Conference vmszoo::rc

>>  Coating the Fuel tank compartment with epoxy.
    
    The answers to this question are not obvious.  I'll find them and
    keyword them maybe tonight.  Meanwhile ....
    
>>  ... to coat the compartment ... with epoxy glue???  Why???  
    
    To fuel-proof the wood to 1) keep the wood from getting punky (I
    don't know why that happens, but it sure seems to do so.) and 2)
    allow future repairs (Glues don't like oil soaked wood.).
    
>>  .. epoxy glue (the 4 minute stuff) ... use .. it ... in 4 minutes.  

    Not quite.  Thin it up to 50% with isopropyl alcohol of low moisture
    content (i.e. a new bottle from the drug store, not one that has long
    been opened) and paint it on.  The alcohol will allow better
    penetration, extend the coverage, and also slow down the cure. Once it
    is applied, the alcohol will have done its job; I then put a hair dryer
    near it to dry out the alcohol and warm the epoxy (to accelerate the
    cure).      I then crash the plane so badly it doesn't matter. 
    
Welcome to the hobby.

    Al has advised you correctly. The purpose of coating the inside
    of the fuel tank compartment is to protect the compartment from
    spilled/leaked fuel.
    
    It is not uncommon for a fuel line to break or leak spraying gas
    all over the inside of the compartment. The tank itself can also
    develop a leak over time, or due to a sudden stop.
    
    The point is, you usually discover problems like this when you fill
    the tank and notice fuel pouring out of the bottom of your plane.
    
    Follow Al's instructions and you'll be all set.
    
    Regards,
    
    Steve

    While Al is correct, I, personally, prefer to use the 30-min variety
    of epoxy, thinned 50% with alcohol.  I'm not usually in too big of
    a hurry, so an overnite cure(in a heated house) works fine for me.
    
    Chuck
    

    Two products that I have used in the past with great success are:
    Balsarite and Loctite Coating Epoxy.  Either does a great job.
    
    Balsarite is marketed by Coverite (Black Baron) and is commonly used as
    an adhesive for heat shrinkable coverings.  When dry at room
    temperature Balsarite is hard and looks like varnish on wood.  When
    heated it becomes tacky  and is a strong adhesive.  Why use Balsarite
    to fuel proof an engine compartment?  Simple, it dries clear and hard
    but weighs next to nothing.  If weight is a problem use this stuff.
    
    Coating Epoxy by Loctite, now Z-Poxy is just what the name implies, it
    is used for laminating veneers to foam core wings, glueing down
    fiberglass tape, etc.  If you want to make absolutely sure nothing
    penetrates the coating use epoxy!  This stuff is easy to apply, fairly
    thin, and dries hard and clear.  It can be heavy if you over do it but
    its like steel!
    
    A couple of additional tips - Epoxy can be thinned by applying heat but
    this also accelerates the curing process so be careful.  It also
    creates more fumes!  If you thin with alcohol, go to your local
    hardware store and buy isopropyl alcohol in the can, it has less water and
    it costs less.
    
    When using Balsarite make sure you're in a well ventilated area or
    you'll be higher than your plane will ever be!
    
                --|--             Happy (con)Trails!
                 (O)             
          _______/ \_______       Scott Cox
    
    

    
    Another option.  I fuel-proofed the fuel tank compartment (and cabin
    interior just for looks) the same time I fuel-proofed the engine
    compartment.  I used K&B epoxy paint, matching the color to
    the covering material.  It's easy to brush on, you have plenty of
    time to work and it only takes 1-2 coats to get good cover.  I'll
    put a couple coats of K&B clear over that in the engine compartment just
    to _really_ bulletproof it.
    
    Whatever you use, do fuelproof the fuel tank compartment - if you ever
    split a fuel line and fill the tank compartment with fuel you'll be glad
    you did!  It's not pleasant to deal with fuel/oil soaked wood.
    
    Bill

    You know I never thought of it but why not put a drain in the fuel tank
    compartment also, that way hopefully it will be obvious if you have a
    problem.  Also try to keep raw foam rubber out of the way as this will
    soak up any of the leaking fuel and trap it and keep it damp while it
    slowly soaks into the wood.  YOu could try placing all foam rubber
    pieces in a plastic bag before you place them in the compartment.
    
    I have one for you.
    
