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#14
02-07-2016, 09:07 AM
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Quote:
coosa/Penske board will not hold a screw - there's a specific technique required,when using fasteners with composites.i've described that technique,in detail quite a few times... composites,require thru bolting and sleeving... when blind,or self tapping fasteners are needed : determine thickness - use a small piece of hosing over the drill bit - this will prevent drilling thru.drill the hole - avoid drilling through ! chuck up a sharpened allen bit,slide it in and remove some of the coring - fill the area with a thickened epoxy - I like west system,mixed with 403 adhesive additive.after the area kicks,locate where the fastener needs to be - use it this way: you want to use a 1/4-20 machine screw ? drill the hole 3/16" - put a dab of 3m 5200 over the hole and run the screw in with a screw gun - this will actually tap the epoxy.need to remove the screw ? back it out with a screw gun... using self tapping fasteners with composites,without following that technique,the fastener will fail and become loose - the composite is brittle,vibration will cause it to fracture,making the screw hole loose - inexperienced individuals will use a larger screw - only to make the hole bigger ! you see this occurring on a bunch of foam cored boats - one manufacture used those stainless steel "toggle" style bolts to hold their T-tops onto the divinycell cored deck - I've repaired those failed fasteners,on more than 3 occasions.toggle style bolts will fail !
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