Bottom paint

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karlos263

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Sep 4, 2012
21
macgregor 26d port maitland, on
Last year I had my 26D in the water all summer without any bottom paint on it. There was a lot of algae growth when I took it out. I power washed it and got most off. This year I'm putting bottom paint on and am now in the process of sanding the whole bottom to clean it up. My question is;
since it is all sanded do I need to put primer on before the anti-fouling paint?
thanks, Karl
 
C

canderson1867

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Jun 11, 2010
40
Mac Gregor 26M House
karlos263 said:
Last year I had my 26D in the water all summer without any bottom paint on it. There was a lot of algae growth when I took it out. I power washed it and got most off. This year I'm putting bottom paint on and am now in the process of sanding the whole bottom to clean it up. My question is;
since it is all sanded do I need to put primer on before the anti-fouling paint?
thanks, Karl
Click to expand
Hi Karl,
I did my boat last year. It had been in fresh water and there was no barrier coat. I researched the subject and found that without a good barrier coat, water can create blisters in the fiberglass. West Marine advisor has a real good article on this problem, and of course, more than willing to sell you the barrier paint. It calls for 5-6 coats before applying the bottom paint. I ended up with 6 coats and 3 coats of bottom paint. Took me most of the summer, but it was worth it. My boat has been salt water for over a year and only a small amount of slim. Maybe someone else can add some info on this.
 
Sumner

Sumner

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Jan 31, 2009
5,254
Macgregor & Endeavour 26S and 37 Utah's Canyon Country
As long as you are doing it I'd also recommend putting the barrier coat on before the antifouling. You can get a 2 gallon kit of Tuff Stuff for $150...

http://www.bottompaintstore.com/tuff-stuff-highbuild-epoxy-primer-by-sea-hawk-paints-p-9473.html

... and put it on right before the antifouling. We used it as it has a higher build per coat vs. some of the other products so you put on fewer coats. We put 2 coats on the Mac and are putting 3 coats on the Endeavour.

If you don't have blisters now you might not get them but if you do then you will have to remove all of the bottom paint, fix the blisters and then put on barrier paint and antifouling again. That is a long expensive job vs. spending $150 now and being done with it.

I have more info and and how we painted...



...our boat here....

http://purplesagetradingpost.com/sumner/macgregor2/outside-39.html

Sum

[FONT=Arial, sans-serif]============================[/FONT]

Our Endeavour 37

Our MacGregor 26-S Pages

Our Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links
 
finding41

finding41

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Nov 23, 2011
2,023
MacGregor 26D London Ontario Canada
I just sanded my bottom of the new boat (26D). It had little pimples and lots of staining. It took me 4.5+ hr and I killed one random orbital sander. I used 60 grit and switched to 80 grit when I ran out of 60.
I applied 2 thick coats of Interlux barrier coat and then 2 coats of Blue Aquaguard ablative paint. (I used Aquaguard last year and it worked great for the zebra mussels and blue green slime and grass. I wouldn't have to repaint the old boat if I hadn't been so power washer happy! lesson learned. I sail in fresh water but I see on the site it works in salt too.)
I plan two more coats of Aquaguard White over the Blue. I am having a hard time getting the White here in London Ontario.
Pic's; 1 Little bumps, 2 Hole I patched in Laz, 3 bottom after sanding.
 

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Piotr

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Dec 6, 2010
848
MacGregor 25 Rock Hall, MD
If the boat is brand new DON'T SAND IT !!! Interlux has a primer that goes directly on the gel coat. I primed my catalina 18 with ONE coat of primer. Did not have any problem with the antifouling paint for the next 15 years...
 
Sumner

Sumner

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Jan 31, 2009
5,254
Macgregor & Endeavour 26S and 37 Utah's Canyon Country
Piotr said:
If the boat is brand new DON'T SAND IT !!! Interlux has a primer that goes directly on the gel coat. I primed my catalina 18 with ONE coat of primer. Did not have any problem with the antifouling paint for the next 15 years...
Click to expand
I'm aware that they have primers that replace sanding in some instances to create the bond that sanding does, but are any of them also an epoxy primer that will help to protect from blistering. The antifouling won't protect the boat from that and the primers I'm aware of won't either.

Do you have a link to what you used?

Sum

[FONT=Arial, sans-serif]============================[/FONT]

Our Endeavour 37

Our MacGregor 26-S Pages

Our Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links
 
P

Piotr

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Dec 6, 2010
848
MacGregor 25 Rock Hall, MD
Sumner said:
I'm aware that they have primers that replace sanding in some instances to create the bond that sanding does, but are any of them also an epoxy primer that will help to protect from blistering. The antifouling won't protect the boat from that and the primers I'm aware of won't either.

Do you have a link to what you used?

Sum

[FONT=Arial, sans-serif]============================[/FONT]

Our Endeavour 37

Our MacGregor 26-S Pages

Our Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links
Click to expand
hmmm.. likely not, but the boat was in water for 15 seasons with no blisters. I don't have it now, but it was an Interlux gel coat primer. I think it was called 206.
 
finding41

finding41

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Nov 23, 2011
2,023
MacGregor 26D London Ontario Canada
The Interlux I used was a water barrier two part epoxy. InterProtect 2000E With micro platelets... (Ie; stir well!)
The grey is the Interlux and the blue is the Aquaguard. Note; the grey close up is the hole I patched.
The last photo is what I had to work with.
 

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finding41

finding41

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Nov 23, 2011
2,023
MacGregor 26D London Ontario Canada
I don't trust the primer products that say "no sanding required". I've seen too many examples of paint/primer failure. (Also makes people lazy and they don't do any of the other preparation...) You need the physical bond that sanding provides.
By sanding you remove not only a little gellcoat but allot of dirt and foreign materials like grease or chemicals that impede the primer/ paint sticking.
Paint is strong stuff on its own. On its own it will last many years. The problem is we put paint on things. Those things expand and contract, warm and cool at different temperatures than the paint does. This is one thing that releases the bond from the surface. Sanding gives the things surface "tooth" to better hold the primer/paint.
 
P

Piotr

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Dec 6, 2010
848
MacGregor 25 Rock Hall, MD
finding41 said:
I don't trust the primer products that say "no sanding required". I've seen too many examples of paint/primer failure. (Also makes people lazy and they don't do any of the other preparation...) You need the physical bond that sanding provides.
By sanding you remove not only a little gellcoat but allot of dirt and foreign materials like grease or chemicals that impede the primer/ paint sticking.
Paint is strong stuff on its own. On its own it will last many years. The problem is we put paint on things. Those things expand and contract, warm and cool at different temperatures than the paint does. This is one thing that releases the bond from the surface. Sanding gives the things surface "tooth" to better hold the primer/paint.
Click to expand
I guess we have to agree to disagree. I believe in sanding of the gel coat when everything else fails.
 
Sumner

Sumner

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Jan 31, 2009
5,254
Macgregor & Endeavour 26S and 37 Utah's Canyon Country
finding41 said:
.. Sanding gives the things surface "tooth" to better hold the primer/paint.
Click to expand
I also believe in the clean with wax/grease remover and then sand first before painting. The no-sand primers might work, but if they don't for the reasons you mentioned then you are in for a lot of work and re-buying expensive material.

Also if a boat has survived a number of years in the water continuously with no blisters then it probably isn't going to get them. We had no idea if that had ever been the case with our boat so didn't want to take the chance so feel that $150 spent was good insurance,

Sum

[FONT=Arial, sans-serif]============================[/FONT]

Our Endeavour 37

Our MacGregor 26-S Pages

Our Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links
 
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