Small fabric repairs; alternatives to duct tape

Some other Washington State Cub driver suggested starting a series of comments on how to make fabric repairs. No replies.

I need that information. My little tire wearing Super Cub is missing one wing drain grommet, along with some surrounding paint, and two or three others (near the base of the wing, inside the prop wash) are loose on one edge, and will probably go away soon.

The guy I bought the plane from, and who made it look so nice (and as such, obliged me to do my best to keep it both used and well cared for), likes Pliobond general purpose adhesive (glue). I guess I'll probably use a toothpick to apply a tiny spot under the edge where they have cracked loose, and try to keep them down. Any other suggestions?

I'm kind of toying with not replacing the missing grommet, and just putting some paint around the drain hole where the paint tore away with the grommet, rather than glueing on another grommet that will probably fall off again. I have seen that it's the area inside the prop wash (or maybe it's because they are in front of the flaps), what's the best source for drain grommets that will stay put?

I would like to do the right thing, so if there's an experienced technique for securing drain grommets where originals have torn away, let's hear it.

Also, I have a couple of ah,... (eyes down) minor hangar rash markings. No actual rips in open fabric, but a couple of tiny gashes on the elevator edge. I'm thinking just some finish paint to keep the fabric from freying might be the thing to do (but I'm just guessing).

A general overview on how to best apply paint to a small repaired area would also be helpful. Keep in mind that I have zero equipment, supplies, or experience. I have some common sense, but sometimes I come up short there too, so please be very explicit.

So, here again is a chance to reply on how to do (nice looking) small fabric repairs. Just to keep this interesting, I'll post some pictures of what I'm talking about tomorrow.

Thanks!
-->Aaron

Small fabric repairs, alternitives to duct tape

What type of grommets? Sea plane or just flat round ones? What is your aircraft covered with? Dope,Stits, Polyurathne, Duct tape? All kidding aside just get some Poly Tak fabric cement and glue the replacement grommet back on. Do what you want to do with the tooth pick and get some glue in where the others are loose and stick them back down. The problem with plio-bond is it's a contact cement and you have to get some on each side for it to stick and in small areas it's a pain in the ass. As far as the hanger rash goes well that is a judgement call. Some will say that just painting will be fine others will say it needs to be patched.

Hope this helps.

Matt

You need to figure out what type of covering (polyfiber, ceconite, ect.) you have and what the color coats are (dope, polytone, polyurethene, ect). Hopefully your log books will provide this information but if not your IA ought to be able to tell you. Then buy one of the manuals put out by the manufacturer. I am familiar with the polyfiber manual and it's inexpensive and has lots of useful information about recovering, painting and repairs.

More on the grommets and other stuff

Just flat round ones, they appear to be nylon washers. They don't seem to be sticking very well. I've posted a bunch of pictures in the album (hopefully this won't be considered an abuse of the album), you can see the first of ten here:
http://www.supercub.org/gallery/view_photo.php?set_albumName=Supercubs&id=afb

The first six pictures are of missing or broken grommets. The seventh in the series is my hangar rash incident (head bowed). The last three are of two grommets that aren't even open! (How did that not get noticed before?) What's the best way to open the plugged ones, and handle the loose ones? Not all are this bad, just the most inboard ones.

According to the rebuild 337 paperwork, the recover step was:
"Painted fuselage tubing with Stits EP-420 Epoxy Primer, installed Stits Poly-Fibre covering material on all fabric surfaces and painted in accordance to Stits Poly-Fibre Procedure Manual No.1, Revision Fifteen, Seventh Edition in compliance with STC SA1008WE."

So I guess that's about the best supported covering system around. I have the learner?s kit, and I've toyed around with it a bit. Unfortunately, I got it about a year ago, and the Poly-Tak in particular, and probably everything else, has dried up.

I'd like to do this right, and fix both the grommets and the tiny gash on the elevator to last. I'd also like do so with a minimum of fuss, and without having to buy much painting equipment. How do you apply drain grommets to last? What's the problem here, amateur installation?

