Auburntsts

Well Known Member
So I managed to ding my cowl. It's a dent insofar it does not penetrate through to the other side (I'm holding the nutplate just for scale). So what's the best way to repair it?

cowl.jpg
 
I'd sand it, clean it, and mix some epoxy with cotton flocking. The mixture is called flox. Wipe it in, just a hair low. When it's cured or mostly cured, mix some microballoons with epoxy and wipe on the top.

When that's cured, you can sand the microballoons smooth and fair.

Dave
 
I agree with the above post unless it is a structural area. In that case you would need to add some glass behind it. based upon the picture, I am guessing this is not the case.

Larry
 
I'd sand it, clean it, and mix some epoxy with cotton flocking. The mixture is called flox. Wipe it in, just a hair low. When it's cured or mostly cured, mix some microballoons with epoxy and wipe on the top.

When that's cured, you can sand the microballoons smooth and fair.

Dave

I second this one. You might want to remove the part that is bent in and filling the honeycomb behind it with flox, and try to get a little into the honeycomb cells that have good surfaces in inside and outside (undercut) to bond the repair beyond where it is damaged. You could use micro for the final fix or a lighter and easier to sand filler (like a stronger version of bondo).
 
I second this one. You might want to remove the part that is bent in and filling the honeycomb behind it with flox, and try to get a little into the honeycomb cells that have good surfaces in inside and outside (undercut) to bond the repair beyond where it is damaged. You could use micro for the final fix or a lighter and easier to sand filler (like a stronger version of bondo).

Thanks for the replies. This the crux of my question-- whether to remove the the bent in area and risk making it worse or just fill and press. I'm familiar with FLOX and micro-- this is more of a repair prep technique question than a materials question.
 
NO is the short answer, fatigue propagation for composites is way different than steels and aluminum. Google it and learn more.
 
I'm of the mind to follow Jesse's advice and just go ahead and remove/clean out the damaged area and fill it in with FLOX as the area is pretty small.

That's what I would do too. It's very similar to how the hard points are done on the cabin cover. I had to customize my lower cowl for the Rod Bower ram air mod. When I cut the honeycomb, i cleared out about a half inch and back filled with flox.
 
That is a puncture through one face with core damage. Remove the damaged fiberglass, remove the damaged core and "core back" under the top face about 1/4", vacuum out debris then fill with structural epoxy (JB weld works well). Let cure then sand and smooth as necessary with epoxy and micro balloons or high quality body filler.
 
Plus one for Mike. I'd slice out the damged area of the shell with a dremel. Then, use a hook/angle thingy to dig out the core 1/4 inch or so. Pack with flox. Finish with micro.