    I used to fly 1/4 scale Power, you guys know the noisey ones with that
    hunk of wood on the front that goes round and round that acts like a
    airconditioner (if it stops turning the pilot starts sweating).  This
    plane was mostly Foam that had a outer shell of lexan that was silk
    screened on the inside.  It was a neat concept, a little heavy though
    and tough to repair and have it look good. 
    
    Well you know 1/4 scale is mostly gasoline engines not glow fuel.  I
    had a 16oz fuel tank and a 16 oz smoke oil tank.  Of course they sat
    inside the plane just resting on the white expanded bead foam.  Well
    much to my knowledge while fueling it up one day I noticed some fuel
    dripping out of the bottom of the plane.  I take a look inside the
    plane and notice that all the foam from where the gas tank was sitting
    to the back of the radio compartment is MISSING! and all that was left
    was the lexan skin and the plug in spar boxes.  
    
    Yes Gasoline is DEADLY to white expanded bead foam.  Just ask someone
    who has tried to get some gas in a white foam coffee cup.
    
    Well I got some of the foam in a can and sprayed it back in.  Kinda
    funny though.  I lost 1/4 of my plane that day just because of a leaky
    gas tank

"...I then crash the plane so badly it doesn't matter." - Now That's what I
call encouragement. 

Really, though, the concensus seems clear - do it - and I will. 

Thanks for the info and the advice.  

Roger

    Doesn't fuel-proof dope or urathane accomplish the same thing?  I'm
    building my first RC plane, and the instructions for my CG Eagle 2
    don't mention coating the fuel tank compartment with epoxy.  It simply
    says to use a fuel-proof paint.  Can the experts out there please clear
    this up.
    
    Thanks,
    Joe

    Fuel proof paint or dope will work, it's just that epoxy will work
    better. Kind of like the difference between water colors and oil
    paint.
    
    Steve

    Joe,
    
    What Steve says is true.  Dope wil work but, to get a _really_ good
    seal, you must apply _many_ coats and, even then, dope is not nearly as
    impervious to raw fuel as epoxy or polyester resin.  One coat of either
    of the latter and yer' set; the wood is _really_ sealed and protected
    from fuel soakage.  But, as an earlier reply stated, don't use epoxy
    "glue" for this purpose...it's more difficult to do, requires that you
    thin the glue to do it right and is more expensive.  Go to yer' local
    hardware or chain paint store and get some stuff called Enviro-tex or
    equivalent epoxy finishing resin.  Mix this up and apply full strength
    with a junk/throw-away brush, let it cure and yer' all set.  Fiberglass
    polyester resin (which is what I use for this purpose) works equally
    well but there's a caveat to heed: polyester doesn't cure over epoxy
    so, if you've used epoxy to install the firewall, engine-mount beams,
    etc. you'll have a problem using polyester.  Yer' best bet is probably
    to stick with the epoxy resin.   

      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)

    Al...my fuel tank compartment is now coated with two coats of Pactra
    Formula U urathane.  From your comments elsewhere, I think there will
    be a problem trying to cover it with ANYTHING.  Should I just put on
    more coats of 'U, or will the K&B epoxy paint work?
    
    Thanks for any advice you can give.
    
    -Joe

    Joe,
    
    Yup!  Yer' committed (or should be) now.  :B^)  The only thing that'll
    go over Formula-U is more of the same (or Cheveron Perfect Paint...it's
    the same stuff) or epoxy paint such as K&B Super-Poxy or Hobby Poxy. 
    And, I'd go carefully/lightly with the epoxy 'til a coupla' coats were
    applied to avoid blistering/lifting the polyurethane (Formula-U).
    
    Actually, though, I'm not sure why you want/need to apply anything more
    to the tank compartment.  The only reason to apply _anything_ is to
    seal the wood and protect it from fuel spills so, other than more
    Formula-U to assure a good seal, why would you worry about putting
    anything else over it?
    
    Note to moderator:  Al,  If you'd like to move these last two replies
    to the "Let Us Spray" topic (288?), please feel free.    

      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)

I've always had great luck with a little zip-guard urethane out of
the paint cabinet - it's light, and easy to use.  I usually coat the entire
fuel and radio compartment.  Seems to work fine.           

It's funny how the fuel line breaks at the most opportune moments and 
starts draining out the bottom! :*)


Brain J.