Question about ordering Kitfox Series 7 STi Firewall Back Kit. Planing to Use Oratex

[Denalifox]

Curious about the glue you used when repairing the hole. The factory insists on pre-mixing their glue and shelf life is a concern. Would be nice to hear Lars was stocking small bottles for repairs.

Funny you ask. Its actually too cold to use the Oratex glue and I didnt have a place to warm it up (plane basically lives on a dirt clearing). The hole was more of a tear of sorts about an 1" wide and about 4" long dead center in between two ribs. I know you cant just apply over an unsupported area. What I did was cut some 0.016 Aluminum as a backing plate and superglued the entire circumference. Then applied 2" tape over it. Worked like a charm! I also know Lars stocks bottles of glue. Ive had to stop by and get an extra bottle before when I ran short. Kind of nice being 30 minutes away.

[buckchop]

Well u guys do what u want with ur sewing threads, i myself will not use the waxed thread, cleaned or not. The problem is u never get all the wax out of the thread so it contaminates the Oratex glue, u say u encapsulate it in Oratex glue, thats good, BUT when u heat the Oratex glue/ hot melt adhesive at 280 or more to anchor or to shrink, ur fabric the wax leaks out of the thread and contaminates the strenth of the hot melt adhesive, sure it will stick now and mayb forever, BUT i say not worth the chance for ur fabric to come off in flight, Right Lauren?? cause thats where its comin off at, not sittin at the airfield or in hanger. Ive done 3 complete planes and one set of wings now in Oratex, went to the Oratex install class they gave in my hanger a few yrs ago that Joe from Oratex did, and no have sold of all my Poly products.
Im just sayin, there a reason Oratex says use no wax thread. It cant burn off the wax like the solvents in Poly does. Te wax mainly is for eas of knot tieing, And when u slide away from Oratex products ur “Warranty” goes south for GOOD not great when u spend $10-12,000 to cover a super cub.
Also Oratex says to follow ur manufacures recommendations on sewing ur wings, under-camber wings should b sewn, and dont b lazy and add the sewing to have more piece of mind while u enjoy flyin ur friends and family will love u more too boot.

JUST MY TWO CENTS AND RULES I FOLLOW, Like Dad always says “ do it right the first time so u dont have to do it again”

[Denalifox]

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Mine was a Trailing edge vanity tape that came off. This was a different roll than the rest of the plane. All my rib stitching tapes are rock solid.

[Eric Page]

The short glue life is my only complaint with the Oratex system so far, and with the Better Aircraft Fabric (BAF) and Oratex companies specifically. Neither Lars nor Janina mentioned the short shelf life when I ordered my covering kit last year. The glue that I received in early fall 2020 (shipped direct from the factory) appears to have been bottled in Feb 2019 and had about six months to go on its two year lifespan. So, I've got three liters of expensive "expired" glue on the shelf.

That said, I have a hard time believing that a water-based, heat activated glue that's factory sealed, stored in a cool, dark closet and shaken monthly to prevent settling will be unusable. The bottles say, "Best before...", which is different than, "Do not use after...", so I plan to try some test articles before I order new glue.

I would offer a few tips to anyone planning to use Oratex:

There are basically two types of fabric (plain, which light can pass through, or with an opaque black backing that hides internal structure), and both are available in two grades (I can't remember the names, but I'll call them first and second: first has no flaws, and second may have small cosmetic imperfections). Second grade fabric is significantly cheaper, and that's what I ordered.

Because the second grade fabric isn't made intentionally, there are limited quantities available. With that in mind, it pays to contact BAF early in your build if you want to get the second grade fabric. That way you'll have plenty of time to wait if the factory doesn't have a bolt of your desired color immediately available.

However, I would delay ordering glue until you're sure that you're about to start covering. My shipment from Oratex in Germany took about ten days to arrive, so if you order a few weeks before you're going to start, you'll have no trouble getting it in time, and it won't sit around and expire before you get started.

Oratex sells finishing tapes in various widths, and with plain or pinked edges, so you'll need to decide whether you want a clean, smooth look to your tapes, or the more conventional, classic look of jagged-edged tapes.

The Toko T14 waxing iron that BAF sells is available on Amazon at a significantly lower price, as are numerous digitally controlled heat guns.

[alexM]

Well this is...interesting.
I too optimistically ordered my Oratex adhesive and supplies earlier this year. I knew Eric's adhesive had turned into a pumpkin, and for some reason I had a 90 day shelf life in my head. Not sure where that came from but it seemed accurate: My adhesive has a "best used by" date of August 28 (just over a month ago now).

Reading Eric's comment about shelf life being two years I went out to my garage hoping I misread the label and it was Aug 28, 2022 but no such luck. I also see Eric's comment about his batch being produced in 2019. My bottles don't show a date of manufacture, I only see a single box with "stand 2019". I did a google translate to see if "stand" means something in German but it means pretty much the same thing it does in English. Disclosure, my German is about like my Spanish. I can find a bathroom and order an adult beverage but that's about it.

