C-Forum

Royalex? Got a scary void that has formed under my right knee pad and I would like to repair it from the inside before water gets in there.

Yes! I used one of those syringes they give you to dose kids with medicine to inject Gorilla Glue into a boat we repaired. I drilled a pattern of holes about 2" apart covering the area and injected glue in each. It's held up well.

If you go with a urethane adhesive, remember you need moisture to cure and it will expand - use a sandbag or similar to help it stay in shape, but not too much weight... G-flex should be good, too.

Sure. You don't need a real big syringe because you don't need to inject a lot at a time. Take the plunger out, fill the barrel of the syringe leaving enough room to get the plunger started back in, turn the syringe tip up, let the epoxy settle, and expel the air.

I like the curved tip "dental syringes" available from Jamestown Distributors, West Systems, and a bunch of other suppliers: http://www.jamestowndistributors.com/us ... y+Syringes" onclick="window.open(this.href);return false;

Sweet Composites also sells syringes: http://sweetcomposites.com/Tools.html" onclick="window.open(this.href);return false;

You guys are awesome. Only on Cboats would people know the answer. Scott, re. the urethane adhesive, I have some 3M structural adhesive and I was not aware that it needed moisture to cure. Are you thinking of a different kind? Ordering my syringe now....Thanks!

Theoretically, with the correct catalyst it shouldn't require water, the water undergoes a side reaction with the Isocyanate monomer to form a carbamate-acid which breaks down to release Carbon Dioxide.

This is exploited by adding slightly more of the reactive monomer to control the amount of foaming, so realistically you're always going to have a degree of foaming*, but dependng on the adhesive composition it could be minimised.

Gflex works well in a syringe when you need to repair crushed/rotten foam core in royalex boats.

shoe goo all the way all the time.

C1-Etienne wrote:shoe goo all the way all the time.

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So have you injected Shoe Goo into delaminated voids in Royalex? If so, how did it hold up?

I don't know about today's Shoe Goo, but I tried some for shoe repairs once, maybe a decade ago, and it got, stiff, hard, and failed within a couple of years. Also, I think it would be a struggle to force it through a dental syringe.

A urethane with just a mild tendency to bubble up, maybe Gorilla Glue (which I otherwise do not admire) would tend to fill voids in the foam layer. The urethane should be chosen because it is known to stay flexible over time, like Aquaseal.

Or, maybe one could mix Seam Grip, a thinner urethane, with microballoons and force it through a syringe. But a mildly foaming urethane adhesive would be cheaper.