Roger has prodded me, gently, being the man he is, to post my "notes". As I've stated elsewhere, I have zero building experience, zero fabric experience, and am not paid by nor endorsed by Oratex, so anything I post should be taken with 5 pounds of salt. I am posting, hoping that those with experience will correct me and share the better way of doing things. This stuff is absolutely basic and am sure that those with any experience will either laugh at how stupid I am or find it boring, or both. These comments are specific to Oratex 6000. It is thicker and I suspect tougher to work with than 600.
The truth is, these are lessons I had to learn as the specifics of how to do things are not found on youtube and I had no manual to go with. The basic instruction to make a frame and practice is minimally helpful. If you want to practice before you start, get a non-serviceable rudder and do it completely from beginning to end. Once you've completed the finishing tape stage, disassemble it, at least down to one side in fabric. You'll need all the skills you've just learned, including the disassembly. Save the rudder with one side done so you can practice your rib sticking if you're doing any. I made the mistake of trying to take all the tail feathers through the same stage and one time. I wish I'd done one structure completely before doing the rest. Much to learn and made same mistake on all the pieces.
These posts are just a few things I'll share now.
I'll start simply. I didn't like the way the fabric pulled back from the rudder horn after shrinking. Those building may have solved that problem by building a shelf on the rudder horn to attach the fabric to prior to covering, or maybe you used less heat when shrinking and didn't have a problem. Not an option for me--I just had a problem to solve--it's experimental.
Gap at Rudder horn
Rough prototype. Can be painted to match, or covered with fabric. Thinnest I had was .020 aluminum, maybe you could go thinner?
Marking the cutline for the inside of the tubing is a problem when the fabric is already adhered at the leading edge, and using a compass as I've seen on legacy fabrics wasn't going to work with this fabric. I started inside at one end and creased the fabric at the factory recommended 270 degree wrap around, maintaining approximately the same wraparound for the entire length of tubing. Check to make sure your meeting the 270 degree wraparound and adjust as needed. Cut line. Actually, this pic is from when I overlaid the two fabrics. You could probably use a compass here.
Tools I've found useful so far are seen in the photo below.
Ruler used to ensure tape ends are square. Place across the width of the tape, with end parallel to sideline, cut across the width.
Five inch hemostat (slightly curved needle nose pliers) is my wife's favorite when laying down fabric/tapes. Lars heats his tapes from the glue side which blows them away from the structure and keeps them from prematurely adhering. I alternated sometimes...just because...heating the material from either side and used the pliers to keep the fabric away from the tubing. Saves on finger burns.
I'm not great with following straight lines when applying glue and used blue painter's tape (not Lars favorite) for ALL my glue lines on the fabric and when prepping for finishing tape. Remove the tape as you go and do not wait until you've finished the whole piece, say a whole rudder. The line will be crisper and not stringy if removed right away. Remember that both the fabric and tape can/will shrink in all directions, so make an allowance for shrinkage when you place your glue and don't expect the fabric/tape to lay down exactly where you thought when you bent it over.
Hobby store "craft wood", can be bought in popsicle size and smaller and was used to remove excess glue. The procedure is to soak a rag in a one part vinegar, three part water mixture and lay it on the glue for 3-5 minutes. The end of the craft wood was used as a push tool/scraper to roll the glue off. The ends of the sticks are contoured. The fabric is amazingly tough and unless you are trying to take dry glue off without soaking first, you will not damage the fabric. The wood ends dull quickly, like razor blades when working with this fabric. Lars mentions that you cannot remove glue that has been activated by heat, but I'm not sure about that yet. It seemed to me that I had some heat treated glue I removed by re-heating it slightly and putting my vinegar rag on it, followed by scraping. I'll have to test that theory out to be sure.
The staining pad is next. They had HDX brand at the box store, but I've used other brands. It worked much better for me than all brushes I tried. You get a much a smoother coat, less brush strokes, no bubbles, and no deposits of glue that harden into tiny mountains. The glue nibs seem especially problematic when your gluing the top side of fabric to be covered by more fabric. Throw your pad into a container of water as soon as you are no longer applying glue if you don't have time to rinse it out. I've rinsed mine repeatedly and set them out to dry. They were good to go the next day.
The last item is the chalk. I show it to say stay away from it. It was hard to find something to mark the cut lines on the fabric, as most markers bleed through, so I tried chalk. Great stuff, or so I thought, washed off with water easily, but the next day I found the chalk had bled through to the other side and had to be washed off again. At least no permanent markings remain.
I would appreciate any tips you more experienced Oratex guys have discovered, especially for the problematic areas like sharp radii on curved structures, the transition to vertical fin from the dorsal stringer, etc. I have a ways to go.
Lloyd