Talking with Eric previously I had mentioned that I saw some sort of test procedure for the adhesive (like there is with most aerospace chemicals which expire). Usually you use a sample of the adhesive and do a peel test to verify the strength. Before I opened my big mouth I did a google search and did find where someone posted a BAF FAQ on a Rans forum. And I quote (bold emphasis added):

5.) I opened a bottle of Oratex adhesive glue, but noticed that as I applied it, it was “lumpy”, and would not spread evenly?
Shelf life: Oratex (ready mix) adhesive glue has a limited shelf life (as is the case with most modern chemicals). The safe guaranteed usable life span of the glue is 6 months, so pay close attention to your expiration date. Depending on storage and conditions encountered, the Oratex adhesive glue may last up to a year. When the glue exceeds its shelf life, it turns from a uniform white liquid into a white liquid with concretions that appear like curdles in milk. The appearance of a thin watery top layer in a glue bottle that has been stationary for a while can be normal and non-problematic. Simply agitate the glue through vigorous shaking before using, as it is essentially solids, made up of nano-&-micro-particles suspended in water. If the glue appears semi-solid like a stiff yogurt or has a yellow-brown oily substance separating out from it, it has been frozen en route, or by accident while in storage and cannot be used. The glue is a non-hazmat material and can be disposed of without any special precautions, handling, or by any special restrictions.
Special note: You can, also, purchase Oratex adhesive glue in separate components, which, when stored under proper conditions, will last almost indefinitely. Then, you simply mix the individual components in measured amounts, when you are ready for applications.

That caused me to run back out to the garage to look for curdles or brown stuff. Note that I have some Oratex adhesive dated 2016 which came with my project for comparison. I opened both bottles after attempting to disturb them as little as possible. My new stuff still looks quite tasty with no sign of curds. The old stuff does show signs of separation and brown stuff indicating not only its advanced age but it has also likely been exposed to freezing temperatures.
PXL_20210930_190817580.jpg
2016 on the left
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2021
PXL_20210930_190831457.jpg
Yuk.

That 2nd to the last sentence in the quote above is interesting. If one could order the components individually that would solve any shelf life issues. But that FAQ is from 2012 and I don't see them offered that way in the current online catalogue.

[efwd]

Lots of good info here. I recommend non pinked edge. I used it for Nostalgia reasons I guess. I have not had that much trouble with too many triangles lifting but as much attention as I paid to ironing down the edges, I am annoyed at those that I have had to tack back down. That is all pretty much behind me now but I did have my reinforcement tape delaminate at the transition up the vertical stab. That is very likely because of the challenges of installing it in the first place. BAF does have small (30ml) bottles of glue. I have one suggestion that might improve the application and adherence of reinforcement tapes. Wherever possible, try to get something behind the fabric that supports the work area under your iron. You can look at my tapes I installed on the bottom of my plane in my thread. They look perfect. A year later I had to lay on the hangar floor and apply the iron over all the tapes again because I found numerous air pockets underneath the tapes. So, we all acknowledge how nice Oratex is when it comes time to repair. Probably a good thing that is case. I am hoping it doesn't require a recover at ten years. Don't use black paint. I have bubbles on my leading edges of both wings only where the black invasion stripes are.

[Eric Page]

Very interesting info, Alex. Makes me glad I've been shaking my glue bottles fairly regularly, though I have no idea where I got that idea. It would really be nice if there were some tech data that showed a test method, or at least a minimum pull measurement to induce delamination.

Re my glue's age, I think it must have been the "Stand 2019" that I saw and believed to be a manufacture date. My bottles say the same thing but "expired" at the end of February, so I guess that's not it.

I'm fairly close to being able to cover my wings, so I'm going to keep shaking my glue and see what happens. I'm almost tempted to take them to Home Depot and ask the paint guy to put them in the can shaker for a minute apiece!

[bumsteer]

Eric

Not sure if you've already seen this or are looking for another test but page 86 of the factory manual or pages 24-25 of BAF's Tips and Tricks show the Trial Attachment and Bonding Check to test the glue's ability to withstand peel. I've tested year and a half old glue (kept in a cool dark place) and it passed the test.

Rick

[Eric Page]

Beautiful -- thanks, Rick! A had only skimmed the Oratex manual, so I wasn't aware if that. I'm glad to hear that you had good results. Fingers crossed...

[buckchop]

Dont shake ur bottles of glue once u open and start to use them, u introduce air bubbles into the glue and that will fight u when u lay the hot melt on for ur two layers. All this tiny air bubbles have no glue in them, bst to roll ur bottle around and not get air mixed in the glue.
Yes the glue has a 6month shelf life, mostly to sell product and keep BAF in a better spot to complain if u have troubles, and that stuff is spendy, i had to buy 5 new bottles myself at $650 bucks, and when i look at the other 5 bottles they look just fine and glue tests r great, but i still got sucked in and bought new ones for doing the Pa12.
I have taken the BAF tips book and changed a few things as i have been doing my planes with it, different temps on somethings but mostly the temps on stickin the finish tape and when u do u anchoring to airframe

I HAVE NEVER HAD ANY TAPES PEEL OFF OR COME LOOSE, MAYB I CAN HELP FIGURE OUT WHY ITS HAPPENING.