Quote:
Originally Posted by Bushwacker
There is one trick to working with screws in fiberglass that many folks don't know about: drill and tap the oversize/epoxy filled holes for MACHINE SCREWS! 1/4-20 ss screws have worked very well on my galley and pedestal seats. You can even use blue locktite to keep 'em tight. DON'T use wood/sheet metal or self tapping screws . . . vibration and relative motion between parts cause the sharp threads on cut into the glass!
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this is correct - to a point,,,
first - if you're drilling thru something - you need the ability to hold that product in the hole - otherwise,gravity does it's thing...
wood:
when you you have access to the underside:
small hole saw - example,you want to use 1/4-20's - use a 1" hole saw.go through it,use a piece of painters tape - the good blue tape,tape underneath - fill the hole with a thickened expoxy - I like and use west system,with 403 adhesive additive...
once the epoxy kicks - locate where the fastener goes,drill a 3/16" hole - drop a shot of 3m 5200 over the hole and run that 1/4-20 in with a screw gun....it will thread the epoxy as it goes in - no need to "tap" anything !.the 3m 5200 will make it waterproof and keep the fastener tight...need to remove it ? use a screw gun - it'll back out
working with no access from underneath:
determine the thickness - slip a small section of tubing over a drill - setting the depth...
don't drill through the panel...drill the hole and fill the area with the thickened epoxy...
if the wood core is rotted - you're wasting your time !NONE of this will work !
composites - use a sharpened allen wrench - grind the short end into somewhat of a blade - slide this in the hole and remove some of the composite coring...fill with the thickened epoxy...use the same procedure I described above,concerning drilling and running holes...
ocean yacht used this technique for years
this technique is required for using fasteners in composites,when thru bolting/sleeving isn't possible...