Imperfections

[VaporGlobalAviation]

Just purchased a 72 ECA. Posting photos of some imperfections to gather opinions on repair/rejuvenation or let it be.

 

[Big Ed]

I would gradually fix. Nothing there that really NEEDS repair, but it's always good to keep things up so they don't get worse. Plus you learn new skills.

My advice is don't half ass it. Find out the covering system and use the correct materials and methods for that system. First, pride of craftsmanship is a habit. Second, mixing systems may constrain your repair options down the road.

If it is original dope or recovered with Stitts, repair is extremely easy and materials are not expensive. Both coatings blend nicely. I can't speak to urethane, but it looks harder to do well.

Most important thing is get some silver on any bare fabric to block UV.

If it is dope, here is a hot tip: dope is just lacquer paint with plasticizers. Which means you can save bucks by using ordinary lacquer thinner for stripping and clean up.

 

[Bob Turner]

Looks pretty rough from here.

I would replace the U bolts on the gear legs before any further flight. If you are not going to recover and do not care what it looks like, maybe Stewarts patches? In spite of what they say, you can wet-sand the Ekofill so you have almost invisible patches.

There are some who say that you can consider the patches a minor alteration and just finish with custom-mixed rattle can. I can assure you that it is safe, but not sure about legality.

 

[VaporGlobalAviation]

It is original dope.

Looks pretty rough from here.

I would replace the U bolts on the gear legs before any further flight. If you are not going to recover and do not care what it looks like, maybe Stewarts patches? In spite of what they say, you can wet-sand the Ekofill so you have almost invisible patches.

There are some who say that you can consider the patches a minor alteration and just finish with custom-mixed rattle can. I can assure you that it is safe, but not sure about legality.

Bob,

Thank for your inputs. Why replace the U-bolts? Did you see something in the pictures or is that just a general recommendation for Citabria owners. The pre-buy was thorough, and U-bolts were not a concern.

Pete

 

[Bob Turner]

U bolts have been breaking with some regularity. I personally do not replace stuff “just because,” but consider these the exception.

 

[VaporGlobalAviation]

U bolts have been breaking with some regularity. I personally do not replace stuff “just because,” but consider these the exception.

Thank you.

 

[Big Ed]

Dope is crazy easy to repair because it never cures or hardens. It just dries out, but remains fully soluble in thinner. Each coat melts and blends with the coat below. That means you can rejuvenate old, brittle dope by spraying plasticizers mixed with thinner, then topping that with a new coat of dope.

If you have never done dope work, let me know and I'll give you a quick summary.

If you use other processes to repair, such as water based or enamel paint or Stitts, and you later decide to rejuvenate the entire coat, you will have made your job harder. Butyrate dope does not stick well to other products, so you would need to strip any non-dope patches before you rejuvenate.

 

[VaporGlobalAviation]

Dope is crazy easy to repair because it never cures or hardens. It just dries out, but remains fully soluble in thinner. Each coat melts and blends with the coat below. That means you can rejuvenate old, brittle dope by spraying plasticizers mixed with thinner, then topping that with a new coat of dope.

If you have never done dope work, let me know and I'll give you a quick summary.

If you use other processes to repair, such as water based or enamel paint or Stitts, and you later decide to rejuvenate the entire coat, you will have made your job harder. Butyrate dope does not stick well to other products, so you would need to strip any non-dope patches before you rejuvenate.

Thank you. I would appreciate the summary as I have found it hard to find the “dope 101” class. I am in AC 43 and Vol 1 Maintenance Manual.

 

[Sully]

Try this for starter

 

[Bob Turner]

It is well beyond any statute of limitations, so maybe I can claim "young and foolish" or maybe "minor alteration."
We had a 7ECA - brand new engine, but horrible fabric, oversprayed with auto paint. It was probably unplasticized urethane.

It was cracking everywhere, so in a desperate attempt to preserve fabric strength, I re-taped all the upper wing ribs, using Stewarts glue and Ekofill. Wasn't my airplane; I was just trying to make sure the sunlight didn't rot the wing fabric.

So after that, it flew a lot, but was parked outside for six months. Looked horrible, but I knew I had successfully blocked sunlight.

I finally got so tired of looking at the zebra stripes I shot the tapes with white butyrate dope. Didn't care whether it stuck or not. Took 30 minutes start to finish. I did mop the dirt off first.

It did stick! Another year outside, and it was still ok when the owner sold. I think he took $19 grand - engine was worth that. It was actually a pretty nice airplane.

