Sanding bottom paint on 35 footer?

[sanibel sailor]

I have ablative paint on my boat and some blisters. Considering stripping the paint and barrier coating. How long should I (skilled DIY'er) estimate to sand the bottom? Is this a one day job? The yards I am considering don't allow blasting.
I am sure this will cure me of wanting a bigger boat.

[JPA Cate]

I just asked my Jim how long it took him to scrape back 17 yrs. of bottom paint when he did it in NZ, and he remembers it was 50 hrs. The boat was a PJ Standfast 36, so a fin keel rather than a centerboarder, but about the same size, and he was 52 or 3 or 4 yrs. old at the time; neither of us remembers which year it was. When he reached 80, he has hired others since then to do that part of the job, and the last 3 times has also hired the painting. You sure get a nice bottom when it is sprayed onto a well prepared hull!

Good luck with it, your boat will appreciate it. Tell us how you prepare the centerboard trunk for its paint, too, please.

Ann

[Tetepare]

There was a thread on this last week. Search for belt sander. There are other options. My 30 took about 20 hours with a belt then finish sanding. I’d not do it myself again.

[freshalaska]

My 39 foot boat which at the time was 39 years old and had many layers of boat bottom paint, I sanded the bottom with a 9 inch angle grinder and 36 grit discs. Took me possibly 60 hours to get all the old paint and gelcoat off. What a dirty job. Then applied four coats of epoxy barrier. Then of coarse the anti fouling paint.

[sanibel sailor]

https://www.cruisersforum.com/forums...me-181210.html

Just found this thread which has me rethinking the whole plan.

[wingssail]

We usually do the bottom of our 43' boat annually, and for most of 30 years (until I quit) I sanded it myself with a random orbit electric sander. Two long days, as a rule, got most of the paint off; I never went down to the bare glass.

That was two day of very hard and dirty work.

A few times I hired it when I wanted a more complete job.

Filling the blisters and then painting was a piece of cake compared to the sanding. Even repairing the keel (a frequent requirement) was easier than sanding. But if you want to do it yourself, get a good, powerful machine, a full painter's suit, good breathing mask, and go for it. It's possible.

Now we pay a couple of Mexicans to do it, and including the painting, it's $600 dollars, plus paint.

I'll never sand the bottom again.

[Rucksta]

I use a pneumatic 6"random orbital sander with 80 grit.
Assistant with a water blaster to direct a water mist to the work site
43" fin keel takes 5 hours including coffee, lunch & beers.

47' multi with mini keels takes 8 hours and more beer.

To remove build up use a scrapper with a tungsten blade.
For stubborn areas e.g. waterline with build up and cracking of old paint an electric plane makes short work of it.

Scrapping is done the same day as haul out while the paints still a bit softer

Wet sand makes the job way less messy.
Use hi quality abrasives. (RevCut)

Change abrasive discs often 43' uses 25-30 discs Multi tales 40-45.

[soopad00pa]

I used a decently powerful (middle of the pack rigid) orbital sander connected to a shop vac. i used a buncha 80 grit pads.

It took two 8-9hr days to do my 30ft catalina plus not quite 2 gallons of paint.

[Rumrace]

OP are you doing an Epoxy. Parge?
Drill and drain takes days.
That’s to open the blisters and drain water out. I’ve drilled a blister and was stunned the amount of damage.
Until you assess your damage you don’t know. The best sander is a block sander but getting paint off blasting can’t be beat. It’s also going to give you a great grip for the new barrier coat.
Systems west for POX holes everyone will tell you. Add micro balloons to one pump mixes. West wants to pour right back out. The balloons turn into little connectors and thicken the mix.
I had mine bottom painted Have no idea how long it took but there was no hull repair.
They moved it in the cradle and gave it back in a week.

[wingless]

This reply shows my sanding to bare gel coat prior to barrier coat using my Festool vacuum sander. It is a very clean job, almost no mess, almost no need for eye protection (just enough to still wear goggles and mask).

On mine it is a long job. The fore / aft chines, plus the strut tunnels add to the difficulty.

[deltaten]

"One day job"?
LOL
A couple or 3 yr back, I did the hull of my Watkins 27 Somewhere between 2 and six coats of ablative and a nasty, lumpy hard coating of what appeared to be coal tar epoxy. Several days of arm wrenching scraping. Many more of sanding and a few of nasty spots grinding. Then a clean up of a couple days more finish sanding. All down to clean, well prepped gel coat. Estimated in hindsight as 60+ hrs of back-breaking, bone wearing, filthy, muscle-cramping hell. Then onto barrier and bottom coating....wheeew! Thank goodness that's the last time. It'll outlive me, Fer sure
Given that mine is a "one gallon/two coat" hull and yours, by other's estimates , will take 2 gallons....... adjust as necessary
I'd recommend hiring ot a blast job, perhaps DIY any pre-coat repairs
Estimated blast cost? Somewhere between $600 and $1200
Savings to your muscles and sanity.... Priceless !!))