Restoration of 1981 C-22 swing keel #10580

[CloudDiver]

I forgot the reason I came on here was to ask if you put the keel spacers on yet and if so pictures? Thank you

I did put the spacers on and believe it or not I think I have to grind them off! I made a template from a piece of wood that matches the taper of the keel pocket. At the base it is the widest, about 2.25 inches. All the way at the top of the pocket (where CD recommends you epoxy the spacers) the pocket tapers in to 1.75 inch. The top edge on my keel is measuring 1.85 wide, so it looks like I never should have even epoxied them on.
I'm going to call CD tech support and ask the if the intent is that the spacers actually jam and flex out the wall of the pocket a little. Without knowing the answer I can already say I don't like the sound of that. I think I'll use my belt sander and try to shave the spacers a bit to match the taper. More on this subject later....

 

[CloudDiver]

A little upgrade...

This is something I decided to do while messing with cleaning out that keel pocket. I looked at the new design keel hangers I have and the original mounting areas of the hull. The bronze hangers have rounded backs and the pockets are square. When I had initially removed the keel there was some 4200 or whatever in there along with a nasty mess of rust, dirt, and growth. When I remount the keel I don't want to have to fill that with a bunch of 4200 because I will get some squeeze out, probably too much. So how to deal with this? Instead of making a round peg fit a square hole, I made the hole round.

Here is the stock set up, and you can see the gap with the hanger in place;

 

[CloudDiver]

So I waxed the back and bottom of the hangers with zipper wax and then mixed up some epoxy thickened with low density fairing filler to peanut butter. I slapped a dollop in each square void making sure I had enough to get squeeze out but avoiding the areas where the bolts go. Then I bolted the hangers in place and let the epoxy cure. They popped right out and left a nice molded shape of the round backed hanger. I used acetone to clean off any wax residue on the cure epoxy and then a sanding board to clean off the area where it squeezed out into the keel pocket. Then I used my oscillating tool with the triangle sand pad and some good old hand sanding to clean it all up. As you can see in the second pic there is no longer any gap, so when I finally install the keel I'll only use a light coating of 4200 and I will comb it out. There should be little to no squeeze out with very even coverage and consistent thickness.

 

[CloudDiver]

I just avoided a total disaster! Blister repairs!

I have to thank you guys who have been reading and commenting on my thread, you are keeping me on my toes. As you make comments and ask questions it keeps me thinking, so I decided to do a little home work...

I mentioned before as I began stripping my bottom paint that I had believed the bottom of this boat had been previously re-done and the blisters repaired. Boy was I WRONG!!!! I thought that this boat used to be blue and was later painted white. You can see in all the pics the evidence of those layers. I guess they must have used 2 color coats of gel-coat at the factory to monitor thickness or whatever, but regardless the white on my bottom is gel-coat for sure. You may have noticed them in the a few pics from before but they weren't showing up too well so here is a close up of the blisters. There aren't really that many, maybe three dozen total averaging the dive of a dime;
(Basically the majority of my blisters is where they formed between the blue gelcoat layer and the laminate, there were only three that were imbedded into the glass itself)

 

[CloudDiver]

Blister Repair continued...

So, like I said I did some homework. I watched several videos on YouTube about osmotic blistering and repairs. Most of them are crap, just showing the processes that professional yards use to do big boats, not really a DIY video. Then I found this one;

https://www.youtube.com/watch?v=9T_eFVF6vOw

Not the best production quality, but this guy shows everything and is very straight forward. After watching his two videos I decided to test those areas of my hull like the ones pictured above. I flicked out my favorite buck billed knife and started lightly stabbing the tip of the blade into those areas. I noticed the fiberglass flexing and collapsing with only very light taps, you can see that in the lower of the two spots in the pic where the blade collapsed the outer layer. In one blister I got a little squeeze out of that nasty styrene smelling acid goo!

So basically I just avoided completely wasting my time and throwing away a bunch of money invested in Interlux paint. Had I gone ahead and painted the bottom those blisters would have reappeared and I'd have to do it all over again!

