[mvidalr]

Hello all,

Maybe a dumb question, but I woulnd't leave it unanswered to my standards...

Should I deburr/file all edges and holes in fiberglass parts and fairings after I make cuts, trims, or holes in them? (Just like anybody would do so on aluminum)

Would non-deburred areas be an area of concern for cracking under stress? (Like wingtips).

Thanks guys you rock

 

[Ironflight]

You don't have to worry about deburring holes in composites to prevent crack propagation - the material itself takes care of that. I sand the edges of glass parts to prevent cuts and scratches during fabrication or maintenance.

 

[flion]

If you want a really good finish on drilled and countersunk holes in composite, use thin CyA (CyanoAcrylate, or superglue, available at a Hobby Shop). Put a drop on the hole and it will immediately wick into any frayed areas; wick the excess away with tissue (I used to keep a roll of toilet tissue on my R/C model building table for this task). Once the surface is no longer tacky to the touch (depending on how much you apply and how well you wick the excess away, this usually takes less than a minute), pass a drill through the hole by hand and also touch lightly with a deburring tool to remove any fibers that were raised by the glue application. The CyA is not a finished surface; you will want to either paint after permanent fasteners (rivets) or before removable ones (screws) so that oil and water don't penetrate the raw edges.

 

[mvidalr]

It is..

..interesting!!

Thank you both for your wise feedback, as always.
Will not deburr, only buff lightly.
And will also consider CyanoAcrylate after drilling holes.

Would priming the inside areas of the fiberglass do any better conserving them through time?

Thanks again

 

[flion]

I'd say not for stuff like wing tips. It's a good idea to seal raw edges, but interior surfaces should be fine. On the other hand, the cowl, which gets exposed to a lot of fluids and particles, is a good candidate for at least priming. I painted the inside of my RV-6A cowl with thinned epoxy; I'm considering painting the inside of the -10 cowl with an epoxy paint for a more finished appearance.