I’m looking for a trick or a tip, if it exisits. I’m up to 180 glassed boards of all sizes and types. Almost all free lapped probably half epoxy and half PU. The problem I’m having is that I’ve just started to wetsand the boards to 600 for cosmetics. I let the paper get pretty worn and it’s probably closer to 800 or 1000 in grit.
Because the finish is less hazy and more shiney it is showing more of the imperfections in the lamination. The problem is that the smallest threads of the glass especially on the deck are standing out. Not sanded through just very very visible. They are really more catching the light at certain angles like facets. I know it’s not structural but to me it looks bad. If I just go to 220 which has a fuzz or haze you can’t see them. Its just at the higher grits that they are starting to show. It is also only on the Pu/Pe ones.
These aren’t long stray threads but more of the edge of the glass on the free lap. I pull out several of the of the long strands of glass on the edge just before lamination to prevent threads getting loose onto the deck and the weft? strands running 90 degrees to the stringer are the ones showing. Laps are prepped with an angle grinder and are as flat as I can get them without eating into the foam. Even if I glossed and polished the boards they would still show and even more so. Also the lap isn’t dry in spots either. Lastley this is almost only on the deck.
Am I missing a simple trick? A quick baste before the top lamination goes on? A little extra styrene? Does the lap edge need to be laser clean on a free lap to not have this show? I’m a bit perplexed.
Sorry for the lack of pictures but it would be very hard to take a picture.
Thanks for the quick reply! I’m thinking that your probably right about the glass. This really only shows on the deck and the deck is pretty much where the entire lap gets prepped with a 90 degree air die grinder and a 36 grit 2" head.
The bottom lap gets basted with sanding resin and prep sanded with a hard pad and 60 grit before the final sanding coat.
My guess is that I should be making sure the 36 grit head is clean for each board as it gets gummed up with lam resin after a board or so. I usually will do 2 or 3 boards before I throw it in acetone to clean off the gummed up head. I’m suspecting that the head is dirty with resin and isn’t cutting the lap as much as shredding the fibers.
The hard thing is you can’t tell until until you start to put a shine to the final coat.
Also the lap should be cured enough for sanding. I’m using uv poly and making sure it gets at least 10 minutes a side in full sun.
Yeah I hear you. This is what I get trying to do production glassing. I’ve gotten too many board orders and need to out source my glassing. Trying to do too many boards at once is straining my backyard skills.
I understand what your saying about the gloss coat but in this case it would only make the problem look worse. At certain angles in the sun the fibers really stand out.
I think Kensurf is right about the sander paper. On the epoxy ones I’ll use 100 grit and a hard pad on the laps and even though the epoxy isn’t quite like poly the laps just disappear. As you know the epoxy usually doesn’t gum the paper and you can get those suckers flat as flat before the next lamination.
If I can’t get this under control I might have to do the decks to 220 and the rails and bottoms with the 600 wet.
Most people use 4 to 6 oz. fiberglass and this in my opinion is the least flattering weight of cloth cosmetically as far as resin tints, cloth print through, weave etc…
Multiple layers of finer 3.16oz. crowfoot E-glass show up less than 6oz… The weave is so tight it disappears… Less pinholes too!!.. If your standard deck lam. is 6oz. + 4oz. deck patch, 3 @ 3.16oz. is lighter (especially when vacuum bagged) and way smoother… I cut lap every time, just a habit…Sorry…
36 grit is a bit intense. I might have to try a finer grit and see how it goes. Laps are tight, just going over them real quick to prevent snags in the cloth during the next step and take care of any folds near the nose and tail. Takes less than a minute with the angle grinder.
Mahalo for the tip on the glass. I still have some tight weave stuff laying around from my kiteboard building days. It’s just that I’m using full rolls of cloth now. It starts to get expensive if I can’t buy a full roll. I’m using 4, 6 oz. warp and some S on special request. I’m almost embarrassed to say I’ve never done a cut lap or a pinline. I just don’t have the time. Been doing all glass-ons on my personnal ones and experimenting with painting but I’d never do one for a customer. I’m a horrible artist and my fin jobs are only just starting to get better.
I’m honestly working towards getting busy enough to have someone else glass. I don’t mind glassing, it’s where the money can be but I’d rather shape.
I know there are way better ways to make a buck but shaping is still very enjoyable. I’ve had so many odd jobs for extra cash over the years I’d rather do something that scratches my very seldom used right side of my brain.
I’m shaping a triple stringer 11’ knee paddler gun right now and the guy wants a yellow tint with glass ons. I can’t wait to drop it off at the glasser and have him deal with it. It scares me just thinking about glassing the thing.
I’ll post pictures of the board when it’s done just so it doesn’t seem like I’m blowing smoke out of my okole. The board is a monster!
I know exactly what you are talking about. And Ken hit it pretty good, its the mashing down of the cloth when you sand. You need to make sure the cloth cuts, and not smashes. Make sure the board is a bit more cured, change paper, finish off grinding laps with 100 grit after you hit with 36-60. Gloss won't fix it...It's under the gloss already.
Huie, Yorky thanks! This is what I get for being an epoxy whore first and then trying to convert to a respectable lady using poly after, oh the shame!
Laps should be cured enough. Got to be the paper grit and gummies causing problems. Another board in the series same glass job, same blank, and same grit head is all good. Just one of the others had the glass ends showing.
When laminating, wet the whole lap quicker, while the mixed resin is as fresh as possible.
In my experience by the time you get to wetting the laps the resin has lost it's liquid freshness and commenced curing, then doesn't soak deep into the fabric as thoroughly, leaving that slight thread visibility you are talking about.
Sanding and grits may possibly have nothing to do with it.
You're over working your laps with the die grinder. Too coasre of grit and too much grinding. Once around the block with 3M Green 50 disk is all you should have to do. You will of course have to hit the nose and tail a little extra, but once around should take care of it. After you've lammed everything with a Thalco squeege, switch to a hard plastic squeege to get the nose, tail and rails tighter. A tight freelap results in less grinding of the freelap. When you hit the lap too hard and too often with coarse grit you are removing resin and thereby exsposing the glass weave. Some guys do what is called a "piss coat". Which is nothing more than a thinned second hotcoat that is sanded by hand. Not worth the extra work if you can lam a tight rail and not over grind the lap.
I appreciate all of your guys input. Just the way the ends of the lap are showing under the glass sounds like they are getting over-worked.
Once again thank you. I guess you can get your laps too flat or flattened the wrong way. I just love the way the die grinder rips through the laps though. Got to stop listening to all that rap music when I sand.
I’m rolling my laps with fresh resin and then doing a final tuck with the hard yellow squegee, epoxy style. Still cheating the clock with UV resin. Laps are fully saturated and tucked tight. Watching all that extra resin curtain onto the floor poly style is too disturbing for my epoxy trained brain.
Mahalo aplenty! I knew you guys would have an answer.
you could try a metal file, razor blade, curved rasp, or 60 grit on a little block. if the laps are clean, all those will work to get the ‘sharpness’ off your lap edge to keep the deck glass from snagging and making air bubbles. also, maybe leave it in the sun a few more minutes before attacking it? i like to use a little dremel sanding drum on the epoxy laps but those just gum up to fast on the poly…
