paint

[Linley blayden]

Automotive and marine paint how much difference is there?

[Cheechako]

Wish I could tell... Auto Paint more expensive for decent stuff. I figure if it holds up with road oils, bugs, 70mph wind, snow, rain, road salt gotta be great stuff.

[JPA Cate]

A few years back, we had our topsides sprayed with automotive LPU, which at the time and place was far less expensive than marine LPU, and says shinier longer. Has to be re-done after about 10 yrs., I'm told. The old marine LPU did not last in good nick, had become chalky by then. It's not yet that old, so we'll see. But at this point, I'd go with the automotive LPU again!

Ann

[Zach]

The biggest difference is the thickness each product will build. That is to say, if the boat is fair and smooth now it doesn't make much difference. If the boat is not fair and smooth, and you want it to look like a mirror then there is a bigger difference in what you can do with boat products vs automotive products.

Automotive products are also much, much faster to work with. Look at the recoat windows. With awlgrip, you spray today and sand tomorrow. Some automotive products you spray today, sand in 3 hours, fix whatever issues you seen, spray again and topcoat over the primer wet on wet.

Car primers build in 1-3 mil thicknesses.

Awlgrip has a few that are good for 60 mils wet.

Gelcoat is good for 20 mils.

If you don't have an epoxy built boat, fair it:
1. Gelcoat and 3M High Strength filler with a dab of EverCoat 407 ultra smooth glazing putty here and there.
2. Or use fiberglass, resin, and gelcoat.

In either event my favorite primer in all the world is Awlgrip 545. You can topcoat with awlgrip, or shoot PPG twin pack paint over the top. JAU is the name of PPG's single stage color coat that doesn't require a clear coat. It's full name is: Direct Gloss Acrylic Urethane.

It is clear coat, that gets a color pack mixed into it. It sprays like a clear coat, which means it comes out of the gun almost a mist... It is thinner than Awlgrip and builds slower than Awlgrip, which is saying something to anyone that has sprayed it. Awlgrip sprays like milk. PPG sprays like cooking spray.

Neither are what you would call, overly easy to spray. Temperature matters, humidity matters (If dew falls, they don't shine) as does the mixing technique and how much thinner is put into each batch. You need a dryer on the airlines, as condensed water blown out with the paint makes bubbles. You need a big enough compressor to keep and hold the pressure so you get the same results every time you squeeze the trigger.

It also helps to have a decent gun that atomizes fairly well at a steady pressure. Cheap guns can spray thin products well, but the flow rate goes to the moon and you have to move your body, not just your hand fast enough to apply an even coat.

It goes with out saying, that spraying awlgrip topcoats and isocyanate paints is bad for you. It'll make your children be born naked, and you should respect the products as they can kill you. They really should not be sprayed without an air supplied respirator, as a carbon cartridge respirator is still slow suicide (after 15 minutes, you are soaking in the isocyanates... as is spraying without a full suit and goggles.

Spraying epoxy primers is bad enough. Atomized epoxy hardens up in your lungs, never to come back out. Folks don't last very long around these products if they don't protect themselves... and even then exposure is still to some of the most free radical chemicals you can choose to expose yourself.

Zach

[Cheechako]

Great info Zach! A few years ago I had my old Mustang painted two tone. I only had to buy a quart of each paint and there was paint left over! Doesnt take much for a car I guess. it wasnt top of the line paint, but was quite metallic. Seems I remember it was about $400 a quart....

[minaret]

Originally Posted by Ann T. Cate

A few years back, we had our topsides sprayed with automotive LPU, which at the time and place was far less expensive than marine LPU, and says shinier longer. Has to be re-done after about 10 yrs., I'm told. The old marine LPU did not last in good nick, had become chalky by then. It's not yet that old, so we'll see. But at this point, I'd go with the automotive LPU again!

Ann

Don't believe there is an automotive LPU, most are acrylics.

[minaret]

Originally Posted by Linley blayden

Automotive and marine paint how much difference is there?

Lots. Auto paint does hold up fine, but you will never get a finish of the quality of an LPU using auto paint. LPU has much more depth and gloss when done right.



In the US, the most commonly used auto paints on boats are Imron, Deltron, and PPG. Imron is easy to work with and wet sands and polishes nicely. Also much easier to make repairs on than LPU.