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CA + coupler = wow

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neil_w

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I always CA the insides of the ends of my various paper body tubes and whatnot to protect them, works great. Today, though, I CAed a coupler for the first time: this was the coupler on my Odd'l Cyclone. I gave it a nice coat of medium CA inside and out, and then sanded it down smooth. It now slides in and out of the top portion very nicely, and should stay that way.
ImageUploadedByRocketry Forum1477687300.301187.jpg

I have to say, though, I was not quite prepared for the results. The coupler is now rock hard. I guess the porous outer surface really soaked up a lot of CA and I cannot believe how solid it ended up. This is no big revelation (CA dries hard after all) but I was still surprised by the extent of it.

I'm going to make sure to do this to all my stage-to-stage couplers from now on (don't ask my why I didn't before).
 

Lowpuller

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Word of caution, this will cause the coupler and body tube to expand and contract, due to temperature, at different rates resulting in ballistic......like this!

ImageUploadedByRocketry Forum1477706194.712788.jpg
 

dixontj93060

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I prefer using wood hardener. Not as caustic as CA. Don't know about temp sensitivity though. Never had a problem with that.
 

TangoJuliet

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Hmm... I'm thinking if the booster coupler and the end of the sustainer BT are both CA hardened, then any thermal expansion/contraction would be minimized and relatively equal, thus negating any friction issues. But that's just me thinking.
 

Gary Byrum

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You may or may not remember, I did this to the coupler in my Magic Dart. It was my first time to treat a coupler with CA and I can testify that it was a really good move. That's where the rocket separates in the center. As far as having any weather related swelling or contracting on said part, I have yet to see any. I've flown it 4-5 times at different points of the summer, and as anyone from the Piedmont area will tell you, this place is plagued with humidity issues and super dry conditions like we are experiencing right now. Worked the same every time.
 

Lowpuller

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Gary,

The above happened at Orangeburg. It was my fault, everything was loose at home but got tight at the range. I hurriedly sanded but obviously not thoroughly.
 

Gary Byrum

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Gary,

The above happened at Orangeburg. It was my fault, everything was loose at home but got tight at the range. I hurriedly sanded but obviously not thoroughly.
I can relate. O'burg had a tendency to be way more humid in the sod field than outside of it. I've had untreated couplers and wooden nosecones swell up something fierce out there. So bad that, I could hardly get my 2 & 3 stage rockets separated. I prolly should treat all of those as well.
 

Zebedee

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If you CA the inside of the body tube as well as the coupler does that cure the differential expansion rates?
 

timbucktoo

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Has anyone ever used sanding sealer instead of CA on paper tubes?
 

Micromeister

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I prefer using wood hardener. Not as caustic as CA. Don't know about temp sensitivity though. Never had a problem with that.
Ditto Dixontj on the Min-Wax Wood hardener over CA on couplers. Wood hardener is not as subject to humidity and temp expansion as CA.
 
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