Fiberglass hull paint prep - simulated plank joint grooves

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GREZ

GREZ

Member
Joined
Jan 8, 2024
Messages
8
Vessel Name
Slow Groove
Vessel Make
1983 34' Marine Trader DC
For my 34' Marine Trader, I am having the hull painted by a professional, but am doing the prep myself. A PO had applied a clear coat that is flaking badly in places, and totally gone in some other places. My job is to sand the remaining clear coat off, down to the 'paint'. The hull is fiberglass, with the little horizontal grooves to simulate wood plank joints, and the clear coat is perfect in those grooves.
Question is... what is the efficient, effective method to remove that clear coat? A special tool perhaps? My elbow? Chemicals? If you have 'been there' any experience or advice is most welcome. And as always, Thank You!!
Grez
 
I would experiment with some strippers. Perhaps one of the citrus based ones to start? Does Acetone do anything? It would be painstaking at best the completely sand those grooves.
 
Another possibility might be a Fein type oscillating sander. The Fein comes with a sanding block attachment with tight radius, about what would fit in those grooves. Could be modified to fit exactly it is was off too much. If the clear coat was P.U. like Awlgrip, then almost no chemical will touch it.

Still going to take awhile - I don't envy you the job.
 
I would try to find a tool that is about the width of the grooves and try to scrape them out.
 
GREZ said:
For my 34' Marine Trader, I am having the hull painted by a professional, but am doing the prep myself. A PO had applied a clear coat that is flaking badly in places, and totally gone in some other places. My job is to sand the remaining clear coat off, down to the 'paint'. The hull is fiberglass, with the little horizontal grooves to simulate wood plank joints, and the clear coat is perfect in those grooves.
Question is... what is the efficient, effective method to remove that clear coat? A special tool perhaps? My elbow? Chemicals? If you have 'been there' any experience or advice is most welcome. And as always, Thank You!!
Grez
Click to expand...
Sounds like the PO put the horrible PoliGlo on the hull. Sand it with 120 grit, you will spend way too much time and money with so called “strippers” and the surface will still need the 120 prep for the primer coats anyway
 
Poliglo does make a stripper for it I believe. Don’t know if it works or not.
 
Plank lines are a pain in the rear, that’s for sure. There are sander attachments for oscillating tools, and there’s a tool by porter cable called a profile sander that have the right shape tote in there, but I actually prefer to use hand sanding blocks. I have a bunch of different shapes of these by dura block. Mostly I use them for car restoration projects, but they work the same on boats.
Use self adhesive paper on them. I use a fairly coarse grit for plank grooves. You want the surface to have some tooth so it holds the paint instead of letting it run out the bottom.
You may be surprised how fast you can work your way down a plank line with an eleven inch sanding block.
 
Comodave said:
Poliglo does make a stripper for it I believe. Don’t know if it works or not.
Click to expand...
Apparently not for total removal, mine was old and required sanding. The only good things you hear about it is from the retailers who sell it.
 
I had a boat with the simulation wood groves. When we painted it we had to use a soft sanding block by hand. It wasn't that bad.
 
They say Poli Strip will remove it but I have never tried it.
 
The radius might be too big depending on the size of the grooves, but I really like these foam sanding blocks for hand sanding into corners. This is the first thing I would try. If you need something with a smaller radius I would try and make my own block out of wood or rubber, and use adhesive backed paper with it. Someday I will be doing this same job on my own boat, so I would be curious what you find that works well.

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I have one other idea that might work, especially if the clear coat isn't adhered very well. You might be able to scrape it out with a Bahco carbide scraper. (These are an amazing tool to have on your boat in general). They sell round blades for them but ther radius is likely too big. You could get a carbide grinding wheel and grind the tips of the triangular blade to the proper radius, then gently scrape the clear coat out of the grooves.
 

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Bmarler said:
Plank lines are a pain in the rear, that’s for sure. There are sander attachments for oscillating tools, and there’s a tool by porter cable called a profile sander that have the right shape tote in there, but I actually prefer to use hand sanding blocks. I have a bunch of different shapes of these by dura block. Mostly I use them for car restoration projects, but they work the same on boats.
Use self adhesive paper on them. I use a fairly coarse grit for plank grooves. You want the surface to have some tooth so it holds the paint instead of letting it run out the bottom.
You may be surprised how fast you can work your way down a plank line with an eleven inch sanding block.
Click to expand...
Grez, where are you? I have a Porter Cable profile sander I have never used if you are interested. However I think Bmarier's idea of using a soft block and doing it by hand will be faster and much less chance of an oops. Just change the paper often. You may be able to shape foam sanding blocks to just the right profile if you can not find a commercially available one.

