Rib reinforcement tape

Joe

Joe

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The original covering on my 79 8KCAB has a 1" rib reinforcement tape that appears to be Dacron under the rivets. Does anyone have a spec on what that tape is? It seems I would have an easier time poking 500 rivets through Dacron than through the poly-fiber reinforcement tape. The poly-fiber manual spells out using poly-fiber tape, but it also spells out to attach the fabric exactly the way the factory did. I think I can make a case for going either way. Any thoughts?IMG_20220828_172910_HDR.webp
 
70's factory spec was Dacron fabric and tape with dope coating, equipment to Ceconite. Both Ceconite and PolyFiber are Dacron. Only difference between the two is the brand stamp on them.
 
The reinforcing tape(s) are interchangeable between Polyfiber's and Ceconites processes.
The tapes are required to keep the air loads from pulling the fabric away from the attachment (in this case rivets). They come in different widths for different width ribs. 3/4" is good for Citibrthon type airplanes.
As to making the holes for yor rivets a cheap soldering pen (60 watts and 1/8" diameter) will poke a hole in both the fabric and the reinforcing tapes but you need to move quickly...a quick poke gives a nice finished hole all ready for a rivet.
The section you refer to in the Polyfiber manual is discussing the various types of fabric attachment; rivet, lacing, clip or screw and washer. Decathlons use rivets.
The Polyfiber manual is a great resource for how to cover an airplane even if you don't use their wet goods...

Chris
 
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To rephrase the question. Polyfiber and ceconite reinforcement tapes come in 1/4, 3/8 and 1/2" and measure about .0011 including the glue. The 70's era reinforcement is 1" and measures around .0006. Does anyone have a factory specification on what the 70's era reinforcement tape was?
 
I too had wondered about that. I never got a satisfactory answer.
So the parts list above seems to indicate simply using 1" surface tape. Can you buy that in 101, or the heaviest weave?

Good idea on the soldering iron. I just started doing that for grommet holes. Easier and better - seals the edges.

I hate pop rivets - but one of the mechanics in the local shop (I am an honorary employee) lent me his Milwaukee rivet puller. It is the only way!

I do mostly rib stitches on Cubs - and in October on the Stearman. I now use the rabbit and palm tree method.
 
I can't find it in writing anywhere, but I believe the correct procedure is to lay down 1" tape, rivet thru that, then cover with 3" tape. The 1" tape seemed thicker than normal, and might have been cotton. Parts 2, 4, and 23 on the drawing suggest that same method, but do not depict it clearly.

Edit: 1" under rivets, 3" over is exactly what Joe's picture shows. Can't tell from the photo, but the 1" reinforcing tape that I have previously seen looked considerably beefier than standard dacron tape, and had a different weave.

Edit 2: Spruce sells a "reinforcing tape" for this purpose. FAA approved under the Ceconite process, which uses mostly identical materials to the original factory dacron and dope process. It is polyester twill, not dacron. Narrower than the spec. The current Ceconite process uses Super Seam II cement for adhesive, which is a hell of a lot stronger than dope or the old Super Seam I. It is also reportedly the same stuff as Poly Tak.

www.aircraftspruce.com

Ceconite Reinforcing Tapes | Aircraft Spruce ®

Ceconite Reinforcing Tapes (FAA APPROVED) Polyester twill with adhesive back. Applied under rib lacing, pop rivets, or PK screws to prevent fabric from ripping. 60 yd. length.
www.aircraftspruce.com www.aircraftspruce.com
 
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I think the current spec is a fiberglass tape. I'm most familiar with Polyfiber. Spencer says they can match my Randolph Colorado Red in Polytone. I suppose it would be best to stick with the Polyfiber reinforcement and not try to justify a deviation from their manual. It's just a pain to push a awl through their tape and it not take on an hour glass shape. I've used a soldering iron for drain holes, but never had an opportunity to try it on rivet holes. Chris did you have an easy way to mark the hole locations?
 
Joe said:
I think the current spec is a fiberglass tape. I'm most familiar with Polyfiber. Spencer says they can match my Randolph Colorado Red in Polytone. I suppose it would be best to stick with the Polyfiber reinforcement and not try to justify a deviation from their manual. It's just a pain to push a awl through their tape and it not take on an hour glass shape. I've used a soldering iron for drain holes, but never had an opportunity to try it on rivet holes. Chris did you have an easy way to mark the hole locations?
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Are you recovering or making a repair? If making a repair to the existing factory dope covering, I strongly recommend sticking with the Ceconite process. It is the same chemicals, butyrate dope, whereas polyfiber is totally different. If ripping it off and starting from scratch, well then go with whatever you want. But if you mix and match Ceconite and Polyfiber on one surface, you will make further repairs more difficult, because you are now dealing with blotches having different compatibilities.

