Blister Filling Question

[Sailor 99]

Originally Posted by Fore and Aft

A couple of questions Dark Horse. I see your in Toronto Canada so is your yacht in the water all year? When you say Poly Fair is that the pink filler commonly called car filler or builders bog? Another question, why 6 layers of glass Mat.Why not a structural layer of 450gm double bias and skip a couple of Mat layers?
Just curious, I love the hole punch idea.
Cheers

The yacht wintered in for 4 years so far


POLY-FAIR ® F26 Fast Setting Polyester-based Fairing ... - Scott Bader


https://www.scottbader.com/wp-content/uploads/15905_sb-tds-f26-mar-16.pdf
Introduction. Poly-Fair F26 is a water resistant, low-density polyester-based fairing compound. Poly-Fair F26 has good adhesion to cured fiberreinforced ...


Not Car Bondo.




As for the mat..


When we cored the hull we found that the boat was mostly mat anyway with only 2 layers of roving and it was plenty strong so why change it.



In addition hulls are curved. vinylester breaks the binders up in the mat so the random fibers take the shape of the hull. If you used a woven product you would be hard pressed to get it to take the shape of the hull.

In fact even boats that are hand laid are mostly mat for this reason. The roving is simply too hard to lay properly. Is mat the strongest.. No but its plenty strong enough as we can see.





The boat was repaired in its cradle so the glass was being applied upside down and the glass has to stay on the boat by simple adhesion of the vinylester to the boat and you need to get enough resin in the fibers that it is not a dry layup. Then it needs to cure for at least an hour before you can put the next layer on. Using anything heavier than 1.5 oz mat would have been near impossible as it would have fallen off due to gravity and the resin would have run out. You can not cover it with plastic to hold it up and you can not use wax or the next layer will not bond without sanding.




Poly and vinylester do not cure completely if exposed to air. The cured resin is still chemically open. If you come back even a week later and put on another layer of glass it bonds the same as if it had been put on an hour later. Its not just a mechanical bond like epoxy it is a chemical bond.



It was a bit of a job. 3600 sq ft of 1.5oz mat and 90 gallons of vinylester resin.


Epoxy will not work because 1) it is too thin and will run out before it cures. 2) Epoxy does not dissolve the binders in the mat. 3) Epoxy is not acid stable and after osmosis the hull is acidic.



I talked to a yard down in the Chesapeake area. They peeled a hull and put the glass back on and 18 months later while sitting at her mooring the entire new bottom fell off just like it had been unzipped. ( his words)





There you have it. Long story but the details are important here because its a big job you only want to do once.



Cheers

[Sailor 99]

Originally Posted by Fore and Aft

A couple of questions Dark Horse. I see your in Toronto Canada so is your yacht in the water all year? When you say Poly Fair is that the pink filler commonly called car filler or builders bog? Another question, why 6 layers of glass Mat.Why not a structural layer of 450gm double bias and skip a couple of Mat layers?
Just curious, I love the hole punch idea.
Cheers

I see your a surveyor so I will tell you a bit more.


The hull measured over 30 with a moisture meter. When we exposed the glass we found that it oozed a brown liquid out of the threads in the glass. This was phthalic acid and glycol. Osmosis as you know is the break down of the polyester by water. The hull looked like a very dry layup because the polyester had dissolved. The hull measured high because its measuring the glycol and the acid. This was only in the part of the hull that was in the water. Above the water line the hull went back to a nice dark green color. The guy using the peeler told me all the hulls he did were like this. Washed out straw like glass in the water where the osmosis was and then above the water line it was good.



The acid/glycol is oozing out because its in the hull under pressure. The boat's entire weight is on hull held up by water. 600 sq ft is 86400 sq inches and all up the boat is about 44K lbs. So about 1/2 lb pressure per sq inch. The dissolved polyester is being pushed into the hull down the threads of the glass.


It oozes out slowly and then drys hard sealing the hull but with little brown spots. Its water soluble so you can wipe it off but it comes back next day. That's why the epoxy is destroyed. The acid keeps pushing out.


So to fix this after peeling and re sanding we took a 4000 psi hot water pressure washer and pressure washed the hull every day for 30 days. The hull went from measuring 30+ to measuring 7. Wash off dried bits, heat hull and let it ooze some more.


After that we reglassed.



Tough job.,

[cburger]

Originally Posted by Dark Horse

I see your a surveyor so I will tell you a bit more.


The hull measured over 30 with a moisture meter. When we exposed the glass we found that it oozed a brown liquid out of the threads in the glass. This was phthalic acid and glycol. Osmosis as you know is the break down of the polyester by water. The hull looked like a very dry layup because the polyester had dissolved. The hull measured high because its measuring the glycol and the acid. This was only in the part of the hull that was in the water. Above the water line the hull went back to a nice dark green color. The guy using the peeler told me all the hulls he did were like this. Washed out straw like glass in the water where the osmosis was and then above the water line it was good.



The acid/glycol is oozing out because its in the hull under pressure. The boat's entire weight is on hull held up by water. 600 sq ft is 86400 sq inches and all up the boat is about 44K lbs. So about 1/2 lb pressure per sq inch. The dissolved polyester is being pushed into the hull down the threads of the glass.


It oozes out slowly and then drys hard sealing the hull but with little brown spots. Its water soluble so you can wipe it off but it comes back next day. That's why the epoxy is destroyed. The acid keeps pushing out.


So to fix this after peeling and re sanding we took a 4000 psi hot water pressure washer and pressure washed the hull every day for 30 days. The hull went from measuring 30+ to measuring 7. Wash off dried bits, heat hull and let it ooze some more.


