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From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: Drilling Holes in Fiberglass
Message-ID: <>
Date: Wed, 02 Oct 2002 17:35:06 -0400

On 02 Oct 2002 19:00:55 GMT, (NGAAllegre) wrote:

>Hi all,
>I need to drill four 1/4" holes in the fiberglass body of my RV to install a
>license plate.
>Is there anything special about drilling through fiberglass?
>Do I use a drill motor and an ordinary bit for metal?  Or do a I use a wood
>bit?  Or some special bit?  Or what?

There is a specially ground solid tungsten carbide bit for fiberglass but
since you're only doing a few, a regular NEW TiN coated bit will work.
Fiberglass very quickly dulls non-carbide bits and dull bits splinter the
fiberglass instead of cleanly cutting the fibers so be sure to use a new bit.
The TiN (gold colored) bits resist the abrasive glass particles a bit better
than standard bits.

I recommend taping over the spot with duct tape or masking tape before
drilling.  This helps control the splintering.  Use the highest speed you have
available and very light pressure and have a positive grip on the drill during
breakthrough.  If you don't, it's likely to grab and cause serious

Personally, I'd be leery of drilling my rig's skin.  Have you considered
gluing the tag on, perhaps with a good slathering of RTV?  RTV is removable
when necessary but would hold the tag securely.  If you do drill, I highly
suggest slathering each hole with RTV to make it water tight.


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