Cleaning Homemade Fuel Tank

[Chancey Chorney]

I just completed building a metal fuel tank to use on my Ringmaster Jr. Now, I cannot somehow find the post that showed the next steps to cleaning it. I know I have to plug two of the lines and submerge in  water and check for leaks. But then I cannot exactly remember what was recommended to fill the tank with and swish around to help get rid of the flux, and residue inside the tank. I have some 90% alcohol, and some thinners available to use. If someone could please let me know, or can post a thread, it would be greatly appreciated.  Thanks.

[Chancey Chorney]

Seems I had a similar post a couple years ago.... However, it appeared that the best resolution was an antifreeze boil, as a poster made mention other methods were not as good. I have a little old fuel here I will try out. There is some Flux on Tehran outside that I will try a couple of solvents on before filling the tank up.

[Dave Hull]

Use lacquer thinner in a 24 oz. pickle jar. Place the front of the tank in first. Watch for air bubbles coming out one of the tubes indicating that the thinner is going in somewhere. Let it soak a few minutes and slosh it around thoroughly. Be sure to put some after run oil in the tank immediately after you clean and leak test it to prevent the inside from rusting up.

If you used rosin core solder and rosin flux, it is made from pitch (pine sap), hence the name. Your solvent needs to cut that. I have been most satisfied with the lacquer thinner---but at times this topic is nearly as controversial as "...why can't you mix rattle can paint, two-part paint, epoxy paint--all over the top of either butyrate or nitrate, because the builder doesn't remember...."

Isopropyl alcohol will cut it, but not nearly aggressively enough. It works on PC boards mostly because you can scrub the board with a brush to get it clean. When cleaning a fuel tank you don't have that option.

I don't doubt that crocking the tank in antifreeze would work, but it seems a fair bit of overkill.

An ultrasonic clean would also be good, if you have one.

Divot McSlow

[Dan McEntee]

  When building or repairing tanks, I use rosin core (electrical) solder and Ruby Fluid flux. There is no need to put flux anywhere on the inside of the tank. Assemble the parts, brush a little flux on the out side of the joint, then solder away. Flux on a solder joint is one of those things that some people think that if a little bit is good, a ,lot is better and that just ain't so. A little bit goes a long way and less chance of any whicking inside the tank. There is no substitute for a tight fitting solder joint. It takes less solder and flux and it's stronger also. Once you are finished soldering and checking for/fixing leaks, flush it out with white vinegar. That will neutralize any acids left from the flux that may have gotten inside. Just fill with an old syringe and give it a good shaking. Force it out with an empty syringe, then repeat a couple more times and see how clean or dirty the vinegar comes out. When satisfied, flush with fuel, then fill with fuel, cap it all off until you are ready for it. If you made a wooden form for the tank when building it, another use for it is mocking things up when finishing the engine/tank compartments. If the first tank you built leaves a little to be desired, keep making them and and soon you will be a pro at it. Practice making and bending mock ups out of manila folders like Al Rabe does. That will help you develop the forming skills. and then just join with scotch tape.
   Type at you later,
  Dan McEntee

[M Spencer]

Boiling for 5 or 10 minutes with a tablespoon of baking sodas ok .

A block of wood in it stops spiraled tanks, at times .

[Dave Hull]

I tried the on-line translators (I tried 'stralian to English, and English to American, both) to figure out what a "spiraled tank" was, but no luck. The closest thing seems to be a "flavor device" that is used apparently on e-cigarettes. And why a block of wood is needed inside to stop it from spiraling...I just couldn't say. But no doubt, it is important to keep it from spiraling. My greatest fear, though, is that even using the block of wood, it may still spiral without warning. That sounds exceedingly dangerous to a fragile stunt plane. So assuming that Matt is not suggesting a way to enhance stunt plumbing using e-cigarette parts, I am now forced to ask--what the heck are you telling us, Matt?

