Painting 101 - Questions

[TooCoys]

I've been researching costs, materials, and methods for painting my boat, as well as watching videos about how to do it. However, the more I research, the more questions I have.

These are mostly topside painting questions. Bottom jobs are pretty understandable.

1. A lot of people recommend using thinners for extra flow to allow the paint to "lay down" after tipping. Others recommend using it straight out of the can. Which method makes it more "forgiving"?

2. Some folks insist that rolling and tipping is a two person job, and others do it single handed and make it look like a cake walk. Does the paint dry SO fast that you really need a second person, or is it easy enough for an expeditious person to tackle?

3. Manufacturers guides usually give at least three temperature ranges for drying times - 50, 75, and 90 degrees. However how much does humidity play into those temps?

4. When planning out your project, is 1 day per coat ample enough time to allow drying in between? Or does this go back to question 3, and dependent upon temperatures?

5. No one really states how long their paint lasts. After applying a one-part poly paint, how often after the initial coat do you have to reapply to keep the shine on? And does waxing in between painting extend the life?

6. If you're going to be paining over original white gel coat, is it necessary to apply a primer?

Those are just a few of the things that I'm having a hard time finding clear cut answers on. I appreciate any input from those with experience.

Thanks!

[Suijin]

Originally Posted by TooCoys

I've been researching costs, materials, and methods for painting my boat, as well as watching videos about how to do it. However, the more I research, the more questions I have.

These are mostly topside painting questions. Bottom jobs are pretty understandable.

1. A lot of people recommend using thinners for extra flow to allow the paint to "lay down" after tipping. Others recommend using it straight out of the can. Which method makes it more "forgiving"?

It depends on the product, the conditions, and your technique and application method. It would be wise to do a few tests to find out what works best in your particular circumstances. The whole painting process is so labor intensive (and expensive) that it merits the test if you don't have applicable experience. You want the best result possible, so invest the little bit of extra time required to find out what works for you. Generally yes, you're going to add some thinner, but how much is fairly critical. It's the difference between it flowing out and getting runs or poor coverage.

Originally Posted by TooCoys

2. Some folks insist that rolling and tipping is a two person job, and others do it single handed and make it look like a cake walk. Does the paint dry SO fast that you really need a second person, or is it easy enough for an expeditious person to tackle?

Again, this is paint and conditions dependent. I think you'll find that a lot of those who say it's a one person job are working on smaller boats in a garage or some other more manageable scenario. The bigger the boat the more difficult it is to do this solo, between moving staging/materials, mixing more paint, etc.

Originally Posted by TooCoys

3. Manufacturers guides usually give at least three temperature ranges for drying times - 50, 75, and 90 degrees. However how much does humidity play into those temps?

A general rule of thumb is that you want to paint when the humidity is below 85% and the dew point more than 3 degrees different than current air temperature (although that is cutting it close), so that relationship revolves around dew point, not the actual RH.

Originally Posted by TooCoys

4. When planning out your project, is 1 day per coat ample enough time to allow drying in between? Or does this go back to question 3, and dependent upon temperatures?

It actually depends on what paint you use and how you apply it. If you're spraying, you'll be putting down coats in relatively close succession, ideally all in one day (three coats of primer one day, three coats of topcoat a different day). If you're rolling and tipping the paint has to be dry enough to not be marred by the roller and brush of the next coat but still able to form a chemical bond with the next coat (of the same paint type). Data sheets are your friends.

Originally Posted by TooCoys

5. No one really states how long their paint lasts. After applying a one-part poly paint, how often after the initial coat do you have to reapply to keep the shine on? And does waxing in between painting extend the life?

This is entirely dependent on conditions, application, etc. No paint manufacturer is going to set expectations because they don't know if you're putting their product on a tugboat or a museum exhibit.

Some manufacturers, like Awlgrip, advise against waxing, but sell their own cleaning products. Down the line a polish (and then probably a wax) will revive and extend the paint's life, but dullness is basically the beginning stage of paint failure and you probably want to start thinking about top coating it again soon at that point. Much easier doing the job before the paint fails than after.

I'll add that I put one part on the topsides of a Flying Scot that spent 6 months in the water and 6 months on a trailer outdoors and it lasted 20+ years. I was shocked. Wish I remembered what brand it was lol.

Originally Posted by TooCoys

6. If you're going to be paining over original white gel coat, is it necessary to apply a primer?

If you want the best result possible, absolutely. Primer not only provides the "glue" between the gelcoat and the topcoat, it also reveals any flaws that you missed when prepping the gelcoat. It will extend the life of the topcoat significantly.

You won't find a professional painter who would agree to just putting topcoat right over gelcoat. That should tell you something. And so much work goes into painting a boat that skipping this step is pennywise and pound foolish.

[atmartin]

Suijin beat me to the punch, all good advice.

I'll just add a couple things.

Item #1 - The moon and the stars rarely align, and whatever paint you choose is going to need some conditioning, depending on circumstances.

Item #2 - Many professionals roll and tip larger hulls solo, but rarely outside, in wind or any other condition that reduces working time.

Item #3 - In my experience, wind is usually a bigger problem than humidity.

I like to point newbies to this piece. It's intended for people painting shop machinery, but is an excellent tutorial for brush painting:

http://wiki.vintagemachinery.org/Get...20Painting.pdf

[leboyd]

Originally Posted by atmartin

I like to point newbies to this piece. It's intended for people painting shop machinery, but is an excellent tutorial for brush painting:

http://wiki.vintagemachinery.org/Get...20Painting.pdf

Great artice! Thanks for the link.

[Jim Cate]

Item #3 - In my experience, wind is usually a bigger problem than humidity.

This was my experience as well. Variations in wind strength during the day, added to changes in temperature mean that the amount of thinners needed changes rapidly, and to complicate it more, it changes the rate that the thinners flash off from the roller tray. Covering the tray between roller chargings helps, but I found the changing conditions very challenging... very!

Rolling 2 pack paints outdoors is a bitch!

Jim

[Tornadosailing]

What those guys said. I've painted with Perfection a few times. Made the mistake of spraying it once. Roll and tip gave me better results, but you can wet sand and polish the orange peel and get great results. Perfection is designed around DIY roll and tip, not spraying. Awlgrip is made for spraying by professionals.

The roll and tip flow and laying down will come from properly thinning your paint. The more thinner it gets (not to exceed what the label says) the longer it will stay active and lay down for you. You can also use the spraying thinner (or mix a little regular thinner and a little spraying thinner) to get a longer life from it without overdoing the thinner.

Of course there's a trade off. The more thinner you have in it, the easier it runs.

One tip I didn't see above was to be very careful with the amount of paint you roll on at a time. It's very easy to put on too much paint. It will look fantastic right after you tip it, but when you're 5 feet further down the hull you'll look back and see a giant run. When (not if) this happens, DO NOT go back and try to fix it. Let it dry, then deal with it.

https://www.dropbox.com/s/8o3r4y09rn...30.37.jpg?dl=0

[TooCoys]

Thing is, the cheapest bottom job around here is $1200.

However, with the cost of paint, haul/block/launch, and daily DIY yard fees, I could do the bottom, and the top side for about $1500.

I feel like this is a job that I could do with a little practice before jumping in. I may go troll the boat repair yards for some pieces of old oxidized fiberglass to practice on.