Ye Olde Rocket Forum

Ye Olde Rocket Forum (http://www.oldrocketforum.com/index.php)
-   Building Techniques (http://www.oldrocketforum.com/forumdisplay.php?f=6)
-   -   How do you prepare your plastic nose cones? (http://www.oldrocketforum.com/showthread.php?t=12515)

K'Tesh 05-16-2013 03:04 PM

How do you prepare your plastic nose cones?
 
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.

stefanj 05-16-2013 03:13 PM

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.

ghrocketman 05-17-2013 09:04 AM

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.

foamy 05-17-2013 09:42 AM

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.

ghrocketman 05-17-2013 11:40 AM

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) ?

foamy 05-17-2013 01:12 PM

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.

Pem Tech 05-17-2013 03:00 PM

I like my nose cones lightly brazed in butter with a cream sauce.

Chas Russell 05-17-2013 05:14 PM

Yes, but Lanye, do you deglaze the pan before plating the nose cone?

I sand with 320 grit after filling the seam and then wipe with isopropyl alcohol. Working a nose cone from the reissued Estes Maxi Honest John from years back. Seems that the seams are deeper than I remember. Been using the Tamiya white putty since I can get it at Hobby Lobby with the coupon.

Last built a Maxi HJ back in the mid-70s and flew it on F100s, E60s (successfully), and an AVI Gold Series E11.8-4.25. Lost it in 1994 at the Bonneville Salt Flats on a prototype NCR E20. Up part was good, but no ejection firing. Durn that salt is hard. Have one more reissue and two original issues.

Chas

hcmbanjo 05-17-2013 06:48 PM

In addition to the white Tamiya filler, I've had great luck seam filling the plastic seams with the cheap, medium CA from the Dollar Tree store.

http://modelrocketbuilding.blogspot...-nose-cone.html

It stays on the plastic and sands glass smooth.

modeltrains 05-17-2013 09:39 PM

Plastic nose cones get similar treatment to plastic models:
Wash with old really soft toothbrush usinf either dish detergent or mild abrasive household cleaner.
Scrape/file/sand/fill molding seam marks with Squadron White putty.
(wonder if Hobby Lobby over in city here carries Tamiya putty?)
Sand and rinse.
Prime. Unlike plastic models, nose cones get DupliColor car primer.
for painting I mask off shoulder then tape cone to dowel, tube, stick, something to hold it.
somewhere along the way something got me started painting nose cone bases in colors which look like greenish or yellowish zinc chromate primer. Why? Dunno, just enjoy doing so.


All times are GMT -5. The time now is 03:08 PM.

Powered by: vBulletin Version 3.0.7
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.