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Thread: Tips and tricks for laying down glass over ply.

  1. #1
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    Default Tips and tricks for laying down glass over ply.

    OK, so I'm almost ready to lay 6 Oz glass down over my new ply decks. 50 foot boat so quite a bit if it. She's in the water at her berth. Weather for the next week or do is forecast dry and around 30C in the day, 15C overnight.

    Today I'm doing some filling and sanding and rounding off the edges of the deck. Toerails and fillets from the deck to the toerails, cabin sides etc will come later. So I'm just laying flat glass.

    I'm planning to use peel ply for a nice finish, and I'll leave it on to protect the glass from UV until I'm ready to apply a finish.

    I'm worried about outgassing and bubbles forming in the heat. Even the evenings are quite warm, it doesn't really start to cool down until shortly before sunset. I have no fences or rails to tie tarps to so I can't see a way to make shade. Any ideas? I guess do small areas, working in the last hour or two of light, over several days. That may also solve the problem of trying to access and work such a large area of wet epoxy and glass all at once.

    Id appreciate any and all advice, experience and wisdom on what I'm about to do. I have no experience in laying glass over ply and it's one of those get it it right first time deals.

    My general plan is to roll on epoxy with a foam roller, let it get tacky, then lay on the glass. I'll recheck YouTube but I think the peel ply goes on over the glass, then more epoxy. Or is it epoxy then peel ply? Anyway I seem to prefer the idea of epoxy then glass rather than glass then epoxy.

    .

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    Last edited by Phil Y; 03-12-2019 at 03:51 PM.

  2. #2
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    Default Re: Tips and tricks for laying down glass over ply.

    I am no expert but, in the videos I have seen, the peel ply goes on after the epoxy.

    Also, while I know it can be done both ways, the recommendation of the video experts was to lay the cloth down dry and then wet it out. As I recall the series on the Off Center Harbor site, the process was: Lay the cloth down dry; Roll on a coat of epoxy that is enough to soak the cloth and reach the sub-surface; it was recommended to roll from the middle to the ends in short sections to drive the air bubbles out as much as possible; there were warnings not to overwork the epoxy and cloth with the roller - that doing so would cause it to lift from the surface; there were also warnings that too much epoxy in the 1st coat would cause the same problem; there was no effort to completely fill the weave of the cloth with the 1st coat - its only function was to soak in and get the cloth and sub-surface attached; an hour or two after the 1st coat went down, a 2nd coat of epoxy was rolled on - this time to fill the weave.

    I am a little fuzzy on the next steps and where the peel ply came in. I think that, if you were going to sand the surface, and 3rd coat of epoxy was recommended. You never want to sand down to the cloth, so that coat needs to be a pretty thick one. If I were doing it, I think I would put the peel ply down over the 3rd coat so as to reduce as much as possible the need for sanding.

    I would tempted in your climate to wait until dark before I started on this job, and to do it in fairly small sections that were manageable.

  3. #3
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    Default Re: Tips and tricks for laying down glass over ply.

    Phil, If you do not have "Fiberglass Laminating Rollers" you should obtain them. A fairly large roller for the flat decks and a small radius short roller for the filleted corners when you get to them.

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    Pretty hard to avoid, but if you can, avoid direct sunlight by shading, that is a good thing. You may want to keep this in mindalso, , to minimize bubbles (outgassing), you want the temperature to be dropping not rising,
    Denise, Bristol PA, Oday30, Anchor Yacht Club, On tidal Delaware River. my current project; http://forum.woodenboat.com/showthre...0-Ducker-Resto

  5. #5
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    Default Re: Tips and tricks for laying down glass over ply.

    Phil, could we get more pics of your boat? She looks interesting. What is she?
    Simpler is better, except when complicated looks really cool.

  6. #6
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    Default Re: Tips and tricks for laying down glass over ply.

    There is no way in hell that I would try laying dry glass down into wet epoxy for a large area. While you are working over here, the resin will be changing consistency over there before you even get to that part. You run the risk of it getting too thick to properly work, at which point, it will be ruining part of your cloth. I would use the dry method instead, sticking it down and saturating it as you go and have an assistant who can carefully and properly mix a steady stream of small to medium sized batches of resin as their ONLY job. Cloth also likes to move a little bit as you saturate it and get it stuck down. The dry method yields a more consistent weave pattern as you can sweep excess away as you progress, rather than just cramming the weave together because it's stuck in wet resin and can't move. Rough-cut the dry cloth slightly large, work toward the ends or edges with the resin and do your final cuts when you get to them.

