cotton flux

[grdev]

I am buying an early model 4. I found an ad for cotton flux usen in the wing apoxy was this ever resolved?

[Floog]

Say again?

[grdev]

From what I understand a mistake was made with some kits where cotton is supplied to be mixed with the epoxy used to attach ribs to spars. Some kits were shipped with fiber glass. Instead. As the kit I am buying already has the rips glued I don't know what was used as I wii be the 3 owner of this project. I found this in the Kitfox directives

[Kahle76]

Welcome! The cotton flox is a structural component and micro balloons are used as a filler. The micro bolloons do no add any strength. If you make it to SE Missouri, stop by. We have 3 owners in the area.

Mike

[HighWing]

I can only guess on this, so take it for that. The time the Service Bulletin was issued was a very busy time for Denney Kitfox. They were very thorough as indicated by the letter. I would suspect if their testing found a significant structural strength issue, a follow up letter would have been issued.

I would think if there is access to any of the wing rib attachments where the epoxy could be sanded, you could visually determine what the filler was. The Micro Balloons result in a very easy to sand surface, whereas the cotton flox would be much more difficult to sand. Then sanded Micro as it is called has a very rough surface microscopically as the glass balloons are exactly that - tiny glass hollow spheres. Sanded cotton flox might actually show evidence of the cotton fibers if looked at with a magnifying glass.

I just checked my Model IV and it looks like the only way to check would be with the wings folded.

[kmach]

Wouldn't taking a wing tip off give you access to some rib to spar glue joints ?

[HighWing]

Wouldn't taking a wing tip off give you access to some rib to spar glue joints ?
Thanks for the heads up on that. My wing tips are permanently attached and I didn't consider that most builders opt for the removable tips.

[SkyPirate]

1-model 3 ,3 model 4, 2 model 5 and a model 7 over here west of you between houston MO and Joplin and south between the 2 👍

[jeffcoaj]

Do you use cotton flox with epoxy to glue ribs to spars? Thanks

[grdev]

My Model 4 project is in the U-Haul out in the drive way. Now there will be another Fox in SE Missouri. I was going down the list of directives issued from Kitfox, and one of them was a mandatory Cotton Flux. I had no Idea what that was. Reading on I see Kitfox may have shipped a fiberglass instead of cotton, and they were not sure if it was adequate. It went on to say they would do testing, but I can not find test results, or a solution if you wing ribs are already glued in place.

[jiott]

Per the SS7 manual, yes you do use the cotton flox mixed with Hysol epoxy to glue wing ribs to spars. You mix in enough to get a toothpaste like consistency-not real critical-don't stress out about how much. It does two things: increases the epoxy strength, and more importantly stiffens the epoxy so it will stay where you put it and not sag away while curing.