About to take possession of my new '79 Super Decathlon 8KCAB. It has the original fabric and dope. The wings look very good, but the fuselage is rough. I don't want to spend the money or absorb the downtime now to recover it, so I am going to try to bring the coating back from the grave. Will use this thread as a running discussion for questions and advice.
Super D Ceconite patching and rejuvenation
- Thread starter Big Ed
- Start date
First and most pressing problem area: small 3-4" tears at the aft ends of the upper and middle fuselage stringers on both sides. The previous owner says that this is partially from him pushing with his hip instead of lifting with the handle. However, it is also probably symptomatic of decades of slipstream slapping the side of the fuselage.
My plan for these is to strip, glue on ceconite patches, and dope. I don't see a big challenge here, except for the weather here in Florida. Temperature and humidity are well out of spec. I ordered retarder, but I am still worried about blushing. I don't have a lot of flexibility on time.
My plan for these is to strip, glue on ceconite patches, and dope. I don't see a big challenge here, except for the weather here in Florida. Temperature and humidity are well out of spec. I ordered retarder, but I am still worried about blushing. I don't have a lot of flexibility on time.
Next biggest problem area is the dope on top of the fuselage up towards the skylight. I don't have any photos right now, but the dope along the upper longerons is cracked, and fabric is exposed in a few small places. I believe this has happened in just the past few weeks, probably as a result of the change in climate, because I did not see it when I looked at the plane before making an offer. I need to get silver on the exposed fabric quickly to prevent UV damage. Right now my plan is to flake away any loose dope, sand the edges back, spot apply rejuvenator, then brush silver into the cracks.
The big question is: should I make all needed repairs, then spray the whole fuselage with rejuvenator, then shoot a new color coat of dope? Or, should I spray the rejuvenator, then make the repairs, then shoot a new color coat?
Will post pics later.
The big question is: should I make all needed repairs, then spray the whole fuselage with rejuvenator, then shoot a new color coat of dope? Or, should I spray the rejuvenator, then make the repairs, then shoot a new color coat?
Will post pics later.
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Next issue: these spots along the lower side appear to have been repaired with something other than dope; either poly-fiber or enamel rattle can paint. Can I strip that with solvent, or do I need to sand down to bare fabric? Or should I expect to cut it out? Also, what is that protuberance in the middle of the repair?
Linear tear under the door will need to be taped.
Linear tear under the door will need to be taped.
what does the aft fuselage structure look like under the fabric?
i'm not an expert on fabric so I'm just going to watch. good luck with it
i'm not an expert on fabric so I'm just going to watch. good luck with it
Bob Turner
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I am not going to recommend roughing it up a bit and glueing a fabric patch anywhere there is a boo-boo. I am likewise not recommending that you try Stewarts glue and Eko-Fill (expensive) followed by a rattle can or Butyrate color. I am not going to tell you it has been tried with spectacular results.
I am not going to even suggest that a local Decathlon fuselage got completely retaped that way, and then finished with a beautiful coat of Aerothane, and then sat outside for three years and still looks gorgeous.
Because to do any of that is simply out of bounds - just like putting Mylar tape on is.
But after you strip down to bare fabric in a few small areas, don't be tempted to do it the easy way. Somebody might be watching. I guarantee that it is easier to recover than to do repairs that way.
I am not going to even suggest that a local Decathlon fuselage got completely retaped that way, and then finished with a beautiful coat of Aerothane, and then sat outside for three years and still looks gorgeous.
Because to do any of that is simply out of bounds - just like putting Mylar tape on is.
But after you strip down to bare fabric in a few small areas, don't be tempted to do it the easy way. Somebody might be watching. I guarantee that it is easier to recover than to do repairs that way.
Don't care at all about pretty. Do want repairs that will hold up in hot, humid climate of Florida.
I'm not sure what your experience level is with aircraft paint/fabric but it's super easy to do repairs with Stewart Systems' water borne finishing system. You would have to verify the legality of it for yourself but it's a matter of sanding down to the silver and then using their components to do your repairs. They can match colors and it's all water based so there are no solvents to deal with. I sent a pair of needle nose pliers into the side of my fuselage and the rip was about 3 inches long. The repair couldn't have been easier. Also added wider tape over the center belly stringer where it had caused cracking like yours. Sanded it smooth, added the tape and filler (EkoFill) coats and then just primed/painted with the rest of the fuselage.
If you're going to rejuvenate the whole fuselage then that would rule out using Stewart System for patching and repairs.
If you're going to rejuvenate the whole fuselage then that would rule out using Stewart System for patching and repairs.
I don't know for sure if I will rejuvenate, but I do not want to prematurely foreclose that option. Therefore I will make all repairs using dope, and attempt to remove prior repairs made with other systems. Right now it appears the latter is only in a few very small areas.
Does anyone have a quick and dirty non-destructive method for testing repairs to determine if they are not dope? Does butyrate thinner do anything to polyfiber and enamel?
The new Ceconite process is similar, but you have to go down to Nitrate instead of Silver, either by sanding or using thinner. My initial repairs are small, so I'll give the thinner method a shot. If that turns out to be too labor intensive, I'll reevaluate. For now, I intend to follow the STC to the letter.
