Help! Sealing and painting balsa glider fuselage


Before I jump into this project I'd like to get some feedback from balsa builders. I'm building a RC Glider Kit Sunbird Electric Sailplane, 1.6M Laser Cut Balsa Kit, the fuselage is solid balsa and was thinking of painting it instead of covering. I've read people say that using covering strengthens the balsa. The fuselage is quite strong and would rather use paint.

Any thoughts?

I was going to use sanding sealer, then spray paint?



Legendary member
Sanding sealer will work fine, though the method I prefer is to thin PVA glue in water and brush or spray it on. Dope will also work just fine for this, but it has a wicked smell and respiratory PPE must be worn if you don't want to sacrifice braincells. There's this stuff called Eze-Dope which is usually used on tissue models which if you thin it in water will also work, without all the noxious effects, though it's a little on the expensive side. Whatever method you choose, do many light coats, and sand between coats. Beware of just how much you put on the airframe - weight stacks quickly!

As for paint you have a lot of choices since you don't have fuel to protect against. Rattle cans will work just fine, though if you want custom colors you can use latex. Name of the game is again, many light coats.

Covering on sheet balsa does strengthen it a bit. It adds torsional stiffness, but an all-sheet box fuselage has enough strength by itself when the grains are oriented correctly that this is not entirely needed. It makes the balsa a lot more resistant to scratches and dings though. Since this aircraft is a belly lander, the bottom will probably end up with quite a lot of these over time.

A very lightweight method that provides this protection is to seal and paint the fuselage and then cover it with 1.7 mil Doculam. It weighs basically nothing and is clear so whatever paint job you put on the fuselage will be perfectly visible. It also gives your airplane a nice shine :)


Thank you @speedbirdted for the information, this is helpful. Interesting about the PVA glue, I'll test this out on the glider's hatch, I think I am going to go with the sanding sealer method, I'm not a big fan of using dope.
BTW, your Cub taxing video should be called "Cub taxing obstacle course" - nice plane and nice engine :)



Master member
You can also use Elmers wood glue add talcum powder to it and thin it with water to where it is brush able. Clear Laquer paint mixed with talcum works very well too,

A little side not Elmers mixed with balsa dust works excellent for making fillets like where the rudder meets the fuselage etc.