Drilling Holes In Fiberglass Tips

[mossemi 279]

I stumbled across this tutorial while reading about a Balmar battery monitor and thought it contained some excellent information.  Although the article is really about re-bedding deck hardware on boats with through bolts and butyl tape, I thought the discussion about drilling holes and finishing with a countersink bit would be of interest to other OTTO's.  And the Balmar battery monitor also looks like an interesting product.

 

https://marinehowto.com/bed-it-tape/

 

Mike

[DavidS 239]

I think I am like Mike in doing research on the web before tackling a project. Sharing information here, with a good title for the post, is a great idea.

 

Before using Mike and Carol's instructions on moving the TV, I did a lot of research on drilling thru fiberglass. This web site helped me on drilling thru fiberglass, and this web site on using a hole saw.

 

I also followed John Davies' advice to put down masking tape to prevent splintering of the fiberglass gel-coat.

[Overland 792]

I haven't had good luck countersinking with a metal bit - the gelcoat always wants to chip.  But a tapered grinding bit on a Dremel seems to do the job well.

[mossemi 279]

I have used both with equal results.  The countersink bit is faster.  I haven’t tried reverse drilling with the countersink, but that may be an option.  I would be willing to bet a cup of joe that my countersink is more dull than yours?.

 

Mike