Bottom paint “FILLER”?

[SKS]

Hello all,
I probably should have planned to have the bottom professionally sand blasted then prepped, Too late now.
After spending two days scraping loose and accumulated bottom paint I now have a “moonscape”. Some paint held firm but I have dozens of areas with large bare spots up to ~1/16”-1/8” deep. If I bottom paint over this it will look awful.
Any thoughts amongst the Trawler Forum brain trust about options.
Perhaps a filler/primer that I can apply over bare spots, then sand to blend prior to painting.
Also, thoughts on an ablative paint in the future to avoid build up would be welcome.
Thanks and Stay Well!
Steve

 

[rgano]

First rule of repainting, where paint sticks, leave it. While a disagreeable sight, once the ugly edges are underwater, who cares? Unless you are a racing snailbote, is it going to harm your top end? OTOH, you could feather the edges before repainting, but the dust will be toxic, so take your corona virus mask and goggles along.

 

[Frosty]

I can't see exactly what you are dealing with but I have used Interlux Watertite filler below the waterline.

Watertite Boat Filler | Interlux

 

[Comodave]

What speeds do you run at? Unless you are going to go fast, I probably wouldn’t do anything except paint the bottom. If you are going to go fast then maybe fair the old paint.

 

[Bacchus]

Agree with others... I wouldn't do too much.
On a previos boat the PO must have been anal about putting on another coat every season and the thickness build up showed where it came loose. I scraped annually and touched up bare spots but didn't worry too much about what the fish could see,
Along the water line I scraped and feathered edges, then applied a well thinned coat to keep it looking good and fresh. Eventually i got most of the worst areas off but it took quite a few yrs of the above... nobody ever noticed or at least mentioned it to me.

 

[SKS]

Good morning!
Thanks to all for the replies. I kind of figured I was too concerned about perfection. Being a trawler, 9kts is the most we run at. It makes sense to be practical and just repaint, feathering only the above waterline spots, maybe some of the deeper craters below also.
To avoid build up, any thoughts about switching to an ablative paint going forward?
Thanks Again,
Steve

 

[Pete Meisinger]

I took the bottom of my trawler on the starboard side down to pure white gelcoat, 100% by hand. Nasty job. So nasty in fact that I hired the port side soda blasted.

If you are concerned about the patches of paint still sticking on the bottom, get back under there with the sander. You will probably be glad you did, just for your own satisfaction when the bottom is on display.

However.. I agree with the others, not required. You don't say if you are fresh or salt water. I would be more inclined toward perfection in a salt water location.

Your barrier coat paint will actually fair out the lumps and imperfections. Especially if you apply the recommended number of coats, as many as five. Also note that barrier coat if left in the pan for a while will actually thicken up almost to body putty consistency, you can actually apply it with a spatula or putty knife when it is partially thickened.

pete

 

[Chrisjs]

Seems to me that applying any "filler" including excessive barrier coat to fill paint valleys is going to cause problems in the future when the original "hard" paint eventually ablates or falls off. Then you are left with the "negative" version of your hull with solid non-paint lumps
Best option if still concerned is to sand feather the hard areas making sure to use a mask (if able to find one) and a vacuum sander, then repaint the whole bottom including the feathered sections.

 

[Bacchus]

Good morning!
Thanks to all for the replies. I kind of figured I was too concerned about perfection. Being a trawler, 9kts is the most we run at. It makes sense to be practical and just repaint, feathering only the above waterline spots, maybe some of the deeper craters below also.
To avoid build up, any thoughts about switching to an ablative paint going forward?
Thanks Again,
Steve

Steve I have used ablative on 3 boats over last 30+ yrs and it works well for me.
I hesitate making bottom paint recommendations on the forum as my thinking is it depends on your circumstances & environment... fresh vs salt, warm vs cold, seasonal vs constantly floating, etc What works for me may very well be the wrong choice for you.
Best info might be to poll others or a yard in your area / circumstances to see what they are using and ask why they use it, like it or not and why?

 

[Chrisjs]

If memory serves me right (??) non-ablative "hrd" paints become useless after they dry out during storage, whereas ablatives can be freshened up with a simple scouring before relaunch. Also repainting over ablative is much easier, just a light scouring and repaint. Sure you can find an ablative that will work for you anywhere in US. Only reason IMO to use a hard bottom paint is on go-fast vessels where an ablative would wear off relatively quickly.

 

[RonR]

I had a similar thought on the bottom not looking right after I scraped and sanded. The Port side and aft looked like crap. I faired it down a bit with a sander and called it good as its a lot of work/time to do it by hand. After a prim coat and 4 coats on the sides/aft and 3 on the bottom and once in the water you cant see any of it.

 

[firehoser75]

SKS,
Good info so far. Also remember that not all paints "play nice" (compatible) with one another. First you need to ensure you know what paint is currently on your boat, then determine what choices you may have for overpainting with an ablative that is compatible. Carefully check manufacturer's material or contact them directly for advice. Good advice from Bacchus about area specifics.

 

[SKS]

Great insight guys!
I believe I’ll finish the scrape and sand-to-feather operation then use the same bottom paint and see how it goes. Sure beats $6000+ for a haul, blast and finish job that I cannot get done before mid June. I’m less discouraged after all your collective experience and practical advice.
I’ll get with manufacturer about compatibility of switching to an ablative for next year. If It’s doable that should help with the build up issue going forward.
Thanks again!

 

[Comodave]

Generally you can put an ablative on top of a hard paint but don’t put a hard paint on top of an ablative. Generally. Not always so do check with the manufacturer.

 

[Northern Spy]

Sharp scrapers is the key. The hard bottom paint dulls them fast. When I took Spy down to gelcoat on her first haulout after I bought her, I had 5 scrapers and about 15 blades. I would go through the 5 scrapers, take a break and spin the blades. go through 5 scrapers , take a break and change the blades, repeat until arm falls of or all scrapers are dull. Sharpen scrapers with a stone and a beer or two in the evening.

I random orbital sander with 80 grit got rid of a few spots on the edges where I didn't want to damage the gelcoat. Once I sanded though, there was no hope of using a scraper, as there was no edge left to the paint to get a start.

There were 13 different color coats of hard paint on her bottom. I now use ablative (Hemple Olympic) on the hull and hard paint (Interlux sumpinornuther) on the bow thruster tunnel and thruster prop.

 

[FF]

Forgetaboutit , launch and enjoy.

 

[mike66]

Rough up or use dewaxer on those bare spots before painting. I've had great luck with Petit Eco water-based paint here in Rhode Island in Salt water. I put it on everything. No copper, so no harm to underwater metals. Put it on the prop, rudder, etc. I do a coat every two years. Boat comes out very clean in October. Compatible with all other bottom paints.

 

[FoxtrotCharlie]

Good morning!
Thanks to all for the replies. I kind of figured I was too concerned about perfection. Being a trawler, 9kts is the most we run at. It makes sense to be practical and just repaint, feathering only the above waterline spots, maybe some of the deeper craters below also.
To avoid build up, any thoughts about switching to an ablative paint going forward?
Thanks Again,
Steve

Yep, if you use hard bottom paint, eventually you will have to sand/blast it off. Ablative for trawlers is the way to go. Just pressure wash, maybe sand a bit, then re-paint