Stupid Fabric Covering Questions

[Mark Dickens]

Everything I know (and that ain't much) about fabric covering I've gotten from watching the Stewart Systems videos. I plan to use SS and am interested in the concept of double covering using two layers of the Superflite 104 fabric. My confusion comes from the idea that the second layer is the tape for the first layer. Conceptually that makes sense, but what doesn't make sense to me is the idea (if it's correct) that the second layer requires no tape.

So, I cover an elevator (for example), rib stitch it and essentially get it to the point where tape would be applied on all seams and over the rib stitching, but instead I simply add another layer of fabric. Do I still need to tape the seams?

I warn you, this is only the start of many elementary and stupid questions!

[AKKen07]

That’s a good question, the double cover method has some oddities. No tapes are required at all. Nothing extra on the stitches. Remember that a tape is just a strip of light fabric anyway. You will find, however that laying a 2nd layer over certain protrusions will be impossible to do elegantly because you have to glue it down moving in one direction, this is kind of hard to explain. Hinge points etc. don’t look great so I put patches over those between the two layers of fabric for mostly appearances. Then the 2nd layer fairs those in nicely. You could put them on top of the 2nd layer too depending on your taste. Also, don’t tape the “seams” which I think you mean edges of the 2nd layer. You should overlap your 2nd layer on itself a bit anyway. Like 1/2-1”. You won’t be able to get the edges to mate perfectly so this guarantees full coverage by the 2nd layer.
think about it this way. The 1st layer on, say, a stabilizer will overlap itself - leaving the edge preferably on the bottom surface- (if you use one piece to wrap the whole thing) or if you use one piece for each side, top and bottom, the top piece will overlap the bottom one, again leaving the edge on the bottom of the stab.
the way I see it you have two viable options for the 2nd layer: either do it the same as the first by wrapping the bottom piece up over the edge then the top piece down to leave exposed the edge on bottom, or the way I decided that I liked was to double cover the bottom without wrapping around the edge, just get right up to it, then wrap the top layer of the double cover around enough to overlap the bottom dc by any amount you like. The overlap isn’t required structurally, it just prevents gaps which are mostly cosmetic.

[Mark Dickens]

Good stuff here to think about, thank you! I've decided to hold off on any covering until after Oshkosh where I'll ask the SS folks what their thoughts on all this are.

[Bcone1381]

Ken;

I suspect if you did a you tube video on this topic....how you did it, common issues you ran into, errors and fixes you developed, ....it would be very helpful and popular.

[AKKen07]

Yeah I have several videos I'd like to put together actually! I edited all of my videos on layovers which I haven't had since COVID hit. So that's why there haven't been any in quite awhile.

[robcaldwell]

Yeah I think after you meet with the Stewarts people, especially try to meet and talk to Andy Humphries (if you haven't already), you will be much more enlightened on their process. Stewarts support is really great!

What's interesting to me is, I never heard about double layering until after I completed my fabric covering. Now that my plane is covered and flying, I'm not sure why I would need it. I will be interested to hear more about this technique.

[AKKen07]

I have to agree with Rob about SS Customer Support. The sales end is just as good - they were very patient as I figured out my overcomplicated order. Also I've been on the phone with John H more than my fair share and he has been super helpful. I'm still in the painting process as we speak and am trying to get clips and pictures so maybe if I ever have a layover again I'll have time to edit some video. In the end I do NOT think anybody NEEDS to double cover a Bearhawk - I sure don't. I was just interested in the idea and like the cleaner look with few to no tapes. It just piqued my curiosity frankly. I learned quite a lot and would do it again (and do a much nicer job now that I have some experience). I can't verify the weight savings especially since I'm such a novice painter and doubt the consistency/quality of my painting will take advantage of the double cover.

[Mark Dickens]

I'm not sure I need to do it either and I have a stock of all the finishing tapes if I decided not to go that path. The SS guys will know me well by the time I go home!