Does anyone have a quick and dirty non-destructive method for testing repairs to determine if they are not dope? Does butyrate thinner do anything to polyfiber and enamel?
The new Ceconite process is similar, but you have to go down to Nitrate instead of Silver, either by sanding or using thinner. My initial repairs are small, so I'll give the thinner method a shot. If that turns out to be too labor intensive, I'll reevaluate. For now, I intend to follow the STC to the letter.
aftCG
Well-known member
Two observations that won't really help your fabric repairs. I would lose my s*** on someone who pushed on the fuselage sides on my plane. Some of the fuselage shape is created with steel tube (the two lowest and the very top) but the rest of the longerons are just wood doweling - and it's all very old. My plane has handles on both sides and I can be seen sometimes putting my hand on the leading edge of the vertical fin, but I don't push on the fabric just under the tube for any reason.
Second, I'm real sure my plane has tapes in the area you show near the door. Maybe it's just the picture, but I don't see any tapes in that neighborhood.
Second, I'm real sure my plane has tapes in the area you show near the door. Maybe it's just the picture, but I don't see any tapes in that neighborhood.
I assume the horizontal crack 1" above the bottom longeron is the upper edge of a tape.
That spot looks like the impact point of someone's foot getting in and out of the cockpit repeatedly. Looks to me like it was repaired with enamel. I'm going to try and flake that off with a knife back down to silver. Failing that, will sand to silver. Then recoat with butyrate filler and color. When I get to that point I will post pictures. If fabric sketchy, I will cement a reinforcement patch over the area.
Other than cosmetics, is there any inherent issue with flying on patches coated to silver?
I have a few trouble spots with exposed fabric that need immediate action to prevent UV deterioration. However, I'm going to be in a large common hangar for several months while I wait for a T hanger to open up. Also, the climate in Florida is NOT conducive to spraying dope right now. High heat and high humidity every day without fail from now thru October.
I'd like to sand and fill a couple of the spots with brushed on rand-o-fill now, then leave it alone until Winter. By then I should have a hangar to work in, and the weather will be perfect for dope work. I can take my time to do it right.
I have a few trouble spots with exposed fabric that need immediate action to prevent UV deterioration. However, I'm going to be in a large common hangar for several months while I wait for a T hanger to open up. Also, the climate in Florida is NOT conducive to spraying dope right now. High heat and high humidity every day without fail from now thru October.
I'd like to sand and fill a couple of the spots with brushed on rand-o-fill now, then leave it alone until Winter. By then I should have a hangar to work in, and the weather will be perfect for dope work. I can take my time to do it right.
Bob Turner
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No regulation against that. And silver has, in the past, been regarded as a top coat - see the Cessna 120, or the postwar L4 Army fleet. No rule that says any coating has to be sprayed - unless you take procedure manuals super-literally.
Finished first round of repairs. Patches went reasonably well. Stripping took about 2 hours, not too bad. Faster once I got the process down. A few lessons learned:
1. Thinner runs easy. Mask all areas below the repair, and have a rag handy
2. Scuff sand the repair area to knock the gloss off.
3. Brush thinner on and immediately scrape it off, rather than letting it soak in. You'll take one coat at a time that way, but won't have to work hard at it.
4. A putty knife works well for scraping, but watch out not to abrade high spots such as stringers.
5. Clean the iron regularly when smoothing. I did not do that, and it drug the the tips of the pinked edges up. I will have to sand those down.
Will post pictures of repair in silver tomorrow. Colored dope on the way.
1. Thinner runs easy. Mask all areas below the repair, and have a rag handy
2. Scuff sand the repair area to knock the gloss off.
3. Brush thinner on and immediately scrape it off, rather than letting it soak in. You'll take one coat at a time that way, but won't have to work hard at it.
4. A putty knife works well for scraping, but watch out not to abrade high spots such as stringers.
5. Clean the iron regularly when smoothing. I did not do that, and it drug the the tips of the pinked edges up. I will have to sand those down.
Will post pictures of repair in silver tomorrow. Colored dope on the way.
I also did some spot rejuvenation. That worked surprisingly well, for the amount of effort and expense. I'll post some pics tomorrow.
My key goal was to stop further deterioration by rejuvenating the largest cracks and covering any exposed fabric with silver, to buy me time to find a more suitable working area.
My key goal was to stop further deterioration by rejuvenating the largest cracks and covering any exposed fabric with silver, to buy me time to find a more suitable working area.
very nice work! give any thought to fading the edges and trying to blend the old/new into each other? I have no idea what is better, just asking.
if you're staying with the same colors it might not be much to lightly sand the whole thing and give the fuselage only a light top coat to bring it all together when the patches are done. if it's dope there are probably people local that can do it without it being insanely expensive and it the same colors are used it won't add much weight.
if you're staying with the same colors it might not be much to lightly sand the whole thing and give the fuselage only a light top coat to bring it all together when the patches are done. if it's dope there are probably people local that can do it without it being insanely expensive and it the same colors are used it won't add much weight.
BB57
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