Covering with Oratex

[jaredyates]

Have you had a chance to see an Oratex plane in person? If not, I would say that should be a mandatory data point. It is a different type of finished product.

[Utah-Jay]

Have you had a chance to see an Oratex plane in person? If not, I would say that should be a mandatory data point. It is a different type of finished product.

I could not agree more! Oratex is not the same. I knew that going in… But if you expect/want a wet look finish then Oratex is not for you.

[U2fletch]

I spent a lot of time talking with Lars as well at Oshkosh. Unlike my experience with other iron on coverings, Oratex can get around curves not just by shrinking, but by heating and stretching the fabric. In other words, a lot of people just think you get rid of wrinkles by shrinking the fabric. Not true, you can eliminate a lot of them by strategic heating and pulling when laying it down. That was new to me. I recently covered all the seats, and this knowledge helped a great deal in negotiating the tight corners.

[svyolo]

I have never covered an airplane with one of the normal systems but I bought a couple of yards just to compare. Regul;ar cloth has some stretchiness to it which you can use during application, and you could probably use heat as well. Oratex has essentially zero stretch without heat. You have to heat it to stretch it.

[arborite]

Have you had a chance to see an Oratex plane in person? If not, I would say that should be a mandatory data point. It is a different type of finished product.

Yes, I’ve seen a covered plane and am fine with the finish look. Sort of like my old cub. Even if I use Stewart’s, I’m not going for the super glossy look. Too heavy.

[paulodonnell]

Just started covering with Oratex Silver / jet black backing...lovely product to use with a very nice glossy finish.

I've covered a biplane before with trad Ceconite etc but decided to go with Oratex to save time weight & numerous coats of spraying etc.

I'm also using their 'engineering design change' option which is a system of bonding 1.2mm beech ply strips to the ribs which eliminates the need for rib stitching. This system is also EASA certified for various aircraft notably the Pitts Special and cub types. In testing the pull strength, they said the wooden ribs failed before the fabric could be pulled off. After degreasing, the strips are bonded using aviation grade epoxy dispensed from a rather expensive 'gun' ..€450! The bonding side of the strips are first impregnated with an Epoxy primer from Oratex.

The strips take out the the tiny height difference between the leading and trailing edges on the flaps and ailerons to the rib surface and I should end up with a very smooth finish free of bumps from stitching and the tapes are also eliminated.

cap strips.jpg cap strips2.jpg

[Utah-Jay]

IF you use heat AND stretch Oratex you will not be happy! It develops a terrible grainy texture.

[svyolo]

How did you do the base of the tail without heating/stretching? Any pictures prior to shrinking the wrinkles out? I didn't even attempt it. I made a composite fairing for the base of the tail, which turned out good.

[Utah-Jay]

Ahhhh, so finally someone ( svyolo ) has asked the correct question, i knew someone would eventually.

No you can’t stretch the Oratex to fit the curve from the top of the fuselage to the rise at the start of the vertices. Colby Osborn tried and it did not work, I did extensive testing after watching Colby’s videos and thought I had the problem solved…. I was wrong.

The only way I found to make it work was to have relief cuts on both the right and left side pieces of fabric. The use of tapes is the final piece to the puzzle.

Oratex wants to shrink, NOT stretch, so the relief cuts are the only way.

The other gotcha location on the BH is the compound bend just behind the skylight and above the window on my Companion, but all BH’s have the same compound bend area. Is “bend” the correct terminology? Dunno… The way to deal with this spot is to go from the bottom up, in my case from the top of the window up to the longeron and wrap the fabric around the longeron. Next when you are putting the whole side fabric tack it all down and then make a relief cut from the low point of the compound bend and let it continue down to the window. The takes one tape as the wide point at the top of the window is only about 1/2” wide.

Hope this helps

There are no other gotcha points for Oratex on the BH

[svyolo]

My first plan was to add a strip of metal forward of the tail to terminate the fabric, then cover the tail separately from the rest of the fuselage. I am pretty sure that would have worked just fine. As I was adding those terminations, someone suggested that he wanted a composite fairing for the base fo the tail. So I covered just the base of the tail with Oratex, which worked OK, and I used that as a mold. Turned out so good I used it. I added some nutplates to the termination strips, and Tigged some tabs to the longerons to attach it.

[N204jh]

Jay, you have any pictures of the cuts? I poured over your Oct - Nov 2022 builders log photos and see the issue and the finished result, but was hoping you may have some pics of the process. Of course, we can wait until Spring and I'll just have to fly you up to Washington for on-site "consulting."

[Utah-Jay]

I offloaded all my photos onto an external hard drive so not sure. I am happy to try to find them when you need and if I don’t have good photos I can do drawings for ya