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Three yrs in a slip & never touched the boat other than washing off the hull " No Problems" other than slime ,but I think this is due to the fact I slip on a river mouth & the water is always flowing at a fairly good rate

J

For now......... we will have to settle on, agreeing to disagree..
I might Make Time to attend to my pin pimples this summer. IF I DO ? I will photo and post what I find.. I have a electric plane... the proper way to remove gel coat and I might??? Use it on a small area to prove someones point.. what will be will be.. BTW if you have broken the hard surface of the epoxy on you hull you may well have now caused yourself more issues than you were trying to fix..
Over 10,000 of these boats and we see pin head issues not US quarter coin size let alone coffee can size..issues. We have seen zero fiberglass deterioration..
I have not worked on many fiberglass boats over the years.. But I have worked on a few.. Its those older boats that By and Large develop real issues.. Issues with fiberglass deterioration once violated.. What I do know for a fact, is, after having worked on numerous ones is ....Corvettes!
The Chemical make up of the fiberglass ( epoxy) bodies changed Drastically sometime between 1958 and 1972.. and again sometime between 1972 and 2003.. This last change.... was HUGE!
All The Old issues are now Gone...did the boating Industry follow Chevrolet or was it Chevy following their lead.. No matter Factory Fiberglass no longer has the issues with decomposition and delamination it once did..
I believe you said you used epoxy primer? Good choice.. Did you prep it properly?
I thought I did ...."Her" 1970 MGB.. The Car was ready do go and just one more prep an a wipe down with Dupont Prep Sol.. and shoot her .. My wife is a keeper for sure... among other things she does on her own.... is she'll cruise through my work shop regularly and pick up any and all the rags.. She washes them drys them folds them and returns them to the shop.. BUT to my surprise She uses a laundry detergent that has fabric softener already in it.. 99.999% of the time that would be fine it would be wonderful.. Not for paint prep!!!
I ..Drain the water separator and change out the filter on the compressor Fill the pot and shoot paint.. SH_T!!
Whats wrong? Dang! Try another panel.. try ANOTHER panel.. Heck its a total wreck... fog the whole dang car and see where this stops??
I called the Factory paint rep.. in the end it was those clean spotless rags.. Yes she uses a detergent that has Fabric Softener in it ... I might as well have spray the whole car will silicon spray .. Strip all the paint and start all over again.. How did he know Right away? Its a common mistake among DIY guys.. even those with some background in what they are doing.. If I was you I would be checking that epoxy primer real close for fish eyes ..It may be hard to do unless you DA'd the bottom after grinding...1 day 1 month 1 year.. if you have that issue brewing.. All the paint the entire job will Have To Be removed and Super.....cleaned and done again.. Live and learn and Ive done this paint thing a bunch...for money....Go Figure...

I repair fiberglass and gelcoat problems on a daily base at a major Water Park. I also have lots of experance in fiberglass hulls with Polyester Gel coating. Better built boats use the epoxy or Vaynal resin .
Mac. uses the cheap poly resin gelcoat that is poris and absorbes water. A epoxy barrier coating of at least 10 mils thick (2-3 coats of Interlux 2000) is needed at a barrier coat to prevent water penitration for boats left in water on a slip.
Apoxie Barrie coating seals the gelcoat from water penitration.
Water does not penetrat epoxy barrier coating if don proper.
Dave

Divecoz wrote:DaveB .. Yes as from your pictures.. when I think of blister issues? THAT is what I envision.. Not the pin pops ( smaller than the head of a straight pin, less than 3/32's of an inch in diameter) I see on mine or other Mac boats .. Yes mine should be repaired.. However IMHO if they are not and the F.G lay up is proper that F.G is not going to degrade as shown.. Our Gel Coat is porous..
Why might we have the pops? Tiny voids ( during fabrication.. so much as a speck of dust ) between the F.G. and the gel coat.. Gel coat is porous and water travels through to the epoxy and is there by trapped between those two layers. One issue or another causes expansion and POP! or pin bump..
With close to, if not more than 10,000 of these boats plying the waters of the world.... I have yet to hear of what I think of as blister issues with any of these boats..

