Topside paint over bottom paint

[wbttk]

I need your help here guys. I have a parker 18 cc that I keep on a trailer. I bought it used and it had bottom paint on it, but it is starting to fade and look ugly. I want to use a one part topside paint (like interlux brightside) instead of bottompaint because I want the gloss finish. The local boatyards keep telling me that topside paint will practically fall off once it's in the water because of pounding on waves and being immersed in water.

I don't know what to believe. I've got interlux brightside on my deck but it takes a lot of abrasion to chip it. Also, when I'm running the boat, the areas by my scuppers are wet all day, and there's no paint peeling. On top of it, there's a boat with a painted bottom in my storage yard that looks great. The biggest problem that boat has are little scratches, but they're the type that can be touched up in a few minutes with brightside. So I'm not sure what the durability issues are all about? Periodic touch ups aren't a big deal to me.

The one thing that does make sense is the problem of a topside not adhering well to a bottom paint for chemical reasons. I went into the boatyard asking if I could deal with this problem by sanding off the bottom paint as best I could before applying topside paint. The guy there never really answered my question because honestly, I don't think he really knew. He started telling me one problem was oil base/water base adhesion issues without asking me if I had oil or water based bottompaint on my hull (or seeing the boat). Then he said it was specifically copper content that caused the adhesion issues.

I've read about the paint chemistry issue, but how big an issue is it? Like will the paint completely fall off or just the potential of something happening, likely a lot less severe (this is what I'm hoping anyway)? I'd love any suggestions you have. I was even wondering if there's some type of barrier coat I could use to solve the whole problem? That would be perfect! I really appreciate it guys, just want my boat looking spiffy for the summer! Thank you!

Zack

[Mardi Gras]

Looking spiffy and looking proper are two different ballparks.

Regardless how the bottom paint looks it serves a purpose, best advice is to keep it in good repair and find a color that you like.....

Going on the cheap with top side paint will only agrevate you, ante up the $130 per gallon and get her done right.....

[wbttk]

Looking spiffy and looking proper are two different ballparks.

Regardless how the bottom paint looks it serves a purpose, best advice is to keep it in good repair and find a color that you like.....

Going on the cheap with top side paint will only agrevate you, ante up the $130 per gallon and get her done right.....

I want spiffy, not proper. My boat lives on a trailer, not in the water. It came with the paint, I wish it didn't have it. Unfortunately, the only purpose bottom paint serves for me is looks. 2 part is great but I don't think its worth the price and hassle because I just want to use a paint that looks better than standard flat black bottom paint, and brightside does by a mile. I am wondering about adhesion issues if I decide to use it, thats all.

[SCAngler]

I use pettit on the bottom of a couple of my boats. i use the white and you can barely tell it's there.as long as you are keeping your boat on the trailor and not in the water for 7 days or less you should be fine

[wbttk]

I use pettit on the bottom of a couple of my boats. i use the white and you can barely tell it's there.as long as you are keeping your boat on the trailor and not in the water for 7 days or less you should be fine

Yeah I've heard the vivid is good stuff. Sounds good, I'll take a look at that. Good looking out

[rchanner]

Most bottom paints (at least the ablative type) are very soft and are only good while they are in the water. Once they are out of the water long enough to get a little chalky, they aren't any good and serve no purpose anyway.

To address your question, if you paint over it, pretty much anything will peel--it needs to be removed as thoroughly as possible. I would start with a high pressure steam cleaner (hot water), which should remove most of it if it's old enough, then sand it (without going through the gelcoat if possible) and wipe down thoroughly with Naptha, wiping in one direction and changing rags often.

Following the cleaning process, I would suggest priming, followed by wet-sanding and another naptha wipe-down prior to painting, and for painting, the tip you got about using Petit is a good one.

[wbttk]

Most bottom paints (at least the ablative type) are very soft and are only good while they are in the water. Once they are out of the water long enough to get a little chalky, they aren't any good and serve no purpose anyway.

To address your question, if you paint over it, pretty much anything will peel--it needs to be removed as thoroughly as possible. I would start with a high pressure steam cleaner (hot water), which should remove most of it if it's old enough, then sand it (without going through the gelcoat if possible) and wipe down thoroughly with Naptha, wiping in one direction and changing rags often.

Following the cleaning process, I would suggest priming, followed by wet-sanding and another naptha wipe-down prior to painting, and for painting, the tip you got about using Petit is a good one.

Thank you Rich, that was very helpful. I'll see how much of the bottom paint I can get off before painting. When I sanded a small spot on my boat just to test it out, the stuff was really chalky and started coming off easily without a lot of effort. Getting all of it will be tough, but I'll try it.

[JeffK]

You're going to need a respirator, goggles and moon suit to protect yourself from the toxins in that old paint. It will be worth it; you'll probably pick up a knot or two in speed.

JeffK

[wbttk]

You're going to need a respirator, goggles and moon suit to protect yourself from the toxins in that old paint. It will be worth it; you'll probably pick up a knot or two in speed.

JeffK

Well this is encouraging to hear that what I'm trying to do is at least possible. I'm ok with taking my time and wearing protection for the sanding. For sanding this intensive, I was thinking about a rotary or random orbital sander. Any opinions on this?

[rchanner]

Well this is encouraging to hear that what I'm trying to do is at least possible. I'm ok with taking my time and wearing protection for the sanding. For sanding this intensive, I was thinking about a rotary or random orbital sander. Any opinions on this?

Random orbital all the way....rotary will gouge and leave swirls. I would suggest that you decide what grit you think you need for the job, and then get the next finer grit. It's better to go through more sanding discs than it is to remove material you didn't want to remove! Also be very careful (or hand sand) at corners/edges.....material comes off much faster there than it does on the large flat areas.