Air voids in outer lamenent

ok lets dig a little into some of the causes of what you got and get a little understanding ! When your boat was made there could have been a long list of causes for what actually happened the list sort of goes something like gelcoat spray with wrong or strong catalyst maybe even at the wrong ratio ! the thickness of the gel in in this list as well . gel coat if sprayed thick could be air rated ! the gel going hard to fast does not allow time for the gases to escape so the gel starts its life filled with tiny bubbles so step one of porosity and salt water would have started in a very short time after launching and never stopped since even if the boat was out of the water for a length of time it would have allowed enough moisture through the gel into the poor quality glass behind ,once into the Possible emullsion binder in the glass it would have spread like wild fire and as you pointed out above the water line it could be fine almost .
e glass csm is held together with a emulsion binder that is soluable in polyester resin if the resin gels to fast the emulsion is never completely disolved and when the water eventually founds its way to the bundles of strands and the emulsion it disolves in water and so away it went along one bundle onto the next and so on and so on . the woven roving could possibly slowed its migration as it had no binder and the strand bundles would have wet out better than the csm . so the water could have almost halted at that place . poor workmanship and poor glassing skills in combination of lack of understandig what they were doing and useing is the raft of things all together gave you what you are trying to fix .
glass cloth with a csm matt stiched there nothing wrong with it if you are using epoxy . The csm has no binder so will wet 100% with resin and if you bury the scm against the surface of the old glass it could be a really good advantage to take up some of the ungulations in the rough surface but use peel ply over he top and a steel or hard roller to roll the glass and the peel ply completely flat
Or you could use it the other way round and the csm outermost as a semi sacrificial layer of csm glass when you start to sand and fair the outside .
Turn what other see as minuses into pluses !! either way i see it as a advantage not a disadvantage !!

 

I found some 24 ounce bias with 3/4 ounce mat online, according to the add it take about 1/2 gallon of resin per 3 feet of 50" wide material, seems like it would be a lot to handle overhead

 

Li'l worse on the bottom

Me arms are a bit sore
Finished stripping gel coat off starboard side. Seemed like the gel coat was harder at the bottom around keel, pretty sad when you grind it down with 24 grit and have a smoother finish than what was there. When I bought the boat it had very thick anti foul paint on it, The one picture there is after pressure washing off most of it.

 

keep at it !!

The things we do !! wow what a mess !!
i worked with glass for long time and never seen a case this bad .
I made swiming pools and spa pools and never seen anything like it as well .
The 24 oz material is a bit over kill and it will be much thicker than what you taking off i would think !!
18 oz would be that much thinner and better suited and if it has a 275 gram csm id still use it one way or the other csm inside or csm outside .but getting to a position of doing a big patch at a time will make you feel like you getting some where !!
I walked past 4 full rolls of 1708 laying in the factory floor this morning and immediatly thought of you !! its 45/45 + 275 gram csm and its soft to touch so would lay real easy !!.

 

Yep if we didn't like it and plan on keeping it for retirement I sure as heck wouldn't go this repairing it. Still not sure what I will build back with yet, lightest, strongest with the best impact resistance would do

 

impact resistance ?? are you a bit of a rought driver are you ?? the double bias 800 gram should take good care of that side of things speciallly if you get it in ,in big bits and using epoxy .You shoud be fish scaling the joins and any overlaps from the back to the front not the other way round !!

 

LOL
The swing Keel and trunk would be the weak point anyway, Just have to keep it off the rocks.
Its strange that about the forward 1/3 of the bottom does not feel as stiff as the rest, maybe the damage is deeper in the forward laminate from the water pressure or they did a lighter layup. I think what I am going to do is drill a few small holes one forward, middle and aft so I can measure the hull thickness just to see whats what plus it will give me an idea of how much to build back to after removing the mat layer. Game plan on removing mat is after I finish stripping off the gel coat on the other side is give it a light sandblast, that should open up all the blisters and if it works like where I tested it, the bottom of the pits will be where the roving is and give me a visual guide to grind to.
Supposed to be 108 tomorrow and work up to 110 over the weekend, wont get much done in that kinda heat.

 

What about working at night ?? tempratures usually drop a little just have to keep an eye on the humidity .late at night ,early morning is the coolest times in most countries .

 

In the mornings have not been to bad, I managed to get all the gel coat stripped and got a good start at removing the mat layer. Lot of larger blisters around the keel area and the mat layer is a bit thicker. The glassing will be easy compared to the prep work!

 

Raka inc has 17 ounce biaxial "no mat" on sale $4 yard for 20 yards or more, 38" wide so I figured up what I needed and place my order, Figured 1 layer to start and doubled up around keel area, came out 22 yards of material should give me some extra, rough guess 3 gallons of resin. Game plan on layup is to run the 38" wide strips chine to chine skipping 36" gaps 'keep it cradled that way" After cured 24 hours feather back edges and move slings and finish interconnecting strips. end result 1 layer resin,blisters filled and fared , 1 layer 6 ounce cloth 2 at the bow and then a layer of 17 ounce biaxial doubled in the keel area. It should add a lot of strength/ stiffness back if not I will add 1 more layer to it.

 

I sat with the young designer yestereday looking at you pictures and he asked what caused !, there is no simple one answer so i went away sat with a cup of coffee and made a list of probable causes , its not one in particular but a contribution of many things !
Heres some of the possable causes and its a contribution of more than just one single cause !

