I've had a mixed bag of results with this method (more success than failures), so I'm looking to see what others are doing.

For my blown plastic nose conses from my Estes kits, I first sand with 220 grit in a circular pattern to get rid of the seam lines. Then completely sand the entire nosecone until all the gloss/semigloss of the virgin plastic is gone. Next I sand again using 320 grit to eliminate the deep scratches that 220 leaves behind. Then it's onto 400 grit (wet or dry). I last use 600 grit (wet or dry) to really make things really smooth.

I'm next using toothpaste to give it one last abrasion before washing it with soap and water. I dry it, then (presuming that it's not the same color as the body tube) paint it with the final color. If it is the same color as the body tube, I'll spray a coat of primer before doing the top color.

3 of my last 4 nose cones turned out looking pretty sharp (all of them were a contrasting color to the the body tube) The last one however had odd dimples in the paint that I think may have been caused by a small amount of water (or droplets from a sneeze) that I need to get out.

To paint, I'm using some poster putty to secure the nose cone to a dowel, and painting it in its entirety (rather than masking off the shoulder). I leave the nosecone on the dowel (parallel to the ground) for as much as a day to allow the paint to dry; especially if it's a gloss color.

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Dreaming of making the rockets I dreamed of as a kid (and then some).

"The Guide says there is an art to flying", said Ford, "or rather a knack."
"The knack lies in learning how to throw yourself at the ground and miss."

Launching is Optional... Landing? That Depends on Trees.

I use the edge of a sharp knife to get rid of the seams.

Wet sand with really fine sandpaper.

Sludgy paint-on enamel to deal with the seams. Sand again.

I use polishing compound rather than toothpaste, but it is basically the same stuff . . . just cheaper.

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NAR #27085 - Oregon Rocketry - SAM

I rarely use plastic cones, but when I do I wash them in really hot water and Cascade, then I wipe them down LIGHTLY with Dope thinner (not enough to melt/craze them), lightly sand with ultra fine sandpaper (600), then prime & paint.

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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, TURMOIL, FIASCOS, and HAVOC !

Not that I'm any whiz-bang, but I just sand the bugger with 400 grit or whatever—doesn't make a lot of difference to me, fill and sand any seams, wipe with alcohol (no, I don't use my rum) and go ahead and prime it with the rest of the rocket. I figure it gives the paint something nice to grip on to. Sand as usual with the rest of the rocket.

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Retro-grouch

Foamy-
I like the Alcohol wipe idea better than my use of Dope thinner; no chance of the Alcohol attacking the plastic...I think I will switch.

What kind of alcohol are you using ?
Denatured (Ethanol) Alcohol, Methanol, or Isopropyl (which does not sound good unless of the fairly uncommon 99% variety) ?

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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, TURMOIL, FIASCOS, and HAVOC !

Denatured if I have it, Isopropyl (91%) if I don't.

I usually grab a mayo jar of denatured at the boat barn as that's what we use to prep surfaces before caulking and mounting hardware or painting. The isopropyl works fine too, but you have to let it dry for a bit before you paint as it's not as quick to evaporate as the denatured.

Speaking of the boat barn, "Flyer" will see the sunshine for the first time in over two and a half years this coming Tuesday. I'll post a pic in Free for All when I can. We're quite proud of her.

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Retro-grouch

First wash with a Scotch Bright pad to get any mold release or oils off the plastic. Next I use a hobby knife to remove the seam lines then sand with 400 then 800. Finally I wash again using dish soap and a scotch bright pad to remove the anything that might be left on the plastic.

Final step before spraying anything is a wipe down with rubbing Alcohol. If the nose cone is white I simply shoot it with a couple of quick coats of adhesion promoter then it's time to paint. If the nose cone is any other color I shoot adhesion promotor then a couple of coats of SEM White high Build primer and let it sit.

I also do a quick wipe down with alcohol between coats. Never know when something is going to drip on the rocket or someone who shouldn’t be messing around gets their hands on it.

I marinate them in worchestershire sauce and lemon juice...

I usually just hit them with a scotchbrite pad and clean them with alcohol. I have been known to use beeswax tack cloths to remove dust before laying down primer and paint, but it usually isn't necessary. I had a phase where I wanted everything perfect.

If there is a seam that will show, I use Bondo Spot Putty to fill and sand. It is easy to use, available at Walmart or any automotive shop, and dries fast.

Next comes lacquer primer. I don't usually need high build for a plastic cone, but if it's all I've got I use it. I have to use lacquer primer cause it dries fast. If I have to wait very long for slower drying primers, I get out of the mood to sand. Ok, I never really get in the mood, but I get into a tolerable sanding zone.

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I love sanding.

Try a nice glass of red wine and some soft music. Generally good for getting in the mood...um, er...ok. Hmmm...you were talking about sanding, weren’t you? Dang. Ok, skip the wine and music. Those won’t help. Well, the wine, maybe. LOTS of it....

Earl

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Earl L. Cagle, Jr.
NAR# 29523
TRA# 962
SAM# 73
Owner/Producer
Point 39 Productions

Rocket-Brained Since 1970

Maybe, but I have a feeling those airfoiled fins won't end up looking too good.

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I love sanding.