Fabric rejuvinator question

[nemecek]

I have a Skybolt that has a few small cracks in the paint on a lower wing, due probably to an inspection cover being lost in flight. I was wondering if anyone has experience with and/or any suggestions on fabric rejuvenator such as if it really works, how well it works, and how to best to use it. I really hate to even contemplate recovering the wing.

[cub builder]

Fabric rejuvenator is designed to melt the cracks back together in nitrate/butyrate dopes. But you don't say whether your finish is Dope, Polyfiber, Stewarts, PolyUrethane, Acrylic Urethane, or some other kind of paint, or what materials were used to build up the wing. (Nitrate/butyrate, polyfiber, Stewarts, or ???) Those are pretty key questions. The only rejuvenator I have seen is designed for dope finishes, so will only work with Nitrate/butyrate dope build up with a dope finish. If your finish was built up with a different process, or painted with anything other than butyrate dope, it's not going to work for you. But all is not lost. Depending on what kind of paint is on there, you may be able to lightly sand the finish down into the substrate, then reshoot that area and the finish coat. If you haven't done this before, it's best to have an expert in fabric finishes either help you with the repairs, or do the work. Good luck with it. -Cub builder

[nemecek]

Thanks for the info and reply. Unfortunately I bought the Skybolt, which was built in 1976, there is no data on what was used to paint it. I am 97% sure it has Stitts fabric (it does on the fuselage anyway). "Bahama Blue" is written in the inside of the inspection cover for the tail, which happens to be a Stitts color and is the same shade of blue as is on the plane, this leads me to believe that the white is also a Stitts color. I am certain its not epoxy based as I touched it with some acetone and it came right off. This suggests to me that it is probably Stitts Polytone. That leaves me with 4 shades of Stitts white for me to choose from. Polytone does make a rejuvinator so that is probably the direction I will be heading in. Thanks again.

[Bill Berson]

Dope rejuvenator won't last long for deep cracks that will return in a few months from the same original stress.I repair deep dope cracks with 2" finishing tape doped on. Looks good. Quick.

[iterk]

Bill, Sorry for the slow reply. 1) Bahama Blue is a stock color in many paints including the various butyrate dopes (i.e. Randolph) as well as in the Stits/PolyTone product. The fact that lacquer thinner dissolved the finish still only shows that the product IS rejuvenateable and that it is most likely either Stits/PolyFibre or 'Dope' ala Ceconite. 2) take a look at the inside of the fabric (through an inspection hole or in the fuselage). If it has a strong pink tint that is the ferrous oxide tint that Ray (Stits) added in later years (post '79?) to help see the build up. (They still will sell clear Poly Brush if you ask. We use it on restorations where the interior would show and the pink would be out of place). IF the inside of the fabric shows a yellow, blue or greenish tint then the process is one of the nitrate/butyrate (Ceconite type) finishes.) That color comes from one of the (copper/copper sulfate?) based anti fungal additives left over from the days of cotton/linen. Depending on which finish you have you might rejuvenate with that product's rejuvenator. In the '70's Ray Stits sent us dealers a memo that said that it was a sound and acceptable procedure to rejuvinate EITHER process with the Stits/Poly rejuvenator (RJ1200) followed by a couple coats of silver Poly Spray and Poly Tone or Aerothane finish. DO NOT GOT THE OTHER WAY (Butyrate rejuvenator over Stits). The processes will only work with Stits OVER dopes. I have had to argue this old process with the FAA since the current owners of the process do not have ALL the old files and the old Service Letter was never "FAA approved" ( they didn't require such an approval back then as long as the letter was from the manufacturer.....I've been around with this...) BUT.. You have an Amature built aircraft and can go this route. It means repainting the whole airplane. IF you just want to spot refinish areas use the rejuvenator for the base, i.e. Butysolve J3000 over butyrate finish or the PolyFibre RJ1200 if it really is Stits. Take a look at the 'correct' procedure manual (on line..) for whatever you figure out is your base an FOLLOW THE INSTRUCTIONS B-))!!It is my guess, given the nature of what you described, that you have an old Nitrate/butyrate (Ceconite type) finish. Stits WILL crack if it's too thick or if the builder took shortcuts and used lacquer thinner instead of Stits reducer to save a buck... but use the inside color to try to tell. You are welcome to call me (904 403-3360) and feel free to take a look at my 'pedigree'... I know enough to know I don't know it all...but I've been at this a while B-)). Terk

[nemecek]

Terk,

Fantastic, this is the info I was looking for!!!

Thanks for the detailed reply. It will likely be a few weeks before I can get to the plane as I am up to my neck in other projects. I appreciate your offer for a phone call and will probably follow up, possibly this spring.

Thanks again,

Larry

Bill, Sorry for the slow reply. 1) Bahama Blue is a stock color in many paints including the various butyrate dopes (i.e. Randolph) as well as in the Stits/PolyTone product. The fact that lacquer thinner dissolved the finish still only shows that the product IS rejuvenateable and that it is most likely either Stits/PolyFibre or 'Dope' ala Ceconite. 2) take a look at the inside of the fabric (through an inspection hole or in the fuselage). If it has a strong pink tint that is the ferrous oxide tint that Ray (Stits) added in later years (post '79?) to help see the build up. (They still will sell clear Poly Brush if you ask. We use it on restorations where the interior would show and the pink would be out of place). IF the inside of the fabric shows a yellow, blue or greenish tint then the process is one of the nitrate/butyrate (Ceconite type) finishes.) That color comes from one of the (copper/copper sulfate?) based anti fungal additives left over from the days of cotton/linen. Depending on which finish you have you might rejuvenate with that product's rejuvenator. In the '70's Ray Stits sent us dealers a memo that said that it was a sound and acceptable procedure to rejuvinate EITHER process with the Stits/Poly rejuvenator (RJ1200) followed by a couple coats of silver Poly Spray and Poly Tone or Aerothane finish. DO NOT GOT THE OTHER WAY (Butyrate rejuvenator over Stits). The processes will only work with Stits OVER dopes. I have had to argue this old process with the FAA since the current owners of the process do not have ALL the old files and the old Service Letter was never "FAA approved" ( they didn't require such an approval back then as long as the letter was from the manufacturer.....I've been around with this...) BUT.. You have an Amature built aircraft and can go this route. It means repainting the whole airplane. IF you just want to spot refinish areas use the rejuvenator for the base, i.e. Butysolve J3000 over butyrate finish or the PolyFibre RJ1200 if it really is Stits. Take a look at the 'correct' procedure manual (on line..) for whatever you figure out is your base an FOLLOW THE INSTRUCTIONS B-))!!It is my guess, given the nature of what you described, that you have an old Nitrate/butyrate (Ceconite type) finish. Stits WILL crack if it's too thick or if the builder took shortcuts and used lacquer thinner instead of Stits reducer to save a buck... but use the inside color to try to tell. You are welcome to call me (904 403-3360) and feel free to take a look at my 'pedigree'... I know enough to know I don't know it all...but I've been at this a while B-)). Terk