ORIGINAL: jwalsh1
I really dont know where to post this question, so if its in the wrong forum, I apologize in advance and Ill move it.
If one has a full balsa sheeted airplane (NOT fiberglass/composite), what is the advantage of "monokoting" vs. priming and painting the airplane?
Some say a weight savings, but is there really a noticable weight difference once the painting and sanding have been completed? What are the advantages of the traditional heat shrink?
Im not talking about a scale airplane, but something like a sport flyer, along those lines.
Thanks!
The advantages of covering the plane in a film covering are:
1. Relative ease of application.
2. The covering is already fuel proof.
3. Less time involved than painting.
4. Weight savings (more on this further down )
Disadvantages:
1. Depending on the size of the plane, is cost. The bigger the plane, the more covering (and $$$) you go through.
2. Unless you are careful when applying the covering, you will have a lot of bubbles.
3. The color(s) you want may not be available.
4. I have found that the quality of the adhesive AND the shrinkability of MonoKote has deteriated in the last several years. Ultracote still has excellent adhesive and shrinkability, as does SolarTex (fabric covering ).
Advantages of painting:
1. Depending on the size of plane, the costs may be noticeably lower (larger planes is where you really see the $$$ difference ).
2. An infinite selection of colors.
3. Depending on the type of paint you use, you can litterally have a mirror finish.
Disadvantages of painting:
1. Specialized equipment is needed (This is normally a one time thing and you may already have some of the equipment - compressor, spray gun, airbrush)
2. The sheeted surface MUST be perfect as the least little defect will show.
3. The balsa MUST be sealed. If it is not sealed properly the grain of the wood WILL show. The "old time" method for sealing balsa was a mix of clear dope and talcum powder, then sanding when dry. I imagine commercial wood sealers would do the same job with less work at about the same (or less ) weight. The dope/talc mix can add weight to a plane in a hurry.
4. After a couple of years, the paint/finish will show cracks due to the wood flexing and drying out.
5. Paint CAN BE heavy (most paints usually are ) when compared to a film covering. Latex is the only exception I am aware of, and it needs to be clear coated to make it fuel proof.
If you really want to paint the plane with a minimum of weight gain and problems, I would suggest glassing the plane using the polyurethane method, painting with latex paint and then clear coating the latex. The above mentioned method will add about 8 oz - 10 oz to a 60 size plane over monokoting.