What is everyone using for clear plastic fin material on scale birds these days?

Here are a couple of suggestions about clear plastic material for fins. One is to use clear sheet styrene such as the stuff from Evergreen Plastics. Here is a link to their site:

http://www.evergreenscalemodels.com/Sheets.htm#Clear Sheets

Another idea came from Chris "Hans" Michielssen who use the plastic "glass" from oridnary picture frames that you would find at Wal-Mart or any dollar store.

In the end, the clear plastic fins I used popped off on landing, much like the fins did on the early Estes Thor Agena B and Gemini Titan.
Attaching the plastic using clear dope (as in the old instructions) felt like a good bond at first. In a few days, the joint got weaker.
Unless I found a good, compatible plastic and glue, I'd probably go with through the wall clear fins next time.

__________________
Hans "Chris" Michielssen
Old/New NAR # 19086 SR

www.oddlrockets.com
www.modelrocketbuilding.blogspot.com
http://www.nar.org/educational-reso...ing-techniques/
Your results may vary
"Nose cones roll, be careful with that."
Every spaceman needs a ray gun.
Look out - I'm the Meister Shyster!

In Europe, plexiglass (perspex) is often used as clear fin material.

__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
NAR #54895 SR

I have always heard that plexiglass (acrylic) is brittle; my experience is that clear polystrene is as well. Lexan (polycarbonate) is better in that department, but Carl told me that his laser cutter does not cut Lexan efficiently.


Bill

__________________
It is well past time to Drill, Baby, Drill!

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Please unload your question before you ask it unless you have a concealed harry permit.

: countdown begin cr dup . 1- ?dup 0= until cr ." Launch!" cr ;

Give a man a rocket and he will fly for a day; teach him to build and he will spend the rest of his days sanding...

I used to have the R2-D2 rocket a long time ago and the clear fins used a small screw to attach to the legs. I don't remember what type of plastic that was but it was not that durable and cracked.

All transparent plastics tend to be brittle. I think that it has something to do with the chemistry involved in making the plastic see-through in stead of opaque. I think that the classic Estes kits with clear fins (the Gemini-Titan (K-21), the Thor-Agena B (K-28), Saturn V (K-36) and the semi-scale Saturn V (K-39)) used clear butyrate for the fin material. Lexan that is thick enough may work well, but it would have to cut with a blade. Just my $0.02.

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'Til next time,

Mike Toelle

NAR 31692 L1

SAM 0373

The clear slotted fins that came with my Centuri Saturn V were flexible. They worked great, but because of the way they attached, they gave the Saturn a slow roll. They never came off in flight, and I don't even recall one popping off on landing.

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I love sanding.

Two thoughts: The laser cutter's beam might not be impeded enough by the transparent Lexan to heat the intended cut line enough, but maybe if the beam hit it at a shallower angle that might improve the heating of the cut line? Also:

Polycarbonate is also commonly used by European model rocketeers for making clear fins, but another possible material (that I have never heard of being used for clear fins) is clear polyurethane, which at least some of the polyurethane casting resin suppliers offer. SynAir Corporation, the initial producer of the Por-A-Kast polyurethane resin, also sold a clear version of the resin that their product specifications said would not yellow over time. Other polyurethane resin makers such as PolyTek, Ciba-Geigy, and Alumilite might also have clear resins. In addition:

If clear polyurethane resin is physically similar to the opaque formulas (quite stiff even in thin sections, but not brittle, and having just a bit of "give"), it should work well for making durable clear fins. As well, maybe a laser cutter would work well enough on clear polyurethane resin to cut it well?

__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
NAR #54895 SR

IIRC the substrate material of CD and DVD is a polycarbonate. I usually end up with a pair of "blanks" (disc of substrate material w/o any of the foil recording surface) on the ends of a spindle pack (as I usually go through a spindle or two every few months, I've accumulated a stack of these "blanks"). The material is quite resilient compared to clear styrene (you can bend a disc almost to a point where it resembles a taco shell -- which requires a fair amount of force to apply). At a certain point you'll start noticing a cracking noise, and eventually followed by a rather spectacular shattering of the material (might not be a significant problem as rocket fins -- it takes considerable amount of flexing before this happens -- and probably would require several hard landings before such a failure would occur -- by then the rocket is probably toast anyway). I haven't checked to see what adhesives work on this material. The other downside that I can see is that the size of fins you could cut out of this material is somewhat limited.