater

If you are getting down to bare metal with a freshwater boat, I’d just use Rustoleum self etching primer, then Rustoleum bare metal primer, then the Rustoleum oil based enamel

hockeyref18
Posts: 13
Joined: 07 Sep 2015, 18:03
Location: Detroit, MI, USA

Question regarding paint

Post by hockeyref18 » 28 May 2019, 19:45

uttexas wrote:
28 May 2019, 19:01
I would only consider zinc chromate if planning on lots of salt water exposure
It is extremely toxic and not worth the risks if primarily using the boat in freshwater

If you are getting down to bare metal with a freshwater boat, I’d just use Rustoleum self etching primer, then Rustoleum bare metal primer, then the Rustoleum oil based enamel
Thanks again! Now for application, how long do you wait between primer coats and paint?

uttexas
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Joined: 31 Oct 2015, 09:51

Question regarding paint

Post by uttexas » 28 May 2019, 20:15

Apply a light coat of the self etching primer
Wait 30 minutes and apply a light coat of the clean metal primer

Then

You have two options on when to coat over a light application of clean metal primer
If you have time constraints, do it after 30 minutes (if you coat over it within the first hour, topcoats bond well with the primer)

The other option is to wait 48hrs, then light wet sand with 400 grit, wash down with mineral spirits and tack cloth, then apply topcoat

If you have time, I’d wait 48hrs, wet sand, then apply topcoats. It’ll look better and last longer

So your schedule might look something like this:
Day one—self etching primer and clean metal primer
Day four—wet sand 400 grit wash down with mineral spirits and apply first layer of topcoat. Wait 24hrs
Day five—wet sand 400 grit wash down with mineral spirits and second layer of topcoat. Wait 6 hrs and apply third layer of topcoat. Wait 24hrs
Day six—wet sand 800 grit wash down with mineral spirits and fourth layer of topcoat

Done

hockeyref18
Posts: 13
Joined: 07 Sep 2015, 18:03
Location: Detroit, MI, USA

Question regarding paint

Post by hockeyref18 » 28 May 2019, 21:41

uttexas wrote:
28 May 2019, 20:15
Apply a light coat of the self etching primer
Wait 30 minutes and apply a light coat of the clean metal primer

Then

You have two options on when to coat over a light application of clean metal primer
If you have time constraints, do it after 30 minutes (if you coat over it within the first hour, topcoats bond well with the primer)

The other option is to wait 48hrs, then light wet sand with 400 grit, wash down with mineral spirits and tack cloth, then apply topcoat

If you have time, I’d wait 48hrs, wet sand, then apply topcoats. It’ll look better and last longer

So your schedule might look something like this:
Day one—self etching primer and clean metal primer
Day four—wet sand 400 grit wash down with mineral spirits and apply first layer of topcoat. Wait 24hrs
Day five—wet sand 400 grit wash down with mineral spirits and second layer of topcoat. Wait 6 hrs and apply third layer of topcoat. Wait 24hrs
Day six—wet sand 800 grit wash down with mineral spirits and fourth layer of topcoat

Done
Thanks as always for the response. I may not have the time to do the painting in 6 straight days. By chance, could I wait a weekend between the third and fourth coats?

uttexas
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Joined: 31 Oct 2015, 09:51

Question regarding paint

Post by uttexas » 28 May 2019, 22:16

Sure, no problem to wait 48hrs between topcoat layers
Might even get better results
Be sure to wet sand with 800grit and wipe down with mineral spirits prior to the final topcoat application

With the final layer of topcoat I doubled the amount of hardener for the final topcoat layer—the final topcoat layer was 1oz of hardener + 1oz mineral spirits + 14oz paint

ppine
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Joined: 02 Jul 2017, 12:31

Question regarding paint

Post by ppine » 31 May 2019, 18:57

People seem to have a lot of anxiety about painting aluminum.
For a fishing boat, there is no need to get exotic and use epoxy paint for instance.
Priming is important. I have had good success using Rustoleum rattle can enamel and and also applying quality marine enamel with a brush.

hockeyref18
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Joined: 07 Sep 2015, 18:03
Location: Detroit, MI, USA

Question regarding paint

Post by hockeyref18 » 06 Jun 2019, 14:41

uttexas wrote:
28 May 2019, 22:16
Sure, no problem to wait 48hrs between topcoat layers
Might even get better results
Be sure to wet sand with 800grit and wipe down with mineral spirits prior to the final topcoat application

With the final layer of topcoat I doubled the amount of hardener for the final topcoat layer—the final topcoat layer was 1oz of hardener + 1oz mineral spirits + 14oz paint
Thanks as always! Now that I have an idea of what to get, how many spray cans would it take to cover a 14 ft aluminum with a deep v hull? That way I can have an idea of how many cans of primer I will need. Then for the main paint, how many cans did it take you to do the three top-layers?

Thanks again

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DaleH
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Location: Eastern Mass

Question regarding paint

Post by DaleH » 06 Jun 2019, 14:54

Painting aluminum simplified ...

Bare Tin:
1 - Sand
2 - Wash with white vinegar and copper scrubbie pads, then rinse
3 - Primer (I would use Zn-Cr on SW boat)
4 - Paint, rattle can or roll/tip

Painted Tin:
1 - Sand
2 - Prime
3 - Paint, rattle can or roll/tip

Done
#1) 1st tin rebuild, 18' Lund http://forum.tinboats.net/viewtopic.php?f=21&t=36583
#2) 25' Parker refurb from EMPTY hull http://www.classicparker.com/phpBB3/vie ... p?f=15&t=6
#3) 16' V-tin rebuild http://forum.tinboats.net/viewtopic.php?f=21&t=36465
#4 Procraft SV14
#5) 16' Starcraft entirely NEW Transom Skins http://forum.tinboats.net/viewtopic.php?f=3&t=37548

gwar822
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Joined: 06 Apr 2019, 16:18

Question regarding paint

Post by gwar822 » 09 Jun 2019, 15:06

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