After light sanding the "fillers" all pieces got a white undercoat and light sanding. This was followed up by gloss red enamel.
On the left side is the CWF filled balsa. There is still some grain and the pores are raised slightly. The final gloss is not as shiny as the wood glue test piece above.
On the left is the sprayed raw balsa, no sealer or filler.
The paint soaked in and dried with a dull flat finish. The balsa grain is very obvious.
On the right is the wood glue coat balsa.
The grain is still evident, not filled. But -
The wood glue did "seal" the wood. The paint didn't soak into the wood and dried to a decent gloss sheen.
On the right is the piece hit with filler/primer only. There is still some slight grain seen. The filler/primer does seal the wood and the gloss red is a little shinier than the wood glue coated piece.
The clear winner is this final piece using one coat of CWF and sanding, followed by filler/primer and sanding.
The CWF fills 80% of the wood grain. A single follow up spraying of filler/primer and sanding fills any remaining grain.
This test piece is the smoothest with the best gloss.
This is how I normally fill balsa pieces. It's a simple two step process. One brushed coat of CWF and sanding, one spray of filler/primer and sanding.
Everyone has their own methods, do what works for you. I doubt I will change, I've used and developed my practice of CWF and F/P for years now.
Nifty experiment! Have you a scale and would you mind giving comparison weights? -- Bob P, Sparks, NV
ReplyDeleteHi Bob,
DeleteFor consistency, I should have weighed and picked "like" balsa pieces before filling and painting.
Here's how they ended up:
RAW BALSA (no filler) just paint - .17 oz.
WOOD GLUE and paint - .25 oz.
CWF only and paint - .31 oz.
CWF, F/P and paint - .34 oz.
When I sand down the CWF and F/P I take it down to surface, there isn't much of the fillers left.
Going beyond a contract build? Glad to see it! :)
ReplyDeleteStill some pretty gnarly orange peel on that red with the CWF and F/P.
ReplyDeleteHi Anonymous,
DeleteIt is much smoother than it looks. That's how my camera picked up the overhead light reflection.
Heck, the FP looks pretty good by itself. How much did you have to spray to cover the grain? Since it is hard to find a quality balsa sealer, I make my own now. Brodak stopped carrying their dope based sealer, it was good stuff. For balsa filler, I thin Testors Putty in Dope thinner and it works great. For sealer, I add a small amount of Testors putty or Zinc Stearate to clear dope. Scigs
ReplyDeleteHi Scigs,
DeleteThe FP only piece surprised me, it did some grain fill and sealed the balsa. There was still visible grain, though. I used one shot of Duplicolor FP, applied fairly thick.
I didn't include Brodak as it's hard to find now, OOP. I probably won't be mixing my own dope filler, still using the thinned down CWF.
Rand-O-Fil Silver is listed as replacement for sanding sealer
Deletehttps://brodak.com/finishing-products/dope/sanding-sealer-4-oz.html
Also, did you use a flat white or gloss white under coat? I actually like the raw piece other than it is flat and would not take waterslide decals very well.
ReplyDeleteHi Scigs,
DeleteI used gloss white undercoats as my usual practice.