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-   -   CA or epoxy? (https://www.rcuniverse.com/forum/kit-building-121/7525880-ca-epoxy.html)

millertym2000 05-21-2008 10:38 PM

CA or epoxy?
 
Ok, I just built a tiger 60 wing and Im at the point of putting the cloth over the mddle of the wing. do you use CA or epoxy to cover it with. I cant seem to find that part in the instructions.. thanks guys.

CrateCruncher 05-21-2008 10:48 PM

RE: CA or epoxy?
 
I always use 30 minute epoxy finishing resin on the center reinforcement. The long cure time allows the resin to be absorbed into the sheeted surface insuring a strong bond and allows me to take my time and do a neat job. "Finishing resin" is just epoxy in a thinned down consistency. I've successfully thinned regular 30 minute epoxy with pure isopropyl alcohol but have heard it could weaken the the joint so I avoid it in critical structures like wing centers.

If you use ca it will probably work fine and be just as strong but you will use a lot of expensive glue and the large amount of fumes can be dangerous to your respiratory system if not adequately ventilated. I also doubt it will have as nice a surface as the epoxy without a lot of sanding but I've never tried it.

millertym2000 05-21-2008 10:51 PM

RE: CA or epoxy?
 
thanks alot, thats what I was looking for.

combatpigg 05-21-2008 11:19 PM

RE: CA or epoxy?
 
Medium CA works pretty good. I mist the cloth very lightly with spray adhesive, then apply it to the surface of the wood. Take a latex glove finger and spread the glue out on the cloth. You will be surprised how little it takes. It sands out pretty good, I've made several cowls this way with a foam plug/mold that you discard. For limited use this is a good method but those fumes are killer.

outdoorhunting 05-22-2008 07:36 AM

RE: CA or epoxy?
 
C/A & epoxy work well. I've had good luck using fiberglass cloth & resin on wing joints. You can mix the resin "hot" if you're in a hurry, or use less hardener for the strongest adhesion. I guarantee you it's easier to sand than C/A or epoxy. It flows on like a dream & you can use a brush to "put it" where you want. I have cartwheeled a plane down the runway, the wing broke at the edge of the fiberglass. Try it , you"ll like it.

Campgems 05-22-2008 10:46 PM

RE: CA or epoxy?
 
Food for thought. Most of the ARF wings are not glassed in the center, but just epoxied together with a strong joiner. I've tried this approach on a couple scratch built wings as well as on two ARF wings. I have also built two 4*60 where I used the CA on glass tape. All of these have crashed beyond repair, but none of them broke up at the center section of the wing. No difference in strength that I could see.

Now, if I'm kit or scratch building, I span the center with the bottom sheeting. Easy to finish and easy to sand. Just as strong.

Don

snurckle 05-23-2008 08:19 AM

RE: CA or epoxy?
 
When building a kit, when should one opt to use epoxy instead of CA?

combatpigg 05-23-2008 12:16 PM

RE: CA or epoxy?
 
The number #1 reason why guys think model building is drudgery is because they choose methods that make it more work than need be. Too bad, because with the wide array of products out there, it has never been easier to build quickly and light.
Use medium CA for everything that you are in a hurry to put together, including gluing in the firewall. If the model has good joint design, the CA will be stronger than the surrounding wood. I think using Zip Kicker makes CA more brittle, not sure if that notion is chemically sound.
Epoxy is best used as a fuel proofer.
If you want to use a glue with good resiliency and fairly fast drying time, use Titebond or Elmers wood glue.
Whenever you are gluing end grain balsa, make sure that the end grain is well saturated...don't use thin glue of any kind here, it soaks back into the wood and leaves the glue joint weak.

TomCrump 05-23-2008 01:21 PM

RE: CA or epoxy?
 


ORIGINAL: combatpigg

The number #1 reason why guys think model building is drudgery is because they choose methods that make it more work than need be. Too bad, because with the wide array of products out there, it has never been easier to build quickly and light.
Use medium CA for everything that you are in a hurry to put together, including gluing in the firewall. If the model has good joint design, the CA will be stronger than the surrounding wood. I think using Zip Kicker makes CA more brittle, not sure if that notion is chemically sound.
Epoxy is best used as a fuel proofer.
If you want to use a glue with good resiliency and fairly fast drying time, use Titebond or Elmers wood glue.
Whenever you are gluing end grain balsa, make sure that the end grain is well saturated...don't use thin glue of any kind here, it soaks back into the wood and leaves the glue joint weak.

I couldn't agree more. I've built complete Giant Scale models, that never saw a drop of epoxy.

manks 05-23-2008 01:37 PM

RE: CA or epoxy?
 
I like Epoxy, spread it with an old credit card (or your wife's current one), I find that it makes a much smoother surface, it is also a lot stronger bond.

manks 05-23-2008 01:41 PM

RE: CA or epoxy?
 


ORIGINAL: snurckle

When building a kit, when should one opt to use epoxy instead of CA?
For most of my planes I use standard Yellow wood glue. If I need a specific job done fast, I will use CA with the kicker. If I really want a strong joint (Firewall, Stabs, wing joint ect) I will use 30 minute Epoxy. Once in a while I will have applications for other glues, but generally I use those three. I love the wood glue, much longer working time, easier to sand ect. CA is great but can be a mess to clean up ext.


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