Your correct on all points DaveB and your pictures showed we dont have those.. kinds of issues.. Not IMHO and not as I have seen here ..
Yes Roger uses cheap gel coat one of many items that keeps the price down and he gets away with it because.. by definition... these are trailer sailors .. "not" intended for living in the water
I am sure with you working with F.G daily your more than aware of the need for proper prep and, that if silicon or the like, is between the base coat and the hull? It doesn't matter how many coats of anything is applied afterwards .....you still have adhesion issues to the hull ...

E-Mail me and will give you my phone number and I will walk you thru what needs to be done.
Be sure you mention Mac. on your e-mail..delete a lot of spam.
Dave
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Divecoz wrote:Your correct on all points DaveB and your pictures showed we dont have those.. kinds of issues.. Not IMHO and not as I have seen here ..
Yes Roger uses cheap gel coat one of many items that keeps the price down and he gets away with it because.. by definition... these are trailer sailors .. "not" intended for living in the water
I am sure with you working with F.G daily your more than aware of the need for proper prep and, that if silicon or the like, is between the base coat and the hull? It doesn't matter how many coats of anything is applied afterwards .....you still have adhesion issues to the hull ...

Sorry, my laps of this forum rules. Thanks for the reminder.
Dave

Hamin' X wrote:

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My boat (2003 M) has barrier coat. For seasons ago I lost my dagger-board and got replacement from the plant. I never bothered to do epoxy barrier on the new dagger-board. During summer period boat sits in water (Georgian Bay). There is no any problem on the hull itself but I got blisters on the bottom part of the dagger-board by the end of the second season.
Does it make any sense to do barrier coat on the dagger-board as long as it is filled by water and penetration could happen from inside?
What to do to prevent osmosis within the dagger-board well? Did somebody got osmosis there? What about osmosis within the ballast tank?

I'll get beat up for this again ....but here goes .. Yes coat the board.. Its penetration through the gel coat your addressing..I as of yet dont have what you describe.. 6 years of 6 months or more each year sitting in a very warm fresh water harbor and 4 months sitting in saltwater in and around Port Charlotte Fla.
#2. No Gel coat in the ballast tank there by no possible issues with separation / osmosis..

Misha wrote:My boat (2003 M) has barrier coat. For seasons ago I lost my dagger-board and got replacement from the plant. I never bothered to do epoxy barrier on the new dagger-board. During summer period boat sits in water (Georgian Bay). There is no any problem on the hull itself but I got blisters on the bottom part of the dagger-board by the end of the second season.
Does it make any sense to do barrier coat on the dagger-board as long as it is filled by water and penetration could happen from inside?
What to do to prevent osmosis within the dagger-board well? Did somebody got osmosis there? What about osmosis within the ballast tank?

Don't know about anyone else on this board but if I had my hull bottom down to bare glass a layer of vinylester and biax fiberglass is going back on. One layer over the whole bottom and one layer down the centerline. Since I'll be doing all that I don't really care if it blisters. And if between now and then the hull opens up and has a major failure I will publish an expose.
I know blisters. I've fixed them before. I've had them go right through the hull. Barrier coats are only marginal.
Each boat is different. Made on different days different temps left to cure for different times.
Unless these Mac hulls are wet out with plenty of resin then squeegeed and rolled off there are tons of voids.
Resin starvation is a big cause of blisters as is cheap resin and glass.
Quality control and good materials reduce blisters. Many modern boats are vacuum bagged to ensure tight lamination. I doubt these are. Too bad because one hour with a good roller per laminate more will mean the difference between blisters or no blisters.
The only sure fix is grind that puppy to bare glass and re laminate with glass and resin. Enjoy the added stiffness and strength while you are at it. Fir those worried about added weight I guess your out of luck. Keep waxing and dry store the boat as much as possible.
As for the inside of the water tank? Who knows. On my boat that whole system is eventually going bye bye. I'll get the trailer reinforced or buy a bigger one. I do not like the feel of the boat without her ballast so why not just just do it right. Lead, secured and down low. Water tank drained and sealed for added flotation.
If I ever sell the boat I'll just take my lead with me and the NO can use the water tank once again.

So far as other quality issues, there is a soft spot on deck that the company explains is not uncommon and appears interested in arranging a fix. The other minor issues were not the manufacturer but the dealer.


Ixneigh

As an aside anyone know the actual clear profit Roger makes on a mac26?