Rob
 
GREZ said:
For my 34' Marine Trader, I am having the hull painted by a professional, but am doing the prep myself. A PO had applied a clear coat that is flaking badly in places, and totally gone in some other places. My job is to sand the remaining clear coat off, down to the 'paint'. The hull is fiberglass, with the little horizontal grooves to simulate wood plank joints, and the clear coat is perfect in those grooves.
Question is... what is the efficient, effective method to remove that clear coat? A special tool perhaps? My elbow? Chemicals? If you have 'been there' any experience or advice is most welcome. And as always, Thank You!!
Grez
Click to expand...
On our GB 36cl we used a wood dowel wrapped with sandpaper. It does go pretty quick. Wrap the paper about 1/2 way around, pinch with your fingers and sand. When worn or clogged, real quick to move to a fresh spot on the paper. Set up staging so your not going up and down a ladder all day. Will speed the job up too.
 
I'd think the bigger issue is where do you stop sanding? Do you sand all the clearcoat off? What about what's under it? Safest bet is everything down to gelcoat.
 
sean9c said:
I'd think the bigger issue is where do you stop sanding? Do you sand all the clearcoat off? What about what's under it? Safest bet is everything down to gelcoat.
Click to expand...
Remember, the paint job is only as good as the prep. We went to gelcoat. The whole hull was painted. We had damage after super storm Sandy
 
We have painted several boats entirely. Prep is 80%+ of the work. If you don’t do the prep work correctly and completely then you will get a crappy paint job. We had hundreds of hours of prep work on one boat but the PO was a charter member of the Coalition of the Docking Impaired. He hit everywhere on the hull.
 
Just a quick comment on Poliglo. If the hull was painted Ploiglo is not used on paint.
I have used it for 20 years as an inexpensive short term alternative to a total paint job. The proprietary stripper takes it off with very little effort. BUT- nothing else can be used to remove it.
 
GREZ said:
For my 34' Marine Trader, I am having the hull painted by a professional, but am doing the prep myself. A PO had applied a clear coat that is flaking badly in places, and totally gone in some other places. My job is to sand the remaining clear coat off, down to the 'paint'. The hull is fiberglass, with the little horizontal grooves to simulate wood plank joints, and the clear coat is perfect in those grooves.
Question is... what is the efficient, effective method to remove that clear coat? A special tool perhaps? My elbow? Chemicals? If you have 'been there' any experience or advice is most welcome. And as always, Thank You!!
Grez
Click to expand...
How about VERY JUDICIOUS use of a heat gun. I have to do the same type prep to paint mine. I was thinking that a piece of ply attached to a piece of wooden dowel of the diameter to match the grove with some abrasive paper. Wrap the the paper around the dowel and up the sides of the ply. You can hold the paper on the plywood part. I haven't tried it yet but that will be my first approach unless I can come up with a better idea.
 
Hello all... I am remiss for not replying sooner. This boat project is an on-again-off-again thing, and I have been off for a while.
In the last few days, however, I have discovered that, as some of you suggested, a piece if stiff wire the size of the groove (which the DIY yard provided ala Herb-O-Matic / and a dowel would certainly work as well) with 120 grit wrapped around did the job perfectly. I think I had maybe 6" wrapped around using two hands, and it went actually pretty fast. Followed by a 220 grit sanding block to finish. I cut 1" slices off the block which allows me to 'pinch' it into the groove. My goal is to just remove the 'shine' of the clear coat. Alas, power equipment or chemicals will work here - dang it! If/When you have occasion to tackle this project, just fire up some Doobie Brothers on the smart speaker and get in the groove.
That's it. Thank you Thank you for your time and perspective.
Cheers!!
 
Crap... error above... power equipment and chemicals will NOT work here...
I did proof this. It's amazing how one's mind sees what is not there.
Cheers again!!
 
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