General Info: Gel Coat Blisters Above the Water Line

[DotDun]

Originally Posted by wongai64

I realise that this is an older post .. but I've just been dealing with my own issues with the same problem .. solution .. stripped back to glass .. above waterline .. Q CELL filler and 3 x epoxy layers over the lot .. then Primed with 3 layers epoxy before antifoul .. should last a few years

Interesting! You may be the first Belize owner to have blister issues. Most blisters were/are associated with the switch from FP's vacuum bagging to infusion processes. The Belize was one of the last models vacuum bagged and never exhibited blister issues.

[Dragon Lady]

I haven been told that this issue was caused by the resin used not the process and that FP successfully sued the resin manufacturer. Whilst vacuum bagging produces a lower resin to fibre ratio which is highly desirable for strength and weight it doesn't change the resin's ability to take in water molecules.
Was yours a late model Belize?
Maybe it had the suspect resin used on it?

[DotDun]

Originally Posted by Dragon Lady

I haven been told that this issue was caused by the resin used not the process and that FP successfully sued the resin manufacturer. Whilst vacuum bagging produces a lower resin to fibre ratio which is highly desirable for strength and weight it doesn't change the resin's ability to take in water molecules.
Was yours a late model Belize?
Maybe it had the suspect resin used on it?

I haven't heard that....interesting!

[wongai64]

Originally Posted by DotDun

I haven't heard that....interesting!

The Resin itself isn't the issue for starting osmosis .. it's the risk of exposed fibre ends becoming exposed to seawater and "wicking" it into the fibre , creating a starting point for osmosis.

Vacuum bagging simply removes all the air and "bubbles" from the fibreglass .. the only way to prevent osmosis with a degree of certainty is to either use an all epoxy resin from new build or a healthy top coat barrier .. I have just sanded my hulls to glass and triple layer epoxied the entire hull to above waterline ..

[Lucky]

Hi all FP owners,
I have read some of the posts and see that there are a lot of misunderstanding of what is actually happening when blistering in the fibreglass comes visible.
Luckily my Belize 43 do not suffer from that at all, so I'm in a good way there.

However I think some of you migth benefit from reading the below text shamefully cut from the www:

Happy lead free sailing from Lucky

What is Osmosis?
Osmosis quite simply is the physical process by which a liquid from a weaker medium is drawn through a semi-permeable membrane into a stronger liquid medium. So what does this mean and how does this relate to boat hull damage?
The simple answer is probably not a lot! Contradicting earlier theories, the damage from “osmosis” is not caused by excessive water permeation. There are absolutely no osmotic forces involved as the gelcoat is an absorbing material which can never act as an osmotic membrane! Instead it is the process of hydrolysis, which creates the water soluble corrosive products which in turn create the familiar cavities. (Hydrolysis is the general term given to the reaction of any material with water, for example organic compounds like polyester resin, itself the main constituent of GRP laminates.)
Once the cavities have formed, then excess water will enter giving rise to high moisture readings. This process may normally be slow, but the presence of free acids or alkalis will greatly accelerate it.
The first point to note is that it is the phthallic acid, formed in the process of hydrolysis of polyester resin, which causes the chain reaction and subsequent laminate damage, not the water! The acid forms as water insoluble crystals and cannot be washed out of the laminate as claimed by some. Even after years of hard-standing and weekly washes, the acid will remain in the capillaries and cavities, fixed in styrene and glycol. However, water will react with PVA binders in the laminate, reducing them to acetic acid. It is this that gives the strong smell of vinegar when blisters are burst. Even so, it must be noted that the laminate can become severely damaged before any warning blisters appear.
Osmosis blisters are not only a cosmetic problem. They are the visible sign that the hydrolysis of the polyester has affected at least one laminate layer.By the time the first blister shows, hydrolysed alkali products will have reduced the bond between fibre-glass and polyester deep in the laminate below the water line! This in turn, will have caused a 20-30% loss of structural strength which no “dry and shield” treatment can restore. Without a proper treatment large parts of the laminate layers will sooner or later have larger areas of polyester hydrolysed with only soft wet fibreglass left.
Studies of hundreds of larger hulls with heavy woven roving mats in the laminate have been undertaken. All were found to have numerous sites inside each roving layer and direct evidence of de-laminations deep in the bulk caused by degrees of severe hydrolysis. Significantly most hulls showed no telltale blisters at all!
For further information on “Osmosis” and its chemistry, we do recommend you visit Osmosis blister repair book and read what Bengt Blomberg has to say. You will be able to buy a copy of his book from that site, which is one of the most comprehensive (and controversial!) on the subject. The comments above are drawn from his text.

