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

[U2fletch]

I also decided to use the cap strip technique on the flaps. Rib stitched all the other surfaces so got to experience that fun. Surprisingly therapeutic after all is done. But I was curious about the idea of no rib stitching and tape on the flaps. Doubt if there is any time saving involved once you factor in the prep work and gluing of the cap strips. But it does look nice. It is hard to capture the look with a camera because there is nothing for the camera to focus on, and our flaps are white, but here is our result.

DSC_0405.jpg

[Allen B]

I’ve seen several people make claims that Oratex would save hundreds of hours of labor. I’m interested in understanding how that estimate was reached. Even if you don’t paint the fuselage or flaps/ailerons, you’re still needing to paint 70% of the surface area of the plane. I can see how it would save some time but all the issues with painting still exist and I simply can’t get to an estimate of ‘hundreds of hours’ in savings. Has anyone logged how long it took to just paint/prime the fuselage? I’m in the process of heading up to ANC to speak to Lars about it. Very curious about the product. Thanks

[svyolo]

I used heat shrink stuff on model airplanes 50 years ago, including something called Coverite which is very siimilar to Oratex. I have painted lots of stuff, but have never been a professional painter.

My opinion is that Oratex saves no labor, unless you take shortcuts. If you follow the instructions as best you can (a whole nother subject), it is very tedious. It saves sanding and making a mess. But the application of adnesive also DEMANDS cleanliness. You won't be doing dirty stuff in your shop while applying Oratex.

It does save sanding and making a mess. It is also very light, and that is VERY repeatable. It would be hard to make Oratex heavy.

[Allen B]

It seems like all the time and energy spent setting up a paint booth, buying equipment, etc is still going to be the same. If I was covering a fabric wing this would be a no brainer but there’s a ton of painting to be done after the fuselage so I see no time savings there at all. The Stewart videos are amazingly well done. I feel like with Oratex there’s going to be more time spent figuring out the product and a potentially higher learning curve. I like the Oratex product but I’m not sure that there’s 100 hrs of time savings. It’s going to take more time to learn and apply the Oratex vs SS product and that has to be factored in as well.

[U2fletch]

There are several factors at play here besides time. It takes me a day to glue all the parts that need covering. It took me a day to cover each control surface. Then another to do the rib stitching and trim tape. They are now completely done. Painting those parts would add at least another full few days. Repair is ridiculously simple. Clean the affected area and apply a patch. Done. The learning curve is a factor with any covering system. Don't look too close at the tip of our rudder. There are some cosmetic issues up there. The rest were a lot easier after the techniques were learned.

The durability is also something we are hopeful about. We are planning on a lot of off airport ops. Our Sportsman is currently taking a serious beating from rocks on the aluminum horizontal stab.

We have a large paint booth, and area to place it in the hangar, so can't get around the amount of paint required for the whole plane, but it is pretty convenient for us.

[Allen B]

For what it’s worth I spoke to an IA today who I happened to be flying with. He lives up in Alaska and was the first person to put Oratex on a champ. He claims since doing so he’s had issues that I haven’t read anyone talking about. In very cold temperatures he’s had the fabric expanding. He’s had to re-iron the Oratex over the Winter. I’ve never heard of such thing and I wonder how that would effect the longevity of the material. For the record we’re talking sub zero temps, not just normal Winter weather. Has anyone heard of this before?

[paulodonnell]

I've covered couple of biplanes in ceconite etc in the past and have found that using Oratex was a pure joy in comparison. I used their silver with black backing which seems less dull then their other colours.The hardest thing I found was the stretching of 2 or 3 inch tapes on the rudder and elevator tips without puckering the edges....however having the Germans just a phone call away from me in Ireland sorted things out, it was really just that I wasn't applying the heat over a long enough length of the tape while stretching and pulling. Siegfried Lanitz, the owner even called me back a couple of times to follow up and ensure I was happy. It has worked out very well though I've yet to do the main fuselage which will happen in the next couple of weeks... will be interesting to see how I fare on the tail end transition! On the tapes I only discovered on talking to Siegfried that the pre-impregnated tapes they sell need a primer applied and this was sent to me in the form of some granules that you dissolve in acetone. This means that unlike the normal glue you can just apply heat and pull it off easily to renew it.

[U2fletch]

That stretching and pulling of the trim tapes is one of those times when you need at least 3 hands. One pulling, one applying heat with the gun, and a few more working the felt blade to adhere it around the curves. Works great once you get it sorted out.