proper anti-chafing tape for PA-39 cowlings

[Gomer Pound]

My 1967 B model has a woven cloth type anti-chafe tape installed for the cowlings. The tape is recent. The problem I have is the tape is unraveling where the holes have been cutout for the Camlocks. The "ears" on the stud keep getting caught in the fabric tape and causing more unraveling, as well as preventing the Camlock from locking. I would like to know the best anti-chafe material and the proper thickness. Some of my Camlocks are extremely difficulty to twist and when set, the heads are more sunken than the Camlocks that are easier to set. I plan to install stainless steel Phillips large head Camlocks, so I want to be sure the anti-chafe tape is correct for depth and to try to stop the unraveling at the hole edges.
Clear Skies,
Gomer

[Phillip Larson]

I realize this is a really old post....I'm new here, so just going through the forums.

Here's the stuff you're looking for though:

https://www.aircraftspruce.com/pages/ap ... fetape.php

Aircraft spruce sells a variety of it. I've seen high quality duct tape (gorilla) used (questionable legality), and speed tape (legal, but not the proper use).

I've used left over B 1/2 sealant, trick is to mask off the area well, apply sealant (thin) then apply a plastic barrier and close the cowling. Clean anything that squeezes out. Let it set up overnight. The next day peel off the plastic and you have a custom fit cowling seal. It'll last about as long as the tape, and can be painted.

I heard gorilla was getting a PMA....so I'd stick with the gorilla tape myself. It works better and looks better than any other solution I've seen to date.

[Gomer Pound]

Hi Phillip, Thanks for that idea. I had not heard of B 1/2 sealant, so I found it is a fuel tank sealant. Interesting. So you don't need a very thick coating from what you say. Do you close the cowling tightly, with the sealant and saran wrap, then open it back up temporarily so you can remove the excess that squeezes out, then close the cowling back? Do you tighten the camlocks when you do this? I am considering buying silicone tape to replace the woven tape on my plane.The silicone is a lot more expensive.
That will be ineresting if Gorilla Tape starts selling anti-chafing self stick tape. Funny, I wouldn't think the "cloth" part of the tape would hold up nearly as well as woven anti-chafe tape.
Clear Skies,
Gomer

[Phillip Larson]

I did the sealant once for a custom engine overhaul for a customer. He was the sort that wanted perfection at all costs. I had a lot of hours into it, and it turned out great. It was actually on a cessna 414, so there were several overlapping panels to do. Once it is dry, you can easily cut any excess that squeezes out. I haven't tried it on a comanche before, but yes...you do tighten the camlocks.

I've told myself that I'd do it on my own plane the next time I do an overhaul. But I'm not sure when that'll be. I keep losing out on comanche deals, and I don't own a plane currently.

[Gomer Pound]

Hi Philip, Your fuel tank sealant is really new to me. Numerous CamLoc's on my Twin Comanche's cowlings are VERY difficult to lock. They appear to be the original steel slot head CamLoc's. Both the upper and lower cowlings were rebuilt by the prior owner, George Ahlsten, shortly before I bought the plane. I am pretty certain he used the original CamLock Retainer section, so I wonder if for some reason the aluminum used was slightly different in thickness. At any rate, I ordered a set of 3 different sized stainless Phillips head CamLoc studs from SkyBolt so I could see if a longer stud might take care of the problem. I just haven't had time to "map" out the the correct lengths for the replacement studs with a diagram so I can order them as a set. Once I have mapped the CamLoc studs, I will install them. Then, I may very well try your method for the new anti-chafing material. I gather the fuel sealant is 3M "Type B'" 1/2 hour curing? Does the sealant stick pretty well to the aluminum without causing corrosion?
Clear Skies,
Gomer

[Clarence Beintema]

Fuel tank sealant stick to everything and is non corrosive. As to Camlocs, early Comanches used Southco studs later Comanches used Camlocs.

Camlocs have a larger diameter head and a cross pin, Southcos have a smaller head with the locking devise formed as part of the stud.

Clarence

[Phillip Larson]

Clarence beat me to it, and answered your questions well.

Camlocks are not difficult to redo, and kits can be obtained from Genuine Aircraft Hardware. Not cheap though. Properly installed, it's a nice upgrade that will last a long time if the right lengths are installed. There is a camlock tool available which helps get the retainers on the backside of the camlock sockets. I know there is one in my tool box somewhere...but I don't remember where I sourced it from. I believe they are pretty readily available and not too expensive. I used to sell aircraft hardware, so I had a large assortment kit from GAH which I just replenish individual sizes as I use them.

[Gomer Pound]

Phillip, How do you mask off the holes for the openings in the underneath (engine side) panel where the Camlocks pass through do the B 1/2 does not seep through? They are about 3/4" in diameter, I believe.
Gomer