Have you treated osmosis?

[Troppo]

Windchaser has osmosis. Up on the slip and hull cleaned down, I was shocked to see all the osmosis blisters.

osmosis.jpg (420.52 KiB) Viewed 4485 times

In the pic you can see a section of the hull that has been pressure blasted then lightly wet sanded with 80 grit. The osmosis blisters in this area are small, others are 50 cent size.

When I last slipped Windchaser, 2 yrs ago, I noticed several small odd spots I thought may have been osmosis. The professional survey done in 2010 pointed out that there was some sign of small osmosis restoration but no mention was made about active osmosis.

So, my baby has an outbreak of the boat pox and I am not a happy chappy. Have you had any experience with removing osmosis in your Top Hat?

cheers

Troppo

[bornfreee]

Yes mate we all have this guy will cheer you up it is very easy to fix i did the full bottom with epoxy system 4 different coats in the system was quite enjoyable and came up a treat hope you enjoy this guy i did.
http://m.youtube.com/watch?v=9T_eFVF6vOw

[Phillip]

Louis,

Not a big problem. While you have many small ones I had one that was 100 mm across

I ground them out [with an electric grinder] so that the GREEN LINE HAD DISAPPEARED.

Let them dry out overnight and then I had a fiberglass expert come and fix them.
I reckoned the cost of hiring him, meant that I could sleep well at night, which in relation to osmosis I do!

I did the finishing such as sanding smooth, priming etc.

Funny thing was that I only had osmosis on the port side, must have been a bad day.

PS. Take care when you first break into the bubbles as the bubble is caused by water pressure inside and it will spurt out!!

[bearmcnally]

Troppo those blisters are only under the gelcoat by the photo ? Like Phil said sand etc ,If they only a couple of mil deep mix up some epoxy and talc and skim over them .

Cheers Bear

[Tales]

I have treated about 25 altogether over the years.
It is very important to grind away until there is no sign of damp. Its easy to see the fluid soaking into the dust.
I scarf it out at about 15:1 and use woven cloth in preference to mat.
Make successively smaller patches until full thickness is restored.
I lay up on a piece of plastic sheet then apply the lot in one go.
It is important to put the biggest patch against the hull to get the best adhesion.

The first few blisters were 'fixed' by a 'professional' in the yard. He ground out the main blister but there were several little wet dots where the fluid ran along the fibres of the original lay up. He just put acetone on to 'dry it out' and either put thickened epoxy or bog in the depression.
A few years later I had to grind all these out as the wet voids kept growing and made a blister again.

It is nothing to be frightened about but like all repairs, needs to be done properly or it will come back to bite you.
Cheers,
Tom

[storm petrel]

Knock on wood, I have never had any on my Mk2 and when I had the hull soda blasted last year no old repairs showed up either. I guess it comes down to the weather when the hulls were laid up and the type of resin ahat mix that were used.

[bornfreee]

Mark formit built these yachts inbetween making fibreglass toliets

[jjvvss]

I found 82 blisters ranging in size from 50c to 10cm. Very easy to fix just takes time. One day to scallop out with a grinder. One day to dry. One day to fill will chop strand and epoxy. Make sure you slightly overfill and roll out all air. Once you start you get into a rhythm. One day to fair. One day to anti foul. After I anti fouled I noticed 8 that I didn't see. Next time. 68 of the blisters were on the port side. Must have been laid up on the Thursday arvo before easter ; )

[Dolphin]

Blisters? they're not blisters,

These are blisters;
viewtopic.php?f=6&t=628
This was a professional repair.

I use a wood chisel on the smaller ones. You'll easily dig out the soft glass and not gouge into the good solid glass underneath.

Don't worry, osmosis is overrated but it can be used to your advantage if you're buying a boat with it in.

[storm petrel]

Mark formit built these yachts inbetween making fibreglass toliets

Well I guess they were making good dunnies when they built my Mk2.