Oratex is like Yoga Pants

[BucF16]

Outstanding John!
Thank You
Bruce

[FlyerChief]

I don't know about Oratex, but the standard Just Aircraft kits came with a short length of bias-cut fabric. (I think there was 4 feet or so of the stuff.) Bias-cut tape conforms to the compound curve of the tail without a lot of the triangle cut-outs shown in John's post, although it can be a little tricky to get the edges aligned with the straight tapes leading up to the curved section. Bias-cut tape conforms to curves nicely, but stretches and shrinks in the length and width dimensions as you move it around, so you have to be careful not to tug on it as you lay it in position, glue it down and iron it. Usually on the second attempt it's pretty easy to lay down a single layer of bias tape around the tail curve and get a really nice look.

With Oratex you could just cut a piece of fabric at 45 degrees to the weave and make your own bias-cut tape from a scrap to try it.
Dan

[Tralika]

I used ceconite fabric that was supplied with my kit from Just. It came with piece of bias ply tape to cover the joint where the fabric is glued to the compound curve on the front of the vertical stab. The bias ply tape, as well as all the other tapes, are used to reinforce the glue joints. As far as I know there is not way to make fabric glue joint with tape. If that's what you did when you covered your plane could you share the technique with us? I'd be interested to see how that works.

[FlyerChief]

Hi John,
Sorry for the confusion there... it has been a while since I did my covering, but I was talking about covering the fabric with the tapes to hide the little cut-out sections resulting from the small cuts made to get the fabric to bend around the complex curve of the tail. I made more cuts that were closer together and it conformed nicely without having to make little triangles to place in the openings left by the cut-outs. Once it was covered with the bias tape, Eko-filled, primed and sanded, you couldn't really see any cut-outs in the fabric layer. I'm not saying that you did yours wrong, in fact you did a great job and it looks fantastic; I just know that when I did mine, it wasn't necessary to fill in the little gaps with little cut-out triangles because my bias tape, Eko-fill, primer and paint pretty much hid the fabric joint. As I mentioned in my post, Oratex is likely a different story since it is already finished and doesn't get all the extra coats that hide some of the imperfections.
Regards,
Dan

[BDA]

Few more pics of the covered tail while rigging

I don't think this Silver fabric is translucent at all.

No Finish tapes yet

[BDA]

After finishing the last of the tail, I will share a few more of my "learned the hard way lessons"

- Use the heat gun to apply the fabric - iron after
- pull straight across the middle and tack down first, work out from there - when you are stretching the fabric as you go, it makes a difference
- LOTS of pulling and stretching when going around corners (less wrinkles to deal with later)
- Turn the heat gun DOWN when doing the final edge wrap
- Wipe everything with alcohol (not the drinkin kind) every time before sticking it down
- NEVER EVER leave a wrinkle till tomorrow to fix - glue hardens - no fixing

[BucF16]

Thank you! Please keep us in the loop about your "Lessons Learned".

Bruce

[BucF16]

BDA or all of you Oratex users. BDA discussed “knocking” down some of the welds on the tail structure. I went out and checked mine and saw that there is indeed a lot excess “Rod” used in the welds. I looked at a fuselage I welded with gas and it was much smoother. I’m reluctant to pull out the die grinder, BUT.....

The basic Oratex instructions do not discuss anti chafe tape, but talk about using scraps in the same method to cover rough/sharp areas. There seem to be a lot of those areas.

BDA said they were preaty obvious after covering. But as with anything we build, WE see the imperfections, where others don’t.

So, what is your recommendations?

Thanks in advance!
Bruce

[danerazz]

I just lightly rounded all of the spall with a file. You don’t want to remove much material as it WILL make the welds weaker, but just cut the really high spots and sharp points off so it won’t cut through your fabric over time.

And no need for a grinder, just a hand file will knock everything down pretty fast and easy to control.

Add anti chafe tape to all of the nubs before covering.

[BDA]

If I were doing the tailfeathers again - I would just smooth the larger welds on the leading edge a little to make it easier to get the fabric bonded without having to heat and stretch it over the irregular bump (no air pockets). Paul with Better aircraft fabric also said you can put extra glue around these as "filler" - I did that and it works - but some of the welds on mine are very large and irregular.

As far as using scraps to reinforce or as chafe tape - that works very well, I have also made several penetration reinforcements with scraps too.
** If you plan to do this from the beginning it takes a lot of the stress of getting the cut hole in your large piece of fabric EXACTLY right.

The old Piper aircraft that I have taken fabric off of have had many different kinds of anti-chafe, old dried out crumbling masking tape being the most common. Glueing the much tougher Oratex to the problem area seems like a much better idea to me.

That said - the Yoga pants will show that there is a reinforcement patch underneath...

[kenryan]

I did not grind any welds and I am completely happy with how it all looks. I did cover the few "sharp" spots with scrap. When in doubt, ask Lars! http://www.betteraircraftfabric.com

[BucF16]

Wow, that was fast! Thanks Gents. This forum is fantastic.

[BDA]

weld.jpg (19.89 KiB) Viewed 2027 times

I found a picture of one of the welds I was talking about - after the extra glue and after the fabric you can still see it sticks out quite a bit, (not the tubing), and you can see how the fabric doesn't lay down the same around the weld.

Not too big of a deal, just takes extra time to get the fabric to adhere well around it and lay over the tube well too - UNLESS - you use heat and stretch it over the high spot - like yoga pants.

I should mention that the penetration shown in the picture is tricky and I had to learn by trial and error - mostly error.
You have to stretch the fabric to the tension that you will use everywhere else BEFORE you start the hole for the penetration, then cut a VERY small hole (on the already fixed side) and stretch the fabric over the penetration then strectch/ cut/ stretch the fabric over the object untill it is all the way down then heat/ glue that spot down.
If you start the hole on top of the object it will be TOO BIG by the time you get it all the way down. You have to start just "behind" the penetration.

[AV8R Paul]

When I went to the Valdez Flyin in May there was one SuperSTOL at the event. It was covered with Oratex. That was the deciding reason to not use Oratex on my plane. Here are some photos of the plane. It was a an OK looking SuperSTOL not the best workmanship. I liked the minimal instrument panel, and the plex boot cowing area. I didn’t care for the opacity (I think that is the correct word!) of the material. Also the Tapes we a completely different shade of yellow, The tapes on the top rear of the fuselage were different than the tapes on the wings. They must have been 2different runs.

[alan]

Translucency. Or lack of opacity.