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Catalina/Capri 25/250 Sailor's Forums

General Sailing Forum

Bottom Job (advice needed)

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Bruce Baker
Captain

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USA
402 Posts

Initially Posted - 04/04/2006 : 09:55:36

A couple of months ago, I asked the list on what kind of paint to use on my C-25. I decided to go with VC-17m for racing performance in fresh water. I've stripped the old abalative paint (at least four coats) down to bare hull using the West Marine product. Overall, it worked well. But I've got a couple of questions / issues I could use help on:

1. I've found a couple of dime sized blisters. Should I lance them or paint over them? I don't have time to let them dry out (much). I've received some advice that I should pop the blister, inject acetone into them, then fill with Marinetex. Do you agree?

2. I've started sanding the bottom with 220 grit sandpaper, but it's going slowly. I don't want to get too aggressive and sand off my gelcoat. How much gelcoat is down there? I'm thinking of using a 120 grit paper and finish with the really fine stuff. I don't have time to put on a new barrier coat. I've also scratched the gel coat with my scraper blade, but the scratches are not deep.

3. There appears to be a ring of silicone around the depth meter transponder that I had never seen before. I think maybe the chemicals have softened it. What should I do? Cut it out and put in more silicone? Remove the transponder from inside the boat?

4. The boat yard put a huge gouge in my side, just above the waterline. They have agreed to repair it. It looks like they poured some clear stuff in the hole. I assume they will put some white stuff on top. Does this sound right?

Thanks,

Bruce Baker
Falls Church, VA
"Yee Ha" 3573
'83SR/SK

Edited by - on

Gary B.
Admiral

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USA
969 Posts

Response Posted - 04/04/2006 : 10:25:08

Your boatyard has NOT fixed your boat. Certainly it sounds like it needs a fiberglass repair with gelcoat over.

I would NOT waste my time with 220 grit paper at this point. The gelcoat is thick enough, and usually not sanded enough, that it should hold up well to sanding with 120 grit or so. I have used 80 with no problem (before the barrier coat I put on). You could certainly then do a light sand with 200-ish grit for smooth.

I would NOT use silicone for the transducer/transponder. Take it out, clean it well, and reinstall with a good poly sulfide ( I think that is the term I want). I like BoatLife and have had good luck. I would NEVER use 5200 for anything, in that it would then NOT be removeable.....

As for the blisters.....I might be tempted to just paint over them (since you are not barrier coating), and then fix them more permanently when you have a chance to dig them out and let them DRY before filling with epoxy or even Marine-Tex....

A couple of little blisters should not impede performance much at all, and certainly should not be considered "serious" at this point. The ones I dug out, dried and filled with epoxy, have not reappeared (this was before the barrier coat several years ago).

Gary B.
s/v Encore! #685 SK/SR

Edited by - on

coach
Navigator

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USA
231 Posts

Response Posted - 04/04/2006 : 11:04:43

When I need a bottom job, I just call my wife.

Edited by - coach on 04/04/2006 11:04:58

Ericson33
Admiral

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USA
892 Posts

Response Posted - 04/04/2006 : 11:08:16

1. Yes I would pop the blisters if you have the time. I would use Marine-tex or West Systems with a Micoo Ballon filler.

2. I would not sand the bottom with anything finer than 120 right now, Apply several coats of the VC17, then sand to perfection, its the final coat that does the trick.

3. I would also remove the tranducer and re-apply a good seal around the tranducer. This is one place I would use 5200, but thats me. This is the one area I don't want a leak in.

4. Just watch the yard as they fix the boat. The clear stuff is most likly a Polyester resign, They should fair it down then gelcoat the hull back. This normally would take me 1 day to do, So if they are messing around with your schedule, I would bug them to get a move on.

Edited by - on

takokichi
Captain

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USA
321 Posts

Response Posted - 04/04/2006 : 12:03:39

"I don't have time"

Make the time - you're going to be sorry if you rush this job, and really really happy if you do it right!

"5200 make things permanent" - Not true. But its really good at preventing water from coming into your boat from below the waterline! If you use 5200 and you want to remove something, you take a guitar string - available just about anywhere for a dollar or so - and wrap the ends around two dowels and use it as a wire saw. No fuss.

Edited by - on

Daniel
1st Mate

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78 Posts

Response Posted - 04/04/2006 : 17:13:07

Re: sealant for the transponder.

I installed a new transponder for the depthsounder in my C25.. It is made mostly of some kind of plastic (polyethylene?) and I seem to recall the directions called for a silicone sealant. I used a marine grade that was labeled OK below the waterline. It has not leaked in 2 yrs.

