ORIGINAL: Konrad</p>
I have a question about formulations. It is my understanding that the dope of today is not compatible with the dope of yesterday (15+ years ago). I was told that the formulation was changed to meet some EPA mandate. I'm told that the new formula will lift the old formula when trying to make a patch repair.
So I'd like to know if this is in fact true and if so does it apply to both Nitrate and Butyrate dopes.</p>
All the best,</p>
Konrad
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Konrad,</p>
Ican hardly believe that this is you.
So nice to see you here.</p>
I do not know about the formulations.
I do know that some recently acquired dope can be used to repair (patch) old doped covering.</p>
I have patched a wing that had a tear about 3 inches long between two ribs.
It teared because it was not a strong fabric. It was heavy tissue paper like we see for Xmas wrapping that had been doped with Berry Brothers dope about 40 years ago. So, real old dope.</p>
So I experimented knowing that dope penetrates previous coats (fuses) .
I first used some butyrate thinner to wet the area around the tear.
The old dope softened enough to scrape off a layer this removing any dirt, wax and get to the inner part of the layer. I applied some new Sig clear butyrate dope and it did not seem to create any problems. It cured in about 30 minutes (dry to the touch).</p>
I cut a piece of similar tissue and applied dope on boh the wing and one side of the patch tissue and matched them together. I was amaxed of the results when the dope cured. I applied more dope on the outside surface of the patch and the repair is visible but ok.</p>
Perhaps the bad results reported might be due to leaving dirt and waxy stuff</p>
Zor
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