Tanks......

Okay, can anyone provide with info for Tank materials? I need Tin, and Solder and Torch.

The other day at Wal-Mart in the Hardware dept. near the bigger plumbing torch they had a micro-butane, refillable torch. I think it was around $30, is this the kind to use?

I find a torch to be just too much heat for the thin metal we use. Even so, occasionally you need a little extra heat to take a tank apart- removing the front-plate or back-plate, for example. For this task, I set the cook stove element to med and set the tank on the element and in short order the solder melts throughout the joint and comes apart easily with tongs. For regular solder jobs, a Weller soldering station beats any of the guns, as does almost any iron. My opinion- others will surely disagree. Back to tanks, I'll never install another metal tank- I like the plastic Sullivan RST types. Again- my opinion- others will surely disagree.

>Okay, can anyone provide with info for Tank materials? I
>need Tin, and Solder and Torch.
>

I strongly discourage you from using a torch. You can do OK with an electronics pencil soldering iron, but I use the largest of the Weller gun types - 325 watts. They are very inexpensive for a quality tool.

For tin, use K&S "Easy Solder" Tin (really .007 tin-plated steel) from the K&S display. While you are there, get some Copper tubing - not brass. Use 60/40 Rosin Core electronics solder. I like the 1/16 diameter, and it makes some difference in the ease of use.

Paste flux, torches, etc. are not required and not desirable. Aggressive flux and torches remove the tin plate, after which your problems multiply. It takes just seconds of excess heat from a torch to boil away the plating. It's impossible to get it that hot with a gun. Also, don't use a wire brush or any sort of abrasive - it''s just not necessary. The rosin will clean it well enough.

Frankly, if I get in a situation where a signifcant amount of plating has been removed, I usually just make a whole new tank. It's so easy and quick to make them with clean materials it's just not worth spending much time trying to solder the bare steel. I know full well how to solder this (heck, I welded up an aluminum tank using eutectic welding rod), and I can do a good job, but it's just fussier than doing it from scratch.

If you need to remove the backplate or disassemble it, make sure it's empty, rinse it out with water, and set it on the stove on super-low heat. Don't worry about the water - it will remove the and dilute the methanol, but the oil will remain and nothing wil corrode. Once it's all apart, and whatever you wanted to do is done, just blow dry it with a heat gun or hair dryer.

Take it from me -I have made probably 100 tanks over the past 10 years, with good results. Starting with clean and fresh metal, and taking pains to use plating to your advantages, is really the easy way to go.

OK. Brett's reply is the gold standard. This is how it is best done. It upsets me when people ask a question and get a gold standard answer only to have them say "Yes, but, this is how I do it." I know this isn't the case here, but it is important to point out when Brett or Ron, the F4F guy, answer a question, it is usually the gold standard for that particular technique.

I build a lot of tanks too, usually because standard tanks won't fit my models. Brett's reply is exactly how I do it except I find the Weller 140 watt gun to be enough. I also use .07 tinplate. My local hobby shop doesn't carry it so I get mine from Brodak in one foot square sheets for my larger tanks.

(snip)
>I build a lot of tanks too, usually because standard tanks
>won't fit my models. Brett's reply is exactly how I do it
>except I find the Weller 140 watt gun to be enough. I also
>use .07 tinplate. My local hobby shop doesn't carry it so I
>get mine from Brodak in one foot square sheets for my larger
>tanks.
>
>Al

Brodak buys this tin plate for tanks in 4 foot by 8 foot sheets, so you can get it as big as you like. I have gotten several 8 inch by 4 foot sheets and had them stick it in with a kit order. Of course I specified that once and then they rolled it. The whole idea was to keep it flat and use it with minimal waste. It is easier for them to simply lob a section off as well. But make sure they keep it flat. The one foot square sheets that Al gets are easier to put in a box.

Only thing I would add to the above is practice on a few "tin" cans. You can cut them apart with tin snips and practice forming, cutting & soldering before you use the good stock.

The weller gun your using is it the gun or pen type? The highest pen type I can find around here is 35 watts for light electronical work...

I can order larger sheets from Brodak? The stuff at my hobby store will do a 3.0 ounce tank max...

Great response Brett!

I build most of my tanks. However, I use an Weller soldering station (for electronic use). I don't believe it is more than 60 watts. This works fine, and as Brett states, you won't remove the tinning. With a low wattage iron, you must keep the iron tip tinned to allow best heat transfer to the tank material.

Torches are handy to disassemble a tank, but you will lose the tinning.

The enclosed image is my latest tank built from K&S tin plate. The tank needed to be longer than 4 inches (the width of the K&S sheet), so I made a lap joint (not visible) and joined 2 pieces together prior to forming the main body.

Fred

>Great response Brett!
>
>I build most of my tanks. However, I use an Weller
>soldering station (for electronic use). I don't believe it
>is more than 60 watts. This works fine, and as Brett
>states, you won't remove the tinning. With a low wattage
>iron, you must keep the iron tip tinned to allow best heat
>transfer to the tank material.