Small fabric repairs, alternitives to duct tape

Rookie I've looked at the pics and now for my opinion, I've read what you have written in the forum of what your log book says and from looking at the pics you have Aerothane on the aircraft. If you don't know Aerothane is Poly-Fibers (Stits) urathane finish. So what does that mean to you well to put the new grommets on just use Poly-Tak and glue some on. The ones that are loose try and get some glue in where it's loose and stick them back down. When I use these grommets I always cover them with a dollar patch so they stay on better. Now why they came off. Most people glue them on ( most of the grommets are made of plastic today) and from the different heat cycles and from the fabric drumming they will loosen up over time and get blown away by the slip stream. The older inspection rings and grommets were made from cellulose acetate and would adhere much better. To open the holes in the drain grommets take a soldering iron and burn them in. Fabric patching is going to be a pain in the ass. Purchase the manual if you have'nt already. Sand the area down to the poly-brush. Poly-brush a patch on. Spray on some poly-spray. Sand. Spray on some Aerothane. Buff to blend. (Good luck) Before you ask about how big of a patch ect.... Buy the manual and get a copy of AC43.13, talk to your mechanic, if everythings a go the only way to learn is to do it.

Matt

Fabric Repairs

If your color top coat is "Polytone" and not "Aerothane" you can wipe the top coats off all the way down to bare fabric with MEK on a rag, if you want to. Polyfiber also has a rejunivator to soften and lay down any cracks or blemishes in the coatings. The coatings are all compatible from Polybrush to Polyspray to Polytone paint. They are all vinyl based products. Polybrush is the "attachment" coating that is brushed on and forced into and through the fabric weave. Nothing sticks to polyester fabric. This first coat saturates the fabric and encapsulates the fabric weave front and back side. It's the stuff the dries on the backside of the fabric that keeps everything attached to the front side. Polyspray is Polybrush with aluminum powder in it to block the sun's UV rays from damaging the fabric. Polytone is Polybrush with pigment added for color. If you have Aerothane paint, nothing will soften and lay down this polyurathane paint. You have to sand out and respray to a break or paint stripe. Otherwise you will have orange peel around the spot you sprayed and polyurathane is hard to rub out on fabric. One trick I use is to thin down the paint or dope and spray the area with several light coats with my kid's airbrush. The airbrush is so controllable you don't even have to mask off the rest of the plane when spraying. Take care! Crash

Ever stick a hot probe through a grommet?

Thanks for those comments. I'm starting to get the picture. If I want to be able to do this right, I'm going to have to put together some elementary mixing and spraying gear. Shopping for an inexpensive airbrush kit for spot painting might be what I have to do.

Hey, I see someone uploaded a "rock strike on vg" picture:
http://www.supercub.org/gallery/view_photo.php?set_albumName=Supercubs&id=afl
What jumps out to my eye is that the grommet in that picture has a round patch too. So, what are we looking at, a thin aluminum grommet, as seen in the Poly-Fiber catalog, sandwiched under a round patch? In the catalog blurb, they make mention of burning with a hot probe. Man, that sounds like what I'll have to do to fix those closed grommets I have, but I'm going to have to do a bunch more research before I try to burn anything on my plane.

Gee, I'm starting to feel a bit silly. Most of my questions have answers here:
http://www.polyfiber.com/techquestions/grommets/index.htm
So, there's my definitive web resource. It looks like my current grommets are definitely not right, I should probably just plan to do all of them. Once I get my supplies, I'll start with the practice kit test frame. That will be a lot easier than working upside down on the bottom side of the wing.

More research. Maybe I'll run into some of you at the "Fabric Covering Maintenance & Repair" workshop Saturday 8 AM, July 13, at Arlington, WA (see schedule http://www.nweaa.org/). I'll probably fly in Friday, and spend the night. I'm likely to have my plane parked in front of Cunningham Covers.

First thing you should do is: test the finish with MEK in a non conspicious spot? If it is aerothane, the MEK won't touch it! If it is Poytone or Buturate it will come of like mud with soap! (that would be the best) Again, another reason to stick with either Dope or Poytone! Cubs were made to fly/work not go to "cruz-ins" at airports! Paint, (even by Stits own manual) will crack and it is a pain to fix!

Don't wory about burning down your plane with a soldering iron! If you don't have one get any pencil type and heat it up and poke it through the grommets.

It sounds like the plane may have been "painted to sell", not uncomon but usually it is covering up neglect or age. I would check it out throughly and "start saving your money". To much fiddling around isn't worth it if it was "painted". you will be putting a bandaid on a broken leg!

