by kittyfritters » Fri Mar 13, 2009 2:52 pm
This became an issue for me when I returned to model building, after a 30 year hiatus, because my wife has many allergies. Fortunately, techniques and materials had changed a bit since my Duco and dope days.
I started building with TiteBond II, aliphatic resin (yellow carpinter's glue) quite successfully, and recently changed to TiteBond III. No offensive odor, strong, waterproof, but once it's set, it's set...un-gluing is simply not possible. I think that the TiteBond II gives better results with balsa and may go back to it. I use a Monoject 412 irrigation syringe to apply the glue where I want it.
I do keep some Smith Brothers, medium thickness, gap filling, cyanoacrylate (super glue) around for difficult bonds and field repairs, but I don't use it much. When I have tried to build entire models with it I found that it is heavy and that I am sensitive to it myself.
I attach tissue and silkspan, both wet and dry, with Uhu gluestick (purple) and have been very happy with the results. I shrink dry applied tissue with 70% rubbing alcohol. It doesn't use all the shrink and if there are any wrinkles left I can apply straight water to the wrinkles to pull them tight.
I have had difficulty replacing dope for sealing the tissue while still keeping the models light enough for flying. So far, the best thing I have found is Krylon #1305 spray fixative. It works well, but is not completely waterproof, and while not as toxic as dope, I still have to use it outside. I have been experimenting with Future acrylic floor finish thinned with alcohol and sprayed with an air brush. Has possibilities, but more experimentation is needed. Thinned white glue works but is just too heavy for flying models. I have tried a very thin white glue mixed with Knox gelatin (makes it sandable), and may be sprayable with an open mix gun, but that's still an experiment.
For finishing, when I am not using colored tissue, I use Testor's Acryl or Tamaya acrylic paints. They have a full variety of authentic colors for aircraft. They airbrush well over Krylon fixative, or nitrate dope although I had one instance of the color going off when sprayed over dope. I have also airbrushed with acrylic artist's ink which is more expensive than the acrylic paints, but seems to be lighter.
I still have not found anything as good as thinned nitrate dope mixed with talcum powder for balsa sanding sealer. Until I can find a non-toxic, non-odoriferous substitute all frame sealing will have to stay out in the garage when my wife is not around.
Hope this helps.