marti314

My Feedback: (1)

What is the best way to put the gas tank in so it does not move around during flight? The fit is snug when you slide it in, but not totally locked in place. What should I use to keep it from moving??

Crashem

I pack mine in foam keeps them from moving and helps reduce fuel foaming caused by vibration. Did you remember to fuel proof the area where the tank will be located?

marti314

My Feedback: (1)

What do you mean by fuel proof the area? Put down some foam or something under the tank just in case of leaks??

Crashem

I usually paint the compartment with dope or epoxy resin. Fuel really soaks in to balsa making it spongy. I also fuel proof the firewall and engine comartment in the same manner. I have a four year old Cub and I believe this makes a model last longer.

MinnFlyer

My Feedback: (4)

Definitely! Fuelproofing the engine compartment is a MUST, fuelproofing the tank compartment just makes good sense. Mix up some 30 minute epoxy, and add a few drops of alcohol until it's thin enough to brush on.

And definitely wrap your tank with foam. Without this protection, the engine vibrations will cause your fuel to turn into foam which, in turn will cause your engine to start fine, but it will lean out in flight. It could cause major damage to your engine.

Crashem

Take minflyers advice and only use a few drops alcohol.

Mixed up a batch last night to use instead of polyester resin (fumes kill me in basement) added to much alcohol painted on Cubs cowl (re-fibreglassing don't ask why) anyhow when mixture dried epoxy was soft and rubbery instead of hard had to redo since fibrglass cloth wasn't as ridgid as I would have Liked

Giant Scale

Crashem,
Epoxy hardens by means of a chemical reaction which means that if hardner and resin are in the correct proportions then the epoxy will harden. Too much of either component will not cause it to cure properly. The alcohol does not take part in the reaction of the epoxy.The alcohol merely thins out the mixture. Most people when they use epoxy either don't measure correctly or don't mix it properly. The proper way to mix up epoxy is measuring each component resin or hardner on a scale. This is a pain so I use 10cc syringes or mixing pumps used on West system epoxy. I take 10cc of each and mix for several minutes, scrap the sides of the container and mix some more. I then add alcohol to the desired consistency and paint in on. As the epoxy sits in the mixing container the alcohol evaporates and the epoxy begins to harden. I have never had a problem with the epoxy getting rubbery.

Crashem

Giant Scale

I also thought that was the way epoxy worked. But I can't think of another reason why when I added alot of alcohol it cured soft.

Redid the cowl last night with no alcohol in the mix and the epoxy cured hard as a rock. go figure?

Maybe I got the proportions out of wack on the first batch?

rcav8or

My Feedback: (5)

Are you using rubbing alcohol, or denatured alcohol? I believe you need denatured, as I think that rubbing has water in it...

Correct me if I am wrong...

And yes, epoxy is solely a chemical reaction - we all know someone that added extra hardener to hopefully make it harden faster - it just leaves the excess hardener, and I have seen it possibly make it brittle...

Just my $.02 worth...

Crashem

rcav8or,

Just call me bonehead.

I was rubbing alcohol. Never thought about the difference!!!

MinnFlyer

My Feedback: (4)

Crashem,
When you add alcohol, it increases the curing time. I would be willing to bet that in a day or two, that epoxy will be cured. Make sure you keep it warm!

Crashem

MinnFlyer,

Thanks for the Tip next time I'll wait longer for it to cure.