Color matching should not be a problem since the same company owns and produces Randolph dope and Polytone.
 
Color matching should not be a problem since the same company owns and produces Randolph dope and

Yeah, right. They cannot even match their own pre-1990 colors, and all the beautiful Randolph colors from when they were in Carlstadt have the same names and numbers, but are not at all the same! Yellows and whites are the worst. Colorado Red is now transparent - need multiple coats over white. Red pigment must be costly!

On the reinforcing tape - apply dope or Poly Brush to the tape after you stick it, and let it dry before you poke holes. Presto - no "hourglass."
 
Bob Turner said:
On the reinforcing tape - apply dope or Poly Brush to the tape after you stick it, and let it dry before you poke holes. Presto - no "hourglass."
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I will give that a try, thanks. If the color is not a perfect match, I will practice up on my fast taxi so that no one will notice.
 
Recovering went like this:
After getting the covering attached and shrunk (don't forget the inter rib bracing tape(s) prior to covering) and prior to putting on your reinforcing tapes, backlight the wing and locate and mark the holes in the ribs. I always just used a sharp pencil to pop the hole and then draw a short line (4") 90° to the rib so I know where the holes are. Now apply the sticky-backed reinforcing tapes along each rib. Because you have the line across each hole in the rib you now know where to punch each rivet hole. It helps if you clean the fabric where the tapes go with either MEK or the Polyfiber 3310 cleaner so the reinforcing tapes stay stuck...now punch/drill/melt each rivet hole, stick in a rivet and proceed!
That's just the way I did it...other folks might have different tricks they use.

Hope this helps.
 
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I did it like that (except for the MEK) the first time. Hourglass where I poked the holes. Ugly.
Yeah, pencil marks. For rib stitches I stretch a string along all ribs, so the stitches line up.

I think you want to do the initial brush coat before sttaching tapes. That was true even before the tapes came with adhesive.

Original Stitts tapes looked like glass-reinforced packing tape. They were superior to the new Polyester tapes now available - doping before poking was not necessary, and they went on straight without much struggle.

The inter-rib bracing was important with Grade A - now it is superfluous. Fabric is shrunk before any coatings attach it to the ribs, and if a rib goes crooked you can straighten it with a needle. I think it is still "required" but it is now just in the way. Opinion.
 
Joe said:
The original covering on my 79 8KCAB has a 1" rib reinforcement tape that appears to be Dacron under the rivets. Does anyone have a spec on what that tape is? It seems I would have an easier time poking 500 rivets through Dacron than through the poly-fiber reinforcement tape. The poly-fiber manual spells out using poly-fiber tape, but it also spells out to attach the fabric exactly the way the factory did. I think I can make a case for going either way. Any thoughts?View attachment 5660
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Joe,

I ordered my covering materials from the factory. The reinforcing tape that the rivets go through is Polyken 296FR. It has a self adhesive layer that doesn't naturally stick to the fabric so you have to pre-coat the fabric with 3M 30-NF adhesive. The ACA spec says fiberglass tapes but I got ceconite tapes from them. I don't think they're using fiberglass tapes anymore.

2" Ceconite tapes go over the 1" reinforcing tape.

I've been meaning to check my stuff at the hangar the last couple of weeks but have either been working or just forgot! Sorry! I checked my stuff at the hangar today and also with Dale at ACA.

Hope that helps.
 
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Bob Turner said:
Well, there is the answer. Fiberglas cargo tape! I was pretty sure Ceconite wasn't strong enough.
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just remember it doesn't stick to the ceconite. pencil in where the tape line will be, apply a nice even layer of glue and then put the reinforcing tape into place. It really sticks aggressively as soon as it hits the glue layer on the fabric!
 
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A little supplemental info. The first attachment is an excerpt from the L-16 structural repair manual. It shows 3/4" surface tape, then washer and screw. The second attachment is an excerpt from the Ceconite 101 manual stating the fabric attachment should be the same as the manufacturer's method. Granted, this is the Aeronca method at the time, but I doubt (other than the fabric type) the method has changed.
 

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Is that an Aeronca Champ reference? Citabria and Decathlons use fabric rated pop-rivets with 1" reinforcing tape on the tail feathers, not sure about the wing ribs other than the fact they use rivets also.
 
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