Ye Olde Rocket Forum

Go Back   Ye Olde Rocket Forum > Work Bench > Building Techniques
User Name
Password
Auctions Register FAQ Members List Calendar Today's Posts Search Mark Forums Read


Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 07-09-2021, 02:34 PM
BobP_in_Nevada's Avatar
BobP_in_Nevada BobP_in_Nevada is offline
Skill Level 2.8 (Nearly Advanced)
 
Join Date: Aug 2012
Location: Sparks, Nevada
Posts: 81
Default Recovery Plan: Split Fin During Build

Hallo! I have a brief story and a question.

Today I cut out fins to a pattern, and was gang-sanding them down to target dimension. And as I'm finishing up the last edge and thinking to myself, "Gee, I think this is actually the first time I've ever made fins from a pattern..."

***crunch***

All three have a crack along the grain ... but it's not all the way through.

I'd really rather not start over. But I also need this model to hold up for at least six flights (Yep, it's my NARTREK Gold project. It's only a wee 18 mm min-dia streamer model, a little like the Quest Pip-Squeak, and I'm only flying it on 1/2A and A motors. The fins are symmetrical trapezoid in shape and 3/32". )

I think I can, first, rub some wood glue into the fractures and dry under weight to lock down the injury. And then, though I wasn't planning to, I think I should paper them.

What say the Voices of Experience? And thanks in advance.
__________________
Bob Portnell, Sparks, Nevada
NAR #87762, NARTREK Silver, Not an actual Silver Snoopy awardee

"Flying Like It's 1980"
Reply With Quote
  #2  
Old 07-09-2021, 02:55 PM
ghrocketman's Avatar
ghrocketman ghrocketman is offline
President, MAYHEM AGITATORS, Inc.
 
Join Date: Jul 2005
Location: Nunya Bizznuss, Michigan
Posts: 13,443
Default

Just soak the crack with thin CA.
Repair will be stronger than original.
They will hold up longer than you are interested in the rocket. Much longer than 6 1/2A and A flights.
'Nuf said.
__________________
When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL
, if you have to ask what is "NORMAL" , you probably aren't !

Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, and HAVOC !
Reply With Quote
  #3  
Old 07-09-2021, 09:05 PM
mojo1986's Avatar
mojo1986 mojo1986 is offline
Old Canuck Modeller
 
Join Date: Mar 2005
Location: Kingston, CANADA
Posts: 2,160
Default

What GH said. I don't use glues containing water to strengthen fins because I've never been able to control warpage. If you want to make a REALLY strong fin you can use thin CA with tissue paper. Just affix an edge of the tissue paper along an edge of the fin, give it a minute to dry, then drip CA along the fin/paper interface and 'squeegee' it with an old credit card, squeezing out most of the CA. After a bit of experience you can make a fairly smooth fin that requires little sanding, is rock hard, and has the grain almost completely filled.
Reply With Quote
  #4  
Old 07-09-2021, 09:50 PM
Gus's Avatar
Gus Gus is offline
7/21/61
 
Join Date: Sep 2005
Location: North of Detroit
Posts: 2,223
Default

Jeepers!

Two people in a row agreeing with something GH said (yes, use thin CA).

Someone call the Weather Channel and let them know that hell has frozen over.
Reply With Quote
  #5  
Old 07-10-2021, 01:35 AM
ghrocketman's Avatar
ghrocketman ghrocketman is offline
President, MAYHEM AGITATORS, Inc.
 
Join Date: Jul 2005
Location: Nunya Bizznuss, Michigan
Posts: 13,443
Default

C'mon noww, Steve !
__________________
When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL
, if you have to ask what is "NORMAL" , you probably aren't !

Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, and HAVOC !
Reply With Quote
  #6  
Old 07-10-2021, 10:07 AM
BobP_in_Nevada's Avatar
BobP_in_Nevada BobP_in_Nevada is offline
Skill Level 2.8 (Nearly Advanced)
 
Join Date: Aug 2012
Location: Sparks, Nevada
Posts: 81
Default

Well, that's about the most consensus I've ever seen here. So be it.

Thank you, folks.
__________________
Bob Portnell, Sparks, Nevada
NAR #87762, NARTREK Silver, Not an actual Silver Snoopy awardee

"Flying Like It's 1980"
Reply With Quote
  #7  
Old 07-10-2021, 12:51 PM
BEC's Avatar
BEC BEC is offline
Master Modeler
 
Join Date: Feb 2009
Location: Auburn, Washington
Posts: 3,643
Default

Yup. Thin CA for a split like that, either during the build or as a field repair later.....

I'll bet hell doesn't stay frozen over for long
__________________
Bernard Cawley
NAR 89040 L1 - Life Member
SAM 0061
AMA 42160
KG7AIE
Reply With Quote
  #8  
Old 07-10-2021, 03:04 PM
BobP_in_Nevada's Avatar
BobP_in_Nevada BobP_in_Nevada is offline
Skill Level 2.8 (Nearly Advanced)
 
Join Date: Aug 2012
Location: Sparks, Nevada
Posts: 81
Default

Quote:
Originally Posted by BEC
I'll bet hell doesn't stay frozen over for long


With the temperatures here out west lately, any frozen-over place is looking good.
__________________
Bob Portnell, Sparks, Nevada
NAR #87762, NARTREK Silver, Not an actual Silver Snoopy awardee

"Flying Like It's 1980"
Reply With Quote
  #9  
Old 07-10-2021, 05:23 PM
ghrocketman's Avatar
ghrocketman ghrocketman is offline
President, MAYHEM AGITATORS, Inc.
 
Join Date: Jul 2005
Location: Nunya Bizznuss, Michigan
Posts: 13,443
Default

It won't stay frozen for long.
I doubt anyone would approve of my method of starting indoor fireplaces.
It involves MEK and a hand-held BP SU F-motor as the Starter.

That however is far safer than the loon Uncles on my Mother's side of the family.
Way too many incidents with them involve a gasoline can and an already LIT FIRE.
One of their idiot sons actually checked the level of gasoline in a can with a LIT MATCH at age 14.
That was around 1975. He got his face blown in and almost OFF. Darwin award candidate still to this day. He never ceases to find idiotic ideas. When they passed out brains, most of that side of the family was too busy SNIFFING GLUE.
__________________
When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL
, if you have to ask what is "NORMAL" , you probably aren't !

Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, and HAVOC !
Reply With Quote
  #10  
Old 07-10-2021, 08:29 PM
LeeR's Avatar
LeeR LeeR is offline
Retired with Way Too Many Kits
 
Join Date: Jun 2007
Location: Colorado
Posts: 3,222
Default

Quote:
Originally Posted by Gus
Jeepers!

Two people in a row agreeing with something GH said (yes, use thin CA).

Someone call the Weather Channel and let them know that hell has frozen over.


Make that THREE!!

__________________
Lee Reep
NAR 55948

Projects: Semroc Saturn 1B, Ken Foss Designs Mini Satellite Interceptor
In the Paint Shop: Nothing! Too cold!
Launch-Ready: Farside-X, Maxi Honest John, Super Scamp
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump



All times are GMT -5. The time now is 06:30 AM.


Powered by: vBulletin Version 3.0.7
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Ye Olde Rocket Shoppe © 1998-2024