Patching Awlgrip/LP paints

[Delfin]

I'm not sure if this will be helpful, but I've spent a couple of years learning how to touch up Delfin's Awlgrip finish when something gets dinged, and thought it might be worthwhile passing on what's been learned.

Done correctly, it is very hard telling an area I've fiddled with from the original finish, but that is primarily because I'm only dealing with Matterhorn White, Snow White and Mist Gray for colors, and these are far easier to blend than darker colors would be. At any rate, here's what I've learned:

Tools, materials required:

Air brush. I use a little Iwata. Iwata Compressors
Dremel.
Kitchen measuring spoons.
Wax cups.
Paint - anti-corrosion primer, epoxy primer and finish.
3M Vinylester fairing putty. 3M Vinylester Premium Filler - Filler & Repair Resins by Discount Marine Supplies
Spray thinner
MEK for cleanup
220 grit dry sandpaper
600 grit wet sandpaper
2000 grit wet sandpaper
McGuire's rubbing compound - #8, #4 and #2 swirl remover.
Respirator ToolKing.com: Willson RWS-54013 Americas Premier Half Mask Respirators
Small brushes

Repair types:

Gouges, chips, and on aluminum, corrosion bubbling due to SS fasteners not isolated from the aluminum.

Technique:

1. Using a metal burr on the Dremel, ground a dimple into a small ding, or rout out a larger area, removing everything down to bare metal.

2. Immediately apply anti-corrosion primer using a small brush. (http://www.awlgrip.com/MPYACMDatashe...4+A+eng+A4.pdf)

3. 24 hrs later, fill with vinylester putty. Sand with 220 grit around 20 minutes later. Refill again and sand again. This is actually one of the most important steps when you're dealing with an area larger than say, a bb. It is tough to get the filler completely flat relative to the surrounding area, usually with the putty being higher than the surrounding surface. You know you are as flat as you need when the edge of the repair area is sanded down to the point where you are beginning to remove the top coat of the paint.

4. Using the kitchen measuring spoons prepare a small amount of paint. Mix in the wax cups. Plastic cups will melt. Thin liberally, since the air brush will sputter if the material is not thin enough. I usually thin 30-40%.

5. With the airbrush and WITHOUT taping off the repair air, start with a very thin spray (this is why the airbrush is the tool to use - you have complete control over how much paint comes out), moving the tip in a circular fashion until you see the paint gloss over. Then STOP applying paint.

6. Wait 10 minutes or so and repeat two more times.

7. 24 hours later, wet sand the area with 600 grit wet sandpaper. Only sand the repair area. Do not worry about any slight overspray at this point. Dry and wipe lightly with MEK.

8. Mix the top coat and again, without taping, spray on 3 coats 10 to 15 minutes apart, applying paint as above until you see the surface go glossy, then stopping.

9. 24 hours later, wet sand with 2000 grit. This sands off overspray of both the primer and the finish coat. Now you have a fair, painted surface with a very slightly dulled appearance.

10. Polish the area with McGuire's rubbing compounds. Even a large area only requires a few minutes of work at this stage. Finish with an appropriate LP sealer. I use Awlcare.

The end result should be essentially invisible. The whole process above for an average ding is probably an investment of an hour tops. I maintain Delfin's paint repairs in around 6 - 12 hours a year.

Cleaning:

Fill a wax container with MEK. If you have the same style of airbrush I have, remove the mix container and stick the whole nozzle into the cup, with the the suction uptake immersed. Spray MEK through the airbrush to clean out its interior.
Disassemble the airbrush and soak the constituent parts in MEK. Rinse the mix container. Careful not to soak any O rings in the MEK, or they'll dissolve.

Note: The vinylester putty says not to apply over epoxy primer. I've ignored this with the non-sanding primer I use, noted above, and never had a problem, but frankly I can't see a reason not to just apply the vinylester directly onto the bare metal. The problem, I think, is that thick epoxy putty will continue to want to outgas as it cures, messing with the curing of the putty. The very thin stuff I use is more of a wash, so I'm not worried about it.

[pbiJim]

Thank you for the write up. I need to learn more about touching up marine finishes.

[silverp40]

Good post!

MEK is a good and cheap substitute for the range 003-0031 thinners from Awlgrip. It does not fare well when mixed in the Awlgrip mix in the long run longevity of the paint - Awlgrip's thinners are recommended.

Awlgrip and Mek also easily melt wax in a waxed cup, so a plastic mixing containers would probably be safer.

[Delfin]

Originally Posted by silverp40

Good post!

MEK is a good and cheap substitute for the range 003-0031 thinners from Awlgrip. It does not fare well when mixed in the Awlgrip mix in the long run longevity of the paint - Awlgrip's thinners are recommended.

Awlgrip and Mek also easily melt wax in a waxed cup, so a plastic mixing containers would probably be safer.

Thanks Silver. I've found the plastic cups melt and had better luck with the wax ones.

[silverp40]

Delfin, I have used the metered cups (sold in most chandleries and paint stores) for years but never had them melt (except when a good glob of epoxy kicked over too soon!).

A cheaper substitute (and more environmentally friendly) are nonwaxed drinking cups, but the plastic ones can be peeled off and reused a few times

[Delancey]

Great post thanks for sharing. Curious to know why you prefer MEK for the wipe-down post wet sanding? I usually somehow end up reaching for alcohol for my solvent rag at that point. I guess maybe in the belief that because it is less reactive it is better but always interested to know how others work.

Cheers

[Delfin]

Originally Posted by Delancy

Great post thanks for sharing. Curious to know why you prefer MEK for the wipe-down post wet sanding? I usually somehow end up reaching for alcohol for my solvent rag at that point. I guess maybe in the belief that because it is less reactive it is better but always interested to know how others work.

Cheers

MEK cleans the surface and softens it a bit as well, perhaps increasing adhesion of the next coat. That's the theory at any rate.