Covering the Fuselage bottom
So the last few days have gone great. A bit nerve racking dealing with Oratex for the first time. But, that said, I’m 100% more confident already. It’s not as scary as you think and much more forgiving as well. Although, don’t get me wrong, it’s still easy to mess up if you have glue in the wrong place or don’t plan out the shrinking.
I started first with doing the “glue test” as perscribed in the manuals. So far so good. Although, there was a panic moment when I noticed the bottles of glue I was sent expired in 2 days. After some frantic calls to Lars everything worked out and I was able to continue.
First, this is a two person job. I know others have done it alone, but it’s so much easier with some help. We laid the Oratex onto the bottom and clamped it into approximate place. Some relief cuts were made. I then crawled under and used a yellow pencil to mark all of the tubes where glue would need to be applied on the fabric. Once done, the Oratex was placed onto the work bench were two coats of the glue was applied. Thin coats. We also applied two thin coats on the frame.
We came back the following day after giving the glue ample time to dry. The Oratex was then placed back onto the fuselage and clamped into place. From there I used the hot iron to tack one side and then the other under the seating area. Once that was tacked we moved along back and forth along the tail. I tacked it down and the other helped pull and stretch as necessary. Very little was needed.
Once tacked along all edges we continued by fully tacking the Oratex the full 270 degrees around the tubing and following that up with full temperature to set the glue. Everything so far was going great. The nerves were slowing calming.
Now, the next part I realized after the fact that I probably should have waited a lot longer as the manual suggests. Instead, I only gave the glue a few hours before I started the shrinking process. Using the heat gun I nervously started applying the heat to shrink it. It was shrinking. It was actually shrinking a lot more than expected. It was rather satisfying to be honest.
It took a few passes to get use to the distance from material and speed to get the shrink working well. There really wasn’t much to it at this point. I was very happy with the way it was working out.
Next, we applied some more glue directly between the fabric and stringers and then all of the smaller tubes under the main cockpit area. These were previously without glue to allow shrinking first without activation. This was recommended by Lars (whom I had several calls with during this initial process).
Let that dry and then went back and applied the iron to activate the glue along these structures. It’s just a very very thin touch point, but should keep the fabric from vibrating. The bond, even on such a small surface, is very very strong. I was really impressed. It also means that no tapes are required over these areas as in typical Poly-fiber application.
I did add some small circular re-enforcement patches to the areas where the small tabs stick out the bottom. It just helped clean up the look of the cuts.
Time to move on to the sides!