bottom painting prep

[mdbrown]

Now that the sailing season is over here in Central Il, my 26S is relaxing on the trailer after being in the lake all year long. To clean the bottom, I used a power washer with a wide tip. I'm now trying to figure out what paint is there and what I need to do to prep for painting.

There was a very thin black coat on top of blue coat on top of the gelcoat. The black paint was mostly gone, and what remained came off with the growth when I used the power washer.

So to prep for painting, what do you recommend? Do I need to sand the blue off down to the gelcoat and then use a barrier paint or primer first? Or if I sand the blue with 80 grit will that be enough prep that I could apply antifouling bottom paint? It's very unlikely this boat will ever see salt water if that matters.

The day after coming out of the lake:


And then after power washing:

[Herschel]

Let me be the first to say, "I really am not sure what to recommend!" I have never personally painted my 26X. I did have mine painted twice, but left the prep to the "professionals". That said, I will tell you that I have worked on my smaller boats (O'Day Sprite and Snark). When I wanted to add strengthening fiberglass cloth to a painted surface, I would take down to the bare glass and build up from there, priming and painting after sanding new glass surface as needed. But when starting with a painted surface, I have just sanded down until I was sure I had off anything that might conceivably flake or peal off. Then I primed and painted. In working on my little Snark with its peculiar construction (Styrofoam core covered by ABS plastic) and the need to avoid putting oil based products on Styrofoam, I ran across this fellow's blog. He professes to be a chemical engineer that has worked for paint companies. I tried his advice and used latex house paint on the outside of my Snark hull. I am anxious to put his ideas to the test. Just finished the paint job; haven't put in the water, yet. Perhaps others on the forum will have some better advice from actual practice. Here is the link to the blog I mentioned.
http://www.simplicityboats.com/latexcarnel.html

[Sumner]

Do you have any blisters? I can't tell from the picture. If so and you decide to repair them and put on barrier paint you need to take it down to the gel coat.



Had to do that on the Endeavour but had the bottom sand blasted and then repaired (not by me) and then we put on the barrier coats and the bottom paint. Info on that here....

http://purplesagetradingpost.com/sumner ... index.html

If no blisters then I would sand down with 80 grit to the point you had a good base, not necessarily to the gel coat, and then apply bottom paint.



Info on putting barrier paint and bottom paint on our Mac here...

http://purplesagetradingpost.com/sumner ... de-39.html

Sumner

============================
1300 miles to the Bahamas and back -- 2015

The MacGregor 26-S

The Endeavour 37

Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links

[mdbrown]

Thanks Sumner. I've read your blog multiple times and was hoping your add your opinion! I don't have any blisters and no flaking. The pictures look worse than reality.

[FLGSHP7]

Thanks Sumner. I've read your blog multiple times and was hoping your add your opinion! I don't have any blisters and no flaking. The pictures look worse than reality.

Where are you from? Cant be too far from me. I'm in Tuscola area and sail Lake Decatur. First year sailor and boat owner.

[mdbrown]

I'm up in Heyworth. This is also my first year with the M26, and we have a slip at Clinton Lake.

[yukonbob]

Real blister problems require much more than stripping down to the gel. More and more the skin out mat of chopped strand that many manufacturers tend to use must also be removed but is not completely limited to chopped mat, and many blister repair jobs done by professionals have to be re-done within a few years. That not being the issue here I would suggest sand or soda blasting that clean and fairing it out with epoxy. Looks very pitted from your pictures and unless corrected will rob you of speed and gas.

[FLGSHP7]

I'm up in Heyworth. This is also my first year with the M26, and we have a slip at Clinton Lake.

Okay cool!

Did you buy the M26 that was for sale up in Dewitt?

[Sumner]

Real blister problems require much more than stripping down to the gel...

Don't think anyone implied that at least hope my post didn't imply that as I had to spend a lot of money on the Endeavour to have the blisters repaired....

http://1fatgmc.com/boat/end-1/endeavour ... age-1.html

Sumner

============================
1300 miles to the Bahamas and back -- 2015

The MacGregor 26-S

The Endeavour 37

Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links

[yukonbob]

Don't think anyone implied that at least hope my post didn't imply that as I had to spend a lot of money on the Endeavour to have the blisters repaired....

http://www.yachtsurvey.com/BuyingBlisterBoat.htm
http://www.yachtsurvey.com/BlisterRepairFail.htm
http://www.yachtsurvey.com/BlisterFail2.htm

The above is the best laid out description I have found regarding the blister and blister repair issue and is reciprocated by many surveyors and industry professional. With Mac's not using any chop strand mat, blister issues should mostly be limited to anti-fouling paint layers and is non-structural, but it is possible that voids in the roving could blister. Some blister repairs work, some don't, and it has more to do with initial hull construction than anything else, tahts all . Buyer be ware and I hope your repair is a good one Sumner.

[Interim]

Is this a reasonable "yard project"? I'm planning to do mine this off-season too, but haven't committed to doing it myself yet.

I have a couple gelcoat issues that I will repair, no problem. But I need to sand off the old material, and put on the new, while it is on a trailer. For those who have done this, is it a long weekend? A couple weeks? Dangers from toxic materials? Or a "jump in and do it" project?

If you have hired it out, what is a reasonable cost?

--john

[yukonbob]

Buy a good respirator not a dust mask ($50 bucks) and a couple of disposable tyvek suit and fly at it. It's messy but not difficult. Don't get too crazy with the sanding / peeling and make sure you don't go below the gel coat or into the glass. They make bottom paints for trailerable boats (harder) that can be applied directly over a lot of old paints with few exceptions. Just make sure you get a fairly good smooth finish and do a test patch for compatibility then finish it off if it bonds well. Shouldn't be more than a weekend.