Ceconite 7600 Paint

[RichardMaxted]

I wonder if anybody can help with some expertise. According to the documentation I have my aircraft was covered in Aerofill Ceconite 7600 system procedures I.A.W. FAR 43.13. in 2008 I think. However, other than this there are no details of what paint was used etc in the log books or the documentation.

I have a piece of the fabric that was cut out for the wing inspection holes. The fabric is stained green which I take to be the first coat - sort of like Rand-o-Proof. On top of this is the orange top coat - at first glance.

Taking a few flakes from the top coat they are blue on the underside of the flakes - which to my untrained eye suggests some other coat between the green and the orange top coat because I would expect flakes of paint to be the same colour top and bottom.

Wondering if the top coat was automotive paint I cut a small piece from my sample and was able to get the top coat paint colour to dissolve onto a kitchen paper towel soaked in white spirit. As I understand it automotive two pack is totally impervious to white spirit ?

Doing a bit of research it looks like the Stewart System uses a product that is blue - grey in colour - Ekofil/Cecofil ? - very similar to that which underlies my flakes. This would make sort of sense if the aircraft was covered in Ceconite 7600 as this was a sort of precursor to the Stewart System of water solvent paints ?

The reason I ask is that I would like to make sure I don't swap from the Stewart System inheritance of the Ceconite 7600 system to the current Randolf / Ceconite / Super Seam Cement based system.

Any expertise / advise / experience / words of warning would be gratefully received. I have a bit of small repair work ( scuffs ) to look at but it is mainly to make sure I can get a better history. Of course if anyone was involved in the covering of Cessna 120 GBVUZ and can remember that would just brilliant.

[tnowak]

Hi Richard,

I posed your question on another forum and got this reply back:

"Stewarts is approved to repair any other system. Sounds like nitrate butyrate dope but unsure on the top coat. I have seen nitrate that was green and blue. Stewarts glue is light blue but there is an obvious difference where tapes and patches are glued when viewing from the inside."

Hope this helps a bit.

If your topcoat is softened/melted by white spirit then it isn't two pack or butyrate.
What does avgas/mogas do to your sample?

Tony N

[Ian Melville]

I always thought White Spirit was one of the least aggressive solvents? Used to be used in household and artist paints before water based systems came to the fore.

[RichardMaxted]

Thank you chaps for your responses. I am pretty sure it isn't glue - although given it is the cut out fabric from an inspection ring of course it might be. I had reached a similar idea about inspecting the inside more closely to see if I could see blue glue which would be a give away.

So far as I can see the usual fuel spills on the wing don't seem to affected the paint but to be honest I probably need to take a closer look and, as you say conduct a bit of a test on my sample, when I have some fuel testing sample to hand.

I have also had an idea to try MEK and Cellulose thinner on separate pieces of the sample. As I understand it if it is two pack automotive only the cellulose thinner will dissolve it but MEK will dissolve butyrate.

All very interesting stuff and thanks for your help

[Ian Melville]

Cellulose thinner will dissolve 2 pack, but it does not give up easily. A lot of soaking and scraping, just done a it on a large patch

[tnowak]

Richard,

Got some more info:
Quote:
"The ceconite 7600 process has been long gone and I doubt anyone would use it in 2008. The fabric had an epoxy coating on it that makes the fabric yellow in color. The adhesive was green and activated with MEK, and the primer/filler was a medium gray latex, and their topcoat was also a latex base paint. It was easy to use, but it cracked really bad and just did not hold up and as far as I know it went away in the early 1990's. I have 1953 Tripacer that was covered with ceconite 7600 in 1988. The wings and stabs were recovered in 2001 because it failed on annual inspection and today you can push your finger through the fabric anyplace the sunlight hit the fuselage. That plane is currently being restored and will be covered with Poly-Fiber. Latex paint should be dissolved with white spirits."

Hope this helps.

Tony Nowak

[RichardMaxted]

Tony that is brilliant - I have sent you a pm about the pic you sent.

This is interesting information, as what I can see inside is much more like your picture of Stewart System finish. Hard to tell the original colour of the fabric as it is all stained / coated with green . On my aircraft the fabric ( according to my engineer and inspector) is in good condition as are the seams - all of which suggests "ordinary" ceconite. That does rather contradict the documentation I have available unless a somewhat mixed approach was taken after fabric application - in which case it fits together.

I am verging towards the top coat being some kind of urethane although latex paint might fit the bill. The paint does not dissolve in Avgas and having done some more tests with Meths and White Spirit one could stain up a soaked paper towel when rubbing the paintwork but the paint actually did not disintegrate just lost some of its "bloom". I am fairly sure it is not automotive paint as whoever covered the wing, and made such a beautiful job of the stitching and seams, clearly knew what they were about.

Next week is annual time so I will have some larger inspection panels open to be able to get the glue colour.