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Rocket Scientry - Adhesives
#1

I was reading Doug V.'s excellent L3 build thread and noticed that he chose JB Weld for the adhesive when attaching the centering rings for his motor mount.  As he notes it does have a high tensil strength and a high temperature rating.  I never really thought about using it the way he does because I always thought of JB Weld as primarily a cold weld for metal.
My next build will have a larger mount than the 38mm that is in 'This End Up', which means bigger motors and (presumably) higher temperatures in the motor mount.  I used several different epoxies in constructing T.E.U., but wasn't particularly worried about the temperature ratings.  How much of a factor is heat in the selection of adhesives for projects with large (54mm and up) motor mounts?  I had more or less settled on the WEST system for my next build - any temperature issues I should be aware of?

Dale
Dale Stoyer - L3
NAR #91256
TRA #13499
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#2
Dale.
I myself started with JB Weld only.  It is good for high temperature applications as well as a good adhesive for bonding of fin to motor mount and such.  It is a bit on the expensive side as you don't get much for the money.
After awhile, I changed over to the West system.  West has worked wonderful and in my opinion, there isn't much heat transfer between the motor casing and the motor mount that would result in a failure of the bond.  I find either one to be acceptable.  West Epoxy system is easy to use and you get more product for the cost.  West is not cheap but then again, nothing in rocketry is.
So to answer your question, use either one.  They both work fine.
Jim Goggins NAR  L3
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#3
I've only seen JB Weld in those small tubes. Can you find it in somewhat larger containers and where? And where is everyone buying that West System stuff?
David Haas
NAR #13780
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#4
JB weld on my motor retainers as this is where enough heat might pop the bugger loose. but i would not get to crazy with it. most of time we as rocketeers have a bad habit of overbuilding our little toys, jb weld is stonger than your airframe!!

Here at team Clune we use a few different adhesives depending on the job. Bob Smith hobby epoxy from niagara hobby will do just about everything "I just heard a few people grown"

Bob Smith hobby epoxy 5min. I use this to tack the fins to the motor tube. no matter what you use always peal of the glassaen coating if using a paper motor tube. a phenolic or glass tube is realy not worth the money even when the motors get huge!!

US Composites laminating Epoxy. this stuff costs a fraction of west and from what I have seen works just as well. We use this mixed with colidal silica to create internal and external fillets. Some guys use phenolic micro balloons instead if silica which is fine, in a nutshell phenolic balloons make the fillets hard and strong BUT Brittle, silica make them smooth and strong but is flexible. experience has shown that silica fillets will rip away from an air frame taking some with it while phenolic balloons will break.

JB weld to hold in an aeropak but not the fast JB, it cant take heat so JB says. also JB is good for making Kevlar harness loops "more people grown"

my first EX launch was done with a 3" loc tube rocket "labrat ver. 0.5" that was held together with elmers wood glue. I flew that 3 times on a very aggressive 38mm I motor. paper tube and wood fins wood glued to the motor tube no fillets. I600 no disaster.

Wisdom worth a million
Bill Clune L2 | NAR#88583
MARS Club|SRC|METRA|MDRA - Forever
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#5
Dale,
If your using an Aero-Pac motor retainer or a Slimline motor retainer, then JB Weld is the best epoxie to use there. I've had lots of success using West on my rockets since the heat transfer for the few seconds the motor burns is not enough to break down these bonds. As mentioned, West is expensive, but if you would like to use a epoxie that is the same as West, but at 1/2 the cost or better, then go to US Composites and get thier epoxie, ( http://www.uscomposites.com/ ). I use the Medium system and when you order it you get the both the resin and the hardener at once, you just need to order the pumps for it too. By the way, on the pumps, they are all the same, you just have to pump them 2-1, 3-1, or 4-1 times for the correct mixture. Check them out, I stopped using West and I'm only using USC unless I'm gluing on a motor retainer.
I just wanna fly ROCKETS!!

Dutch
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#6
(10-30-2010, 09:21 AM)David Haas link Wrote: I've only seen JB Weld in those small tubes. Can you find it in somewhat larger containers and where? And where is everyone buying that West System stuff?

David - I've seen the JB Weld somewhere in larger quantity but can't remember off the top of my head.  In the Buffalo area you can get West products off the shelf here:

http://www.rockler.com/retail/buffalo-ne...-store.cfm

Probably cheaper online somewhere (and US Composites seems even cheaper but can't find a local outlet).

I bought a healthy quantity of WEST stuff at Rockler when I was working on my last rocket, so will probably use that for most of the next one (at least until it runs out).  I'll still attach the Aeropac retainer with JB Weld since it is a more heat sensitive application.

Dale
Dale Stoyer - L3
NAR #91256
TRA #13499
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#7
US composites stuff is only online. Dave the West Marine store on niagara falls blvd has it.
Bill Clune L2 | NAR#88583
MARS Club|SRC|METRA|MDRA - Forever
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#8
Auto Zone has the large tubes of JB Weld.
Jim Goggins NAR  L3
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#9
That rockler place is AWESOME stuff is soo kewl there i cant afford to shop there. wood workers paradise
Bill Clune L2 | NAR#88583
MARS Club|SRC|METRA|MDRA - Forever
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#10
Quote:my first EX launch was done with a 3" loc tube rocket "labrat ver. 0.5" that was held together with elmers wood glue. I flew that 3 times on a very aggressive 38mm I motor. paper tube and wood fins wood glued to the motor tube no fillets. I600 no disaster.

Quote:Bob Smith hobby epoxy from niagara hobby will do just about everything "I just heard a few people grown"

I can go along with all that. As I build more larger HPR's, I keep sneaking more Elmers wood glue in my projects. There was definatly some used in my successful L2 rocket. I've heard there have been some L3 projects that used almost all wood glue. Did somebody grown again? And I've used a lot of Bob Smith stuff. I'm not convinced epoxy is that much stronger unless you're bonding phenolic,fiberglass, metal or dissimilar materials. For those of us using the "cheapo" wood, paper tubes, etc., I bet wood glue is almost as strong if common sense is used. Epoxy is expensive, messy, smells, and sometimes I think it causes me skin problems. So I use it only when i feel it necessary or in a hurry (5 min. Bob Smith is brittle, though). My current HP rocket's got a lot of wood glue used in it. Mmm, how do NAR CC people feel about a L3 project with 90% wood glue used in it's construction?
David Haas
NAR #13780
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