Divot McSlow

PS--If you are trying to tell us we should suck on all new tanks using our wooden teeth before flying, just come out and say so. I'm sure George Washington did, and didn't he make general?

[Gary Dowler]

Seems like method for testing for testing for leaks is a little different than most.  I fill the tank with water with some detergent mixed in, which acts as a wetting agent. Then I plug 2 outlets and use my fuel bulb to apply mild internal pressure, and then watch for leaks. The soapy water will find leaks that straight water may not.  Then the tank is drained, then gets several rinses before I apply low pressure compressed air for about a minute to remove most remaining moisture.  The final step is a "rinse" with fuel to remove any last moisture.


Gary

[Chancey Chorney]

Great. Thank you all for the advice and tips. I will clean it out tomorrow as I am busy tonight. Then mounting up on my plane.

[Dave_Trible]

Since your tank is already built I'd flush it with a little acetone. That will cut the flux.  As a thought for the future use only resin core electrical solder, No acid core , no high temp, no silver bearing and you need no additional flux at all.  What little flux remains is of little consequence and this solder won't corrode like the others-flux IS a corrosive.  Resin core is plenty strong for this application.  I usually build the tank complete but before I solder the end cap on I rinse it out in hot water in the sink.  Once the cap is on just put it in the plane.

Dave

[bill bischoff]

Using my Matt Spencer to English translator, what I come up with is that if you assemble the tank around a wooden block, there is less chance of the tank having a twist built into it. Or not...


BB

[FLOYD CARTER]

So, Trible thinks the way I do.  Why make it complicated?  Fill the tank about 1/4 with acetone and slosh around.  No need to oil it up afterward because I only work on planes I'm getting ready for the weekend.

[Ken Culbertson]

Using my Matt Spencer to English translator, what I come up with is that if you assemble the tank around a wooden block, there is less chance of the tank having a twist built into it. Or not...


BB

I always had a hard time getting the block out after putting on the endcap.
I still have all of my molds from the 60's  Great way to build tanks.

Ken

[bill bischoff]

It's probably best that you've gone electric. 

[Chancey Chorney]

The tank was just water tested for leaks and passed with none! As of a few minutes ago, I have put about an ounce of thinners inside the tank to clean out the inside. I gave it a good shake around and have it resting on the 'peak', upside down for a few hours, with a shake every once in a while. Later, I will rest it on its flat side to sit and soak for the night. Tomorrow morning, I will suck out what I can, then fill with alcohol or fuel to flush it out before mounting om the Ringmaster. Thanks for the help.

[frank williams]

Spray some carburetor cleaner down one of the vents and gargle.

[Dan McEntee]

So, Trible thinks the way I do.  Why make it complicated?  Fill the tank about 1/4 with acetone and slosh around.  No need to oil it up afterward because I only work on planes I'm getting ready for the weekend.

    What's complicated about white vinegar?  You probably have some around the house, it is non toxic, will cut and eat anything that might be in the tank from soldering, including neutralizing any acids, and it will also dissolve rust! That is handy if it's an old tank. I use it to clean out steel gas tanks on vintage dirt bikes and works wonders with a hand full of aquarium gravel thrown in also. No need for that with a model tank, but it does dissolve rust. Acetone or any other harsh chemical that isn't an acid won't do that. And if you happen to spill some, so what!! It won't harm any paint or other delicate surfaces, or your skin. You can also mix it with some ammonia and make some model cleaner while you are at it.
   Type at you later,
  Dan McEntee
   

[Lauri Malila]

The tank was just water tested for leaks and passed with none! As of a few minutes ago, I have put about an ounce of thinners inside the tank to clean out the inside. I gave it a good shake around and have it resting on the 'peak', upside down for a few hours, with a shake every once in a while. Later, I will rest it on its flat side to sit and soak for the night. Tomorrow morning, I will suck out what I can, then fill with alcohol or fuel to flush it out before mounting om the Ringmaster. Thanks for the help.

..but make the leak test again after cleaning. L