Oratex - What order did you install the fuselage panels?

[tracstarr]

I've been keeping watch and reading over several build threads where Oratex is involved. I'm just starting mine now and have several unanswered questions. I didn't want to hijack those build threads so starting this one.

When applying to the fuselage, what order did you use and would you have changed that? Currently I'm planning bottom, top then sides. My reasoning is to then only apply the 2" tapes such that they are only visible on the top and bottom - not the sides. Additionally it would seem that the transition at the tail would be better hidden if it's wrapped around the tubing rather than trying to make a nice seam on top of a side piece.

The the other big question is if you applied strips of oratex to all the ribs of the wings and tail and then applied your panel on top of that. I've been told contradicting information. What did you do and why was that your decision? It would seem difficult to apply to all the little false ribs without breaking one or more of them. I've not noticed anything of mention in any builds in either direction. Images would make me think it's not been done.

Finally, how did you apply to the LLE? I've seen a few have done it. Did you apply glue to the entire surface and activate all at the same time (thus without stretching it) ? Or just in a small area then shrink and apply? What was your method?

Thanks.

[jrevens]

Keith,

I did the bottom, then the sides and last the top. As far as looks go, everyone has their own preferences I'm sure. I don't mind the look of the finish tapes, and you've got them all over the airplane anyway. As far as those fuselage corner tapes go, one of the primary purposes of finish tape is to provide additional protection and strength at joints and also over internal structure that contacts the fabric. If you don't want them to show on the sides they won't be covering the entire contact area of the tubing there. That's how I see it anyway.

I might be reading you wrong, but it seems as though you think it might be OK to apply finish tape underneath the main fabric instead of on top. That's not the way it's done. There is anti-chafe tape for application to underlying structure when there is a need, but just as the term "finish" implies, they go on last, over the main covering. When there is a hard, possibly protruding surface under the fabric, the finish tape protects the main fabric from external contact & abrasion that could possibly damage it.

FWIW, my LLE is scalloped, and I applied glue just up to the bottom of the scallops. I carefully shrunk behind the leading edge until I had a pretty taunt surface over it, and then started to apply heat & pressure to the LLE to activate that glue. Basically the same thing with the ribs.

[Shadowrider]

I've been keeping watch and reading over several build threads where Oratex is involved. I'm just starting mine now and have several unanswered questions...


Kieth, more than one way to do it as you will get many different opinions. First off, in my opinion, Oratax is a two person job. You will get a much better finish with two people versus trying to do it solo. It can be done solo for sure, but you will get a tighter cleaner finish with two. Remember tighter the better! Some tips. Make sure you read through the tips and tricks from better aircraft as there a lot of good info in there. Biggest problem we had is not getting the little hard bumps. Make sure you have your foam brush wet before starting. Clean the brush as it will start to build up dried chunks that will end up on the fabric. Also on your LLE make sure all the mold release is off it, or it will also cause little bumps.

I would recommend wings first. They are the easiest and then things get progressively harder from there. Glue the entire LLE. We did bottom of the wing, overlaped 4" to the top. Then did the top overlapped 4" on the bottom side. So the seam is on the bottom. We heated and attached front of fabric on and worked back until the entire LLE was attached. Then stretched it to the back of the wing tight. Sand, and wipe clean the top of the ribs to insure a good structural bond.

We then covered the bottom, and then cover the sides. I would start with the razor back. So cover the top center to the bottom, then do the other side from the top center to bottom. Then you will only have one visible seam down the middle. You only need finish tape on seams. Some prefer the looks of the finish tape, but there is no need to tape fuselage tubes or ribs. Oratex states in their manual the only places you are required to finish tape is at seams to help add protection of joint failures. No where else is it needed. You can put it where-ever you like, but its very time consuming and not needed. Oratex is not like other fabrics, you don't need anti-chaff tapes. We then did rudder and lastly horizontal stab and elevators. They are the hardest IMO. If you get a wrinkle, keep the heat on it and fix it right then. Sometimes you have to pull it up and stretch it and re-apply. Think through things on how you want things to look. On the horizontal stab and elevator we covered bottom first and then wrapped top to bottom. No visible seems on the top and the finish tape of the seem is on the bottom. Good luck you will be an expert by the end!

PM me and I am happy to talk anytime. Lars from better aircraft is a great source, also. Call him with questions.