[joehmason]

I have never used Stewarts System nor do I know anything about it. We used Airtech and learned mostly from Robbie Statton's videos (the owner of AirTech). The link below is his video for double covering.

https://www.youtube.com/watch?v=JUIwSNxx09w

We double covered the flaps and ailerons. Turned out awesome in my opinion. Very clean looking. If we had done the flaps and ailerons before the tail, I would have double covered the tail as well. I know Robbie has built a 4 place Bearhawk and he double covered it. I'm not sure where that airplane is now or who owns it.

With his process you cover the entire surface with glue, lay the second layer of 104 fabric over the first as flat as you can, then glue the fabric on the ribs and the edges (where tapes would normally go), lightly iron (just hovering the iron) at 200-225 degrees between the ribs just to pull out any wrinkles, then paint the center panels with thinned glue to stick it to the lower layer of fabric.

We also came to the conclusion that this process might be faster than laying all of the tapes down.

Double covering the tail would be a little harder than a flat surface due to the compound curves between the ribs.

Attached are some pictures that show how we did the flaps and ailerons.

[Flygirl1]

I'll meet your stupid question and raise you one. ;-) What is the purpose of double fabric? No taping?? Extra strength? Need more weight? I've never heard of this before. Dennis and I put a heavier weight fabric on the belly and under the elevator for strength, but didn't see a need for it other places. Covering once was enough for me simply because it was a lot of work the first time!

[Mark Dickens]

I'm hardly knowledgeable about this, but I think the theory is that it saves time from not having to do all the taping. Now, for someone who knows what he's talking about, I'll turn it over to AKKen07....

[AKKen07]

Well please don't confuse me with any sort of expert... but I am working through the process - in the paint stage now. The theory is that 2 layers of lightweight fabric will, after wet goods are applied, weight in LESS than a typical cover job with tapes etc. In theory, the finer weave of the lightweight fabric will hold less weight in filler, etc. This should, according to SS (and Mr. Patey who used 2 layers of medium fabric on "Scrappy") increase the strength of said fabric by acting like plywood with laminated layers. Applying the 2nd layer of fabric is definitely faster than tapes, so its certainly no time or effort burden. Now, practically, the weight savings could only manifest if you only apply the minimum required filler/primer etc. to take advantage of the theory. I am not confident that my painting ability can really do that, but I'm giving it a shot. I hope that the extra durability will help reduce damage from rocks and such, and maybe be a bit stiffer which might have some abstract benefit... I dunno. The only truly tangible benefit for me is the appearance which is impressively clean without the tapes. I like it. I would do it again.

[robcaldwell]

This is Interesting. I personally find the finishing tapes give the plane a retro look. It's artwork!

[AKKen07]

Can’t argue with that

[Mark Dickens]

More elementary fabric covering questions! Maybe I'll be a little smarter after Oshkosh, but don't bet on it!

So...the question of the day concerns brackets and other things mounted to the stringers and how fabric is attached to them. For example, most builders (at least from my observation) mount their static ports to a L bracket which is in turn mounted to a stringer. So, do you just glue the fabric to the L bracket around the static port? What about cases where antenna mounts are mounted between stringers? Do you just stretch the fabric across the mount and bolt the antenna through the fabric or do you glue the fabric down to the mount after you stretch it across?

I sure am glad I know how to work with metal, but there are things about fabric which are confounding at this point! Thanks for your patience!

[AKKen07]

For the static port brackets I just stretched the fabric like they weren’t there. Basically I ignored them, haha. The fabric wound up glued to them when I coated/sealed with glue. Later I will cut the mounting hole after all is painted and done. Would be worth a reinforcement if you aren’t double covering ( or maybe either way). I didn’t have any antennae planned for the stringers but would do it the same way.

[alaskabearhawk]

How I did my static ports. Russ Erb did mount an antenna through the fabric, so that would be a resource. My VHF antennas are on each wing and the GPS antenna is mounted just below the fabric. YMMV

http://www.mykitlog.com/users/display_log.php?user=yeeeha&project=527&category=14187&log=292855&row=27

http://www.mykitlog.com/users/display_log.php?user=yeeeha&project=527&category=14187&log=293089&row=19

http://www.mykitlog.com/users/display_log.php?user=yeeeha&project=527&category=14187&log=293478&row=13