Epoxy Techniques

[sveinbjorn]

Hello all, this is my first post to Rocketry forum.

At what engine level do epoxying techiniques become really important? I'm reading all kinds of stuff about Microbaloons, Colloidal silicon, fortified oat bran, and who knows what else to add to epoxy. If I am working with Mid-power and Level 1 stuff, do I really need all these high-zoot additives?

Just curious,
Ed

P.S.
Thanks to Hospital_Rocket for referring me to Rocketry forum. I appreciate the lack of superfluous B.S. in the discussion groups
. :kill:

 

[Justin Horne]

Well, id say, the standard rocketry answer: It depends...

I think this is an opinion kind of thing, so i'll give you mine. I've used no additives up to an I284 with absolutely no problems.. I am almost done with a very high performance rocket. It is fully glassed. I put colloidal silica on just a few tiny pieces (mount to BT). I probably didn't need it, as West System is extremely tough stuff anyway.. Up to L1, you really probably don't need at.. At the same time though, it couldn't hurt.

 

[rbeckey]

I use microballons to make the epoxy lighter. I have use epoxy mixed with an equal amount of M.Bs. to fill or partially fill a paper fairing or transition on model rockets. Hard as a rock, but much lighter.

 

[Stymye]

thickeners are added to make the epoxy less runny , easier to shape and makes less mess

microballons are added to make the joint easier to sand and blend once cured

 

[sveinbjorn]

Ah, OK...so these microbaloon thingies decrease weight thus increasing altitude...That's a good thing. Will the thickeners shorten the working time of the epoxy?
Can anyone recommend a good book that covers these topics in depth?

Thanks, Ed

 

[Stymye]

you can get a good basic manual from West Systems free at the link below
or you can usually pick one up at places that sell West Systems

https://www.wessex-resins.com/westsystem/wsform01.html

there are many other good online resources as well
Raka , system 3, fiberglast, lots of info online

 

[Justin Horne]

Originally posted by sveinbjorn
Ah, OK...so these microbaloon thingies decrease weight thus increasing altitude...That's a good thing. Will the thickeners shorten the working time of the epoxy?
Can anyone recommend a good book that covers these topics in depth?

Thanks, Ed

I haven't seen a noticeable decrease in time with the silica. However, I only use the slow, so keep that in mind...

 

[Stymye]

ED welcome !

you wouldn't want to use microballoons on everything, just where you want to sand the epoxy, like a final fillet..
it does not make a stronger joint than pure epoxy would

If you are glueing wood and paper, yellow glue will be much lighter ,and stronger than the surrounding material.wood glues soak into and link with the fibers, epoxy does not but it makes a nice fillet

if you are glueing plastic,phenolic,quantum tube ect.... epoxy is a good choice

I have mabey a dozen or more different glues on my bench they all have their place

I believe a level 2 bird could be built with wood glue and survive just fine if constructed properly..

there are many answers and glue can be quite a hot topic for debate
so I'll stop here...lol

 

[rbeckey]

What Stymye said. Also, in case I was not clear, the epoxy with microballons in the transition was a filler only, and not used for its adhesive properties. In fact, I had formed the transition with white glue!

 

[Stymye]

here is an excellent deal on all the epoxy and fillers you would need for a while and an excellent book comes with it

https://www.ndic.com/systemthree/trial_kits.asp

 

[sveinbjorn]

Originally posted by stymye
ED welcome !

If you are glueing wood and paper, yellow glue will be much lighter ,and stronger than the surrounding material.wood glues soak into and link with the fibers, epoxy does not but it makes a nice fillet

I believe a level 2 bird could be built with wood glue and survive just fine if constructed properly..

Hmmm... this sounds interesting. I believe I will experiment with how far you can go (engine-wise) with Wood Glue. What do you mean by "constructed properly?"

Ed

 

[Stymye]

What do you mean by "constructed properly?"

to build a L2 wood glue rocket?

In a nut shell, using the right materials, such as, heavier than estes body tubes and good quality plywood
having a good fit between parts.
techniques, like using internal gussets , ribs
and thru the wall fins.

not having Ill fitting parts that are relying solely on a gob of glue to hold it all together

with a little planning a forethought you would have a strong rocket.. ofcourse,it may not be the best way to build a L2 for long term durability

I think a glassed tube and fins will hold up better in the long run
especially if you fly from a hard surface

someone else can chime in anytime now.!

 

[Justin Horne]

Now im the kind of builder that wouldn't build an L1 rocket with wood glue. Can you? probably. However, I say take the same strong building practices and use them with epoxy. That will certainly yield a stronger rocket...

 

[Missileman]

Originally posted by stymye
here is an excellent deal on all the epoxy and fillers you would need for a while and an excellent book comes with it

https://www.ndic.com/systemthree/trial_kits.asp

WOW all that for 20 bucks!! any good?
On the epoxie additive subject.
Microballoons are added to make the joint lighter and easily sandable BUT it does reduce the overall strength.
Colloidal silica, milled glass, ect... are mixed with epoxy to add strength.
I have flown up to an I195 on epoxy alone construction.
I am using fillers on my current project that will fly on Hypertek J class motors.