[tracstarr]

Yeah, kinda the way I was lead on. It would end up being 3 layers. The bottom, main layer and then finish. But, it sounds like the anti-chafe is what I should be doing. I'm assuming you did so? And then you glue directly to it the main layer?
edit From below it sounds like I don't need to do this. It's also not mentioned in manuals - yet a phone call to BAF says I should do it on the ribs. Frustrating. Logically, I would think that if i'm gluing to the ribs there is no need for anti-chafe as it would never rub, it's glued.

[tracstarr]

Kieth, more than one way to do it as you will get many different opinions. First off, in my opinion, Oratax is a two person job.
Yep got some help for this part!


Make sure you read through the tips and tricks from better aircraft as there a lot of good info in there.
I find there is so much contradiction between theirs, the manual from the factory and then actually talking to them. This is the most frustrating thing - and why i'm asking here.



Biggest problem we had is not getting the little hard bumps. Make sure you have your foam brush wet before starting. Clean the brush as it will start to build up dried chunks that will end up on the fabric. Also on your LLE make sure all the mold release is off it, or it will also cause little bumps.
Yeah, noticed this when doing some tests. I'm finding that going back over the glue after about 10 min and you can knock down the bubbles and bumps pretty easy.




We then covered the bottom, and then cover the sides. I would start with the razor back. So cover the top center to the bottom, then do the other side from the top center to bottom. Then you will only have one visible seam down the middle.

So you only had 2 pieces to do sides/top? I'm assuming you had the additional razor back tube added to keep all seams on something... I don't have that so I am forced to do the top as it's own piece since there is no structure along that seam if i was to do it this way. i think I noticed this in your build pics. Took a few looks to figure out that's what you did though. If i was to plan it out again I'd go that route. I don't think my material would allow for that now.


Oratex is not like other fabrics, you don't need anti-chaff tapes.
This contradicts what I was told on a call with Paul (i think that's who it was) and then what's (not in) the manual.



We then did rudder and lastly horizontal stab and elevators. They are the hardest IMO. If you get a wrinkle, keep the heat on it and fix it right then. Sometimes you have to pull it up and stretch it and re-apply. Think through things on how you want things to look. On the horizontal stab and elevator we covered bottom first and then wrapped top to bottom. No visible seems on the top and the finish tape of the seem is on the bottom. Good luck you will be an expert by the end!

Yeah, my plan is to do those last as well.

I've started with the bottom of the fuselage. It seamed like one of the easier bits, and if i messed up it would be on the bottom and also using a cheaper color. The wings cost twice as much for the color of material.

[tracstarr]

As far as those fuselage corner tapes go, one of the primary purposes of finish tape is to provide additional protection and strength at joints and also over internal structure that contacts the fabric. If you don't want them to show on the sides they won't be covering the entire contact area of the tubing there. That's how I see it anyway.

this is another frustration as it varies in the manuals and from what I'm told over the phone. My understanding is that you only need tape over seams, no where else and that there is no requirement for them to wrap over the tube where both layers attach. But, at the same time, I'm told it's both needed and not needed over top of ribs on the wing.

[Shadowrider]

I hear you on the variations on what needs to be done. Paul is the sales guy and not as helpful when it comes to install. You want to talk to Lars. He can help you on install questions. Yes if you rub your hand lightly over the dried glue you can fill the bumps and get rid of them. My understanding the older systems you would reinforce over fuselage tubes and ribs to help keep them from tearing through the fabric. I assume you are using 6000? Lars will stress to you over and over this is completely different than other systems and where the finishing tapes are needed. With that being said I guess they are “experimental”🙂

[efwd]

The way I understood finish tapes was this. On the wing ribs they cover the stitching. On both ribs as well as all the other "fabric touching structure" spaces, finish tapes are the sacrificial layer. I already have one. the finish tape tore but spared the covering fabric.

[jrevens]

That’s exactly right, Eddie.

[jrevens]

Yeah, kinda the way I was lead on. It would end up being 3 layers. The bottom, main layer and then finish. But, it sounds like the anti-chafe is what I should be doing. I'm assuming you did so? And then you glue directly to it the main layer?
edit From below it sounds like I don't need to do this. It's also not mentioned in manuals - yet a phone call to BAF says I should do it on the ribs. Frustrating. Logically, I would think that if i'm gluing to the ribs there is no need for anti-chafe as it would never rub, it's glued.

