Gel coat issue
- Thread starter PabloPicasso
- Start date
pvb
Well-Known Member
Looks like a poor repair job in the past.
PCUK
Well-Known Member
Yes, unbelievably bad repair. Gel coat just slapped on the unprepared stress cracks. A good time to redo it properly.
peter gibbs
Well-Known Member
Were you aware of this unfinished repair from before? Did someone whack your boat and slap on some paste to cover, and walk away? Surely not.
Anyway, looks like a little patience and some fine grit will make it disappear. But what lies underneath? Be prepared.
PWG
Anyway, looks like a little patience and some fine grit will make it disappear. But what lies underneath? Be prepared.
PWG
rib
Well-Known Member
Looks like a old repair ?
Caraway
Well-Known Member
Someone has just skimmed over some hairline gel coat cracks. Now further movement has seen the skim break away.
PabloPicasso
Well-Known Member
Not aware of previous repair. Had the boat 12 years. I wonder why now??
But the real question is how to do a proper repair?
eilerts
Well-Known Member
I agree with the other posts. Also this type of fairly parallel curved cracks indicate that the hull has been depressed at the centerpoint of the curve (to the left) and that you have a hard spot/line right - bulkhead, etc. A fender hanging to the left (referring to the picture) can in a storm (or several storms over time) can cause this damage, but does not leave a mark at the impact point.
PabloPicasso
Well-Known Member
There have been a rake of gales over the last fee weeks. This is only the 2nd winter afloat in 22 years, and the first on a marina.
Eilerts could be right about cause I suppose. But the real question is how to repair. I Could grind out the cracks and fill with a thickened epoxy. But how to redo the top finish?
Eilerts could be right about cause I suppose. But the real question is how to repair. I Could grind out the cracks and fill with a thickened epoxy. But how to redo the top finish?
AngusMcDoon
Well-Known Member
I'd get all that top stuff off as it's going to fall off anyway then decide what to do from there. If the rest of the gel coat is ok apart from the hairline cracks the normal fix is to open them out with a Dremel & fill with Flocoat, sand down to flatness finishing with 800 grit then polish with Farecla. You probably won't get an exact colour match but any minor difference will fade away over time. East Coast Fibreglass can send you everything you need & are always willing to offer advice on the phone.
I don't think epoxy is a good idea as you don't need the strength & there's not much you can cover it with.
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eilerts
Well-Known Member
If you want lasting results you have to consider the cause. Apparently, cracks in the original gelcoat has been covered with filler and this has cracked along the same old cracks, because these represent the weakest point of the hull (or the surface layer) and get most of the bending.
Widening the cracks with a Dremel tool may work fine and is worth trying, but you should not be surprised if they appear again after the next storm. I have repaired a lot of cracks this way, but mostly cracks from cure shrink tension, typical from too thick gelcoat in corners. In the lower part of the picture the cracks are so dense that it make less sense widening each crack. Instead grind away the gelcoat at this part all the way to the laminate. Then you will see if the cracks extend into the laminate and how thick the gelcoat is. If the cracks goes continues into the laminate, the hull is weakened here. The boat will not rip apart, but you will have more bending here and any quick fix of the gelcoat will not last, and the cracks will continue to grow. If the gelcoat is thick and there is no cracks in the laminate, you probably can get away with the Dremel method combined with carefully thinning the gelcoat. The more spread cracks in the upper part can like be repaired with the Dremel method.
Denser group of cracks = higher stress
It is not always easy to see the cracks in the laminate. If you have very small flashlight, 1cm thick and no light going sideways, you place it in contact with the laminate and shine into it at the side of where you expect a crack. A crack reflects light and the laminate will appear darker on the opposite side. If the light spreads evenly out in the laminate, you have no crack.
PCUK
Well-Known Member
All good advice, plus if you can get inside the hull you can stiffen from inside to avoid future cracks.
Keith 66
Well-Known Member
That not a repair, its been pargetted!
LadyInBed
Well-Known Member
Frost got under a poor repair?
MandaJ
New Member
Hello - what sort of dremmel fitting would I need please?
jwilson
Well-Known Member
I'm not entirely sure about the repair being after the stress cracking. Could be the stress cracks (as others have said possibly from fender pressure) could have been recent, but near an old repair, and the same fender pressure distortion partially cracked off a poorly keyed in repair.
What make/model of boat?
What make/model of boat?
KAM
Well-Known Member
As others have said looks like a bad repair but if the gelcoat is over thick these sort of cracks can sometimes appear after winter due to differential expansion particularly on the side that gets the morning sun. Just grind out the whole area with an angle grinder. Sounds drastic but its quicker easier and more reliable than trying to chase out individual cracks.
AngusMcDoon
Well-Known Member
dankilb
Well-Known Member
I use the smallest round burr I can find. I think my preferred one is 8mm (TCT retired from metalwork). Follow the crack with it to get a uniform ‘groove’. A coarse domed sanding stone would achieve the same.
The aim is not to ‘V’ the cracks as much as to ‘U’ them in a shallow, feathered, profile. This maximises the surface area for the gel to adhere to.