THE GEL-COAT AND GEL-COATING
Poor gel coat quality
and poor application
thin gelcoat !
Thick gel coat
High catalyst ratio
wrong catalyst for the gelcoat
Spray equipment !
pressure pot spray and air pressure to high !!
so airated gelcoat!
and combined with the gassing reaction between the gelcoat and the catalyst ,and wrong catalyst all leading to Porosity
Porosity is microscopic bubbles that can break down quickly and lets the sea water get into and eventualy through the gelcoat to the glass layers behind .
Even using a venus spray gelcoat high pressure airless spray gun most to all of these things could still apply .

THE GLASS AND GLASSING !!
No continuaous strand binderless tissue as the first back up glass behind the gelcoat and under the first layer of glass .
The chopped strand matt could be E matt and loaded with emmussion binder that is hard to dissolve and the Binder draws moisture out of the air boats build in survey allow 70% humidity as a maximum at any time .
Glass thats not wet out properly with resin and has not got enough resin to completely saturate the glass fibre bundels !!
Resin used at to higher catalyst ratio and gone hard to quickly before the glass bundles of strands are wet out properly and totally encapsulated the glass fibres within the layer of matt .
If a chopper gun was used dry glass is the most likely one of the leading causes .
not wetting the surface beneith where the glass would be sprayed
combined all these things together and add

The labour and workers doing the job !!!
Lack of worker exsperiance
and poor product knowledge ,
lack of understanding of the laminating process ,
couple this to poor workmanship and a "she'll be right mate "attatude
and the proof is what you see before you !!

One thing i always remember some one telling me long time ago is the problems you cause and cover up today are the troubles and repairs of the future !!

Also Many a true jest has been spoken in words

With glassing bad things happen for seeminly unbeknown reasons ,but dig deep enough you will find those reasons and causes ,so as long as you learn from these mistakes and understand the probable causes they will stop and never happen again unless you let them happen !

 

Tunnels
Hard to say exactly

I would think the biggest factor is the amount of time in the water with no barrier coat , lack of maintenance. Nothing more than more anti foul slopped on. From what I know The guy I bought it from had it in a slip at Millerton lake for about 10 years, he had it in dry storage for about a year when I bought it. From what he told me he bought it from the original owner up in the delta area stored in the water also, boat being 36 years old could have spent most of those years sitting in a slip.
Would it even be possible to do the best of the best layup with polyester resin and gel coat and it keep the water out for that many years ?

 

I hear what you saying but have seen boats that been in the water forever and they never even look 1/100 th as bad as that . that is an exception . I been doing glass work since 1972 and worked in all sorts places and seen some terrible things but that one takes the cake completely !!

 

That is a bad case of blisters, but I've seen similar ones.

Those blisters would have nothing to do with the gel coat, it would most likely be from the binder in the mat (if it's mat, could be chop, if it is then it's less likely), resin type, or improper cure.

Resin type, some resins types just don’t hold up well to long term immersion.

Cure could be from under or over catalyst %, or poor dispersion.

If it's chop and an external mix gun was used, then it's not uncommon for the gun to not be adjusted correctly and the catalyst droplets will hit strands of glass before they touch resin. This leaves over catalyzed strands throughout the skin which are great sites for blisters to start.

You can get a laminate peeler that will remove the gel coat and laminate to a somewhat even depth.

 

Re think again !!!!!

Water getting through and into the glass behind has a lot to do with the gelcoat !!! the gelcoat is the first layer the water has to get through before it gets to the glass behind .so if it is porous and airated then the water gets through quickly . specially salt water !!
This is simply not just one particular problem that you can put your finger on !!! its a whole series of events that would have contributed
to this happening .
External mix guns is another factor yes to add to the list!
My personal choice of any kind of spray equipment is always internal mix and would never ever be external mix . I had 6 external guns in one factory i worked and they were way to temprimental for me .
Internall mix they just go and keep going for ever and ever without any problems what so ever !! so any one continplating buying a gun of any kind get internal mix every time !!!

Barrier coast that are painted over the top of gel coat are always epoxys or simular but the use of barrier layers also starts inside the boat hull being built in the mould as well behind the gelcoat!! tissue or continuous strand fine glass is normally used in conjuncion with Vinylester resins but i strongly feel this needs to also exstend into the next layer of chopped strand matt usually ,only a 300 gram and this also needs to be very resin rich and well rolled with the mohair as well as the hard laminating roller .
Myself i always lay the two together at the same time, its always Vinylester resin , and lastying the two being laid at the same time the cure of that layer is better and that is another key to protecting agains stopping water intrussion is the resin cure !!!.
Glass manufactures have tried to help and have introduced P matt that uses a completely differant process to make the roll of glass and done away with the emmussions of old that used to be most of if not all of the problems of the actuall fibres not being able to wetout properly !.
The binder may have disolved yes but had diluted the resin so the more rolling it gets the better to move the fibres around and break up and seperate the fibres from there bundles . The more the strands spread apart the better the resin is able to hold all sides and the stronger and less chance of water getting in and wicking and traveling any where .

Remember to get up close and personal to gain a better and more complete understanding of all the product we have and use to make boats with .
Learning is constant and never stops , everything we use is changing every day just about ,taking things at face value you might as well go into a dark room ,shut and bolt the door behind you !!.