So now I am for sure not painting this weekend! I will break out my carbide burr and grind out those blisters in the morning (I took Monday off). I will order another gallon of Interprotect 2000E along with the epoxy filler recommended in the above video. I am running low on WEST resin and want to conserve it for other jobs while the Interlux epoxy filler is easier to mix and use on this particular job. So we will see how long it takes for the blister pockets to dry out and then I will get to filling and painting another weekend. I'm happy I found this out now and not after I discover a ruined paint job in the future!

 

[piedpiperIII]

Great job on the hanger pocket, makes me want to look at mine. I have seen that video and I have read up a lot on blister repair, seems like a very big job. I think if the blisters are small and the boat sits out of the water more than in than maybe the little blisters are not a problem. I bought my boat from a sailing club and the man that took care of it did tell me that my little blisters were not a problem unless I was going to race. He told me this after we made the deal so he was not trying to lie to make the deal. He was very honest and a very nice guy. My boat does have the upgraded keel hangers and upgreated winch as well I did buy a new pin. Also I did measure my keel pocket as well for the same reason you did but did not measure the keel yet. I bought the spacers because one was on mine already and the other had fallen off I could see the spot where it was. Keep me updated on youe spacer deal I would like to know. Thank you

 

[piedpiperIII]

I measured my keel pocket at its tightest point it measures 2" my keel measures 1.73" so I will need the spacers on mine.

 

[CloudDiver]

Start the Drying Time Count Down

After doing my homework I bounced my plan off the Interlux Tech Rep. I wanted to be sure I had all my bases covered and I wasn't missing anything. Frank said I was doing exactly what was called for and just be conservative with the drying time (i.e. the longer I can let dry the better, just in case).
Its not totally necessary to peel the gel-coat on a hull as thin as the C22, but it he said if I can I should. That way I can be sure I got everything ground out and once try I can do a complete roller coating of epoxy. He also recommended actually butting some small patches of fiberglass in the ground out areas rather than just straight filler to ensure strength. I'm actually half tempted to do a whole new layer of 6oz fabric over the entire bottom after I fill and fair the holes, but we'll see about that later.

For now I've gotten all the blisters ground out. In the picture you'll see my weapon of choice, a rounded end carbide burr on my die grinder. I can control the speed of the grinder easily so the pockets I grind out are smooth and dished making them easier to sand later. My rough guess is about 160 blisters, the larger areas I ground shallow where there was crazing or cracking in the gelcoat.

 

[Time_Out]

Those blisters are nasty little things. At least that's one thing I didn't have to contend with on mine. I remember looking at some other boats prior to getting mine that were the nautical equivalent of a teenager with really bad acne! Once you get done with this repair, you shouldn't have to worry about it again. Not sure why all boat manufacturers don't just use an epoxy barrier from the start.

 

[CloudDiver]

Those blisters are nasty little things. At least that's one thing I didn't have to contend with on mine. I remember looking at some other boats prior to getting mine that were the nautical equivalent of a teenager with really bad acne! Once you get done with this repair, you shouldn't have to worry about it again. Not sure why all boat manufacturers don't just use an epoxy barrier from the start.

I'm not sure about the periodicity, but my guess is that polyester resins were used in most US boats manufactured up until I'd guess late 80's to early 90's? So after that when the industry began transitioning to Vinyl Ester and Epoxy resins having much greater resistance to moisture intrusion. So when I begin looking for my 'next' boat down the road I will insist on a later model hull, hopefully epoxy... no more blister worries!

 

[CloudDiver]

Some observations on Blister Repair and sanding Gelcoat

1. Sanding gel-coat off is a royal pain. It is a very hard substance when cured (compared to soft wood) and there is wax present that must be removed. Even with my belt sander and 50 grit belts it is very time consuming. I had a go at it last night with a 50 grit belt followed by 60 grit on the 5 inch orbital. I did about 3 square feet and called it quits. I'm going to pick up a more aggressive 6 inch random orbit and 36 or 40 grit pads today and see if it works better. I can see why a gel-coat peeler is a must on bigger hulls!

