Painting/polishing The Eggspress/Scrambler nosecone?

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K'Tesh

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I recently picked up an Estes Scrambler nose cone from ECayemberg, and the nosecone was painted with an unknown brand of grey primer that flaked off with the slightest flexing.

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That's it, second to the right.

I removed all of the paint, and did my best to remove the seam lines, however that dulled the plastic. I tried my color with sharpie, and then sand off to remove all mold lines trick, but that muddled it somewhat. I completely sanded the nosecone with 320, 400, 600, and 1200 grit, but it still looks dull/muddled. I'd like to paint it, but I don't want it to flake off like before.

I'd like to know if anybody has had a similar experience, and managed to paint or polish one of these kinds of plastic nosecone with good results?

Thanks!
Jim

I'll add that I've replaced the cardboard body tube with a piece removed from an old (botched) first attempt at a 1/35 scale Mercury Redstone (coupler jammed, tube was crooked). I got replacement tubes for that build from Semroc.
 
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I've had good luck with Krylon Fusion as a primer on plastic. I bought a can of black and a can of red. The black worked fine, but the red seemed like they forgot the pigment. Three coats and only pale pink. Not wanting to waste five bucks (yeah, I'm cheap) I tried using it as a primer for plastic. Works great. Two coats of Fusion red as a clear primer then whatever color trips my trigger.
Hope this helps.
 
Agree with Mike on Krylon Fusion Paints. Many of the Colors take many light coats to get a decent opaque color but they do adhear will to 320 or 360 grit sanded "Plastics". Including the scrambles Polypropylene cone & transition. This type Plastic is very difficult to sand to a polished gloss. it's not you its the material itself. If you really want to make this type cone very air "slippery" I'd suggest two additional steps beyond what you've already done with your sandpapers to 1200grit.

Next step would be to use Perfect-it-III (a 3m polishing compound) then two coats of Nu-Finish Polymer. it's NOT as wax but a co-polymer that bonds to the substrate to which it is applied. Your other option is of coarse to Paint the Nosecone but I can assure you NO MATTER WHAT product you use it WILL Pop-off Polypropylene cones on landings.
 
Polypropylene parts are Evil (R)(tm) but they can be painted with some effort. The first two or three paint jobs I did on these darn things (LOC nose cones mostly) practically fell off. When I went to repaint I just used some sticky masking tape to yank it all off.

The keys that work for me are 1) get all the mold release off with acetone or lacquer thinner (outdoors); 2) rough up the cone the right amount with ~#150 grit; and 3) use a good 2-part epoxy type primer (automotive or Klass Kote). Doing this seems to convince the paint to adhere OK...it will crack if it flexes too much on a hard landing, but won't come off very easily. Cheap primer has never worked out well for me here.
 
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