DIY bottom paint advice?

[Davidhoy]

I'm planning on hauling my Morgan 462 to paint the bottom, replace the prop, and do some preventative maintenance on the shaft, cutless bearing, rudder, through hulls, etc. Got a quote for $4500 for someone to do the bottom paint, which seems ludicrous, so I'm going to do it myself. I have to go to a different yard, as the nearest yard (LMC in Fort Lauderdale is less than 1/2 mile up the river from me) just changed their policies to no longer allow DIY bottom jobs.

So here's what I need advice on:
1. Paint selection - I have no idea what the previous owner last painted the boat with, other than it's a soft ablative paint. How do I select a paint that will be compatible with what's on there, or do I have to strip it down the the barrier coat?
2. Paint quantity - how do I determine the right amount of paint to buy? Planning on at least two full coats, plus extra coats at the waterline and leading edges of keel and rudder.
3. Best way to prepare the surface - Seems vacuum sanding with an orbital sander, with 80 grit paper, is the way to go. Can anyone recommend a good sander that will be up to the task?
4. Application - I presume rollers to cover the larger areas, and some brushes for the fiddly bits. What nap roller to use?

Any other advice would be appreciated. As would any volunteers to help ;-)

Regards,
David

P.S. Only half joking about the volunteers... I have lots of cold beer!

[Cheechako]

Well it's a big boat, so be prepared for some work. It really is going to depend on the bottom condition very much. You don't need to sand much if the bottom is clean. I would use 60-80 grit. Possible even 40 grit for some. You just want some "tooth". Have the boat pressure washed as soon as it's pulled, then assess.
-be careful, some yards require you to buy the paint from them.
-You may be required to "tent" the boat if sanding. That means you have to enclose the boat bottom with visqueen taped to the sides to contain dust. It makes for miserable working.
-Use only the green tape, if it's hot out and you take longer than expected, it's well worth it. Nothing worse than tape that has hardened up on the fiberglass.
-Ask if you can bring a worker. This a good situation to hire a young worker at $12-15 an hour to do sanding! Some yards will only allow family. So find someone to be your "nephew".
-Thick rollers, at least 3/8".
-I cant remember on my 47 how much paint but I'm thinking 3 gallons would not do two full coats. If you want two full thick coats , I wonder if paint is available in 5 gallons cheaper?
-After sanding wash the bottom with a hose and let it dry overnight.
Have fun if that's possible....
-Buy hooded tyvek throw away overalls for sanding.

[a64pilot]

The yard and other local sailors can likely give you a good idea on what paint.
Great paint for my area, may suck where you are.
I would resist the temptation of adding magic ingredients, like Cayanne pepper etc.
Pressure wash, and then as long as there are not too many layers of paint, no need to strip and or sand off, seems to me that I see a lot of dry wall sanding poles used, idea being I think to prep the surface, not so much remove all old paint.

Depends entirely on what is there, if you have many layers and it's beginning to come off, then you have a lot off work ahead of you, but if the PO just had it stripped down and barrier coated, then life is good

[barnakiel]

We found that if the old paint is soft (ablative) and the condition is OK, you can simply powerwash and dry very well then pain new over old. Ask the ex owner what paint he used last time.

There is a paint volume calculator at (?) International (or possibly Hempel) website.

STIR very well ;-) Then rollers, and extra long handles.

Cheers,
b.

[gamayun]

Before I removed 28 years of bottom paint because it kept chipping off as I was doing the light sanding, I seem to recall that the Petit Trinidad tech support told me that you can test the adherence of the paint, but now I have forgotten it....maybe something like paint over a section and see if it pulls up with tape?? Does anyone know if this sounds familiar? Sorry I can't be more helpful, but I had no idea what paint had been used over the years on my boat and this was an issue I had looked into so I know there's info out there, but it has now disappeared completely from my brain!

[sailah]

I do my own as I suspect a lot of others do as well.