Long story short - butyrate does stick to some stuff it cannot fuse with. At least for the short term.

 

[Big Ed]

Thank you. I would appreciate the summary as I have found it hard to find the “dope 101” class. I am in AC 43 and Vol 1 Maintenance Manual.

The process manual that Sully posted has everything you need to know. You can order a printed one from Aircraft Spruce for the Ceconite process.

For basic cosmetic fixes, you just need some lacquer thinner, and a can each of nitrate dope, silver dope, and colored butyrate dope. The nitrate sticks to bare fabric. The silver blocks UV and fills the fabric weave. The color goes on top. Clear can be used to fill the weave, but for small repairs you can save some money and use silver for both.

If the silver is intact with no cracks and no bare fabric showing, then you can simply mask and spray the spot with color. You can also brush dope on small spots, but be careful because, remember, it melts the layer below, so it's easy to smear. Don't double brush the same area.

If you have hairline cracks in the dope, then sand the area down, brush some silver into the cracks, and spray or brush color.

If the dope is flaking away from the fabric, then you should scrape away loose dope and strip the area to bare fabric with lacquer thinner. Brush a coat of nitrate on the bare fabric and let it dry, then spray on 3 coats of silver and lightly sand. Repeat if you want it super smooth. When done sanding, shoot another coat of silver, then 2 color coats. Small areas can be brushed, but be careful not to smear.

If you have fabric damage or lifting tapes, get some Ceconite Super Seam 2 cement. Strip the damaged area to fabric with lacquer thinner. Thin the SS2 50/50 with MEK and use to glue down tapes or glue patches on. Then nitate, silver, and color.

The mortal enemy of dope is humidity. You get blushing, which is when moisture condenses inside the dope as it dries. This results in a milky finish and weaker bond. To avoid, monitor the weather never apply when humidity index is higher than 50%. In the deep south, that means never in summer.

Ron Alexander is the guru. Here is a series of articles he wrote:

Spraying The Chemicals (Part One) By Ron Alexander | Aircraft Spruce ®

Spraying The Chemicals (Part One) By Ron Alexander Finishing tapes will be used on all major surfaces of your airplane including the fuselage.

www.aircraftspruce.com

All that sounds involved, but honestly it really is monkey proof.

 

[VaporGlobalAviation]

The process manual that Sully posted has everything you need to know. You can order a printed one from Aircraft Spruce for the Ceconite process.

For basic cosmetic fixes, you just need some lacquer thinner, and a can each of nitrate dope, silver dope, and colored butyrate dope. The nitrate sticks to bare fabric. The silver blocks UV and fills the fabric weave. The color goes on top. Clear can be used to fill the weave, but for small repairs you can save some money and use silver for both.

If the silver is intact with no cracks and no bare fabric showing, then you can simply mask and spray the spot with color. You can also brush dope on small spots, but be careful because, remember, it melts the layer below, so it's easy to smear. Don't double brush the same area.

If you have hairline cracks in the dope, then sand the area down, brush some silver into the cracks, and spray or brush color.

If the dope is flaking away from the fabric, then you should scrape away loose dope and strip the area to bare fabric with lacquer thinner. Brush a coat of nitrate on the bare fabric and let it dry, then spray on 3 coats of silver and lightly sand. Repeat if you want it super smooth. When done sanding, shoot another coat of silver, then 2 color coats. Small areas can be brushed, but be careful not to smear.

If you have fabric damage or lifting tapes, get some Ceconite Super Seam 2 cement. Strip the damaged area to fabric with lacquer thinner. Thin the SS2 50/50 with MEK and use to glue down tapes or glue patches on. Then nitate, silver, and color.

The mortal enemy of dope is humidity. You get blushing, which is when moisture condenses inside the dope as it dries. This results in a milky finish and weaker bond. To avoid, monitor the weather never apply when humidity index is higher than 50%. In the deep south, that means never in summer.

Ron Alexander is the guru. Here is a series of articles he wrote:

Spraying The Chemicals (Part One) By Ron Alexander | Aircraft Spruce ®

Spraying The Chemicals (Part One) By Ron Alexander Finishing tapes will be used on all major surfaces of your airplane including the fuselage.

www.aircraftspruce.com

All that sounds involved, but honestly it really is monkey proof.

Thank you!

 

[Big Ed]

Thank you!

Good luck. I think you will find dope to be very forgiving to work with. It's just lacquer paint, so fingernail polish. Start on a small spot in an inconspicuous area. If you screw up, wipe it off with acetone and start over.