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  #1  
Old 04-27-2020, 11:27 AM
RobVG RobVG is offline
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Default Will an ejection charge blow the engine out the back if you don't use a hook?

40 years ago we didn't use retention hooks. We didn't even use tape. I'm planning a ricket and would rather not use one.

Bonus question: Can you brush a thin layer of epoxy on the fins to strengthen them or would it add too much weight?
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Old 04-27-2020, 11:30 AM
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Jerry Irvine Jerry Irvine is offline
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Retain the motor of arbitrary length with tape on the outside. In the older days we did friction fit. Tape on the outside of the casing till it was tight.
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Old 04-27-2020, 12:08 PM
RobVG RobVG is offline
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Thank you for the reading material
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Old 04-27-2020, 12:20 PM
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Thinned epoxy is still dense when the VOC's evaporate. Orange Shellac strengthens wood, is low density and can be far more easily sanded to reduce unwanted mass.

Tech Jerry
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Old 04-27-2020, 01:47 PM
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I use Elmer's Glue straight out of the bottle either brushed on the fins or squeegee it smooth with an old credit card. Just remember you have to do both sides at the same time.

To prevent warping, coat the fins after the fins are glued on.

Elmer's is non-toxic, water clean up, clean, dries clear (mostly), odorless, and is available pretty much everywhere.

You don't have to order it online, worry about "epoxy allergy" , or have to find a hobby shop to get it.

And it's about as cheap as it gets.

It also seals the wood so the wood doesn't soak up the primer.

I've been sealing and strengthening my fins (and nose cones) this way since I was 11 or 12.

I am about to turn 72 and I see no reason to change.

It works!
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Old 04-29-2020, 03:38 PM
RobVG RobVG is offline
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I used Elmers wood glue on the last rocket. Do you use white or wood? Do you sand it or just use sandable primer? I need a gloss finish this time.

Thanks
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Old 04-29-2020, 06:51 PM
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Quote:
Originally Posted by RobVG
I used Elmers wood glue on the last rocket. Do you use white or wood? Do you sand it or just use sandable primer? I need a gloss finish this time.

Thanks


I use the white. Formally known as "Elmer's Glue All".

It does raise the knap of the wood but a quick once over with 220 grit smooths it out ready for primer/paint.

Go light on the primer. The paint seems to bond to the dried glue real well.

Just try to coat both sides of the fin with glue at the same time.
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Old 04-30-2020, 12:14 AM
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Quote:
Originally Posted by sandman

[…]

I've been sealing and strengthening my fins (and nose cones) this way since I was 11 or 12.

I am about to turn 72 and I see no reason to change.



I’m about to turn 68, and I’m pretty much there, regarding change. I wonder what lies in store for me at age 72?
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Old 04-30-2020, 09:08 AM
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Quote:
Originally Posted by LeeR
[snip] I wonder what lies in store for me at age 72?



Want me to tell you?
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Old 04-30-2020, 10:43 AM
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Quote:
Originally Posted by Rocketflyer
Want me to tell you?



I can sum it up in two words..."Everything Hurts!".
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