Dope cracking questions

[sbmackie]

Below are pics of an airplane I'm considering. Are the cracks around the wing strut repairlable, and/or do they indicate a possible application issue when last covered/painted? Are hariline cracks in leading edge "rejuvinatiable" if so desired?

Thanks

Wing dope cracking.jpg (139.97 KiB) Viewed 4330 times

Leading edge cracking.jpg (118.42 KiB) Viewed 4330 times

[8233]

That almost looks like it may have not been painted with dope but with some kind of latex or enamel. Even if it is dope, it looks to me to be beyond rejuvenation. I've heard some folks have had success removing the paint/dope back down to the bare fabric and repainting from there assuming the fabric is in good shape, otherwise you would need to recover. I'm sure Randy or Cooper and others will have some good input. Cracking is sometimes fixed via rejuvenation but this is way beyond that point.

[4004]

sbmackie:

You need to go thru the logs and give more information - when last covered, process used, repainted, if so type of paint, etc. The photo looks like possibly the area has been struck and causing the localized debonding. Any info re hangar/tie down history? History of ownership or just being "flipped"? Presently airworthy - last annual?

I'll reserve comments after additional info and the gurus wade in. I'm "older than dirt" but experienced with Grade A cotton, linen, Polyfiber (Stits), Ceconite but none of the newer processes like Stewart, etc. FWIW 2c

PS: "6233 Dave" has been "listening well" - he touched a lot of the relevant bases!

[8233]

sbmackie:

You need to go thru the logs and give more information - when last covered, process used, repainted, if so type of paint, etc. The photo looks like possibly the area has been struck and causing the localized debonding. Any info re hangar/tie down history? History of ownership or just being "flipped"? Presently airworthy - last annual?

I'll reserve comments after additional info and the gurus wade in. I'm "older than dirt" but experienced with Grade A cotton, linen, Polyfiber (Stits), Ceconite but none of the newer processes like Stewart, etc. FWIW 2c

PS: "6233 Dave" has been "listening well" - he touched a lot of the relevant bases!

Another great point. It also very much will depend on what kind of fabric and/or system was used. We have a Bellanca Super Viking that has Ceconite for example and uses an older system of Nitrate and Butyrate Dopes. You can't mix systems and will have to "dance with the one that bring ya". In our case, we had some cracking issues and discovered someone and sprayed enamel on some of the tail surfaces as a fix. It had to be removed and re-sprayed. I just talked to someone with a Pacer this past weekend that never could get a part of his airplane to not crack, even after going down to bare fabric. Not sure of the cause. Sometimes, cracking can be a tough one to solve. I've heard some systems seem to fair better than others.

Sticking with the same system is important though. Steve Wittman was a tragic loss believed to be caused by fabric delamination associated with mixing different fabric systems and caused adhesion failure.

[2066]

For a fabric/finish system that is in very, very good condition (except for a few minor cracks), spraying rejuvenator and watching the neat results can be a very satisfying repair exercise. I'm talking Ceconite and butyrate as a good example. ...real world is that there's seldom that "ideal" situation where everything is in great shape "except for a few minor cracks". Once there are established multiple cracks/pealing, you can almost be certain that the fabric strength may be compromised. So, as indicated above, just how long it's been "like this"...and, what kind of weather (sun!!) has it been exposed to and what kind of "system" (or "mixtures" of?) it is has much bearing on whether or not it's "repairable" or projected to be airworthy for any significant amount of time. IMO. Mac

[8233]

sbmackie:

PS: "6233 Dave" has been "listening well" - he touched a lot of the relevant bases!

PS: I wish I had more hands on experience (but I do have some). A lot of what I know came from another Ed (my father).

[6643]

Looks like silver underneath. Is that layer intact? If so, you may be able to salvage things, otherwise, unless it's a very localized problem, I'd start budgeting for a recover...

[phil123]

I have heard of an individual that used gorilla tape to remove paint, use at your own discretion and no guarantees but could be a real time saver. As others have said depends on the base fabric condition for any kind of repair.

[8233]

Looks like silver underneath. Is that layer intact? If so, you may be able to salvage things, otherwise, unless it's a very localized problem, I'd start budgeting for a recover...

One of the Super Viking guys once removed his dope layers with a putty knife. He had a bad cracking issue with the original factory dope that had dried out and gotten brittle with age and it just came off in sheets.

[sbmackie]

Ceconite process, 1993, logged. Hangared off and on since then, mostly on. No damage history reflected.

Thanks