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Tandem AirBike Builder's Log

February, 2003 -- Fuselage finishing and misc.

Page 2


Inside the tent now, with the rotisserie in place. I painted all the metal tube structures with this Harbor Freight touch-up gun. Even with its small spray pattern, most of the paint blows by the narrow tubes and is wasted. You'll need several quarts of primer to cover all the metal this way.


MIsc. parts being coated with 2-part epoxy primer



Metallic colors rely on a white undercoat to bring out the luster in the metal flakes. This means that the color coat needs to end up just thick enough to give the proper density while not getting thick enough to totally hide the white undercoat. This made my color coat application tricky, and I'll avoid metallics from now on!


The fuselage tail section on the adapted rotisserie.



Here the fabric and reinforcement tapes and patches have been applied to the fuselage with CecoBond, the fabric has been heat-taughtened and the entire surface has been brushed with diluted CecoBond to fill the weave. Painted surfaces next to the fabric have been masked off, with some upwind surfaces relying on wind flow to keep overspray away. These unprotected surfaces ended up with light overspray anyway, but it was not adhered well and could be wiped off with a rag.

CecoBond is a waterborne contact cement. You brush it onto the frame first and let it dry, then overlay the fabric and brush more glue down through the fabric to reactivate the first coat. Sometimes this works well, and sometimes it becomes quite annoying. For some reason, the wet coat from the outside will sometimes lift the first coat right off the painted tube (scuffed per the instructions), and then you have a problem. It's difficult to get more glue down through the fabric which is already saturated with somewhat cured glue. Then when you do get fresh glue worked into the problem area, there isn't any air in there to cure it so it won't stick. The choices I found were either holding the problem areas down with finger pressure for several minutes (this greatly increases the time required to do what should be a relatively quick job) or come back later and bond the problem area with heat and pressure from an iron. Despite a higher toxicity level, I would much rather use Poly-Tak than CecoBond.

Another thing to be aware of when using CecoBond -- don't let masking tape get near it! CecoBond will bond to the tape's resin with a vengeance, and will either rip the resin off the tape and leave an ugly mess or the tape will rip the CecoBond (and possibly the adjacent paint and fabric) right off the airplane.


Applying the CecoFill with the same touch-up gun.

In my left hand is a trouble light used constantly while spraying as my booth didn't feature nearly enough light for this kind of work. Even this wasn't enough light, so don't underestimate how much light is required to do a good job of it.


The sixth coat of CecoFill.


With the fabric color-coated, the fuselage is about ready to go.


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