    You can use bubble rollers if you want, but the job can certainly be done with regular foam rollers or with squeegees. Have a bunch on hand, as trying to saturate cloth with a roller which is getting stiff or lumpy from previous resin batches is very difficult. I'm admittedly cheap, but my favorite squeegees (both for price and the quality of the work they do) are slabs of ethafoam packing material cut about 1/2" thick on the band saw. You can "comb" the surface of saturated glass cloth out to an extremely uniform, down tight, and properly saturated cloth texture with one.

    I also really question the actual ability of peel-ply to function as a UV blocker. It's polyester, so it will probably have a pretty decent UV lifespan, simply because the fiber itself resists UV deterioration, but that does not necessarily make it a shield for what is underneath such a thin layer of it. I've only glassed boats up to 22' long (using a full double layer of 60" cloth on the bottom and additional pieces wrapping up the sides, but if I was going to try your project, I'd plan on doing it in sections with nice neat overlaps or cut joints between manageably-sized sections and nothing would be exposed without paint for much more than a week.

    Of course the easiest way to minimize outgassing is to roll on a thin saturation coat of epoxy and let it harden before glassing. The bad news is that it will usually raise the grain a bit. Those little stickers make it difficult to move dry glass around without it snagging on them, so it's a good idea to give the epoxy a quick light sanding, just to knock the grain back down before glassing, so it adds more work. I've glassed both with and without the saturation coat first and have never decided which I liked better.

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    Default Re: Tips and tricks for laying down glass over ply.

    Job will go a LOT easier with a helper.
    Steve Martinsen

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    Default Re: Tips and tricks for laying down glass over ply.

    I would also definitely apply the cloth dry. I didn’t use a roller, I used plastic body filler paddles or squeegees. I found it quite easy to control the amount of epoxy with it.
    Attached Images Attached Images

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    Default Re: Tips and tricks for laying down glass over ply.

    Same here...pour on a bit and use a spreader to squeegee it through the cloth. As for shade, since your standing rigging is in place, perhaps you could attach some pvc piping across the beam at the main and mizzen, and for and aft from the forestay to backstay to support a plastic tarp?

  10. #10
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    Ok thanks, I'll definitely lay the cloth down dry and wet it out in 2 or 3 coats. A preliminary saturating coat of epoxy, and sanding, although more work sounds like the way to go too. With the angle of the sun I just have no realistic way to create shade.

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    Quote Originally Posted by Phil Y View Post
    Ok thanks, I'll definitely lay the cloth down dry and wet it out in 2 or 3 coats. A preliminary saturating coat of epoxy, and sanding, although more work sounds like the way to go too. With the angle of the sun I just have no realistic way to create shade.

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    Umm... Wet out, if you luse a brush or roller, the cloth may start floating, the nice thing about the squeegee, it presses the cloth down, and scrapes the excess to the dry area, (less waste too) If you let that layer of epoxy and glass set up till it's hard but still not 100% cured you can add another coat of epoxy. No sanding. You going to try and fill the weave? Then you would need non-skid paint but you would probably need non-skid paint anyhow.
    Denise, Bristol PA, Oday30, Anchor Yacht Club, On tidal Delaware River. my current project; http://forum.woodenboat.com/showthre...0-Ducker-Resto

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    Default Re: Tips and tricks for laying down glass over ply.

    I used some very small pins to tack the glass down with a little tension over my coach house. Saved a lot of problems. Make surface is even and filled to the ninth degree, no sharp corners. With a large area, one person mixing, one or two persons working it is nice.

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    Default Re: Tips and tricks for laying down glass over ply.

    What Todd said. And lupussonic, and...

    You get bubbles when the temperature is rising, causing the air in the wood to expand, so it is a problem for the morning. Once the deck temperature has settled the air in the wood will stop expanding so much. My only additional advice is to drink lots of water and try not to drip too much sweat on the deck.

    At 30C, your pot life will be short. Slow hardener at 30 acts like fast hardener at 25. If you can find a way to cool it until it is applied, it will last (stay liquid) a lot longer.

