How to remove tank adhered with silicone?

[frank mccune]

    Hi All:

    What s the best way to remove a tank that has been attached via a clear silicone?


                                                                                                             Tia,

                                                                                                              Frank McCune

[Paul Smith]

A good question.

I use a heated knife, but I'm interested in a better idea.  The stuff is not easy to dissolve, which is its intent.

[Jim Kraft]

Use a piece of control line or lead out, and saw your way through. Not easy, but it does work if you can get to it. If not able to get it around the tank then try a small saw. That stuff is tough to get through, but it can be done. I learned the wire trick from some R/C guys that tried everything else to remove a retract air tank from a ply fuselage.

[Fredvon4]

Fairly easy on a profile...near impossible in a built up fuselage

even worse if the silicone was used to fix a small tank in a hollow log 1/2a plane

Good luck

On the profile I was able to start a corner with a longish sharp blade and as I pried the tank way, progressively sliced it away from the fuselage...heating the blade was not helping so I quit and just pulled and sliced and pulled and sliced

[RknRusty]

Damn, I'm glad I read this before finishing my Nobler ARF. I've been thinking about using silicon for its cushioning effect as well as adhesion. Maybe I'll just use a mini-kiss on each corner instead of slathering it on.

[Curt D Contrata]

The trick is to not use too much in the first place. I wrote an article in Model Aviation about tank mounting, might want to check that out.

I used to use a #26 Exacto blades for removal before I switched from all silicone. The real problem with silicone is swapping tanks at a contest or even at the field.

Curt

[Mike Griffin]

I have been using RTV Silicone for years to mount metal tanks on Profiles...NOT IN FULL BODY FUSELAGES.  I use the plywood mounting plates that Eric at RSM makes.  The are flat with a groove in each end that a 4-40 bolt goes through that allows you adjust the height of the tank if need be.  All I do is run a bead of the RTV around the edge of the tank where it meets the platform and smooth out the bead with my finger.  This is all you need.  You DO NOT have to slather that stuff all over the backside of the tank and slap it on the fuselage.  That will create some real problems if you ever want to remove the tank from the adjustable plywood mount and even more if you just mount the backside of the tank directly to the fuselage nose.   When I want to remove that tank for another use, I simply remove the two 4-40 bolts holding the ply mount and the tank to the fuselage and take a #11 blade and cut through the silicone bead around the tank.  Then for clean up, I either use some acetone or lacquer thinner to further clean it off.

Mike

[Chris Brainard]

I use it in my full size fuselages all the time. My engines are mounted to 1/8" x 3/8" x 2" to 2 1/2" aluminum via flat socket head machine screws, which are then attached to the crutch through two additional holes in the aluminum. This raises the centerline of the engine 1/8" above the engine crutch. I install the crutch 1/8" higher or lower than shown on the drawing, (depending on whether inverted or upright engine mounting so that the engine is in the correct location). Then I use silicone to "glue" the tank to two pieces of 1/8" thick x 1/2" wide plywood cut to length to match the crutch width, one at each end of the tank. These shim the tank up to the same height as the engine. Once dry, I apply a coat of silicon to the other side of the plywood (which has already been attached to the tank). Then slide into place and let dry. A short piece of scrap banding material will easily cut the silicon between the top of the crutch and the plywood attached to the tank. Once the first piece of plywood is separated from the crutch the tank can be tilted up enough to slide the banding to the back of the tank and cut out. Once the tank is out, clean up the silicon with kerosene. Let it sit a while. The silicon will swell up and soften. A couple of applications will usually get all the silicon off.
Chris

[Brett Buck]

The trick is to not use too much in the first place. I wrote an article in Model Aviation about tank mounting, might want to check that out.

I used to use a #26 Exacto blades for removal before I switched from all silicone. The real problem with silicone is swapping tanks at a contest or even at the field.

   I agree, you almost have to cut through it. It's very tough stuff.

    Brett

[Pat Chewning]

Dental floss will saw right through it too.

BTW:  The letter "e" can make a huge difference
     Silicone is a synthetic polymer rubbery-like soft material for gluing, sealing, and making breast implants.
     Silicon is a hard brittle element that is grown in crystals to make integrated circuits, and is commonly found as quartz (sand).

[frank mccune]

    Hi Pat et.al.:

    You are correct about the "e".  During my second EE course, misuse of those two words would bring the prof's wrath down on you like a brick wall!  Your grade automatically dropped at least 2 letters never to be redeemed!

                                                                                                                            Stay well,

                                                                                                                            Frank McCune

[John Park]

I congratulate anybody who can mount a tank permanently at just the right height to give an equal run upright and inverted.  I've almost always had to move mine up or down during initial test flights, even if only by a fraction.

[Fredvon4]

I hear you John... but I have seen many a modeler ( as I have) use a simple j hook rubber band arrangement to help find perfect/good enough tank height...then dremel off the ugly j hooks, and get rid of the lousy idea rubber bands, opting to semi permanently bond the tank in ( the found correct) place with the silicone on a profile. I have moved on to doing it the way Mike Griffin suggests only using the RTV to attach tank to a adjustment plate

[John Park]

I hear you John... but I have seen many a modeler ( as I have) use a simple j hook rubber band arrangement to help find perfect/good enough tank height...then dremel off the ugly j hooks, and get rid of the lousy idea rubber bands, opting to semi permanently bond the tank in ( the found correct) place with the silicone on a profile. I have moved on to doing it the way Mike Griffin suggests only using the RTV to attach tank to a adjustment plate

Couldn't agree more re. RTV to mount tank on plate with slotted bolt holes.  I've had trouble with soldered brackets failing through vibration.

[Fredvon4]

John I never got to find out if vibration killed the solder on tabs.. I never did use them on a plane..

Must be my technique... new GRW or Brodak tank...pressure check good... add on the Tabs...pressure check...no good   grrrrrr!

Obviously too much heat de-solderd the end cap... screw it.... I mostly use Plastic RC clunk tanks these days

BTW I do and have soldered a LOT in my electronics hobby/career...so I think I have a clue...but tin tanks, building, repairing, or just adding on a simple bracket is near impossible for me...arrgh

[John Park]

The solder always stayed put - it was the bracket that failed at the right-angle bend.  I thought that was because I'd used tinplate, so I switched to brass.  I've just had one of those go the same way.  No more soldered brackets for me.

[Curt D Contrata]

Maybe I misunderstood the original question, I thought it was asking about a full fuse model. As previously stated, I don't like silicone for several reasons. My biggest complaint is the drying time and the ability to swap a tank in a hurry. When looking for some requested photos for another thread, I came across these. I think they are self explanatory, this method allows me to adjust height by shimming from the motor rails and or swap out a tank in a few minutes at the field. Yes, I still put a dollop of silicone in the center of each tab "Just Because", but the foam tape (with sticky side still covered on the tank side) keeps things snug enough to fly. This is the way the tank is mounted in my Satona.

Curt