pre-glassing interior ply hulls

[David Ramsay]

My son and I are building Doug Hylan's 16' Garvey. After building our first two boats, Payton's Gypsy and Gardner's 14' semi-dory, I had wished that I had put glass cloth on the interiors to cut down on maintenance. I am now considering pre-glassing the hull interiors while still full sheets of 3/8" fir ply. I would be using MAS Epoxies and 6 oz cloth. My question is; will I be able to bend the panels around the frames once I have glassed one side? And if it will bend; will the bending cause defects in the glassed surfaces? Thanks in advance for any experience or knowledge on this technique. David and Scott Ramsay

[Ian McColgin]

Preglassing if there is not too much curve will work quite nicely. When I do it, I do it before final cut so that the glass trims nicely.

On most insides and many topsides, you may find that CPES and then some epoxy with paint over it is entirely enough, and no weight of the glass.

G'luck.

[NormMessinger]

I'm too chincy to have done that but I'll offer an opinion anyway. Preglassing will stiffen the panel some but more in tension than in compression. My experience with MAS epoxy (compared with WEST and System Three) is that it stays soft longer. Seems to take a couple of days to harden completely.

So if you want to waste glass and goop AND dull your cutting tools you should be okay.

Next, please.

[David Ramsay]

Thanks Ian and Norm, your info is a big help. I've noticed that about MAS, but OK with it. I had very good results with the MAS on the Garvey. So.... I'll waste goop and cloth, sharpen my tools and get to it. I think I'll be a bit happier next spring when I have at least one boat glassed in the inside.

[Ian McColgin]

By the way, Gluvit makes a nice gloop to set the glass in as it stays a bit flexable forever. It also takes a while to cure. I never got paint to stick on the stuff unless it had cured in warm dry weather for about a week.

[NormMessinger]

My goodness, two advisors who agree. Is that a forum first? I mentioned MAS's cure time as a positive characteristic for bending after glassing but I doubt if WEST (a bit harder than System Three) would check either.

I was also fixated on glassing the entire sheet prior to cutting but if you cut your panels out first then glass, as Ian suggests, you eliminate the waste and tool dulling complaint.

What ever works, eh?

[wingnut]

well,
it sounds like you've already decided but i'll chime in anyway. i just finished stitching my headwater 16 (power dory) together and the panels were pre-glassed and i didn't have any problems with bending the 3/8" plywood. though i wasn't bending them to a form. it doesn't sound like it should be a problem. Hope this helps.
wingnut

[JimD]

David and Scott, like the others say, preglassing works wonderfully, epoxy doesn't run because you glass the ply laying flat, the ply bends, the edges don't chip and and are strong. Go for it
jimd

[David Ramsay]

Jim, thanks for the confirmation. I'll be glassing tommorrow morning. Thanks again, too, Ian and Norm. Yes, it's nice to have a concensus on the answers. Dave ( and Scott)

[gary porter]

dr3,, just one more nod and agreement with the above. Also if you haven't done it yet , there is no need to use too heavy of glass 4oz or 6oz is plenty and do the filling and a final sanding while its flat as well. I've had glassed panels laying around for months and they go on fine..I use System III but I doubt that matters much. If you can mark the approximate area that the final panel will be you can just glass that part.
Good luck.
Gary

[David Ramsay]

Thanks Gary. I'm glad to know they can sit awhile as we can't always get back to work on the project right away. Work and school seem to interfere with the important things in life! -Dave

[JimConlin]

I'd consider topping the glass with peel ply. It'll level the epoxy without repeated coats and leave a surface that bonds and paints well.
If you're weight-conscious, vacuum bagging whole panels is not difficult.

[David Ramsay]

Jim, Thanks for your comments. What is peel ply? Dave

[Steve Lansdowne]

Peel Ply is a lightweight woven nylon fabric that won't stick to cured epoxy. It is squeegeed over wet epoxy laminates. The excess epoxy soaks through the Peel Ply, and then after cure you remove the Peel Ply and you are left with a surface that is ready for painting or secondary bonding without needing sanding. Peel Ply can be cut into strips to cosmetically finish fillets, molded chines, and seams, says the System 3 catalog.

[NormMessinger]

Peel ply (um, I thought it was polyester) will do several things for you. It will suck up some epoxy so when you pull it off you will have a lighter layup--good for airplane construction. Any amine blush that occurs will be on the surface (Duh!) so it comes off with the peel. The surface is prepared for any additional layers of glass you might lay down so no sanding is necessary. And, as Steve said it flattens the weave so much less sanding is necessary to finish. I have never done so but the more chincy types have found that plane white polyester from you favorite fabric store works just fine and is much cheeper. I'd say that is the only way to go if you are going to cover an entire layup using Steves method. Now all you gotta do is determine for sure if it is nylon or polyester.

[Todd Bradshaw]

As I remember, Gougeon's Peel-Ply is polyester, though I'm not sure it matters and the same effect could probably be achieved with nylon. I think it's effectiveness has more to do with what may or may not be on the fabric's surface than what the actual fiber is. If you're going to use much of it, it's worth hitting the bargain table at the local fabric store and buying a few small chunks of similar fabric to do some testing. For what it really is, Peel-Ply seems to be very overpriced. I'm sure it's discovery as an aid for resin work wasn't what the fabric was originally made for and they would have trouble selling enough of it to warrant producing it solely for epoxy application. It may even be one of the forms of "Fleetboat" which is a ployester about 3.5 oz. in weight that has been used over the years for everything from the early Sunfish sails to hamburger stand uniforms and cheap boat covers.

You are looking for a lightweight fabric with no obvious coating and a fairly loose weave, yet it isn't totally limp. It's weave is looser than the ripstop nylon-type fabrics that one would build a down vest from and it feels more like the thin fabrics sold as fabric shower curtains. If you can find one that tests out OK, you may be able to get it for a buck or two per yard.

[JimConlin]

Peel ply is available from Aircraft Spruce (http://www.AircraftSpruce.com) and from Airtech Airtech (http://www.peelply.com)
Its about $2.25/yd and 60" wide.
The dress lining doesn't work nearly as well and is more expensive per square foot.

[David Ramsay]

Thanks for the info on peel ply. Dave

[NormMessinger]

Good on yer, Jim. Show's how I've kept up. Another lesson reinforced. My Aircraft Spruce catalogue is laying on the floor beside my chair in the living room. I was too lazy to go check. :( :mad:

[ 03-30-2003, 11:12 AM: Message edited by: NormMessinger ]