[yeloya]

Being a official service point for FP, we did tons of osmosis treatment under the warranty of the factory..
1-I have never seen nor heard any osmosis issue with Belize, Bahia or earlier models. It started with Lavezzi, continued with Lipari, Mahé and Orana's. We also did couple of Cumberland.
2-Most people have little understanding on osmosis and a lot of confusion is going on.
3-The problem was the resin rather than the methodology. This latter has had some impact to the end result but it's definately not the main reason.
4-High humidity is common in all of FP's with osmosis. Factory says that this is normal as a result of some additive they have used with the resin. We see high reading even just after the treatment. Nonetheless, we never had any boat where the osmosis re-occured even tough they still have high readings even 4-5 years after the treatment. If the reading goes from high to very high and there are significant increases in humidiy level (which we never had) you may start being concerned..
5-We have seen above level blisters (bubbles) on roughly half of the boats that we treated. They are mostly on the inner part of the hulls and under the bridge. The factory says these are cosmethic and are not considered as a part of the warranty. I tend to believe that they are not osmosis, we just grind them and repair with a gelcoat. Sometimes they come back, sometimes not. They have nothing to do with structural resistance of the boat and I have never seen them causing any problem to any boat if they are let as they are.
6-We have seen that every boat subject to osmosis is different; some were in pretty bad condition with partial delamination initiated, some with just couple of blisters. Even worse, some parts of the boat is perfectly dry while some other parts were very wet.


In short, if the osmosis treatment is properly done, there is nothing to worry about. Actually, they are better than the original ones as the boat is re-laminated with gel shield, vinylester and epoxy.
The problem is over since the launch of Helia.


Hope this helps..


Cheers


Yeloya

[DtM]

Thanks Yeloya.

As always truthful and useful.

[rabbi]

Originally Posted by yeloya

In short, if the osmosis treatment is properly done, there is nothing to worry about. Actually, they are better than the original ones as the boat is re-laminated with gel shield, vinylester and epoxy.
The problem is over since the launch of Helia.

Hi yeloya,
Have you seen ≥2011 models of Mahe or Lipari affected by osmosis or high moisture readings? Or have the factory finally cured these issues in 2011?
Thanks

[yeloya]

Originally Posted by rabbi

Hi yeloya,
Have you seen ≥2011 models of Mahe or Lipari affected by osmosis or high moisture readings? Or have the factory finally cured these issues in 2011?
Thanks

The latest hull number Mahé that we treated was # no 107 and she was from 2009. We currently have another Mahé under treatment and she's from 2011. We also have a Lipari under treatment which is from 2010.

In general (if this was yr question) after 2011 the boats were better. I don't recall any FP boat that we repaired, but obviously this doesn't mean that they are all free of osmosis. I would also add again that generally the reading are high in these models even after treatment; this doesn't mean necessarily that they have an osmosis, just check for the blisters underwater.

Cheers

Yeloya

[FPNC]

I spent about 30 years “hands on” in fiberglass boat and mold construction. Hull lengths up to 44 ft and with many varied materials and techniques.

Over those years I have come to the conclusion that 99% of blisters on a vessel are caused by poor work practice or faulty equipment used in the lamination process. Particularly during the gel-coat, skin coat and first structural layer of the layup. This also applies to what people refer to as “delaminated” layers that in reality were not properly laminated to begin with.

A short list of what causes most blisters is as follows:

GELCOAT: Thin gel-coat, under catalyzed gel-coat or poor spray equipment that allows oil, water, or catalyst drops to contaminate the gel-coat film. Spray equipment that poorly mixes the catalyst. Also, in factory repairs to gel-coat.

SKIN COAT: A skin coat that is too thin, an undersaturated skin coat, air bubbles in skin coat, waiting too long after gel-coat is sprayed to apply the skin coat, dust or trash or contamination between the gel-coat surface and the skin coat, under catalyzed resin in the skin coat, spray equipment that allows oil, water or catalyst drops to contaminate the skin coat. Spray equipment that poorly mixes the catalyst.

FIRST STRUCTURAL LAYER: Undersaturated material, air bubbles in the laminate, waiting overnight to apply first structural layer, dust or trash or contamination between the first structural layer and the skin coat, under catalyzed resin, spray equipment that allows oil, water or catalyst drops to contaminate the laminate. Spray equipment that poorly mixes the catalyst. Exposure of the skin coat to sunlight or extreme heat prior to applying the first structural layer.

MATERIALS: Strand mat or chopped roving strand that has an excessive amount or highly insoluble binder. Really cheap resin, really cheap catalyst, really cheap chopped strand mat or chopped roving strand. Use of a DCPD resin (or any resin for that matter) that has poor secondary bonding characteristics.

After the first structural layer is applied and provided it is of sufficient thickness, the risk of poor work practice and faulty equipment causing blisters is greatly reduced. It is not eliminated.

In my experience, the majority of blister and a lot of de-lam that is seen in hull and deck structures are related to poorly trained and supervised applicators, poor work practices and improper or poorly maintained equipment. Faulty materials can normally be traced directly to the builder ordering really cheap and substandard materials.

[rabbi]

Originally Posted by yeloya

The latest hull number Mahé that we treated was # no 107 and she was from 2009. We currently have another Mahé under treatment and she's from 2011. We also have a Lipari under treatment which is from 2010.

In general (if this was yr question) after 2011 the boats were better. I don't recall any FP boat that we repaired, but obviously this doesn't mean that they are all free of osmosis. I would also add again that generally the reading are high in these models even after treatment; this doesn't mean necessarily that they have an osmosis, just check for the blisters underwater.

Cheers

Yeloya

Thanks for the info.
I had good hopes that they had finally solved the osmosis issue with their change to a vinylester layer. But if you have a 2011 Mahe under treatment this has not been the ultimate cure to the problem.

I'm currently not in the market for another boat (just bought a Lagoon earlier this year), but the next boat could be another FP.