After that we reglassed.



Tough job.,

You really have to love the boat, thanks for the science.

[Sailor 99]

Originally Posted by cburger

You really have to love the boat, thanks for the science.

Love nothing. We spent about 25K doing the bottom job ourselves. It would have cost another 100k to have it done by a shop and it would not have been as good a job.



Besides, by this point we had 160K into the boat and could not just walk away.



You gots to do what you gots to do.

[cburger]

Originally Posted by Dark Horse

Love nothing. We spent about 25K doing the bottom job ourselves. It would have cost another 100k to have it done by a shop and it would not have been as good a job.



Besides, by this point we had 160K into the boat and could not just walk away.



You gots to do what you gots to do.

Had a girlfriend who owned a Beneteau Idylle 51, seem to remember to recall they where built for the charter service.

Did you photo document your bottom job?

[Sailor 99]

Originally Posted by cburger

Had a girlfriend who owned a Beneteau Idylle 51, seem to remember to recall they where built for the charter service.

Did you photo document your bottom job?

Most built for the charter service and 10 owners versions. Beneteau does not build them like this anymore. Fast comfortable solid.



No I don't photo document anything. Don't have the time or the inclination.

[Bill Seal]

I repaired a couple of big radomes (TV transmit antennas, about 1000 ft up), used duct tape to hold the mat and resin and squeeze out the excess resin. Even worked at -5 deg f, using bubble wrap and heat lamps.

[Sailor 99]

Originally Posted by Bill Seal

I repaired a couple of big radomes (TV transmit antennas, about 1000 ft up), used duct tape to hold the mat and resin and squeeze out the excess resin. Even worked at -5 deg f, using bubble wrap and heat lamps.

I fixed a deck on my C&C 34 in Feb on Lake Ontario with bubble wrap and heat lamps. Worked a charm but we were only about 10 feet up. 1000' feet is more than I am willing to do and I am a big DIY guy



Hard to do on a whole hull. In that case I would be wrapping under the cradle and running a 30k propane heater for a couple of hours in advance.


Service windows before launch have been very short here on LO for the last 5 years. Spring has not been nice.

[Fore and Aft]

Thanks for the reply Dark Horse, you certainly make a few wild assumptions.
Laying mat in a mould is very easy, the hardest part is laying it down flat so the weave does not distort. I cannot think of any good reason to lay heaps of choppy unless you are a lazy builder and want a heavier boat than needed.
I have helped lay countless 450gm double bias layers upside down on hulls. Some of those game boats at the aft end have almost horizontal hull surfaces. It takes a team of guys but it can be done.
Different epoxy hardner for different jobs, we often started with slow hardner until everyone was in the rhythm then we used a medium hardner. No epoxy ever run out.
The unzip story does not surprise me, I have personally seen one Roberts Spray just get the whole epoxy fibreglass sheathing torn off by hand. I would love to have known who sheathed her and how dry the hull was before they glassed her.
Vinylester or epoxy? Despite the science they both seem to work.
Cheers

[dcstrng]

Originally Posted by gmakhs

epoxy through a lot of surveyors recommend it is not good for big repairs because it cures harder than polyester (search hard spots )...

Hmmmm... Does something like GFlex or the other, more flexible epoxies have any application here?

[Sailor 99]

Originally Posted by Fore and Aft

Thanks for the reply Dark Horse, you certainly make a few wild assumptions.
Laying mat in a mould is very easy, the hardest part is laying it down flat so the weave does not distort. I cannot think of any good reason to lay heaps of choppy unless you are a lazy builder and want a heavier boat than needed.
I have helped lay countless 450gm double bias layers upside down on hulls. Some of those game boats at the aft end have almost horizontal hull surfaces. It takes a team of guys but it can be done.
Different epoxy hardner for different jobs, we often started with slow hardner until everyone was in the rhythm then we used a medium hardner. No epoxy ever run out.
The unzip story does not surprise me, I have personally seen one Roberts Spray just get the whole epoxy fibreglass sheathing torn off by hand. I would love to have known who sheathed her and how dry the hull was before they glassed her.
Vinylester or epoxy? Despite the science they both seem to work.
Cheers

No wild assumptions. All researched by asking people who did this and searching on the net for information. The boat sat there for a long time before I started. I also talked to people who had built boats from scratch.



In the end I had to do it. Many ways to do the job but in the end I had to do it and I was by the shape of the hull very successful.

[ferrailleur]

I have been grinding and filling tons of blisters (Catalina 27) these past few months.... I feel the pain!
do you have pics?

[ferrailleur]

After soda blasting, grinding, washing, rinsing, acetoning and drying the hull from inside I have filled up the grinded blister cavities with West System 105/205. I just spreaded it with my gloved hand on large areas!
I sanded and resanded to get rid of all the epoxy glossiness and rough up the surface for a good bite of my first coat of epoxy barrier (Interlux 2000).
That's where I'm now.... my hull is not a smooth racing hull.
Question: before I apply my first coat of Interlux 2000 what cleaning solution should I use (mineral spirit?) for a final wipe off?

[geoleo]

Originally Posted by ferrailleur

After soda blasting, grinding, washing, rinsing, acetoning and drying the hull from inside I have filled up the grinded blister cavities with West System 105/205. I just spreaded it with my gloved hand on large areas!
I sanded and resanded to get rid of all the epoxy glossiness and rough up the surface for a good bite of my first coat of epoxy barrier (Interlux 2000).
That's where I'm now.... my hull is not a smooth racing hull.
Question: before I apply my first coat of Interlux 2000 what cleaning solution should I use (mineral spirit?) for a final wipe off?

ACETONE