Author Topic: Peel Ply  (Read 151 times)

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Grady300

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Peel Ply
« on: June 19, 2020, 11:32:10 AM »
After hearing for years about how good peel ply works I decided this 30' Kodiak build is soooo big I wanted to relive some sanding hours. So I purchased a 60" x 30 foot long roll of this stuff to give it a try. I can't believe what a difference using peel ply makes. I would guess using this on the entire outside of the hull (not including the bottom) would save me at least 50 hours of sanding smooth enough ready for painting. The cost for the peel ply for the outside sides and transom would only be $300.00. WELL WORTH THE MONEY!!!
My question is I normally apply at least 3 to 4 coats of epoxy to fill the weave prior to sanding. In the attached photo (did a sample run on the side 2x4 stiffeners) I put one coat on while applying the glass. Then about 3 hours later I put a second coat on, with great results not needing a third or 4th coat to fill the weave. The question is do I really need to still put 3 or 4 coats of epoxy on the glass before applying the peel ply or is the 3rd & 4th coats purely to just fill the weave? if I can get away with just 2 coats it will help offset the cost of the peel ply. In the photo the one on the left is the result after removing the peel ply, two coats on each.
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Brian.Dixon

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Re: Peel Ply
« Reply #1 on: June 19, 2020, 12:56:23 PM »
Looks really good on the epoxy coating with that peel ply, and I can see how it looks like it doesn't need any more seal coats.  But manufacturers say that bare wood (no fiberglass) needs 3 well-done coats to waterproof the wood, 4 just in case.  So ... the real question is, since fiberglassing applies glass/epoxy to the hull already, how many coats do I need to seal/waterproof the hull?  The question is more about waterproofing and less about filling the weave.

If you don't have any whitish or dry-ish weave anywhere (FOR SURE), then you might get away with 2 coats after you pull off the peel ply.  3 coats if there's any question about it.  Or you can postpone the discussion until you fair everything in and put final coats on top of the fairing compound.  You can fair the boat now, clear up to the gunnels, add 2 seal coats on top of that and call it good.  You just need to inspect and use your judgment.  The equivalent of 3 coats is the minimum, but when that is met depends partially on how well the glass was saturated.  Obviously the peel ply helps even all of that out so I suspect 2 coats for you.  If it were me, I'd fair the hull before flipping it, add 2 coats of epoxy after fairing.  Later, after flipping and wrapping glass tape over the sheer deck-to-side corner seam, you'll have to fair that in too ... but it'll be all above the chine.  You can add a couple of coats of epoxy from sheerline down to chine then too. 

bd

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Grady300

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Re: Peel Ply
« Reply #2 on: June 19, 2020, 03:43:25 PM »
Brian- Guess I will do some experimenting on a test piece. Roll on 2 coats 4 hours apart, let cure. Then roll on  more coat after light/medium scuff sanding 60 gt. wait 4+- hours then apply 4th coat with peel ply and see how it comes out. Just trying to follow your steps as mentioned in you last post adding more epoxy after fairing.
 My intent is to not use the peel ply until the very last coat of epoxy (spendey stuff) just prior to priming the hull for the 2 part paint I will be using. If it works how I think it will it wont take long to sand smooth just prior to prime & paint. The literature on the peel ply says after pulling it off once the epoxy has cured the very light texture left will fill in with the primer. Also states no need for sanding before any second bonding application of paint or whatever. They claim the peel ply fabric removes any and all wax/blushing or other impurities when pulled off. I'll still give it a quick sand and wash before priming. Sounds like I will be putting on at least 4 total coats of epoxy and probably more, thanks for the clarification. When I flip the hull the bottom thruster tube will be installed, bottom paint applied to 6" above the water line level from the stern forward as well as the entire hull sanded ready for primer. Rub rails and small chine rail will also be finished. I'll report back after I run some samples.
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Brian.Dixon

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Re: Peel Ply
« Reply #3 on: June 20, 2020, 07:11:43 AM »

I like to make good use of the carbide scraper and fair early and often.  I think System III said that it only takes one coat of epoxy to seal up (really 'smooth up') fairing compound since unlike wood, it doesn't absorb epoxy (it IS an epoxy mix).  Basically, I scrape and fair fiberglass edges after each application of fiberglass.  Fix each step before you go to the next step.  A good philosophy for the whole build process.  The only thing I fair all the way to being ready for paint or graphite epoxy while the boat is upside down is the bottom from chine flat to chine flat (including the chine flats) so that the finish coats of paint or graphite epoxy can be done while upside down.  I don't do final fairing of the boat sides until after the glass over the side-to-sheer deck seam is built since it's the last glass that goes on.  Only then do I get out the longboard.  I fair the bottom with careful application of a random orbital sander.  Hope my descriptions aren't too confusing, and note that almost everybody has their own way, their own sequence.  Lots of ways to skin a lingcod...

Brian

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Grady300

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Re: Peel Ply
« Reply #4 on: June 20, 2020, 07:33:26 AM »

I like to make good use of the carbide scraper and fair early and often.  I think System III said that it only takes one coat of epoxy to seal up (really 'smooth up') fairing compound since unlike wood, it doesn't absorb epoxy (it IS an epoxy mix).  Basically, I scrape and fair fiberglass edges after each application of fiberglass.  Fix each step before you go to the next step.  A good philosophy for the whole build process.  The only thing I fair all the way to being ready for paint or graphite epoxy while the boat is upside down is the bottom from chine flat to chine flat (including the chine flats) so that the finish coats of paint or graphite epoxy can be done while upside down.  I don't do final fairing of the boat sides until after the glass over the side-to-sheer deck seam is built since it's the last glass that goes on.  Only then do I get out the longboard.  I fair the bottom with careful application of a random orbital sander.  Hope my descriptions aren't too confusing, and note that almost everybody has their own way, their own sequence.  Lots of ways to skin a lingcod...

Brian
Understood and I agree on your process above other than I like to get the sides all faired out and primed before the flip. Reason being is I think it's easier to do as much finial sanding and prepping while the sides are angled the way they are while it is upside down. Easier to sand with down pressure rather than sanding pressure in an upward situation after the flip.
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Brian.Dixon

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Re: Peel Ply
« Reply #5 on: June 21, 2020, 07:53:05 AM »
Understood and I agree on your process above other than I like to get the sides all faired out and primed before the flip. Reason being is I think it's easier to do as much finial sanding and prepping while the sides are angled the way they are while it is upside down. Easier to sand with down pressure rather than sanding pressure in an upward situation after the flip.

Works for me!

bd



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