Screws into coosa. 5200? Marine Tex? Nothing?

[LakeFever]

I did a bit of testing with screws into coosa and found so long as you pre drill a pilot they seem to go in and hold quite well. That’s fine and dandy for a bench test but considering the pounding the water does to shake everything up and that I have read screws into coosa isn’t so good I figured I’d ask if any of you have tips or suggestions on how to make this work best as possible. Thanks gents

[Turtleherder]

I always thought you could screw into Coosa, especially with some glass backing. Their website lists screw retention numbers. https://coosacomposites.com/wp-conte...al-1.26.24.pdf

[LakeFever]

I’ve done some bench testing and yes coosa seems to hold a screw just fine. It definitely prefers a pilot hole though. I usually use some epoxy when screwing into glass or wood to seal and maintain the hole integrity over time. I’ve had many snaps and roof bracket screws on other boats come loose and need attention over the years which were factory built with no epoxy etc so I’m looking long haul here with the coosa. I’ve also seen some comments here and there about screwing into coosa is not as durable long term as wood which is why I posted. Guess I’m going to have to do some more tests and report back lol

[doug7488]

Maybe check the Geogon Brothers website
makers of West System Epoxy
It is pretty informative and diverse for information
Overdrilling the hole and filling with epoxy comes to mind
Good Luck!

[LakeFever]

Wanted to update this for anyone wondering the same. I used 1/2 20lb coosa bluewater for my floor capped it with one lay of 1708 and the underside with one lay of 1.5oz csm using promoted vinylester resin. I mounted an aluminum 28 gallon tank using stainless 5/16” threaded lags. I pilot drilled the coosa first and using a small brush I coated the holes with vinylester resin and dipped the lags into the resin as well before screwing down.

I ran the boat hard in some very extreme conditions a couple times the whole rig took a pounding. 54 hours of use and these screwed lags are as tight as the day I put them in. Hope this helps someone