I read an RVAtor tip about drilling 3/16 holes in the hinges so that the bonded epoxy oozes out to fill and form a rivet type head. I did this with the top hinge and found the hole to be a bit too large; so on the side hinges I drilled #30 holes between the rivet holes and the epoxy formed a lovely head to encapsulate the hole. This should give the hinge added security.
BONDING
The same article suggests clecoing the bonded hinge and THEN rivet once the epoxy has cured, this allows the hinge to set in it's correct position before rivetting and should reduce pre-load on the eyes. To prevent the hinges sticking together I:
1. Fayed the hinge to within 1/8 of the hinge eyes (masking tape) 2. Masked the edge on the other cowl 3. Wiped the cowl edge after wetting it out 4. Removed any epoxy on the cowl between the eyes 5. Dipped the clecos in some old engine oil 6. Greased the hinge pin 7. Pulled and rotated the hinge pin a few times during curing.
RIVETING
This simply involved wiping cowl after removing the cleco, sand any rough surface, drill out the hole, machine countersink with #40 c/s in the hand debur tool and squeeze the rivet. I did them in pairs.
