Making Balsa Nosecones Look Like Plastic... How Do You Do It????

K'Tesh · Aug 16, 2013

PLEASE!!! Balsa Master's please enlighten this humble builder...

I've been learning a lot thanks to the forums, but one thing I haven't discovered is the method that some use to make their balsa nosecones look like something molded out of colored plastic, rather than a lightweight grainy piece of wood.

Many of my attempts seem to end in miserable failures with me sanding off too much in one spot, and perhaps not enough in another. I don't know, I think I may have been holding my jaw in the wrong position, or something.

Please share the secret so we may all learn the ways of the wood... (photos help)
Thanks for listening to my pleas.
K'Tesh

chadrog · Aug 16, 2013

There's many ways to do it, I've found the fastest way for me is to use extra thin CA. Coat the cone thoroughly, let dry, sand, repeat. Move on to primer after that and you're good to go. Best to do this operation out of doors, the vapors are rather nasty.

K'Tesh · Aug 16, 2013

chadrog said:
There's many ways to do it, I've found the fastest way for me is to use extra thin CA. Coat the cone thoroughly, let dry, sand, repeat. Move on to primer after that and you're good to go. Best to do this operation out of doors, the vapors are rather nasty.

Coat the cone... How? Nosecone pointed down I'm guessing, dribbling it from the 1oz bottle. Do you use Insta-Set? How do you prevent nasty raised bumps when it runs too fast? Do you harden up the shoulder too?

Do you have any photos (before/during/or after) that you can show how well this looks?

Thanks!
Jim
.

JAL3 · Aug 16, 2013

Lots of people like the CA method and get great results. I'm not one of them. Besides the fumes I have problems with the bumps as well. I just sand them down. I'll let somebody who actually does well with CA answer the specific questions as to that method but I have my own that I prefer.

Warning: I am not the best when it comes to finishes because that is not my desire. What I describe in the following though, has given me the results you asked about in the first post.

A TRF member going by the name of MarkG came up with a formula he called "Teamwork". He has since moved on to other methods but I still swear by it.

1. Mix Bondo Spot and Glazing putty with Minwax Wood Hardener 50:50 by volume. I actually thin it a bit more than that. Mix well. This is the "Teamwork" filler.
2. Apply the Teamwork filler with a brush over the balsa. Don't be bashful about it.
3. Give it plenty of time to dry. In south Texas where I am, 24 hours is generally enough but humidity in your area is a concern.
4. The result at this point is nasty looking reddish crud all over your balsa. It gets better.
5. Wet sand with #320. Rinse the paper often and wipe the cone with a paper towel. It should soon look pretty smooth.
6. Some places may need a bit more sanding (where the crud has built up; don't worry. It sands easily)
7. Some places may need a second application in which case repeat 2-7 as needed.
8. I am generally happy with sanding at #320 but you can get much smoother. Progress to wet sanding with #400 or even #600 as per your taste.
9. If you want to go beyond #600, you can get even smoother but your money would be better spent on more rockets and psychiatric treatment.
10. Spray with a high solid primer.
11. Wet sand again.
12. paint

There are lots of intermediate judgment calls for you to make. When is smooth smooth enough for you. You can get even shiner by sanding the paint with obscenely fine sandpaper. To me, its not worth it. To you it may be.

In essence, this is like the process with balsa sanding sealer/filler coat. I find that it goes much faster though with fewer coats needed.

chadrog · Aug 16, 2013

The extra/ultra thin CA is like water, balsa sucks it up like a sponge. I apply it by squirting it on and rubbing it in with a gloved hand - no drips or runs to sand out. I usually leave the shoulder alone. I use the "store brand" CA's from hobbylinc, I think it's BSI.

Marc_G · Aug 16, 2013

To add just a few more specifics around CA, here's my method:

1. Before sanding the cone in any way, shape, or form, coat it with thin CA. All the ways described above I believe give equivalent results. I hold the cone tip down at a ~45 degree angle and drizzle some CA on, then spread around with a CA-saturated q-tip. Rotate cone and repeat until CA isn't soaking in any more.

2. When it cures, it will be rough with fuzzies that have hardened. A light polishing with a 220 or 320 grit sanding sponge will take them off without causing flat spots, since the sponge conforms to the curved cone shape. Use a light touch... it doesn't take much to remove the fuzzies.

