Hi Bud,

As I was trying to find someone to adopt my "Nameless" Project - We found an area of the cabin top that had become delaminated. I guess the thickness of the top layer of fiberglass is so thick (a full 1/2"!) that it didn't seem bad until you really jumped on it hard.

Well - I decided to do an exploratory bore - as If I keep the project I was going to add a hatch in the cabin top anyway.

The core sample shows the lower inside 1/4" fiberglass to still be bonded well - but the top has come loose from the 1/2" center plywood core. The good new is that the plywood appears to be bone dry.

So the question is can this be repaired by drilling holes in the top - and allowing epoxy to fill the space between the plywood and the top fiberglass and then clamping the top together with thru bolts - the headliner is down inside so no problem with access from that side.

I even wonder if there is any merit to leaving countersunk fastener in place to continue to clamp the sandwich together even after the epoxy has set.

I know I'm looking for the easy way out but I would hate to have to give up this 1/2" top layer of fiberglass -- which is in excellant shape.

Another thought is to remove the plywood from below - and that way you could butter it up with thicken epoxy - and then clamp up - but I would not like the job of cutting the 1/4" fiberglass inner surface and the plywood to do this.

http://s1215.photobucket.com/albums/cc520/jengle53/cabin%20top%20core/?action=view&current=core.jpg

http://i1215.photobucket.com/albums/cc520/jengle53/cabin%20top%20core/core1.jpg

Any thoughts would be appreciated.

Jim Engle

Thanks all - I plan to drill only from the top - and use the cement bags to weigh it down. The drilled holes won't be too much of a problem as I was planning to redo the non-skid surface anyway. The top layer is so thick - if I can get most of the two layers to bond it should be good. I am going to do the repair first - then as I saw my hole for the new cabin top hatch - I can see how well the repair worked.

Ken Bridger wrote: Jim, I was reading your blog (can't figger how to post there!).  Don't overdo the bags of cement. You don't want to squeeze all the epoxy out, just get good contact. Also, I agree with the post about sandblasting the hull. I saw a Valiant 32 that was just a disaster after sandblasting. There were millions of holes cut into the glass. They had to fill and re-glass the entire hull. They were just sick of the whole thing and were not even half way done. Barrier coats are usually thin.  On Satori, we sanded and put 5 coats waterline down and then two more coats waterline down two feet (extra at the waterline where things tend to bump).  When Randy overhauled her 10 years later he said she was in good shape so only new bottem paint.  One good resource is Don Casey's "This Old Boat". Tons of good tips in that book. Ken

First - you need to sign in first to post a commnet on the blog - the easiest is with a google account.

Thanks for the comments. I know sandblasting can be aggressive. The heavy coats of epoxy would be difficult to chemically strip and I do need to get most of the gelcoat off as well. I have been interested in mechanical stripping and may go that way - but I have actually seen some nicely done sandblast jobs - from highly skilled operators which take it down to the last few mils of gel coat. I'll add some photos of the bottom - but the layers I need to remove will probably need "aggressive". From all I've read - it is good to completely remove all the gel coat at this stage - to allow the hull to really breath - if not I'll be doing this again soon. This was not done - 20 years ago - and that is a long time - but right now the barrier coat has failed badly.

Funny that you mention a Valiant - because there is one in the yard with me and it has a horrible problem - with huge blisters 2 ft above the waterline! The owner told me that some of the Valiants had a really serious problem with the resin. Did the sandblasting cause the holes -- or were they in the laminate and need to be opened up. I have seen bad sandblasting jobs and they tend to be a local area where the operator just stayed too long.

I can assure you that if I do sand blast - I will be 10ft behind the operator watching and if I don't like what I'm seeing - I'll stop him. The problem with the peeling is that the equipment and talent to operate is limited. Soda - dry ice - chemical strip are probably not going to cut it. I did think about grinding it off -- but what a job.

I have read a bunch on the topic -- and there are successes and failures using all methods. My personal experinence on Entropy II - my Cape Dory 28 (1983) was that I stripped off all the paint (chemically)in 1993 - and the bottom looked perfect - so I lightly sanded the gel coat and followed the application of interlux 2000 to the letter - followed by several coats of Interlux CSC. I thought I was doing something good. In 8 years the Interlux 2000 had blistered badly between that layer and the gel coat. I was told I need to take it all down to the laminate (remove all the gel coat) and let her breath for 3-5 months and recoat with an epoxy barrier. I did that in 2001 - and so far only a very few blister - have reappearred.

It was explained to me that my preventive measure was all wrong - that could have been done on a new boat but my 10 year old boat had moisture trapped under the gel coat and that cause my problem.

I did have a very talented sand blaster on this job - and he did hit a few rough spots but nothings too bad. Yes- the surface was a little rough - if you take off the gelcoat - it is not going to be smooth. But the fairing jog was not all that bad - used some easy to sand compound - and had a good method for spreading it evenly.

So - I do understand there are bad jobs with sandbalsting -- I had a good one - and not sure if I can find a local peeler I can trust. But I am quite sure if I do this job I'm taking the gel coat off - to really get this hull dry out.

Thanks again for your comments - all others welcomed -sorry for the long reply.

Bud Taplin wrote:

The real key to a long lasting epoxy barrier coating job is that the hull laminate must be completely dry.  Sandblasting is a good method of removing the gelcoat, but the hull must be tested periodically with a mointure meter, and no repairs started until the hull is very dry.

The main problem that Valiant had was that they used a fire retardant resin, and that it permitted water to wick in over time.  I heard that some of the boats had to be cut up as they were beyond repair.

I have a big advanatage - I won't have all my other work complete for over a year -- so I'm planning to get the gel coat stripped soon - and give her a long time to dry - maybe 18 months. Even then I will have it checked with the moisture meter - but think in will do fine. The laminate of the hull does appear to be in fine shape.

The Valiant in my yard is probably a candidate to be scrapped -- there are large blisters - the size of silver dollars - 2 ft above the waterline. Below the water is worst -- this boat has been out of the water a long time - but no one knows where to start.

Fire retardant resin? Why? Guess it was a fad?

Thanks for the feedback

Jim