Some caulks should not be used with some kinds of plastic. There is or was info on this in the WM catalog and should also be the caulk label. Check to be sure the caulk is compatible.

Edited by - on

Steve Milby
Past Commodore

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USA
5908 Posts

Response Posted - 04/04/2006 : 17:44:10

After you have stripped all the old antifouling paint off, down to the bare gelcoat, there isn't anything else that you need to sand, except for a very light sanding to prepare the surface so that the paint will bond to it. If there's still some paint stuck to the gelcoat, I'd use paint stripper, specifically designed for fiberglass, to remove it. I would use 120 grit in a random orbital sander, and sand the entire bottom and keel very lightly, in considerably less than an hour. Then wipe the dust off with acetone and paint it. There's no need to follow up with anything finer than 120. You'll just be removing gelcoat unnecessarily. The boat won't be any faster.

I agree that you should fill the blisters. Since there are only two and they're small, there's no need to make a complicated repair. I'd pop the blisters, dry them out, sand them, wash them with acetone, and fill them with Interlux Watertite. The likelihood is that the repair will last. If it doesn't, then you can do the more serious drying out and repair job next time.

Edited by - Steve Milby on 04/04/2006 17:48:16

Bruce Baker
Captain

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USA
402 Posts

Response Posted - 04/06/2006 : 05:34:42

Thanks for your good advice. I'm still stuck on two things:
1. Is it ok to clean out the blisters with acetone, let the acetone dry, and fill the same day?
2. How clean must the bottom be before painting? The bottom has a kind of mottled appearance. I've sanded it, and it's nice and smooth, but there are bits of paint here and there. The black paint is a real pain to get off. Is it a "hard paint?" Is it ok to paint over?

Edited by - on

Steve Milby
Past Commodore

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USA
5908 Posts

Response Posted - 04/06/2006 : 07:22:53

<blockquote id="quote">quote:<hr height="1" noshade id="quote">1. Is it ok to clean out the blisters with acetone, let the acetone dry, and fill the same day?<hr height="1" noshade id="quote"></blockquote id="quote">When you clean out the blister, look at the underlying material. Is it soggy, or is it solid? If it's soggy, I wouldn't just fill it and forget it. It needs to be dried thoroughly before filling. If it's solid underneath, then I'd suggest you dry it with a hairdryer for 20-30 minutes, wash it with acetone, let it sit for a day, and then fill it.

<blockquote id="quote">quote:<hr height="1" noshade id="quote">2. How clean must the bottom be before painting? The bottom has a kind of mottled appearance. I've sanded it, and it's nice and smooth, but there are bits of paint here and there. The black paint is a real pain to get off. Is it a "hard paint?" Is it ok to paint over?<hr height="1" noshade id="quote"></blockquote id="quote"> I stripped it all off with paint stripper, but, once you get started with that stuff, it's hard to quit. If it's smooth, it'll be very fast. How badly do you want to squeeze the nth degree of speed out of it? Enough to do another 2-3 days of hard work? Most people would agree that it's not worth it.

If you didn't put the old paint on the boat, you can't know for sure what it is. If it's hard to get off, it could be hard paint, or it could be coal tar epoxy. In either case, any type of new bottom paint should be ok to paint over. You should call the VC 17 tech support line and describe the surface, and ask if you should put a primer on before the antifouling. I haven't used VC17, but the last fast teflon paint I used needed a primer, if you weren't putting it on bare gelcoat or a barrier coat.

Edited by - on

djn
Master Marine Consultant

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USA
1561 Posts

Response Posted - 04/10/2006 : 18:38:42

Hi All, I was going to wait until next year to paint my boats bottom, but the weather is nice, I can't put the boat in the water for another two weeks so I might as well do it now. After reading all these posts, check me on this, I will sand it until it is smooth with 120 grit and on orbital, dust it off, wipe it down with Pre-Cleano, and paint it. No need to go down further than smooth is there? Cheers.

Edited by - on

Frank Hopper
Past Commodore

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Pitcairn Island
6776 Posts

Response Posted - 04/10/2006 : 19:41:48

My VC 17 went on over clean gelcoat. All I did was wipe her down with the recommended Interex cleaner first and then painted. It added maybe 20 minutes to the job. I cannot say enough about the ease and pleasure that comes with owning a VC 17 bottom.