3. At this point, parts will be smooth but pores and such will stick out like sore thumbs. Depending on how big / numerous the pores are, I use a q-tip and rub on either medium or thick CA. Thick CA is used if the pores are big and or numerous, medium CA (flows a bit better) for those super dense balsa cones with small pores. I go on thick but not to the point of being runny, coating the whole cone. Then let it hang tip down overnight or several hours in a warm / humid garage to cure. Thick CA takes a while to cure fully. Don't rush it.

4. Now, go over it with a sanding sponge again, starting with 220 and going up to 320. Then examine your work. If there are any really rough areas, another dose of thick CA can fill 'em in. I rarely have to do this, though.

5. Rustoleum auto filler primer. Several thin coats that build up to a very thick coat. Let it dry thoroughly, at least overnight. Then, damp sand with a 320 sponge or 320 sand paper. Circular motions. Damp sanding does a better job here than dry sanding. Just a tiny bit of moisture.

6. Most of the time the cone is ready for a white/black primer coat at this stage (I use white or black acrylic primers before my color coats). But, if any blemishes still show through, I use Bondo/3M spot glazing putty to fix them here. Sand with 320/400 and you are ready to go.

That's my technique. Best of luck!

Marc

TheAviator · Aug 16, 2013

Step 0: Pre-sand the nose cone with 220-400 grit paper. A smoother surface to start with means less work later. BMS noses are high quality wood, but the finish can be particularly rough from the machining marks. Estes and Semroc cones tend to start with smoother finishes. Estes cones more because they're ironwood.

Step 1: Use a sanding sealer of your choice, and brush on. I like to use SIG Nitrate aircraft dope thinned to 25/75 dope to thinner. Apply liberally and allow to soak. Allow to dry THOROUGHLY. Sanding before sealer is dry is one of the most futile things ever.

Step 2: Sand the sealer down to the wood. If you hold the cone up to the light at this point, you will see shiny spots where the sealer has penetrated the grain, but not filled it completely.

Step 3: Repeat from Step 1 ad nauseum. (Kidding, two to three coats of sanding sealer usually gets the worst of the grain.)

Step 4: Prime the cone with primer of your choice and allow to dry.

Step 5: Sand lightly, progressing to finer grits of paper as you go. Using a strong light (a desk lamp works well), you will be able to see the parts of the primer that you haven't sanded (they will show up as shiny spots.) For small imperfections, another coat of primer will generally do the trick. For larger imperfections, Bondo Spot Putty works wonders. Repeat until satisfied with the finish.

Step 6: Paint. If you're really looking for a good finish, wet sand the paint and polish it. I'm not quite that anal about my finishes all the time, but Nathan is. Check out some of his posts on finishing if you want to see the creme de la creme of rocket finishing.

Target · Aug 16, 2013

JAL3 said:
Lots of people like the CA method and get great results. I'm not one of them. Besides the fumes I have problems with the bumps as well. I just sand them down. I'll let somebody who actually does well with CA answer the specific questions as to that method but I have my own that I prefer.

Warning: I am not the best when it comes to finishes because that is not my desire. What I describe in the following though, has given me the results you asked about in the first post.

A TRF member going by the name of MarkG came up with a formula he called "Teamwork". He has since moved on to other methods but I still swear by it.

1. Mix Bondo Spot and Glazing putty with Minwax Wood Hardener 50:50 by volume. I actually thin it a bit more than that. Mix well. This is the "Teamwork" filler.
2. Apply the Teamwork filler with a brush over the balsa. Don't be bashful about it.
3. Give it plenty of time to dry. In south Texas where I am, 24 hours is generally enough but humidity in your area is a concern.
4. The result at this point is nasty looking reddish crud all over your balsa. It gets better.
5. Wet sand with #320. Rinse the paper often and wipe the cone with a paper towel. It should soon look pretty smooth.
6. Some places may need a bit more sanding (where the crud has built up; don't worry. It sands easily)
7. Some places may need a second application in which case repeat 2-7 as needed.
8. I am generally happy with sanding at #320 but you can get much smoother. Progress to wet sanding with #400 or even #600 as per your taste.
9. If you want to go beyond #600, you can get even smoother but your money would be better spent on more rockets and psychiatric treatment.
10. Spray with a high solid primer.
11. Wet sand again.
12. paint

There are lots of intermediate judgment calls for you to make. When is smooth smooth enough for you. You can get even shiner by sanding the paint with obscenely fine sandpaper. To me, its not worth it. To you it may be.