Things that make the job easier:

Knee pads
Roller with extension pole, I just use the one from my push broom
3/8" nap roller
Mixing paddle for drill (go slow at first, but mix very well, I mix for 2-3 minutes with drill)
Tyvek suit
2" chip brush for touch ups
hat and disposable sunglasses for the paint drips

My procedure is:

Boat is powerwashed by me when I haul in Fall (i'm in MA) so already clean

I tape off the night before, using 1" & 3/4" blue tape to get around the corners, I apply carefully to follow the Awlgrip bootstripe. Then I overlap 1.5" blue tape over that to give myself 2+ inches of buffer. I use the roll of tape or some type of hard plastic to burnish the edge of the tape so paint can't creep under it.

The past couple years I've done 2 coats. Every time I haul the paint looks good and complete. This year I did 1 full coat. 1 gal of Bluewater 45 does EXACTLY 1 coat on my 37' with no waste or excess. So I carefully meter it from the can into my roller tray to make sure I'm on budget with coverage. Any extra I apply to cutwater and leading edge of keel and rudder.

I have 5 jackstands, 1 under bow and a pair forward and aft. I remove (carefully) one set of jackstands, move them either forward or aft 2' and retension them. Then paint the bare spot. Do the same for the other set. Then the bow. If you don't know how to tension up the chain or feel uncomfortable removing the stands you can always do when in the slings.

I give it a few hours then pull the tape.

I don't sand, my bottom is in good enough shape and that's the reason I try and keep coats to a minimum to not build bulk on the hull. I think that's very regional though, maybe you need 2 coats in FL because of the fouling.

$4500 is nuts. I do mine in a few hours. Takes me an hour to tape off. Few hours to setup and to paint. Bluewater 45 is $107/gal. I could easily do it in one day. Now if sanding is involved

[FionaJC]

I am on the East Coast UK. WE have to antifoul between tides by running up to scrubbing posts so we have done this so many times its a slick operation. I sometimes get someone to pressure wash the mud off after I have used a garden hoe to remove any heavy fouling. WE then don boiler suits and get cheap rollers from the local DIY store about £4 for roller and tray. Start at the front, one of us on each side and finish off the top line by the boot top with a brush. Hard antifoul 3 x 2.5litre tins covers two coats well on a 34ft Colvic Victor. W=hen she comes ashore, once every ten years then its a lot more care and attention using blue masking tape.

Dont forget to self-protect with a mask if you do any sanding. We use gloves, mask and gogles when she is ashore.

[SouthernPride]

All above are good suggestions. Might want to use new paint that is a different color than what is on there now. That way when you start to see the original color bleed through you know it's time to paint again.
Good luck

[Tugwit]

In 40 years of boat ownership I've always done the bottom DIY. A few haulouts ago I bought a Dynabrade RO air sander with vacuum attachment--best investment ever. The air sander is lightweight which reduces fatigue and the vacuum pulls sanding dust so it doesn't end up all over you and the yard.

Our marine environment is seriously degraded due to careless stewardship; this is the main reason it has become more difficult to find yards that permit DIY boat maintenance. In Washington State, yards require vacuum sanders with HEPA filters. While some may chafe at environmental regulations, the upside is that it makes the work much more pleasant to do, not to mention that there may be more fish to catch in the future.

After many years of built-up antifouling which started to flake off in sheets, I stripped the hull and applied an epoxy barrier coat followed by a vinyl-based antifouling paint (VC Offshore). It does not build up like other paints and cleans up well with power-washing making future re-coats easy.

That said, in 2020 Washington State will no longer allow the use of copper-based antifouling paint. A substantial body of research has shown that dissolved copper interferes with juvenile salmon's sense of smell, making them much more vulnerable to predators. New regulations also include a ban on copper in automobile brake pads. Dunno what I'll substitute for VC Offshore when the time comes, but I suspect it's the wave of the future....