Edited by - on

djn
Master Marine Consultant

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USA
1561 Posts

Response Posted - 04/10/2006 : 20:18:34

Hi Frank, my bottom (boat) feels like the moon. I know it will need sanding, I just don't know how deep I should take it. I am just not knowledgeable about all the differnet coats that were applied at the factor and subsequent paintings. Cheers.

Edited by - on

Kip C
Navigator

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USA
243 Posts

Response Posted - 04/10/2006 : 20:27:18

With all the talk about bottom paint, I was wondering if there's any reason to seal or barrier coat the rudder and with what? Assuming it has been sanded or stripped down to gelcoat.

Edited by - Kip C on 04/10/2006 20:28:49

Champipple
Master Marine Consultant

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USA
6855 Posts

Response Posted - 04/10/2006 : 21:46:23

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Kip C
 With all the talk about bottom paint, I was wondering if there's any reason to seal or barrier coat the rudder and with what? Assuming it has been sanded or stripped down to gelcoat.
<hr height="1" noshade id="quote"></blockquote id="quote">

YES...Everything below the waterline is in the water just as much as the bottom. Rudders also indure way more stress than the rest of the boat. Thus Cracking, water and delamination.

VC early and VC often

Edited by - on

StSimon
Captain

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USA
298 Posts

Response Posted - 04/11/2006 : 22:17:34

I too am in the midst of a bottom job. I began sanding Friday night. I only got a small section done, maybe 5'x6' near the bow, but what I found disappointed me. There was probably 10-20 blisters per square foot. They are mostly dime size and some go up to quarter size. I trailer sail so have been putting off the job for some time and wish I hadn't. I have sanded out each blister (in the area sanded) and plan on using an epoxy filler before sanding again and putting the Interprotect on. I am going to follow up with a 4 coats of a hard bottom pint(twice the recommended thickness) and finally sanding.

As far as the sanding goes my workplace has any type of sander, grinder, and buffer imaginable. I started with some 400, then switched to 220, 150, 100, and finally 60 grit. This is with a $35 Ryobi random orbital sander. I may switch over to a DA with a less aggressive grit to cut down on the time & elbow grease. With the speeds that a DA can reach you need to be careful not to overdo it. We'll see. My point in typing this is that one cannot say that this or that grit sandpaper is the best for any given situation. A lot depends on the type of tool or block being used, whether it is wet or dry sanded, and the operators technique. I feel confident enough with what I am doing that there will be no need to use a finer grit after my 60 grit campaign. I will probably use something finer on the epoxy, I won't know until I try it out. As a matter of fact, you don't want the surface too slick before applying primer or whatever coating you plan to begin with. A scuffed surface will give the treatment a better bonding.

Good luck and...

Edited by - on

Bruce Baker
Captain

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USA
402 Posts

Response Posted - 04/14/2006 : 08:07:29

Well, the bottom job is done. I said I "didn't have time" to do everything I wanted to do because the clock was ticking to the tune of $20 a day in marina charges. Here are a few things I learned:

1. The West Marine peel and strip works really well if you give it about 16 hours to work. It works less well if you give it 24 because it starts to dry out. It doesn't work when it's dry.
2. The 120 grit sandpaper I bought from Ace Hardware outperformed the 60 grit sandpaper I got from Home Depot in some heavy sanding areas.
3. I popped some blisters and swabbed the insides with acetone. When I came back the next day, it looked like the acetone had caused the fiberglass to fuse together--I thought it looked really good.
4. VC-17 is weird stuff. It's got the viscocity of aluminum paint, except it's copper colored. Supposedly, it will turn blue in the water. I used a 7" roller (1 1/4 inches in diameter) I got from Home Depot. It worked great! I bought another 7" roller from West Marine so that my helper could also paint, but it wasn't half as good.
5. The VC-17 really shows up the spots you missed with the sander. I'll do a better job next year! It also shows up blisters.
6. I didn't sand the finished product. I hit the VC-17 with my 120 grit to see what would happen, and it sanded it off right away. I know the finish coat is supposed to be done with 330 grit (couldn't find any) and I didnt' want to chance it with 220.

Anyway, I'm in the water now. I paid the marina $400 for the privilege of spending two weeks on the hard, hauling, powerwash, etc. I hope I'm faster!

Cheers,

Edited by - on

Ericson33
Admiral

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USA
892 Posts

Response Posted - 04/14/2006 : 10:41:02

VC17 should be wet sanded with 600 for final results, not with an electric sander but with a longboard. I have seen people use a higher grit than 600, but at some point you have to put down the sanding block and drink some beer :)

Edited by - Ericson33 on 04/14/2006 10:42:11

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