In essence, this is like the process with balsa sanding sealer/filler coat. I find that it goes much faster though with fewer coats needed.

The min wax hardener is becoming difficult to locate. Where are you finding it nowadays? Sounds like a great technique.

VonMises · Aug 16, 2013

troj · Aug 16, 2013

Personally, I suck at it.

Here's how bradycros does it -- if you look at pictures of his builds, his work is just incredible.

Personally, I'm lacking one key ingredient: patience!

-Kevin

JAL3 · Aug 16, 2013

Target said:
The min wax hardener is becoming difficult to locate. Where are you finding it nowadays? Sounds like a great technique.

I used to get it at Lowes. Now its a combination of the local Ace Hardware and Amazon.com.

If I identified the solvent in the Minwax hardener, I would probably try to use just that. The "hardening" is not worth talking about. Right now, though, I am in the "if it works, don't fix it" frame of mind.

JAL3 · Aug 16, 2013

troj said:
Personally, I suck at it.

Here's how bradycros does it -- if you look at pictures of his builds, his work is just incredible.

Personally, I'm lacking one key ingredient: patience!

-Kevin

He does do beautiful work.

TheAviator · Aug 16, 2013

JAL3 said:
I used to get it at Lowes. Now its a combination of the local Ace Hardware and Amazon.com.

If I identified the solvent in the Minwax hardener, I would probably try to use just that. The "hardening" is not worth talking about. Right now, though, I am in the "if it works, don't fix it" frame of mind.

Could also conceivably determine the solvent in the spot putty. It might even say on the little tube. I'm not at home right now, but I'll take a look when I get back too.

PhlAsh · Aug 16, 2013

I just throw a couple of layers of Rustoleum primer down, lightly sand, more primer, then polish it with a ScotchBrite pad.

luke strawwalker · Aug 16, 2013

Hope this helps... Later! OL JR

Joe V · Aug 16, 2013

The applying CA part is much easier if you get the CA with a brush.

luke strawwalker · Aug 16, 2013

Joe V said:
The applying CA part is much easier if you get the CA with a brush.

But thinner soaks in better...

later! OL JR

JPVegh · Aug 16, 2013

Aerogloss products are what I use for that plastic like look and feel. Smooth as a babies butt finishes. Of course there is a bit of sanding involved.

chadrog · Aug 16, 2013

Super thin CA will harden a brush nearly instantly - trust me on that one.

hcmbanjo · Aug 16, 2013

Everybody has their own way of doing it. There's no right or wrong.
You've got to find what works for you.

Well, I'll put my two cents in, for what that's worth -
1. Sand nose cone smooth with 400 grit. As The Aviator said in post 7 - "A smoother surface to start with means less work later".
2. Brush on thinned Carpenter's Wood Filler. Brush with the grain, then against to force the filler into the balsa pores.
3. Sand smooth with 400 grit. CWF doesn't smell bad or load up sandpaper.
4. One thicker coat of Duplicolor Filler/Primer. Sand with 320 then 400, this fills any remaining grain.
5. Two light, white undercoats. Wet sand with 400 grit.
When wet sanding you only have to knock off the tops off any orange peel. You shouldn't be sanding down to the bare balsa.
Try to leave a smooth full coverage of white.
6. Follow with color coats. Two thin coats, wet sanding between then a heavier final coat.
That final "wet coat" is heavy but not so much that the paint runs.
After you spray the final thicker coat, don't just set the model down to dry.
Rotate the model until the paint starts to skin over and you shouldn't see any runs.

Stop by my blog, lots of tips there:
www.modelrocketbuilding.blogspot.com

boomtube · Aug 20, 2013

Way back when; I had a technique of thinning Elmer’s white glue and applying it to balsa fins and nosecones that when sanded and painted left them looking as if they were made of plastic.

