Filling pock marks

JumbleDuck

JumbleDuck

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Well, the paint is now stripped off the bottom of my Hunter 490 after five days of work, fifty quid's worth of paint stripper and much suffering. Under it the gel coat is in a bit of a state. Lots of hemispherical pock marks, which is why I started this - they were leaking fluid under the paint and lifting bubbles in it. Most of them are 1 - 2 mm across and deep, and I'm not worried about them - five coats of gelshield should smooth 'em out and they are under water anyway so no one can see them.

There are some areas, though, probably thanks to poor quality control at Hunter, where the surface is a lot worse, with cluster of pock marks up to 5mm across and deep. Although I am not bothered about a super smooth finish, I'd like to fill these. Doing it with filler will take ages, so I was wondering if there was an easier way. You can do the first layer of gelshield with normal epoxy resin, so could I perhaps mix something in to (some of) that - microballoons - to make a slump-free, brush-on filler? I'm also thinking of putting a layer of glass fibre tissue on top in those areas, to hold things in place and give a smoother surface.

Advice, as ever, welcome. I have two weeks to get the boat launched ...
 
Jumbleduck,

I would be a shame to rush the job having already done most of the hard work.

If the holes are weeping then I suggest you do not just cover them with epoxy as the problem may soon resurface (sorry for the pun)

There is plenty of advise online regading the correct treatment to avoid having to repeat in a couple of years.

I suggest either postpone your launch or leave corrective action until the end of the season when you will have the whole of next winter to work on the problem.
 
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theoldsalt said:
Jumbleduck,

I would be a shame to rush the job having already done most of the hard work.

If the holes are weeping then I suggest you do not just cover them with epoxy as the problem may soon resurface (sorry for the pun)

There is plenty of advise online regading the correct treatment to avoid having to repeat in a couple of years.

I suggest either delay your launch or leave corrective action until the end of the season when you will have the whole of next winter to work on the problem.
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The holes aren't weeping at all - they have been open to the air for almost two years now and are dry as a bone. Removing all the paint has made them more obvious, that's all.

Incidentally, I think the problem may arise from a previously owner's use of two-pack over a damp hull. It's a known problem, apparently, and the two pack would explain why it has been such a pain in the nadgers to strip.
 
I would hose down thoroughly to remove any solvents that are present then fill with marine filler. Shouldn't take too long but no alternative really. Then prime with primocon and apply your final finish system. A bit of unwelcome extra work but as said previously, you've done all the hard work already so why spoil the ship for a ha'pence etc?
 
ghostlymoron said:
I would hose down thoroughly to remove any solvents that are present then fill with marine filler. Shouldn't take too long but no alternative really. Then prime with primocon and apply your final finish system. A bit of unwelcome extra work but as said previously, you've done all the hard work already so why spoil the ship for a ha'pence etc?
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Thanks. My main worry - about from the amount of work - is that getting the fillers I have worked with into such small holes might be a problem. Something a wee bit runnier might get in better.

I definitely want to put the anti-osmosis coating on. Having got this far it would be daft not to, and whatever was going on definitely had an osmotic side to it. When I started the hull was covered with blisters in the antifouling (Trilux) which were filled with an acetone smelling fluid. When these were popped and removed the paint below looked fine, except for tiny little holes with, on further investigation, small pits in the gel coat under them. The first stage was therefore to remove all the blisters and let things dry out. Paint stripping has taken ages, and showed that in some cases the pits were bigger - topic of this thread - which was hard to spot with paint around them. They've been allowed to dry out, pressure washed and allowed to dry out again, so the hull is about as dry as I want it now: the gelshield should stop any more water getting through.

It's odd as osmosis goes because there is no blistering in the gel coat at all, just these little pock marks.

Oops. Sorry to witter on at such length. I'm feeling quite proud of my paintless hull!
 
You can make up your own filler with epoxy and fairing powder to any working consistency you like. If they are really deep you might want to start with epoxy and something with more bulky and harder such as microballoons. The beauty of mixing your own is that you can tailor make it for your specific situation . See the West information on the Wessex Resins website on using epoxy. If you just need to fair with depressions up to a couple of mm deep then International Watertite is very easy to use and gives a good finish ready for further coats or your choice.
 
I expect the small hemisphers in the gel coat are probably from air bubbles when the gel coat was applied. This is what I found on my Westerly and was confirmed by my surveyor.

I found an easy way to fill the holes was to apply the epoxy as normal, then use some of the setting epoxy mix brushed over the affected areas. Over several coats the hole just disappeared.
 
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Tranona said:
You can make up your own filler with epoxy and fairing powder to any working consistency you like. If they are really deep you might want to start with epoxy and something with more bulky and harder such as microballoons. The beauty of mixing your own is that you can tailor make it for your specific situation . See the West information on the Wessex Resins website on using epoxy. If you just need to fair with depressions up to a couple of mm deep then International Watertite is very easy to use and gives a good finish ready for further coats or your choice.
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Muchas gracias.
 
+1 tranona

Be sure you've popped gouged our removed all zits. Don big scary fishermans gloves take a clean rag soak in thinners wipe down treated area on completion start filling per "Tranona " after sand flat then walk away next day another thinner wipe then paint with your chosen product. I tend to use VC tar or any of the epoxy tars 2/3 coats whilst the last coat is tacky anti foul. Job done!

John
 
Concerto said:
I expect the small hemisphers in the gel coat are probably from air bubbles when the gel coat was applied. This is what I found on my Westerly and was confirmed by my surveyor.
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I had them on my Westerly too, and there is one small patches of them on the Hunter which I'll fill with epoxy as you suggest. They didn't raise blisters in the paint above them, unlike the bigger ones all over the hull.
 
JVL said:
+1 tranona

Be sure you've popped gouged our removed all zits. Don big scary fishermans gloves take a clean rag soak in thinners wipe down treated area on completion start filling per "Tranona " after sand flat then walk away next day another thinner wipe then paint with your chosen product. I tend to use VC tar or any of the epoxy tars 2/3 coats whilst the last coat is tacky anti foul. Job done!

John
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Thanks. How does VC Tar compared with Gelshield?
 
Well the simply answer is the price, sorry. Gel shield is basically runny epoxy, the concept being it makes your hull waterproof ? VC tar and nearly all epoxy tars are waterproof ( its used for tank lining) but it doesn't like other paints that's why you anti foul whilst tacky as it gives you a base for the future.

John
 
That wouldn't explain the acetone smell.
Concerto said:
I expect the small hemisphers in the gel coat are probably from air bubbles when the gel coat was applied. This is what I found on my Westerly and was confirmed by my surveyor.

I found an easy way to fill the holes was to apply the epoxy as normal, then use some of the setting epoxy mix brushed over the affected areas. Over several coats the hole just disappeared.
Click to expand...
 
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