Nose Cowling Cracked
- Thread starter mitchell
- Start date
bumper
Well-Known Member
Picture would be good. You might consider using a product such as Loctite Depend 330 to bond a doubler or backing plate in place.
"Loctite AA 330 amber one-part methacrylate adhesive is compatible with ceramic, ferrite, metal, plastic and wood materials with a 72 hr cure time. Provides a 5 min fixture time. Delivers great performance with a shear strength of 2175 to 4350 psi and tensile strength of 1740 to 3190 psi."
It bonds very quickly, incredibly strong, but retains some elasticity so materials with dissimilar thermal coefficients of expansion can be bonded, such as aluminum to fiberglass etc. I made the inlet front lower baffling seals out of aluminum bonded directly to the fiberglass nose bowl - no problem.
The bad news: Depend 330 is pricey and has a shelf life of only one year, so don't buy the large economy size unless you need it! When they say one year shelf life, they mean it. I tried using some that was a few months out of date - no joy.
"Loctite AA 330 amber one-part methacrylate adhesive is compatible with ceramic, ferrite, metal, plastic and wood materials with a 72 hr cure time. Provides a 5 min fixture time. Delivers great performance with a shear strength of 2175 to 4350 psi and tensile strength of 1740 to 3190 psi."
It bonds very quickly, incredibly strong, but retains some elasticity so materials with dissimilar thermal coefficients of expansion can be bonded, such as aluminum to fiberglass etc. I made the inlet front lower baffling seals out of aluminum bonded directly to the fiberglass nose bowl - no problem.
The bad news: Depend 330 is pricey and has a shelf life of only one year, so don't buy the large economy size unless you need it! When they say one year shelf life, they mean it. I tried using some that was a few months out of date - no joy.
groshel
Active Member
I think what Snowbird (Thomas) has recommended (and many have done) is to shim the cowl skin under those last lower screws on the firewall, outward (away from the fuselage) which takes the load off the skin.
I used a 1/4” nylon spacer on the bottom and 1/8” worth of washers on the second one up…..glad I did...your tear is pretty dramatic.
Chris
I used a 1/4” nylon spacer on the bottom and 1/8” worth of washers on the second one up…..glad I did...your tear is pretty dramatic.
Chris
Flying Dave
Active Member
Wow. That’s impressive. Sorry for the headache on that.
Snowbirdxx
Well-Known Member
Thickness as the cowl, but must important it must fit the shape before you glue it on. Otherwise you get tension and new cracks. Overlap 1" each side minimum. So bend it and use a hammer to get the required spherical shape.
Remove the two bottom screws on the other side as well. Never install these on the repaired side agai, unless you ask for more cracks.
BTW the cowl will stay on with the bottom screws missing.
Remove the two bottom screws on the other side as well. Never install these on the repaired side agai, unless you ask for more cracks.
BTW the cowl will stay on with the bottom screws missing.
bumper
Well-Known Member
Probably an ounce or two would be adequate - but I see only two sizes, 25ml and 250ml. At Tomas notes, the "patch" or reinforcement plate needs to be well fitted to the curvature of the cowl, so the gap for glue will not be large. Note that with Depend 330, that adhesive retains elastomeric qualities, so it can flex and stay strong, including gluing materials with different thermal coefficients of expansion. What this means is you can use a stronger material for the backing, such as stainless steel sheet etc. if you wish.
It's also a good Idea to etch the aluminum, prior to bonding, with alumiprep 33 (or any of the phosphoric acid metal etch solutions - sold at Home Depot etc). Many of the rust conversion products use phosphoric acid and will work too. Rinse well and dry before bonding, of course.