You install it in a recession in the lower wing skin, fill inthe recession in the skin with a mixture of resin and cotton (called 'flox') and then put a little fiberglass ring on top of that to lock the whole thing down.

If you aim a heat-gun at the fiberglass ring while the resin is still wet, it will set up the resin faster!

Unless you aim the heat gun at it TOO close, and then you ruin it! The whole ring inflates like a balloon as the air inside it expands and it loses it's strength and gets in the way of the rest of the parts. Then the experts at Composite Assist come over and rip it off and let you try it again, doing better the second time!

OK, the messed-up rings is now removed, leaving the flox around the sump very clear to the eye.

Now we simply fill in the holes around the flox with resin, put on the fiberlgass ring, wet it out with resin, and be more patient to let it dry and we have a good part!