[wrwakefield]

David,

We just splashed the other day after completing our own bottom paint job on our Nauticat 43. We also replaced the cutlass bearing [without removing the prop shaft], dripless shaft coupling bellows [PSI], installed a new forward looking SONAR [Navico], etc., etc.

Our boat also has nothing but ablative [Pettit] and therefore we stayed with that instead of stripping down to the barrier coat.

We pressure washed upon haulout [5000psi- akin to firing a 12 gauge shotgun when you pull the trigger...] with the goal of exposing any bottom paint with poor adhesion. There were a few small paint bald spots when we were finished pressure washing- which we feathered in when we sanded...

We sanded the hull with our Festool Rotex 125 sander and Festool vacuum, negating the mandate to tent the boat during sanding. The yard loved it.

We applied 3 gallons of water based bottom paint [Pettit Hydrocoat- which I mention not to necessarily recommend for you, but to share what we were using...] Three Gallons covered 3+ coats at waterline and leading edges, with 2 coats everywhere else. Pettit has detailed calculators for predicting coverage, and worksheets with preparation and application criteria for each paint, and excellent online support for questions you may have that are not answered on their spec sheets. [I suspect other manufacturers offer the same info and service...]

The haulout, sanding and painting took us 4 days- including an extra day because of rain, and waiting to paint until mid-day when the hull temp met the minimum manufacturer's spec [50°F].

With the other things we were doing, an unexpected snag or two, and hanging in the slings overnight the last night to get the bare spots on the bottom of the keel, the yard time was almost 2 weeks. [We had many other yard dependent projects...]

In case this is helpful...

Best wishes with your project(s).

Cheers! Bill

[Photosean]

Here's the best place for the DIY boat painter. I went local the first time while the fella next to me purchased everything from Jamestown Distributers. His experience was enviable. He swore the folks there were extremely knowledgeable and sold him exactly what he needed at the best prices.

Check them out and let us know your experience.

Sean

https://www.jamestowndistributors.co...portal/main.do

[KP44]

Originally Posted by Davidhoy

So here's what I need advice on:

2. Paint quantity - how do I determine the right amount of paint to buy? Planning on at least two full coats, plus extra coats at the waterline and leading edges of keel and rudder.

3. Best way to prepare the surface - Seems vacuum sanding with an orbital sander, with 80 grit paper, is the way to go. Can anyone recommend a good sander that will be up to the task?

P.S. Only half joking about the volunteers... I have lots of cold beer!

Hi David,

I think your hull is very similar to mine (Kelley-Peterson / Formosa 46) and I use about 1 gallon and 1 quart per coat with Trinidad Pro.

Trinidad has been a stand-by for cruisers with 70% copper. Trinidad Pro is a bit harder and does well. But I hear great reports on Micron 66.

Whatever you choose to use, at least 2 coats. Nothing wrong with 3 coats.


Get a 6 inch RO sander and a shop-vac that can attach to the sander. The 6 inch does the job about 4 times faster than a 5 inch.
Be sure to use a 12 ga power cord. This is important. A smaller cord will burn out your power tools; sander and shop vac. Always use a heavy gauge power cord.
Wear a dust mask and make sure it has 2 straps, not 1. The masks with one strap do little good and we call them "placebo" masks.
80 grit is fine. I used some 40 grit when I took off about 8 coats and went down to gel coat. (I finished with 80 grit and 100 grit.)

[Davidhoy]

Originally Posted by wrwakefield

We also replaced the cutlass bearing [without removing the prop shaft], dripless shaft coupling bellows [PSI], installed a new forward looking SONAR [Navico], etc., etc.

I'm planning on checking, and possibly replacing my cutless bearing too. I don't know how old it is, but it did check out OK during the pre-purchase survey last June. Since I"m planning on some extended cruising in a couple of years, replacing it now means I'm not likely to have to worry about it down the line. I need to replace the lips seals on my Tides Marine dripless shaft seal, and a corroded thrust bearing, so I'm just going to pull the shaft anyway. While it's out, and I'm doing the other work, I can get it checked and reconditioned if necessary.

