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-   -   Epoxy (http://www.oldrocketforum.com/showthread.php?t=2312)

F_O_G 10-12-2007 04:15 PM

Epoxy
 
is it ok to use elmers white glue in place of epoxy?

ScaleNut 10-12-2007 04:21 PM

yes , atleast on model rockets

pyrovette20 10-12-2007 04:48 PM

Why would you want to. I epoxy everything.

Shreadvector 10-12-2007 05:02 PM

Epoxy adds weight because it does not contain water that evaporates.

Heavy rockets can be unbalanced/unstable rockets.

Yellow wood glue is perfect for cardbaord, wood and paper. It will not stick to plastic and metal, but epoxy will.

barone 10-12-2007 06:34 PM

Quote:
Originally Posted by F_O_G
is it ok to use elmers white glue in place of epoxy?

Depends upon what you are bonding. Elmer's white glue isn't very good for plastic to plastic or plastic to wood or plastic to anything. If a plan is specifying epoxy for a construction bond, there is probably a reason for not using the white glue. What is the specific application?

tfischer 10-12-2007 10:12 PM

Another tidbit is that white glue and yellow glue are essentially the same thing, as far as adhesion is concerned. The difference is that white glue has a much longer "open" or "workability' time then yellow glue. I'm a woodworker, and most woodworkers prefer white glue due to the fact that things can be positioned, etc. rather than immediatly sticking. The final bond is the same strength.

With rockets, many people seem to prefer the yellow glue so that the fin (or whatever) will lock into place much sooner without having to be held forever.

-Tim

ghrocketman 10-13-2007 09:56 AM

Depends on the rocket power level whether white glue or Titebond will be enough.
As a rule I use Epoxy for fins and engine mounts for ANYTHING that will see "E" power and above.
Most likely overkill, but good insurance for mid-power rockets using engines from E through G.
Needless to say, for hi-power (H and above) epoxy is a must.

For run of the mill A to D power it just adds weight.

Mach1 10-14-2007 01:19 PM

Quote:
Originally Posted by F_O_G
is it ok to use elmers white glue in place of epoxy?


I'd use yellow carpenter's glue in place of the white glue. White glue will work, but the yellow is stronger. The bond of the yellow glue is much stronger than common model rocket materials anyhow.

Most of the time, (unless I have a special situation) the only time I use epoxy in model rockets is to secure the motor mount. A motor mount can be secured in with yellow glue just fine, but you will end up with a "pucker" ring on the outside of the body tube. The yellow glue shrinks when it dries causing the ring to appear.

ScaleNut 10-14-2007 02:16 PM

Quote:
Originally Posted by tfischer
Another tidbit is that white glue and yellow glue are essentially the same thing, as far as adhesion is concerned. The difference is that white glue has a much longer "open" or "workability' time then yellow glue. I'm a woodworker, and most woodworkers prefer white glue due to the fact that things can be positioned, etc. rather than immediatly sticking. The final bond is the same strength.

With rockets, many people seem to prefer the yellow glue so that the fin (or whatever) will lock into place much sooner without having to be held forever.

-Tim


white glue is Polyvinyl acetate

wood glue is Aliphatic Resin

as far as the bond strength titebomnd III runs around 4000 psi and has a longer open time, it's stronger than gorilla glues !
white glue doesn't even enter the ballpark, however for balsawood it's plenty strong.

here's a prety good essay on glues from a woodworker site
http://www.woodcentral.com/russ/russ6.shtml

tfischer 10-14-2007 04:12 PM

Quote:
Originally Posted by ScaleNut
white glue is Polyvinyl acetate

wood glue is Aliphatic Resin



There's a lot of conflicting information on this on the web, evidently. Some sites say "yellow glue is PVA". Others say it's "Aliphatic Resin". Still others say it's both...

I'm not a glue expert, but my quoted post above was how I understood things to be, at least until now that I'm bewildered... :confused: :eek:

I do know many woodwookers prefer white glue (PVA) due to it's long open time, and use it for things like gluing up table tops...

-Tim


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