2. Why remove the gel-coat? According to most resources I consulted removing the gel-coat will speed up the dry out but also gives you the best assurance that blisters will not happen again. In some cases the pockets of water are not deep in glass fiber but rather just between the gel-coat and the glass. I noticed that having dug out the blisters with the carbide burr and then sanding away the thick gel-coat, afterwards the blister pockets do not appear nearly as deep. To prevent further blistering beyond just the repaired blister areas you roll on a coat of resin to the entire bottom of exposed glass fiber, the epoxy will wick into the fibers and tiny voids. Doing a complete coating rather than just in the blister pockets makes sense to me. Following fairing out the pockets I am certain that I will lay at least 1 new layer of 6oz cloth. Not really for added strength, I am actually going after two other things; to make up for the thickness of gel-coat that I removed and it is additional layer of epoxy barrier.

 

[hawk232]

do you have a da sander? if so, it will make MUCH shorter work of that than a belt or orbital will. if you don't, make sure you have enough air compressor before buying one... da sanders are air hogs!

 

[CloudDiver]

I do, but it does not have dust control and I already know my compressor would not keep up. I literally just got home from Home Depot, I picked up a 3 amp 6 inch orbital (the big one, lol). Coarsest paper they had was 60 git, so I also got some 36 grit belts. I try that combo here in a few minutes and see how it works out.

do you have a da sander? if so, it will make MUCH shorter work of that than a belt or orbital will. if you don't, make sure you have enough air compressor before buying one... da sanders are air hogs!

 

[hawk232]

ahhhh yea.... working inside.... well I guess I better enjoy the ONE time where my working outside is better than your being inside!!!

I will be interested to hear how the 36 grit belts work. I found on my linear sander that the 36 grit paper removed material slower than 60 grit because the grit was so coarse that the coverage just wasn't there. like, it made deeper scratches but instead of removing material "evenly" it just left a lot of scratches with material still in between...

 

[CloudDiver]

I concur on the 36 grit belts, I'm not even going to try. I'll just return them next trip to HD, only $9. I'll continue with the 50 grit belts just to get a good start. It works fairly well aiming the sander fore to aft but moving it athwart ships.
Anyway, the new 6 inch is working pretty well, I got more done in 10 minutes just now than I did in 30 minutes last night!

 

[HillbillyWanderer]

Wow! Are you stripping the hull down to bare fiberglass?

 

[CloudDiver]

Wow! Are you stripping the hull down to bare fiberglass?

Yes, see my previous posts about blister repairs. Only the bottom, gelcoat will stay put on the rest of the hull.

 

[CloudDiver]

No Quarter!

Ok... well, at least one quarter, the starboard fwd quarter. Then 3/4 left! I'm glad I got the right combo of sanders/sanding belts & pads. Last night I was feeling pretty down about this process, now I think I'll have this done by Saturday. And for my next trick, a rolling cradle!

 

[CloudDiver]

A productive holiday weekend...

I'm about 75% done sanding the gelcoat off the bottom, and since I am so sick of it I needed a break. As I mentioned earlier I decided to build a cradle on wheels. I wish I didn't have to do it since I invested $250 in buying used Brownell stands but I just can't get all the way around the hull while it is squeezed into my narrow shop. So to finish the sanding but also so I can wash and rinse the hull (a required step in the drying process) it made sense to roll out into my driveway.
I ended up spending only about $100 on the lumber, 2 boxes of screws, and some bolts to build a pretty sturdy rolling cradle. A buddy of mine was going to lend me some spare tool-cox casters but I ended finding a spare set I had from last year when I built my welding cart. If anyone wants a more detailed build sheet with measurements and materials I can write that up later. Party bonus, I am pretty sure this cradle would work with the boat inverted or right side up; some small modifications may be needed.

 

[CloudDiver]