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Finishing balsa nosecones

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NJnike

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Hey everyone. I'm just about ready to start putting some paint on a new scratch built that has a balsa nosecone from Semroc. It's the first time I've ever used a balsa cone and I'm wondering if there are any recommended ways to prep it for paint. Usually I'll use wood filler on any wood parts, sand and repeat until reaching a desired smoothness, but I'm a little worried of sanding it out of shape. I have a tendency to go a little too far when it comes to sanding sometimes. Any special advice or should I just follow my usual process and be very, VERY careful?
 

lessgravity

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Fill/Seal it - Sand it - Prime it -Sand it - Paint it

I like to use Fil-n-finish to fill/seal the wood and sometimes do several coats of filing and sanding. Then comes the primer and sanding.
Use increasingly fine sand paper and you won't sand away too much. I usually apply the filer sand it until it's almost gone and reapply and sand again
 
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judo

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Try putting some food coloring in your filler. If you begin to see wood grain through your sanding, stop.
 

cornyl

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Hi NJ NIKE,
I'm a little old school but I have always done them the same way.
Make sure you have completely masked off the shoulder of the cone before you start. which also includes the lip. OR Place cone in a piece of scrap tubing.
1. brush on a liberal amount of sanding sealer and let it dry completely.
2. Sand with 220 grit
3. Apply sanding sealer let it dry completely
4. sand with 320 grit
5. apply sanding sealer let it dry completely
6. sand with 400 or 600 grit paper
7. prime and sand with 400 or 600, if you sand off the primer - prime again
8. Finished cone should be all one color of primer and ready for final paint
9. Carefully take an exacto and lightly cut around at the shoulder to break the bond of sanding sealer and primer of the tape or tubing
10. Carefully remove tape or tubing.
11. If painting same color as tube-Place cone on rocket, check for fit and paint finishing coats.

Good Luck,
CornyL
 

NJnike

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Awesome, guys. Thanks a lot! I'll be giving this a shot in the next few days and I'll let you know how it comes out.
 

hcmbanjo

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One thing I've learned with Fill N' Finish is to try and leave a "all-around" coat on the balsa after sanding. You don't want to sand all of it off down into the wood. The thin leftover coat will be a light tan color. If the "pinkish" balsa shows through you've sanded through it - too far.
Fill N' Finish is now called Elmer's Carpenter's Wood Filler. It's got a Blue and Orange lid on a white rectangular tub. They quit making the Fll N' Finish formulation in late 2007. The old stuff was for indoor use, the newer filler is for indoor and outdoor use. It still sands the same.
Thin it with water (don't mix up the entire tub!) in a small reclosable container to the consistency of thick cream. I sand it with 400 grit sandpaper.

Good Luck!
Hans "Chris" Michielssen
 

Bravo52

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I like to seal the balsa with CA first. Then I go with a thinned coat of FnF. I use the brush on CA from CrazyGlue. It's thin and it soaks in the balsa and hardens the wood before I put on the FnF. The only problem I have with just using FnF is that I have a tendency to sand through the coat of filler. Even after two or three coats. And of course it is always my luck to figure this out after the first coat of color......:mad:

The only down side is the fumes from the CA. You have to do this in a well ventilated area. Or not if you like your nose hairs to crystallize and your eyelids to fill like they are glued shut......
 

Micromeister

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On most Balsa and Basswood cones I just do my same old Primer, sand Primer sand thing. Generally 3 coats before sanding, this sometimes takes a second 3 coats but not often.

On Really big cones BT-60 and larger, I'll sometimes use a coat of Minwax Wood hardner just to fill in some of the grain not necessarally make the wood harder. this helps the primer fill the grain faster.
 

NJnike

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Just wanted to leave another "Thank You" to you guys. I went with the thinned Elmers wood filler then sanding with progressively finer sand paper and it's looking great. I've had to reapply the filler to some spots where got it down too thin (like I said, I go a little too far sometimes for some reason) or where I missed small spots on the first coat, but I'm really liking the way its turning out. Today the primer goes on and hopefully soon I'll have another finished bird for the fleet.
 

Boosterdude

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I brush on two coats of semi-gloss Minwax Poly sanding with fine steel wool in between coats. The I take spackle that I thin down and brush on a coat, sand, and brush on another coat. The thinned spackle fill the grain and sands easily. The two coats of poly gives you a nice base to sand down to without getting back down to raw balsa.
 

BobH48

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I brush on two coats of semi-gloss Minwax Poly sanding with fine steel wool in between coats. The I take spackle that I thin down and brush on a coat, sand, and brush on another coat. The thinned spackle fill the grain and sands easily. The two coats of poly gives you a nice base to sand down to without getting back down to raw balsa.
I like using Minwax Polycrylic also. 2 coats and then FnF or spackle. I then give it another coat of the Minwax Poly to seal everything before priming.
 

Bravo52

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I like using Minwax Polycrylic also. 2 coats and then FnF or spackle. I then give it another coat of the Minwax Poly to seal everything before priming.
This sounds like a good idea. Does the Minwax cause any problems with the filler? Seems like it might harden at a different rate over the two surfaces.

I've used finishing resin (epoxy) to get a smooth hard surface that goes down right before primer and that works fine, but it tends to be a pain in the tuckus. Anything that will make it easy to get that killer finish........
 

Boosterdude

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I use the regular Minwax Poly, not the Polycrylic. I don't really like the waterbased product on balsa.
 

dave carver

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I've used things like Red Devil Ultra light spackeling with great success. Thinned with a little water to a thick paint consistency, let dry completely. stuff gets amazingly hard and yet easy to sand. It's the same stuff as Hobby filler at a lower cost, just make sure it's ultra lite, super lite, or something to that effect or you end up with plaster based filler(voice of experence :p )
 

RocketT.Coyote

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Sometimes I coat my balsa cones with aliphatic wood glue, the thick sandable variety. Once it cures, then sand the surface smooth with fine grit sandpaper.
 

Mikus

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On Really big cones BT-60 and larger, I'll sometimes use a coat of Minwax Wood hardner just to fill in some of the grain not necessarally make the wood harder. this helps the primer fill the grain faster.
I use this too. I'm tired of my nose cones getting dinged. :mad:
 

Solomoriah

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I brush mine down with thinned FnF, then sand them smooth; one coat does it. Same for my fins.
 

JimJarvis50

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Just wanted to leave another "Thank You" to you guys. I went with the thinned Elmers wood filler then sanding with progressively finer sand paper and it's looking great. I've had to reapply the filler to some spots where got it down too thin (like I said, I go a little too far sometimes for some reason) or where I missed small spots on the first coat, but I'm really liking the way its turning out. Today the primer goes on and hopefully soon I'll have another finished bird for the fleet.

I just finished a project with a balsa cone, and its time to finish the cone. This thread has/is been very helpful. I turned my cone using a drill press. I started with a dowel down the center and then just lathed out the cone. Then, I cut off the dowel at the base of the cone and drilled a hole in the cone for a tracker. When I started to sand off the Elmers by hand, I got flat spots on the cone using the "shoeshine" method. Fortunately, I can put the drill back into the cone so that I can spin it on the drill press. So far, that is working much better. One question I have is if there is anything I should watch out for if I use the press for sanding the filler and then later, the primer? I know, for example, that the elmers will get hard and difficult to sand if it gets hot. So, I'm using very light pressure. I'm going to try to leave a coat of solid filler covering the surface. Any other tricks for sanding in this way would be appreciated as I don't have any experience turning wood, much less balsa.

Jim

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