I used Sanding Sealer or Balsa Fillercoat for years. When I got back into rocketry in 2006, I couldn't find Sanding Sealer for a reasonable price. I had heard a lot about Elmers' Carpenter's Wood Filler. I found it easier to apply one brushed on coat and sand smooth. One pass with this filler as opposed to four applications of sanding sealer, sanding between coats. That and you don't get a cheap high from the Sanding Sealer fumes.
Does one pass with CWF completely fill balsa grain? Not always. I follow with a fairly heavy spray of Duplicolor Filler/Primer and sanding.
It's easier to do two passes of the new fillers as opposed to four passes of the old Butrate Dope Sanding Sealer.
I am aware of the availability of the new Brodack Sanding Sealer, I haven't tried it yet. I don't want to go back to four fill and sand coats.
Here's the second fin with a brushed on coat of thinned CWF.
There will be brush strokes on the surface.
You can remove the bulk of the CWF coat with light sanding with 220 grit and smoothing with 400 grit.
Both fins were sanded smooth. The glue coat fin was not easy to sand, it felt gummy.
The CWF coated fin sanded easily.
Here's both fins taped down to a piece of cardboard for a shot of gloss white enamel.
On the left is the glue coated fin. Difficult to sand, the dried glue sanded like rubber. Balsa grain is still very evident. Between the grain pores the surface did seem smooth.On the right is the CWF filled fin. It is smooth with no balsa grain pores.
Any new finish medium or building tool requires practice. If you haven't used CWF before, don't expect perfect results the first time. Years back, it took a few rocket builds to learn how to use and effectively smooth Sanding Sealer.
If you are happy with "glue-filling" your fins, that's fine. I feel I get better results with an actual wood fillers followed by a sprayed coat of filler/primer and smooth sanding.
Chris, Just like you I see almost every other day someone asking or trying new methods to achieve the perfect rocket finish. What I don't get is you lay it out so perfectly of how to achieve a catalog finish, its all here on your blog. Some of the finishing techniques I read just make me scratch my head. By the way, I love the fresh smell of dope products in the morning :)
ReplyDeleteThanks Scigs,
DeleteComing from you, your comments mean a lot! I appreciate the time you put into a build and your posted finished pictures.
I often post a link on the forums but wonder if that reader with the question ever looks at it.
I'll never claim my methods are the "only way" to do it. This is just what works for me. I still have finishing problems. The Semroc V2 has been a bear to mask.
Chris, Estes used to recommend using 3 coats of balsa sealer on balsa parts for a smoother finish. Now for some reason some of Estes instructions would have you seal the fins before building and other instructions would have you seal after building. Now Estes instructions have you build the kit, spray primer, sand, primer and sand again. I cannot imagine getting a decent looking rocket with just two coats of primer.
ReplyDeleteFor small nicks in fins and plastic,and seams I have been using Tamiya putty....its butter smooth and sands easy ....my first tube of it and so far I love it
ReplyDeleteHi Metal,
DeleteI've tried the Squadron Putty twice. The tube always dries up before I get to use it again.