When I returned to rocketry I tried to recreate this method with no success. I can only surmise that in the intervening years Elmer’s has changed the formula rendering it unsuitable for this application.

Nowadays I use the Elmer’s wood filler thinned down to the point of just being runny. For reasons I haven’t been able to ascertain the results vary wildly between uses.

I’ve had balsa parts that when painted look like plastic and I have had balsa parts show each and every grain in their structure.

Sometimes I think it is the varying quality of the balsa; which can be extreme even between kits from the same manufacture, and sometimes I think it is humidity temperature which could affect drying time or some other factor I have little or no control over or possibly never considered.

As for applying ACC glue; . . .No!! I won’t go there. The language would undoubtedly get be banned from the forum.

Good luck to you as you work through your own efforts and settle on your own techniques.

cruzsergio · Aug 20, 2013

boomtube said:
Way back when; I had a technique of thinning Elmer’s white glue and applying it to balsa fins and nosecones that when sanded and painted left them looking as if they were made of plastic.

I use this Method ! I use school glue, white, wood any type of glue !
1. Apply glue over the balsa a thin layer.
2. Let it dry, it takes about 4hrs to dry
3. It should be rough, get 220 or close to it sandpaper and sand gently try not to go past the glue layer
4. Add a second layer
5. Repeat two more times.
IT works best with 4 layers of glue !
It seems redundant but the outcome is awesome no signs that it's balsa.
and after a coat of Rust-Oleum or Krylon it looks great !

GDJ · Aug 20, 2013

I've used Polyurethane wood protectant with great success. The Balsa does soak up alot, but a nice thin coat between sandings and the cones come out looking like glass!

Also polyurethane is pretty oil based paint friendly, and Rustoleum likes it too.

jd2cylman · Aug 22, 2013

JPVegh said:
Aerogloss products are what I use for that plastic like look and feel. Smooth as a babies butt finishes. Of course there is a bit of sanding involved.

How much sanding will a baby's butt take? Three wipes with a moist towelette had my baby boy's tushie pretty pink... :eyepop:

Adrian

dave carver · Aug 25, 2013

Only thing I'd like to add is use Rustoleum 2X paints. They have the best spray can paints going right now. I've been impressed with the results, really, really smooth.

dwinings · Aug 25, 2013

At least 4 coats of sanding sealer, lightly sanded between each coat. I used to use Aerogloss, but that is getting hard to find. However you can order sanding sealer from Sig. Note: I prefer sanding sealer over balsa filler coat.

luke strawwalker · Aug 25, 2013

dwinings said:
At least 4 coats of sanding sealer, lightly sanded between each coat. I used to use Aerogloss, but that is getting hard to find. However you can order sanding sealer from Sig. Note: I prefer sanding sealer over balsa filler coat.

If that works for you, great... very old school, that's for sure... and we know that it works...

But man, that's just WAY too much work for me, when I can get the same results in probably half to a quarter of the time, and without the stinky chemicals (for the most part) using just Carpenter's Wood Filler and stuff...

No right or wrong here-- just different ways of getting to the same result...

Later! OL JR

dwinings · Aug 29, 2013

hey I'm old, I've been doing this since 1968

K'Tesh · Sep 4, 2013

So... how do you protect the shoulder from being sanded down too much? How do you protect the shoulder from getting messed up by glue (CA) buildup?

JPVegh · Sep 4, 2013

dwinings said:
At least 4 coats of sanding sealer, lightly sanded between each coat. I used to use Aerogloss, but that is getting hard to find. However you can order sanding sealer from Sig. Note: I prefer sanding sealer over balsa filler coat.

I've found the sig product to be a bit gloppy compared to the midwest stuff. It's possible that I got a bad batch but once burned twice shy.

The Midwest Aerogloss stuff is still pretty easy to find online. Since its 80+ miles to the nearest hobby store I buy most of my supplies online anyways.

Yes it's old school, yes it takes several coats, yes there is sanding, yes it kills brain cells... hmmm, what was my point agian? Oh yeah! It comes out looking really boss and it really does feel like plastic.

I recently picked up some Hobbico Hobbylite filler that I've yet to try out. Perhaps I should give it go and see if it's any good.

Making Balsa Nosecones Look Like Plastic... How Do You Do It????

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