Best bottom paint scraper

[njlarry]

As you can see from the attached pic I have a lot of scraping to do. Went to the paint store and found a varied selection. Would a wide or narrow blade type push scraper or a pull type scraper work better?
For the purpose of this discussion let's leave chemical and soda blast removal aside as that has been covered before.
Thank you.

 

[Justin_NSA]

I wouldn't think wide would buy you much on a curved surface. Too narrow would be more work. This is a Goldilocks and the 3 bears question

 

[dlochner]

Probably need one of each for different areas, wide for the large flat areas, medium for the more curved areas, and narrow for those tight spots.

 

[njlarry]

Thank you. I understand the wide vs narrow but I should have been more clear, a push type that usually has razor type replacement blades or a pull type that usually has 'u' shaped replacement scrapers?

 

[dlochner]

The pull kind will probably work better. An ergonomic grip and comfortable grip will be worth every penny. You're going to spend a lot of time hanging on to it.

 

[Justin_NSA]

I have one of those 'u' shaped blade scrapers. They work well on wood but I wouldn't trust one on gelcoat. Those blades a hard and sharp.

 

[dlochner]

Rounding the corners of the scraper blade may help prevent gouges.

 

[cb32863]

80 grit and a random orbital?

 

[njlarry]

Would like to keep this thread focused on scraper type.
Other issues will be posted on other threads.

 

[Rich Stidger]

I have used the pull type with the U-shaped blades. Good idea about rounding the edges to help prevent gouges. You do need to be careful. My scraper is about 2" wide. On the curved surfaces I just press lighter than when the blade is flat on the surface.

 

[LakeShark]

80 grit and a random orbital?

@cb32863 has the right idea.

Would like to keep this thread focused on scraper type.
Other issues will be posted on other threads.

Speaking from experience working in a boat yard in San Diego scraping alone will not get it all and on your next haul out you will find even more flaking of the paint. If scraping is all your interested in (and a lot are) here is the scraper style we used to use. It's small enough to try and fair the edges where the paint flakes away and the Awl portion is good for popping small blisters to see if they are deep enough to need repair or if it is simply in the paint layers. However you will not get the best job with scraping alone and sometimes if the paint is bad enough the old paint will peel off the boat and wrap itself around the roller when you try and apply the new coat. As we used to say in the yard "Pay me now or pay me later it's your boat"

 

[LeslieTroyer]

I start wide and by the time I'm done scraping my arm tells me 1/4 inch is tooo wide

 

[Charles Erwin]

Larry's photo makes it plain. This is no place for any scraper.

First, scrapers do not work unless kept razor sharp - means a file or sander in your back pocket thus to sharpen the scraper about every 10 passes. Second, the hull is quite curved and your scraper is quite straight. In other words scrapers are good for flat house siding but not very good for curvy boats.

Use 40 - 60 grit 3M on a 6" random orbital with an interface (soft) pad which will conform to the curve of the boat - and you will be done before you know it - about 3 hours for a 30' boat. There are places your sanding machine cannot get into and it is at those places a scraper is useful.

All things considered the scraper overall approach will get you paint ready sometime around next October but you will still have to sand to get it paint ready after scraping anyhow.

Charles

 

[rgranger]

I know you want to talk scrappers but....
About two years ago I posted a receip for home made peel away... do a search with my username
For about $20 you can get 95% of that off with a pressure wash and a drop cloth to catch the pieces

 

[Ned Ludd]

What type of paint do you have? I took off 95% of my old ablative the day I pulled the boat with a 5000 psi pressure washer and a 25 degree nozzle in about an hour. Fastest scraper I have ever used. Need to hit it with 8o grit and paint it in the next 3 weeks.

 

[Sefuller]

Larry,

Our 34 had 23 years of ablative bottom paint and VC Tar barrier coat when I scraped the bottom in 2006. I used 2" wide "u" shaped pull scrapers. I kept an orbital sander and a file close by and sharpened the scraper periodically. Replacement blades are cheap, I bought a few extras. I used the steel blades that were a square with four cutting edges. Rounding the edges of the scraper blades slightly is paramount - they will dig into the gelcoat on those strokes that don't go exactly as intended! I also purchased a carbide scraper toward the end, but I think the thinner edge of the u shaped scraper was more effective. I did my bottom over a winter layup, so most of the days I worked on it were probably between 25 and 40 degrees. I don't know if it was this or the age, but the VC Tar came off pretty well - it was more brittle than gooey. The trick it seemed was to get the edge to bite all the way under the paint and tar, then pull - usually I could get a good 2" swath all the way down to gel coat in one stroke. I tried to do 2' square sections - it seemed easier to get all the way down to gelcoat in one stroke if the strokes were shorter rather than longer. If the scraper happened to ride up onto the surface of the paint it seemed to burnish the tar barrier it making it harder to scrape off. It was a daunting, tedious job, and after I had everything scraped I went over it with a random orbit sander, and some mineral spirits on a rag to remove any remaining tar. I barrier coated with 7 coats of Interprotect 2000 after the bottom was all clean. Let me know if you have any other questions.

This is the scraper I used - guess it was actually 2 1/2":

Scott

 

[Joe]

I've used both pull and push type.... the pull makes me nervous... the push feels more under control. A very stiff scraper such as the one lake shark pictured is my choice. I don't want it super razor sharp because it could cut the gel.... rather than just getting between it and the old paint. If that type off scraper can't release the paint... then hand sanding proceeds. Hand and/or wet sanding will satisfy most environmental restrictions, if you're in a yard.

I agree with Ned Ludd, my first move would be a pressure washer.... it won't damage the gel and will save a lot of time with loose stuff.... then scraper... and sanding for further removal or to fair in the remaining paint to the unpainted surface. When you paint, use a two part primer that will chemically bond the first coat to the bottom surface.

 

[agprice22]

80 grit and a random orbital?

That sounds good. How about a 7" polisher/grinder? It'll save you a ton of time. The advantage of the orbital sander is that you can connect a vacuum to collect the dust. With 40 grit, the orbital will remove material quickly. Hose it down afterward. Let it dry. Apply epoxy barrier coat. Apply bottom paint.
Oh, and VC17 will come off with a pressure washer. And sometimes a scotchbrite pad if necessary. I know they say VC17 is not ablative, but it is very thin, and it washes off after a season.

 

[Gene Neill]

I tried a pressure washer first. It made my bottom paint look better, but only removed about 2% of it at most. I tried a few things, and finally settled in with a 1" wood chisel. Some areas are coming off "easily", others really not at all. On those areas, I do not believe there is a scraper on earth that will work - they will get sanded off when the time comes. For now, I just try to do a square foot or two each day with my chisel.

I'm eating the elephant one bite at a time.

 

[agprice22]

Scraping is a PITA! Grind it off!