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Getting 'glass to lay flat on a 90* corner.

PostPosted: Sun Apr 07, 2019 10:52 pm
by monsters inc
Okay, I am laying a little 'glass on the 14x4x1/2 inch top stop for my keel. I have layer one strip on each side, sanded , drilled , counter bored the holes for fasteners, other wise prepared for a final wrap of 4 ounce fabric. Cut the cloth notched for corners , dug our my vacuum bag stuff and layed out the west system. Just can't get the 1/2 side to lay flat, leaves bubbles no matter what I do. You would think after 8 gallons of epoxy work on the boat I would get it worked out, but 90 degree corners are still beating me up. On the plus side , I may be the worlds best sander.. Any one got any hot tips?
On another note, I have the boat rigged, and spoke to my sailmaker last week. The list is getting short....

Re: Getting 'glass to lay flat on a 90* corner.

PostPosted: Mon Apr 08, 2019 1:04 am
by Tim Ford
I have to admit to doing a ton of "saliva cure." I made up the term, maybe it exists. I dunno. But what I'd do is this (I didn't do this vacuum bagging though, just a straight open-air layup):

Any difficult bend or wrap, I layup in fast hardener and then babysit it with a heatgun (or a stolen hairdryer of my wife's). I've found that the human finger is an incredibly useful tool when it comes to achieving a bubble-free fiberglass layup. If I had a bubbly bit, I'd heat the epoxy up to the point were it was almost ready to kick and become solid, but while still sticky, I'd wet the tip of my finger with spit, and then stroke the goddam thing down into compliance to whatever the particular curve or corner required.

Yep. Not proud, have no idea if it reduces the overall strength of the chemical bond, but it worked really well for getting things smooth and stuck right into place in crazy corners. And I had a lot of crazy corners with the way I ran my radius cockpit benches into the bulkhead and other sundry spots.

KiwiSternStarb.jpg


So, maybe not the most professional practice, but worked a charm for my grotty little boat. :lol:

Re: Getting 'glass to lay flat on a 90* corner.

PostPosted: Mon Apr 08, 2019 2:18 am
by micah202
In the world of production and repairs, everything is radiused.
If it's a sharp edge, there's fillers involved.

Re: Getting 'glass to lay flat on a 90* corner.

PostPosted: Mon Apr 08, 2019 2:32 am
by monsters inc
The sit and watch method was put into play today. Kind of like cement finishing, you have to catch it just as it hardens up. My wife keeps asking why I bolt out of the house to the shop every 20 minutes. Boat building should be recognized as a handicap! Glad it's nearly over. more soon!

Re: Getting 'glass to lay flat on a 90* corner.

PostPosted: Mon Apr 08, 2019 2:10 pm
by Warren Nethercote
Bias (45-45) cloth will work better than 0-90 cloth around corners because the radius that individual fiber sees is bigger, but as said before, if it is a square corner, round it off if outside or fillet if inside. Use filler on rounded outside corners after glassing or run fabric past an outside corner and clean off when cured, then glass the other side of the corner, but this approach has no fabric crossing the corner..

Re: Getting 'glass to lay flat on a 90* corner.

PostPosted: Tue Apr 09, 2019 2:21 pm
by lohwaikin
If the area is small, you can hold down the wetted glass with wide 3M painter-tapes (the blue type), lots of it.
Peels off easily after the epoxy cures.
That's how I perform field repair to my boat in the open yard of the sailing club.

Cheers,