drilling holes

What's the best technique?

The manual for my Shearwater calls for drilling a 3/32 hole and then bedding the screw in silicone before installing. This is for the deck rigging. For the back band they suggest that an awl may be enough of a starter hole.

Nate says for the rigging he drills thru the deck and sheer clamp and fills with epoxy and redrills.

What about oversizing the holes, and filling with thickened epoxy and putting the screws in while the epoxy is still soft?


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RE: drilling holes


If you screw into soft epoxy you will never be able to get the screws back out again.

CLC has been doing this for a long time.  If there was a better way, they would be doing it.  I would stick with the silicone.


RE: drilling holes

I was just following the advice in the shop tips regarding drill, fill, drill:


Is this the better way to go?


RE: drilling holes

Hi Nate,

Yes that is the way to go.  What I was saying to Dan was that if you set the screw into wet exoxy, the screw will be glued in for ever.

The drill, fill, drill works great.  I would still use a little silicone because when you thread a screw into cured epoxy, the epoxy can split or crack.

If you drill, fill, drill and put the screw in the next day you probably will not have a problem. but epoxy that has cured over a long time will split when screwed.


RE: drilling holes

I always thought that tip was for drilling thru panels, not blind holes like the ones that go into sheer clamps. I did not do that originally. BUT, since I had moisture issues I drilled out the holes for the rigging and filled them with epoxy. 

My mistake was that I didn't redrill them wide enough or deep enough. This morning after my deck seam repair had set up I drilled them with a 9/64  bit deep enough so that the screws would not bottom, but not all the way thru the sheer clamp. I then screwed the loops back done, bedding the screws in silicone (#8 by 3/4 screws). Since the holes now had a coating of epoxy I had no issues tightening the screws and no scary cracking noises! And yes, I lined up the slots ;-)


RE: drilling holes

Dan, your idea of drilling oversize holes and inserting the screws into thickened epoxy while it is still soft has been recommended by the Gougeon Brothers, who know a lot about such things:


Cheers, Grant

RE: drilling holes

Note re removing the screws in those circumstances that the Gougeons suggest that:

"If you know that you will want to remove the fastener, you can coat the threads with wax or mold release (contaminating the surface enough to prevent a good bond).

Remove a permanently bonded fastener by applying heat to the head of the fastener with a soldering iron or propane torch. Use a heat shield to protect the surrounding area. Heat will travel down the fastener, softening the epoxy in contact with it. At about 120°F the epoxy should soften enough to allow the fastener to be backed out. Allow more time for heat to travel down longer or larger diameter fasteners."

RE: drilling holes


Thanks for the link !   Thats what I like about this forum, I learn something new every day.

I stand corrected.


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