    Peel ply is a good idea, but I don't know how you will have the time unless you have at least 5 people, one mixer, 2 glassers and 2 peelers. A white strippable coating may work to protect the epoxy, but that is pure speculation on my part (or a load of blethers) And no, I don't know how durable nor where to find some. I have seen strippable polysulfide caulk stick well to a partially cured epoxy paint, so in the unlikely event that you can find and want to try it, give it a week before you apply it.

    I don't remember what brand you are using, but the graph below won't change much for most. Pot life is the time for the viscosity to go up something like 4 times in a cup containing 100 grams of mixed epoxy. Work life is the time it takes to get too viscous to work with. Epoxy in a cup warms up faster than a thin layer in a pan. At 30C.


    https://www.epoxyworks.com/index.php/epoxy-shelf-life/
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  14. #14
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    Default Re: Tips and tricks for laying down glass over ply.

    I once epoxied the inside of a large kayak (deck not yet installed) in direct sunlight. I also did the endpours at the same time. I had the interesting and somewhat alarming experience of watching the epoxy boil out of the endpours. The rest of the epoxy was setting up as I was hurriedly applying it making for a rather tense and miserable epoxy session. Avoid direct sunlight as much as you possibly can while you're applying it. Maybe get one or two of those three sided lightweight beach canopies and move 'em around as you work.

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    Maybe wet out was the wrong word. Apply epoxy was what I meant. I might try a squeegee. I feel more like a roller kind of guy.

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    Default Re: Tips and tricks for laying down glass over ply.

    With either a roller or a squeegee it's possible to create a lot of tiny bubbles down inside the layup, just from the action of the tool. This also may sometimes be wrongly attributed to being outgassing. Moving the roller or squeegee too quickly across the surface texture of the cloth, or with too much downward pressure, will often tend to do this. You are essentially foaming the resin a bit and some of those bubbles trapped down in the weave aren't likely to float to the top and go away before the resin gets stiff. With the roller, too much speed or pressure can also tend to lift the cloth up from the surface as the roller goes past, so thorough roller or squeegee usage, but with moderate speed and moderate pressure are the keys with either application tool. It takes the cloth a little bit of time to absorb the epoxy. You can't change that with force (with the possible exceptions of vacuum bagging or resin infusion, but that's a different ball game).

    A short chunk of a split open Gougeon-style yellow foam roller hot glued into a slot cut into one end of a wooden dowel makes a pretty good brush-like tool for moving resin around in tight spaces, and it's worth making a few to have on hand, just in case you need to fiddle around with problem areas.

    It's also a good idea to make a rule that you never walk away from liquid resin when laying down cloth. Stay on-site and keep an eye on it until it has stiffened enough that it can't move. There are too many scenarios out there where builders applied the cloth, left before it hardened and came back later to see a bunch of spots where big bubbles or other problems formed due to uneven tension on the cloth, which could have been fixed or stuck back down in time if only they had been there.

  17. #17
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    Default Re: Tips and tricks for laying down glass over ply.

    I put the cloth onto a wetted out surface.
    A little paranoia on my part. I glassed a kayak once using the dry method. The wood soaked the epoxy away and caused a starved join in patches that lifted. Had to pull the whole thing off and sand and grind and a whole lot of work to get it back. Then did it the wet way.

    I used a paint brush to lay the cloth onto the surface and 100mm rollers to apply susequent layers of epoxy. I don't overwork the epoxy, so it doesn't foam up. The brush was because i had to push the glass into corners and tight bends.
    With the ply wet the subsequent layer of epoxy for the cloth is just enough to make it go transparent. I get a very tight layup that way.
    I am also more confident that I've given the whole thing an even spread of epoxy. No patches too lean and no patches floating. Everything tight down.

    But that's just me.
    Philip K. Dick 'Reality is that which, when you stop believing in it, doesn't go away'.

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    Oh, now my head hurts. I guess if I do it in sections I can try a few ways and see what I like best. By the time I'm done I should have it about right. I do like the suggestion of putting on a saturation coat first and letting that dry. That would seem to solve 90% of my problems.

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    Last edited by Phil Y; 03-13-2019 at 02:01 AM.

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    Default Re: Tips and tricks for laying down glass over ply.

