Fokker Streaky Camouflage Fabric - Duration Test

G'day, Achim,

Thanks for presenting this report, as well as the previous follow-up on the exposure/duration experiment (which I had somehow missed). With respect to this IWM report, I have either also missed the background details--the who, what, where, and especially the when--in the mass of this thread or perhaps they were not specified. Can I ask your indulgence to repeat them if necessary?

I am interested in whether there is more to come, as what you have so far posted seems limited to the undersurfaces, at least with respect to color--or is it?

I have made some annotations below regarding some of the words that are in question:

Top of main planes (top and bottom of tail planes)

grun wash [["green"?]

2nd series no 5 [any idea what this refers to?]

...this treatment reducing the ordinary retted (netted?) filaments to the ultimate fibre of a pingli (single?) [yes, doubtless "single"] cell,

possibly treated in this manner*to use a coarser grade of flax for finir (finer?) yarns [yes, probably "finer']

then could be obtained with ordinary retting (?)

Under pidu (?) ["side"] of all panes ["planes"]

blue

Fabric cont ["count'] Tist (test) [yes, "test']

of pample (sample?) [yes, "sample"][

compared with British Standard *Fabric

...
Weight of dope film 4.8 osp (?) [probably "oz."] per sq yd.

...
The wright (weight?) [yes, "weight"] of dope covering 1.4 oz per sq: yard

Best wishes,
Stefen

[EdStevens]

Gotta love google. It is indeed "retting":

"Once harvested, flax is dried in the fields. Then the fibers have to be loosened from the pectin gums and woody stalk in a process called "retting."

There are two ways to do this, Libeert says, and both require expertise in timing as well as handling. In "dew retting," flax is laid in the fields to absorb the morning dew, which takes about 3-6 weeks. "Water retting" is done by soaking the flax in rivers, ponds, or more recently, tanks of warm water.

One small retting operation we visit, where huge cement tanks are tightly packed with bundles of flax, Libeert calls "practically a museum." Why? Although much faster (3-5 days long), it takes more manpower and may cause pollution problems. Thus, most flax in Europe is dew retted today. (Amazingly, the same method used by ancient Egyptians.) "

[AchimEngels]

Hello all,

After the piece was out in the elements for 90 days I have cut it from the frame and made the above photograph of it. I then stored it away in my shelfs. Yesterday I took a another look at it and was not badly surprised to see that it it turned considerebly into brown in the meantime. I think this is due to the lineseed cover I placed over the entire surface.

The piece now looks very much like the piece Dave Watts provided images of elsewhere in this thread.

I wonder if the long time neccessary to note that effect was due to the fact that the lineseed cover indeed was applied as a final coat, but with some kind of siccative added to speed up the drying process.

My other experiment that at the end perhaps a clear boat varnsih was applied did not show any sign of "browning out" so far.

I will conduct more tests and keep you posted.

I will also take an photograph of the brown piece by tomorrow and post it here as well.

Best

Achim

[AchimEngels]

Hello,

Eight months later we can conclude that a linseed protection coat if applied to a reproduction aircraft may result in a pretty much yellowish/brown appearance of the aircraft.

Here is how a such treated piece of fabric taken from my first experiment looks today:



The fabric sample does get close to the original fabric sample of triplane fabric held at the IWM. This confirms to me that judging the color hue of a original piece of fabric today does not inevitably give any information about how it looked in factory fresh condition.

Enjoy!

Achim
*

[AchimEngels]

Hello,

Here are some better images of the test results.





The large piece and the small piece are basically done the same way.

The only difference is the use of a final coat of clear boat varnish for the large piece and the use of a final linseed protective coat for the small piece.

Those of you who followed this threat from the beginning on know that both pieces looked absolute identical in the beginning with respect to the appearance of the colors.

Now over one year later we can clearly see a difference.

While the one covered with a clear boat varnish does still look "factory fresh" the other one has considerably turned into a yellowish brown hue.

As a conclusion it can be said the following:

1. The smaller piece, compared to the original piece of fabric of Dr.I 144/17 held by the IWM (shown elsewhere in this threat) might well represent the way it was done back then.

2. It took about half a year until a first shift of the color was noted.

3. Anybody considering using a final coat of linseed protective coat for a repro or a museum piece, should be aware that after some time his plane (or part of) might no longer look the way it was intended.

4. If a long time "factory fresh" appearance is desired, one should consider using a clear boat varnish to finally cover the paint.

5. Judging the color of a 80 year old so treated piece and saying it looked that way when "factory fresh" is not possible.

6. There is no adding of brown necessary to achieve that kind of brownish appearance.

7. The time it took to produce the shift in he color indicates that only very few Fokker aircraft built during 1917 ever actually lived long enough to be still serviceable when they shifted to the brownish shade.

I will conduct further experiments in this way, but will consider this one as closed. I do indeed hope that you (at least some of you) found this interesting. May some of those who told me this thing would prove nothing change their mind - or not. I don´t care! :

Thank you!

Enjoy!

Achim

[Barker]

Great Stuff Achim!

Luck with the build!