# stripped out screw repair



## Brett (Jul 16, 2008)

Pretty good Cap'n, better than my counter sunk well nut.


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## jms (Apr 21, 2011)

> It happens all the time... some critical anchor point has a screw fitting fail (particularly when that screw is into a sandwich of glass and structural foam).



composite cored fiberglass isn't suitable for screwing into - composites will not hold a screw - i've described the correct method a few times

it's also not a good idea to use those "toggle style bolts" - seen quite a few fail,and fail miseribly

when working with composites: if you have to fasten something to it - the correct method is to remove the coring in the area where the fastener is to be placed - remove that core,to the inner "skin",fill that area with a thickened epoxy - i like and use west system with the 403 adhesive additive - fill that hole,with this mix - this will hold a screw - example,if you're going to use a 1/4-20 fastener,drill the hole in the epoxy at 3/16,and put a drop of 3m 5200 on the bolt and run it in the hole - it will "thread" the epoxy...

that's the method to use,when thru bolting and sleeving isn't possible

common mistake people make is to use a larger screw,after the screw "strips" - this is a bad move,only makes a larger hole.

the screws strip due to composites being brittle - vibration causes fractures - this creates a loose screw.certain composites "hold" screws - a dense foam,with interlockin fibers,like coosa/penske board,these "hold" much better than divinycell - the cheap crap nida core will hold nothing...

"hold" meaning,it will stay,however,when pressure is applied,it will pull - this is the reason composites require different techniques...

epoxy: using a gel coat over epoxy - some epoxies "blush" others do not - "two ton" epoxy is something i've never heard of,not sure if it blushes or not - but,epoxy should be washed with soap and water,before sanding - this removes the blush,acetone will not remove it - using a polyester product over an epoxy product,it dosn't really bond very well.most gel coats are polyester based - you can run into problems,attempting to put a polyester gel coat over epoxy,if certain steps are not taken...


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## DuckNut (Apr 3, 2009)

I do it the same as kreepa with one exception. I take a bad allen wrench and cut the short end off a little and put the long end in my drill. Then I insert the short end into the hole and hollow out a cavity between the two fiberglass skins and then fill the cavity.


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