Osmotic blistering

[mainexile]

1978 GW Pacer bowrider, Mercruiser 470 I/O. Last Fall I hauled my boat from the lake only to discover extensive osmotic blistering over much of the hull below the waterline. I took the boat to a restoration expert a couple of hours away, and he said that he would store it over the Winter and start on the hull this Spring. In April, he sanded and planed the hull, but he said that the hull was too wet to re-coat. Five months later, he says that the hull is still too wet, but he believes that is not due to water, rather he believes that it is due to uncured resin seeping from the laminate. My question is: has anyone here ever experienced or heard of this phenomenon, and does anyone have a solution for it? I don't have any pix, but I may have some in a week after I go to his shop to examine the boat. Thanks in advance for any responses.

Steve

 

[Woodonglass]

Yes, this is very common on Marina Boats. I think you'll find this link very informative...


Fiberglass Blistering

 

[gm280]

Yes, this is very common on Marina Boats. I think you'll find this link very informative...


Fiberglass Blistering

WOW WOG, that is a very interesting report. I didn't know any of that. Thanks for the posting...:thumb:

 

[ondarvr]

He could be right that it isn't dry, it takes a very long time to actually dry the laminate out, having uncured resin weeping is a little less likely, although there can be decomposed resin migrating to the surface over time as the water escapes.

The link WOG supplied is a good description of what takes place and the repair procedures needed.

 

[mainexile]

Yes, this is very common on Marina Boats. I think you'll find this link very informative...


Fiberglass Blistering

WOG, Thanks for the response and the link. I found the article to be very informative...although it appears that I may have to discuss the repair more thoroughly with the restoration shop owner. I think that his initial quote would probably double based upon the recommended corrective action detailed in the link. Hadn't really planned on that much expense.:blue:

 

[ondarvr]

Blister repair is an all or nothing type deal, the failure rate is high for less than a full effort. Some people like to dig out the viisible blisters, fill them, then repaint or apply a barrier coat, the problem is there can be hundreds, or more likely thousands, of blister sites that aren't visible, but have already started to form. By just covering them, at best you just delay the blister from becoming visible for a short period of time, resulting in a total waste of time and money.

 

[Woodonglass]

ondarvr has FORGOT more than I'll ever know about this topic. I've learned Sooooo much from him and he's the one that has prompted me to do the extensive research that I have on the subject. I've never owned a Marina Boat nor' one that's had blisters, but I've seen and heard the misery of others and can flatly state that I'm GLAD I never have!!!! From what I've learned, the "All or Nothing" statement seems to be the way to go.

 

[mainexile]

Blister repair is an all or nothing type deal, the failure rate is high for less than a full effort. Some people like to dig out the viisible blisters, fill them, then repaint or apply a barrier coat, the problem is there can be hundreds, or more likely thousands, of blister sites that aren't visible, but have already started to form. By just covering them, at best you just delay the blister from becoming visible for a short period of time, resulting in a total waste of time and money.

Since the restorer has already sanded off the old gelcoat and has planed the hull, do you think it would be worthwhile to have him sand everything deeper then re-glas the entire hull? I know that it will be expensive, but will re-glassing help to flash any uncured resins? Or will the moisture have to be dealt with before refinishing?

 

[Scott Danforth]

mainexile, keep in mind this is a 38 year old boat with a Merc 470 with an NADA value of $2k. is it worth it to you to invest the time and money into a 38 year old hull? if so, then fire up that grinder, remove the offending layer or two of laminate that is causing issues, re-coat with a few layers using VE or Epoxy, fair, barrier coat and go boating. paying someone to do it will be about $5-6k, doing it yourself you will be about $2-3k

 

[Woodonglass]

I'm no expert, but...I'm kinda leaning towards "Cuttin Bait"!!! But...It's not my boat, I'm not there to SEE the condition and all the other variables. I'd listen closely to the Repair Pro's advice and the Cost estimates and make the best, most logical decision. Good Luck!!!

 

[mainexile]

mainexile, keep in mind this is a 38 year old boat with a Merc 470 with an NADA value of $2k. is it worth it to you to invest the time and money into a 38 year old hull? if so, then fire up that grinder, remove the offending layer or two of laminate that is causing issues, re-coat with a few layers using VE or Epoxy, fair, barrier coat and go boating. paying someone to do it will be about $5-6k, doing it yourself you will be about $2-3k

Scott, the GW is like a member of the family. If I even mentioned selling it, my wife would divorce me...after pulling a Lorena Bobbitt :scared: That being said, I have neither the facility nor the physical capability (medical problems) to perform the repairs myself. So, I'll have to see what the restorer has to say and plan accordingly. Thanks for the advice.

 

[mainexile]

I'm no expert, but...I'm kinda leaning towards "Cuttin Bait"!!! But...It's not my boat, I'm not there to SEE the condition and all the other variables. I'd listen closely to the Repair Pro's advice and the Cost estimates and make the best, most logical decision. Good Luck!!!

WOG, thanks for the input. As I told Scott, if I were to "cut bait", I'm afraid it wouldn't be the only thing cut.

 

[ondarvr]

Since you've gone this far, and scrapping it isn't an option, I would clean the surface, maybe do a little sanding, apply a few coats of epoxy, then get it smooth enough to paint. This should hold up for a while, and I would make a point of not looking at the hull again if blisters bother you.

 

[Scott Danforth]

Scott, the GW is like a member of the family. If I even mentioned selling it, my wife would divorce me...after pulling a Lorena Bobbitt :scared: That being said, I have neither the facility nor the physical capability (medical problems) to perform the repairs myself. So, I'll have to see what the restorer has to say and plan accordingly. Thanks for the advice.

when the Admiral gets a look at the estimate from your boat restoration guy, she may find the purse strings are stronger than the heart strings. All I can say, is keep her informed. you do not want this to be NIDS (Nautical Induced Divorce Syndrom)

 

[sphelps]

This is interesting .. On the boat I,m working on it did have some blisters that after grinding down the next day it looked as though it had moisture coming out .. I ground down all of them to fresh glass . Then reglassed with multi layers of csm and poly . I guess there is no guarantee that more won't appear at some point ..
Making me rethink spraying new gell coat .. Would it be a better idea to paint the hull instead ? seeing as gell coat is somewhat porous and your trying to keep moisture out ...
Sorry for the high jack mainexile ....

 

[ondarvr]

The blisters are normally filled with fluid, so yes something would be coming out. Covering that area with a new layup will give you more time in that location, but the surounding area may not be far behind in the blister time frame. It is possible that the blisters can only be localized to a certain area and not on the entire hull though, it just depends on why it blistered, there's no way to know unless in the process of the repair the cause is obvious. Gel coat is more waterproof than about 99% of the paints on the market, although it can be easier to apply.

 

[pauloman]

no boat ever sank from blisters. apply a coat of epoxy paint that will bond to a damp hull be done with it.

Mod EDIT
Paul, please check your PMs


paul
progressive epoxy polymers

 

[mainexile]

The blisters are normally filled with fluid, so yes something would be coming out. Covering that area with a new layup will give you more time in that location, but the surounding area may not be far behind in the blister time frame. It is possible that the blisters can only be localized to a certain area and not on the entire hull though, it just depends on why it blistered, there's no way to know unless in the process of the repair the cause is obvious. Gel coat is more waterproof than about 99% of the paints on the market, although it can be easier to apply.

The guy I'm using wants to go back on with epoxy instead of gelcoat, and he says that the surface has to be dry in order to do so. I have an email in to him to see what the cost would be to grind down to dry laminate and re-glas the entire hull below the waterline. We'll see.