Russel Shaffer asked me yesterday how I built the tank on my Skyray.  I told him I'd tell him later -- then never got the chance.

So, the answer is:  It's bent up out of metal from a Dole pineapple juice can.  I used tinsnips to cut out the metal, and a brake from Horror Freight ($18) to bend it.  The seam on the bottom of the tank is double-bent (I can't remember the sheet metal term) -- in other words, both sides are bent sharply over, with the bent-over part of each one sliding over each other into the fold.  This makes for a reasonably strong seam with lots of solder area.  The end caps are bent from more metal from the same can, then the whole thing is soldered together with 50-50 plumber's solder and a mild acid flux paste (although per a recent discussion here, plain old rosin core solder should work well).

You can (shudder) buy tinplate, if that floats your boat, but I love canned pineapple, so I have no shortage of raw materials.  You can also use a hardwood form to bend up the tank, instead of a brake.  It helps a lot if you have something to use as an anvil to tighten up the bottom seam -- I have some 1/2 inch square aluminum tubing that I clamp in a vise, against which I can hammer if I'm not too forceful.

Put the fuel tubing in when you have the front cap on.  The holes for the fuel tubing are drilled undersized, then bent out with an ice pick to size.  This provides extra solder area, and gives one the freedom to easily make oblong holes for the slanted tubing, by shoving the ice pick in and tilting it over.  I like to tack down the fuel feed and the uniflow at the back of the tank (which is why I don't put the back on until the tubes are in).  When the tubes are soldered in nice and tight, button up the back end.

Pressure check when done, and fix any boo-boos.  I'm using a flux that's mildly corrosive, so I finish mine off by brushing the outside vigorously with a toothbrush, dishwashing soap, and hot water.   For the inside I put in a couple of drops of dishwashing soap in a fuel tube, fill the tank with the hottest water that'll come out of my tap, and shake vigorously to clean the inside.  Then I rinse well, and if I'm not going to use it immediately I put 1/2 ounce or so of 99% isopropyl alcohol in, swish around, and drain.  This should displace most of the water, and let it dry out quickly.  Baking the tank in the oven would dry it out, too.

You can leave the tank bare, the way you saw mine at the Fall Follies, or you can paint it with Rustoleum Protective Gloss Enamel, or just about any other paint that'll go on metal and is fuel proof.  I painted the tank on my Waiex to match the plane, and it looks pretty good.  Just plug the fuel tubes before you paint...

Edit:

There was an article on building tanks from sheet recently.  I think it was in MA, of all places, but it sure seems more likely that it was in FM.  Last few months -- yes, that doesn't narrow it down much, but if someone has in mind the 'zine & issue could they speak up?

Now if someone will come up with a method to make the tank end caps......the commercial ones are stamped and stretched in a die.. I can't do that!  Bending the edges over results in a poor fit and takes a lot of solder to seal.

Floyd

Now if someone will come up with a method to make the tank end caps......the commercial ones are stamped and stretched in a die.. I can't do that!  Bending the edges over results in a poor fit and takes a lot of solder to seal.

  I bend them to fit inside, works great and is easy with the right gadgets. I will take a picture of one such gadget when I get home.

   Brett

It is quite possible to make a tank out of one piece of sheet. Just need to figure out which bends to make when...

This one is out of two parts but I think the one loose cap could be cut as part of the rest. Pic stolen from http://www.aeromaniacs.com/Tips.html , it says: Plans for George Aldrich Uniflow tank

I never thought of bending the end caps around the bare hardwood form!  I bend them around the form with the main tin body in place.  Using the bare form should make the end caps slightly smaller, so they should fit better.

Floyd

I use square tanks (no taper) and they work pretty well.

In the latest issue of "Control Line World" is a very good article on building your own metal tanks.  Bob Z. does a couple of things different than I do.  Well worth the read.

Back when Model Aviation printed such things, maybe in the late 70's to early 80's, there was an article on making control line metal tanks.  They used a wooden plate with a hole in it the same size as the OD of the end caps.  There was a wooden punch or former with the ID and rounded edges.  A piece of metal was put in place and the former driven with a hammer to form the end cap. 

I have been fortunate to obtain a few of the old Dynamic Models tank kits.  There are two formed pieces, a front and a back.  I cut them to the length I want (full length is 4 oz worth). I plumb the pieces before I join them and then join and solder the overlapping seam.  I wish someone would produce a similar tank kit.