Fabric repair question

[1avidflyer 1983]

Hi all,  Was flying Sunday afternoon off a frozen lake here in northern MN shooting landings with a friend who is trying to master the taildragger.  There was a few inches of melting sloppy snow on the ice, and eventually it was more slush than snow from our takeoffs and landings.  I noticed after a while that it seemed like I was pushing forward on the stick a lot harder durring full throttel climbout.  I backed the trim down a bit and all was fine.  Well we did about a dozen takeoffs and landings, and I had to get home before dark so he got in his car, and I headed for home.  Plane was definatly flying different than normal.  Actually noticably better.   When I got home, look at the pics and see what I found.  Left side of the plane was fine, just happened on the right side.  I figure the slushy snow was getting blasted back and started to work the finishing tapes loose.  As far as flying better, the tape on the horizontal stabilizer would have acted like a gap seal, the tape on the elevator would have acted like a trim tab.  Not sure which had the bigger effect on the flying thing.  Well back to my original question.  I've covered 2 different airplanes so far, but always used polyfibre products.  This Avid must have been done with buterite dope as I think a lot of them were.  What was used to hold the finishing tapes on and what's the best easyest way to repair this?  I did put a bit of poly tac on a different spot where I had some tape coming loose, and it seems to be letting go.  Thanks,  Jim Chuk

[EDMO 1078]

Jim,

     You will probably get better answers from folks with more covering experience than me -  If I remember correctly, in either process if Nitrate was used, it was only for the first coat - so any tapes put on would have been stuck on with buterate dope in the successive coats - since Polyfiber now owns Stitz and Ceconite, I would give them a call and ask for their opinion about repairs.

     The only other source I can think of would be AC43-13, but the original manufacturer is always the best source.

     I would imagine some sanding is in order before adding the tapes.

Hope this helps until you post a better answer.

ED in MO

Edited 10 Apr 2013 by Ed In Missouri

[EDMO 1078]

I wonder if it is about time to use a rejuvenator on your dope?

ED in MO

[1avidflyer 1983]

Thanks for the responces Ed. Someone on another site mentioned using rejuvanator on the tapes to soften the butyrate and then sticking them back in place. I think I will give that a try. I think the biggest problem was just the slush is heavy, and getting blasted back there at a high rate of speed. Once one little spot came loose, I think it just worked it's way down the line. Thanks, Jim

[EDMO 1078]

Jim,

     Those tapes running chordwise should have been put on before the leading edge tapes were put over them- That could be a reason they came loose.

ED in MO

[EDMO 1078]

Jim,

     I was looking at my Kitfox 1 manual this morning and found the following written by someone from Denny Aerocraft:

     "The Stits manual recommends using a mixture of polybrush 3 to 1 with Reducer for doping down finishing tapes.   I use a variation of this mixture of my own design that I have found to have better adhesiveness, and it seems to work better............"  " My mixture is as follows:

3 parts polybrush

2 parts poly-tak cement

1 to 1 1/2 parts reducer."

Ed in MO

[1avidflyer 1983]

Thanks Ed, the problem was that Avid used butyrate for the covering system on their kits it seems. I have worked with poly-fibre a number of times, just never with the butyrate materials. Jim

[akflyer 1427]

Jim,

 

One of the local A&P guys fixed a bunch of the tapes on my brothers Pacer that were lifting like yours just using poly tac on them.. this was on a plane that was originally done in dope like yours.  My avid C manual called for polyfiber not dope.  I am assuming you have determined with certainty that dope was used on your plane.  I also think that the Stewarts stuff has been succesfully used over dope finishes too.

 

http://www.supercub.org/forum/showthread.php?36647-Stewart-system

 

[EDMO 1078]

Jim,   Been a while since I studied dopes - well, I did listen to some politicians! 

      If I remember right, the Nitrate is more flammable, and causes more shrinkage, but adheres better.   They didn't use it because of the continued shrinkage, I guess.

        Still, the buterate will shrink unless the Untauntling Buterate is used, I guess?

I like the Stewart glue so much better, that I will use that - but might finish mine with Randolphs - still deciding on that one.

Good Luck on your repairs.

I see you are expecting another foot of snow - Oh well, skis will come off someday soon.

ED in MO

[1avidflyer 1983]

I just went and dug in the builder's manual for my MK IV, printed 8-16-96 and it talks about using

U-500 fabric cement, (made by superflite) and on another page it talks about three cross coats of Nitrate Dope. Just looked at my manual for my first MK IV, odd that it's dated 6-20-91 and it's serial # is about 120 later than my second MK IV. I don't think the 96 manual originally came with the second MK IV. Anyway, it talks about using nitrate dope to attach finishing tapes ect. I have a manual that came with a bunch of C model parts I bought a while back, I'll have to take a look at it also. Long story short, I'm pretty sure I don't have poly-fibre on that plane. The inside of the fabric would look pink color also if it was' from the poly brush (although I think you can get clear polybrush) This fabric is gray looking. I think that's from seeing the aluminum UV blocker showing through the clear dope. I was talking to a guy that's covered a bunch of planes, and he figured that some poly brush would probably work okey. I'm thinking I'll give that a try. Thanks guys! Jim

[EDMO 1078]

Jim,  I guess you know that if you have the 2.7 oz  "certified" Stitz or Ceconite there will be stamps on the fabric - The "uncertified" 1.7 or 1.8 will not have the stamps on it.

ED in MO

[1avidflyer 1983]

Hi Ed, yes I was aware of the stamps and their meaning. I believe Avid's supplied fabric was the lightweight fabric. Don't think it came with a stamp. Thanks, Jim