    If you're an OffCenterHarbor subscriber, there's a new vid there by Russell Brown on laying and epoxying fibreglass on large areas, fairly straightforward but always good to see an expert at work.......

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    In reply to Paul's query above, I'll probably put up a thread when this is all over. One of 3 50' Bluebird of Thorne I know of in the world. The original was riveted iron plate. There's another locally of steel with aluminium deck and cabins. Mine is timber. Built in 1974 in Tasmania. Designed by Arthur Robb. Twin keels and rudders and the designed rig had wishbone booms Mine has normal booms. I'll have to hunt up some photos. Im on my phone atm and don't have a lot on there.

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  21. #21
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    Default Re: Tips and tricks for laying down glass over ply.

    Couple of pics

    image.jpg

    image.jpg

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    Default Re: Tips and tricks for laying down glass over ply.

    Looks very capable, thanks.

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    Quote Originally Posted by lupussonic View Post
    Looks very capable, thanks.
    We bought her in Brisbane, sailed down the East Coast of Oz and across Bass Straight down to Tasmania. Kept her there for a few years, then up to Adelaide. Dealt with some bad weather on the way. She's well built, robust and comfortable. And will soon be dry. She is strip planked and glassed externally.

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    Default Re: Tips and tricks for laying down glass over ply.

    thanks for posting a bit about her
    way cool boat, good luck with the glassing
    Simpler is better, except when complicated looks really cool.

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    Default Re: Tips and tricks for laying down glass over ply.

    Use 207 or 209, not 205 or 206.

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    Default Re: Tips and tricks for laying down glass over ply.

    I have only done mine dry. It helps to flatten the cloth out with a dry 3 or 4 inch paint brush to smooth it out, then push pin in place to hold it there.
    Spreading with a plastic body filler squeegee thing. Pour out the epoxy from the cup so it doesn't overheat and kick off in the cup. You don't want any puddles - spread it out so the fabric is saturated but you can still so the weave. Building coats as the previous one sets up a bit will save you from dealing any blush problems. You need to set aside enough time for this.

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    Default Re: Tips and tricks for laying down glass over ply.

    Quote Originally Posted by Phil Y View Post
    I feel more like a roller kind of guy.
    beware bubbles
    Simpler is better, except when complicated looks really cool.

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    Default Re: Tips and tricks for laying down glass over ply.

    apply in the afternoon as temperature start to go down

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    Thanks. I found another little patch of rot yesterday, in an area around the main shrouds. I had foolishly hoped this area was good as we'd had some professional repairs done a few years ago in that area and it looked good from above and below. I've cut that out now, will glue in new today then do a bit of filling and fairing everywhere. Run a router around the outside edge for a nice curve. Then the first saturation coat of epoxy, no glass. Hopefully get that on today, otherwise tomorrow. Have to start late and finish early today though on account of other obligations. Life is like that.

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    That's 2 votes for pins to hold the cloth in place. I reckon I'll give that a shot.

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    It appears, you're going to glass around deck Hardware?
    Denise, Bristol PA, Oday30, Anchor Yacht Club, On tidal Delaware River. my current project; http://forum.woodenboat.com/showthre...0-Ducker-Resto

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    Quote Originally Posted by DeniseO30 View Post
    It appears, you're going to glass around deck Hardware?
    I don't know what gives you that idea. The mast is staying in. Chain plates pass through the deck and are bolted to ribs inside the hull. Cabins are staying where they are. Cleats, fairleads, toe rails, stanchions, jib tracks, skylight, aft hatch, cockpit sides, winches, aft Sampson post, davits, have all come off. When I do the foredeck there's a bunch of stuff up there that will come off.

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    Last edited by Phil Y; 03-13-2019 at 10:52 PM.

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    Well I didn't get as far as I'd hoped today, but that patch by the shrouds is all fixed now. Just needs a trim along the sheer plank.

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    Default Re: Tips and tricks for laying down glass over ply.

    Another trick if you haven't tried it for handling chunks of cloth is to roll them onto some PVC tubing. Cut them to size, either roll them dry or wet them out on a sheet of poly and then roll 'em onto the tubing so you can start at one edge, lay it down and squeegee the bubbles out as you unroll out to the other side. That was a new trick to me and it worked a treat.

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    Thanks Hugh. Rolling them up wet is probably a step too far, but using a bit of pvc to keep things tidy sounds good

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