Once the shaft is back in, I get to install my freshly reconditioned Max Prop - found it buried in a locker after I bought the boat, very pleasant surprise! It's so nice and shiny since I got it back from PYI.

Funny you should mention your sonar - I may also be installing new forward looking transducers for my Garmin MFD.

Originally Posted by wrwakefield

Our boat also has nothing but ablative [Pettit] and therefore we stayed with that instead of stripping down to the barrier coat.

I'm planning on using Pettit Hydrocoat too. While I do not know the specific brand currently on the bottom, Hydrocoat will go over almost anything. I spoke with their tech support yesterday, so have a good idea of compatibility, quantity, etc.

Originally Posted by wrwakefield

We pressure washed upon haulout [5000psi- akin to firing a 12 gauge shotgun when you pull the trigger...] with the goal of exposing any bottom paint with poor adhesion. There were a few small paint bald spots when we were finished pressure washing- which we feathered in when we sanded...

Good idea!

Originally Posted by wrwakefield

We sanded the hull with our Festool Rotex 125 sander and Festool vacuum, negating the mandate to tent the boat during sanding. The yard loved it.

The yard I'm likely going to use requires the use of vacuum sanders, which I fully support. They rent them too, $75/day. Looking around to see what sander would be best, decide on buy/rent, etc.

Originally Posted by wrwakefield

In case this is helpful...

Very helpful! Thank you. Hope I don't run into the same type of snags as you did...

Regards,
David

[Ken Z]

I use a high speed 7" light weight pneumatic sander, bot sears makes a 6" disk sander, about$75. that will take a 7" disk two speed fairly lightweight, best place to buy disks is lowes you can regulate the sander to throw dust away from you vacuum sander is great .80 grit, 3/8 roller, extension pole tyvek suit for sanding, mask, eye protection, throw away brush tape, liquid motivation, cold.if your on concrete and have asess to an old reclining office chair its slick for bottom sanding to sit in it and roll around under the boat. prime ? depends on condiion after sanding, paint is all over the place, i like hard type, go with a name brand if possible. west marine has had bottom paint on sale lately, id go two coats .most yards in so. fl. are outrageous.

[Aaarrgh]

I've been a commercial/industrial painter/contractor for 37 years.
I've done adhesion tests on cured coatings as required in contracts, as per mfgr recommendations. If you do an adhesion test, make sure that you're ready to deal with the test area if it fails, so choose an area that you can repair easily. This test is what is generally recommended for tough chemical coatings, so you other chaps CHIME IN, if you see any danger in what I describe. (Disclaimer) As you might expect, different engineers
come up with different methods, and different inspectors come up with different inspection criteria. I will not further bore you with details.

The paint adhesion test that I think you mentioned goes like this:

6"X6" test area:
>Make cuts with a sharp utility knife, about 1/4" apart, across the 6"X6" area.
(Just deep enough to cut through the coating being tested)(That's a guessing game)
>Make the same cuts at 90 degrees from the first cuts.
(Should look like an uncolored tiny checkerboard)
>Firmly press a good quality silver duct tape in a single layer over the test area (not the red or black monster stuff they sell these days)(Duck brand is good). Leave folded-over RIP tabs all on one edge that you will grab in the next step.
>After about 5 minutes, RIP the tape off. Emphasis on RIP!

The percentage of tiny squares that are removed from the surface (or underlying coatings) is what inspectors calculate to determine if the test is a pass or fail.

Again, I have no idea if this test is in any way applicable to marine coatings on boats, but it is common on adequately prepared substrates where the testing of each coat(s) is tested , after proper curing time(s), and "passed" before the next coat is allowed to be applied. I speak only about that with which I am familiar (not expert)(fresh water submersible structural steel) (dams, locks, barges, etc.)

Aarrrgh!