Covering is not hard, just labourious! The Stits seminar is a great workshop! Also get to know some EAA'ers and offer to help with a covering project, like doing the wet sanding, stripping, and in a year you will have saved enough to think about covering your own!

Cubs look better with a few dollar patches on them, especially on the belly and the underside of the stabilizer (from willows, rocks and a few sticks etc.

Fly it more, fix it less, You don't build flying hours in the hanger!

Good Luck!

Tim

Thats my cub in the picture with the rock strike. Smashed the VG flat as a pancake. Cover is Ceconite with dope. I got several holes to patch in the stabs to fix one of these days. Nice thing about dope is how easy it is to repair. Best way to repair Stits fabric polytone or aerothane is to tear it off and recover with ceconite and dope.

kase, everyone is entitled to their opinion, however I respectfully disagree with your comment about tearing off polyfiber just to replace it with ceconite/dope. I have had both, on my 18, and both have served me well. The general wear and maintainence has been about the same. I currently have polyfiber/polytone. Each system and coatings has their own characteristics. For best results each should be repaired within these parameters. Too many repair without recognizing to these traits and usually with inferior results.pak

I figured that remark would get a response. My previous cub had stits on it with polytone and it dosent even come close to the durability and reliability that my dope covered cub has given me.

Covering Systems

There is very little difference between Ceconite and Polyfiber "fabric" since Polyfiber purchased Ceconite several years ago. The old Ceconite was more corse in texture and acted differently when tightened. The coatings are basically this... Polyfiber is a vinyl base coating system. Randolf dope is a cellulose (like varnish) based coating system. The dope system seems to tighten up over time and is less effected by tempature changes. It pings when you thump it. The dope is "stickier" and the tapes lay down better and don't keep popping up on a tight bend like Polyfiber. They are both good system when put on right. PAK-man really knows the Polyfiber system, he is the one to ask Polyfiber questions. I prefer Randolf dope because it's what I've flown and have more experience patching. Crash

Crash, I prefer Randolph also for exactly the reasons you mention above. Also it seems that stits has a tendency to crack alot sooner than dope along the longerons, stringers, and trailing edge of the wings.

I Think dope is fine for Crash and others in the northern latitudes. I had a 18 year dope job, that still looked great. I spent 3 weeks in southern Old Mexico with no hanger in the cooking sun. Even after 18 years, when exposed to the sun the fabric pulled swoops in my stringers and pulled the fabric out of the window channels. I agree with Crash ( it does continue to tighten ). Jerry.

Poly vs ceconite, multi vs straight weight oil, car gas vs av gas... aviation has plenty of ford/chevy arguments to debate. Yes, dope is a harder paint than polytone. Yes, dope continues to shrink throughout its life and is evidenced by scalloping between the ginger bread fusalage formers, between the longer spans on the lower longerons and occasionally the wingtip hoop will begin to tip up. Both systems are proven and are excellent recovering systems when applied correctlly(sp).
Crash, on your next plane try this with the tapes that go around an edge. Glue half down then wait to dry, then heat form the tape around the edge. This should help with those 'flippy' tapes.

As to the original question, I would either paint the fabric where the grommet failed or replace it with a seaplane grommet and dollar patch. I usually take a washer as a guide to burn/melt a hole rather than bother with a grommet, unless you are using sea grommets which are very good to have, as they create a negative pressure behind the gromment and this aids in removing any moisture in the wing or control surface. The previous run on sentence is longer than a lot of our landings...pak

To grommet or not

I got a good look at a recent Cub Crafters plane yesterday. It had no grommets on the underside of the wings, just holes, probably made as pak mentions. I'll have to do something with the cracked and missing surface mounted grommets that I took pictures of, but I'm going to do that after a couple of experiments. I just bought a pretty new looking Binks Wren airbrush on ebay, and I think I got a deal!

My plane has seaplane grommets on the bottom of the horizontal stabilizer. Interesting comment about the negative pressure gradient they create.

Pak! I am impressed that you noticed the grammer!! (just kidding) I am always impressed when a mechanic/ pilot actually took time out from daydreamin long enough to go to english class. I am still trying to spell!

Sure appreciate all you guys and your willingness to share information, experiences etc.

Tim

Rookie:
Good luck with the airbrush. If you are going to use dope thru it I think you will have a rude awakening.