I'm considering replacing my fuel and water tank vents with flush style vents. Also might have to replace my original bilge and sink drain through hulls since I found a crack.

The drains might fit the existing holes but it looks like the vent pieces would require a larger opening. Anyone wanna take a stab at how I could tackle making the holes bigger?

Drum sander or hole saw. cut something with a hole saw to match existing hole and bondo in place. Use pilot from filler plug to hole saw proper size.

You can stack hole saws on one bit if you have the good ones. Use the one for the size that you need and put that on first. Then put the smaller one on the inside of that one.

Jon

both excellent ideas

I agree.... two hole saw setup.....

Drum sander bit on rotary tool will work fine also if you only have to increase the size of the opening by a small amount...

If you cutting through any wood, be sure to epoxy coat any exposed wood before closing up the job...

Find a rifle with the right caliber that will generate the correct size hole you need. Pull the trigger and POOF! Instant gratification, no regrets. Use the scope to accurately place the hole.
Otherwise, the stuff they said works good too...

Thanks spaz, I don't think Formula would approve that 'caliber' of modification.

Jim, Jon, et al...much abliged for the good ideas. I thought about the two hole saw deal and wasn't sure if it was just a crazy idea. Hadn't thought about bondoing a plug.

Thanks!

got damn skippy thats a pretty good idea. i usually span a piece of wood across the back and use that to hold the center bit. i like your idea better.

(dont know why i've never heard that one )

You have to be carefull but it does work very well.

BTW, Jon's idea works really well if you can find a "deep" smaller saw and a "shallow or normal" bigger saw. The deep one slides right in way before the outside one touches, centers up perfectly.