Thursday, December 3, 2009

Pseudophenolic

Which surprisingly, is not a new word - Google returns 286 results.

In this case the pseudophenolic is my coating of the Mach Goon with wood glue, which forms a hard plasticy shell - somewhat similar to a true phenolic material, on the cheap. Wood glue of course binds excellently to wood fins, kraft paper body tubes (including the glassine outer layer), and itself, but unfortunately not well to certain plastics like the extruded styrene used in the nose cone of the Baby Bertha.

After one attempt, which sucessfully coated part of the body tube but not the nose cone, I tried again by roughing up the nose cone with sandpaper works. Tomorrow will tell if it worked, or just ruined the cone.

4 comments:

KenKzak said...

But why do you want to put a coat of glue on a plastic nose cone?

Extruding is for making continuous pieces of a given profile.
Some nose cones are injection molded, but most are blow molded.

Phenolic is a specific resin. If you add phenolic powder to the glue, it becomes a psuedophenolic coating. it's still only as effective as the adhesive.

The EGE said...

1) Strength. This rocket will be heading to almost 900 fps in under 1.5 seconds of flight, and that's a lot of airflow and florce on a thin plastic nosecone. The layer of wood glue gives it strength.

2) Thanks, I couldn't remember which Estes nose cones were.

3) I was under the impression that Elmer's wood glue is a formulation very similar to phenolic resin. It is certainly very strong - it's held the Machnum Force together through Mach, the fins on the Nantucket Sound together through some hard landings, and the nose cone on the Nike Apache through a 300 mph lawn dart and a landign stuck on the nose.

KenKzak said...

I don't see a coating of glue adding any strength until hideously thick. If you're really worried, glass the inside of the cone [where it doesn't show].

Actually, all but the thinnest nosecones will handle whatever airflow you can afford to subject them to until aerodynamic heating comes into play.

I may need to learn more about modern wood glues.

The EGE said...

Surprisingly, the thin coat of wood glue adds a lot of strength, especially to the Baby Bertha cone which is incredibly thin. It also soaks into wood fins and smooths them out for really easy finishing.