There is no need for anti-chafe tape on the ribs. In fact it wouldn’t be at all good on the ribs that are glued to fabric, and would probably compromise the strength of the glued joint.

I used very little anti-chafe tape on the entire project - only on very specific areas where I thought there was a probability of movement between structure & fabric.

Just a quick comment or two about finish tape. I never heard Lars say that they were unnecessary, and I talked to him a lot during my project. We talked about finish tapes a lot. I believe I was one of the first to use Oratex on a Kitfox that was documented on this forum. Yes, Oratex is a little different, but it is still a fabric with a lot of similarity to PolyFiber. The process of covering, doing rib-lacing, using finish tapes, specific minimum overlaps at joints, etc., etc. have been developed, used, proven & certified over many decades. In every picture I have seen of Oratex covering jobs done by the company in Germany, they have used finish tapes. If Lars is now saying that they are optional, that is new to me. I’d want to see that in writing from the factory. Many conversations ended with the admonition that when in doubt, follow the same guidelines specified by PolyFiber & other major suppliers regarding these things. The glue system and the temperatures for glue activation and shrinking fabric are unique to Oratex.

[Shadowrider]

Lars Gleitsmann (Owner) (907) 229-6792 or Lars@betteraircraftfabric.com

Interesting.... Lars told me different and I never found that anywhere in the manual. I think this is his frustration. I was told if its touching it, glue it. Finishing tape is only for seams, rib stitching covering, and leading edge. To clarify he is not saying you don't need finishing tapes, but you don't use them the same way you do with the other fabric systems. There is not a need to cover all the fuselage tubes and ribs like you do with other fabrics. If you want to, you can, but its not needed.

[tracstarr]

Can anyone provide some close up images of their seams on the fuselage? And how you did the seam tapes? I'm currently debating if i do top/bottom then sides, or bottom-sides-top.
Doing the top last would make it easier to put in the static ports as I'm putting them near the tail, and leave ample time and room to complete wiring etc. However, I'm concerned about the looks of seams and tape.

[efwd]

No matter what you do, get good at trimming off the excess very straight. Guess I figured the seem was going to be hidden under the tape. Not.

[Shadowrider]

Yes like Eddie stated. Cut off excess as straight as possible as you will see it through the tape. Tape does not hide much.

[buckchop]

If u need some info and pic mayb i can help some, i not long ago finished my PA12 in white Oratex (I did whole thing by myself) that was bought from Better Aircraft Fabric here in Alaska, Larz and Paul had Joe come up to my shop from Anchorage and give a 3day class in the do's and dont's on it. Those guys r awesome people!!!! And they have a guide book they wrote to help understand the factory manual,
Bad thing is i cant figure how to post the pic off my phone to the form.

Their book says, to cover in 4 pieces to do roof last. And work from front to back of fuse, So i say, bottom, both sides, top last. Think how the water will shed off in the rain and not have any chance down the road to get into a bad seam that is unknown about.
But Remember, NO UNSUPPORTED SEAMS, and vertical seams r ugly.

[tracstarr]

New question has come up.

I did talk to Lars the other day and got a lot of things cleared up.

However, I'm not wondering how you guys covered the wing tip attachment area. Did you rivit on the bracket first then just fabric over it? Or did you do something else?

[bholland]

I put the fabric on first and wrapped it around the end rib/wing tip attachment area and then installed the wingtip attachments.

Brett
mykitlog.com/bholland

[Shadowrider]

I did talk to Lars the other day and got a lot of things cleared.
That’s good! For some reason this was not the last post? Yes rivet them on first then cover over. I countersunk the rivet holes. Plan on running 1” finishing tape over the seam when the wing tips are finally installed.

[tracstarr]

Well, my covering is now on hold. Really frustrated. In canada we have an inspection process and just after I cut my material and ready to apply a friend suggested we call the inspector and talk to him. Turns out they require fabric overlap to match what's in the manual from Germany... which would make thing look terrible. 2 inch overlap, then requiring seam tape. You'd have to apply standard 2" tape only on one side, it would look terrible. I'm now waiting to hear back from the head of the service about this, and Lars is reaching out to the German team to see if they can provide some written changes that would allow less. Always something....