Aerowerx
Well-Known Member
I have been pondering wood constructions and looking at various construction blogs, and came across this statement on this web site:
As I suspected, the interior of the rudder had not been varnished. Strictly speaking, that enclosed area doesn't require varnish. However, varnishing the interior does help with dimensional stability of the plywood skin as humidity changes, thereby preventing oilcanning and warping.
Ok, then. My question is: if you varnish the frame work and inner surface of the skins before final assembly, does the layer of varnish affect the strength of the glue joint?
The same thing would apply to ribs. Most likely the ribs would sit around for quite a while (months? years??) before the final assembly, so it would probably be a good idea to give them a coat of varnish after assembly. Then will the strength of the glue joint be weaker?
Obviously, the inside of a component can't be varnished after asembly, so if this is a problem how is it handled?
As I suspected, the interior of the rudder had not been varnished. Strictly speaking, that enclosed area doesn't require varnish. However, varnishing the interior does help with dimensional stability of the plywood skin as humidity changes, thereby preventing oilcanning and warping.
The same thing would apply to ribs. Most likely the ribs would sit around for quite a while (months? years??) before the final assembly, so it would probably be a good idea to give them a coat of varnish after assembly. Then will the strength of the glue joint be weaker?
Obviously, the inside of a component can't be varnished after asembly, so if this is a problem how is it handled?