Like I say, the master at whose knee I learned - Ed Robbert - use a fairly-heavy-duty soldering station type system. It works fine assuming you know exactly what you are doing, but I prefer a little more heat to make absolutely sure that I can always get it liquid over a good area.

Soldering technique is almost always the downfall of budding tank makers. I have seen some that you simply wouldn't beleive - cold solder joints piled 3/4" high like a little volcano around a vent tube (that nonetheless leaked), tanks that sounded like baby rattles there were so many solder balls, stuff like that.

I've thought about writing a tank article, but I have no way of illustrating the soldering techniques.

Hints for everyone - if you solder doesn't have a shiny finish and flow like water when you have the heat on it, you aren't getting it hot enough. If it's caked up, you didn't get it hot enough. If it rolls up into little balls, you either went through the tin and now are trying solder to bare steel (meaning you have to use acid flux, or better, replace the part or whole tank) or, there is some contamination that you should clean off with successive applications of laquer thinner (not acetone - - too wimpy) and good old soap and water. Don't sand it, wire brush it, or anything like that.

I figure that for beginners, and even moderately experienced solderers, having a more powerful iron will tend to produce better results. It tends to take care of the cold solder joint problem even if the novice doesn't have the experience to recognize it.

>
>The enclosed image is my latest tank built from K&S tin
>plate. The tank needed to be longer than 4 inches (the
>width of the K&S sheet), so I made a lap joint (not visible)
>and joined 2 pieces together prior to forming the main body.
>
>Fred

I also use the regular 4" wide material, and make the body in two parts. While it seems like an negative, I actually prefer doing it in two pieces. It's much easier to bend well, and it also allows you to make up for slight bending and cutting errors without the tank getting "racked". Some tanks that I have made would almost demand two pieces in any case, since there are some compound angles that would otherwise require stretching the metal.

I also make my own tanks. Mainly because I use rectangular stunt tanks. This gives the maximum volume in the allowable space. A wedge tank only wastes valuable room. A rectangular tank takes a few extra laps to go dry, but at least you get lots of warning, so you don't get caught overhead with a dry tank!~

One point not mentioned. I use 1/8" copper tubing (K&S) but I first heat it to dull red with a propane torch. This makes it soft and easy to bend without kinking.

Great stuff Brett,

Questions: When you make the body in two parts, where do you put the
seam?

What is the advantages of rosin core over stay brite ?
Not "questioning" your use, just want to feed my knowledge
base. Better tinning ability? More stress resistant?
I have used both simply because it was what I picked up,
but I would like to use the better of the two for tanks.

Thanks!
Bill <><

>Questions: When you make the body in two parts, where do
>you put the
> seam?

Usually, the lower right corner, and the peak of the wedge (if any) looking from the front as it is mounted in the airplane.

>
> What is the advantages of rosin core over stay brite ?
>

Sta-Brite solder (4% silver-bearing solder, NOT silver solder) is fine (albeit unnecessary). The Sta-Brite flux is extremely corrosive, and will eat the tin away (not to mention the tip of the iron, and anything else that it touches). That's why it works so well on soldering hard-to-solder materials - I had no problem soldering to 306 Stainless! It also ate through that piece after a while. It's much more difficult to remove the residue than it at first appears. I spilled some on my dad's cast iron table saw top in about 1975. Despite repeated cleaning with water, and sanding with crocus cloth and oil over the last 30 years, I noted that it has cratered the surface about 1/16", and is still going - as of Thanksgiving, 2003. That's what I call a strong flux! The Weller copper tips will wear themselves away in pretty short order unless you file them down to far below the cratering zone.

Unless you have gone through the tin, you just don't need that much cleaning. Once it's gone, then maybe you need it, but the chance of rusting through is just too high. I'd try the new "pipe-safe" flux thats supposed to be non-toxc for use with copper plumbing first.

Regular old rosin in rosin-core solder will keep the surface from oxidizing while you solder it, and that's all you need. Plain Sta-Brite (without the flux) has a problem because theres no rosin to keep the surface from oxidizing when you heat it. It's only marginally stronger, and certainly nothing like brazing or *real* silver-solder (which, done properly, is as strong or stronger than a standard stick-weld). If you want the slightly stronger solder, then Kester makes the same 4% silver-bearing solder with a rosin core that you can get at any well-stocked hardware store.

I reiterate - if you make good regular solder joints, you DO NOT need the extra strength of Sta-Brite.

Having said all that, Sta-Brite, used in an appropriate spot, works like a charm on music wire, and things like that, and melts at low enough temperature that you won't take out the temper. But keep it away from bearing surfaces!

Thanks, Brett. This is interesting and helpful.

I agree with Al about the gold standard. I would add that one should heed Al's advice, also. I do, but I won't admit it to him.

Not to get off the subject but I don't get it, did I miss something? What is a "Gold Standard" the East Coast version, the West Coast version or the Midwest version.

Brett's post is great and if followed will produce good results but are you and Al saying that is the only way to do it and everybody else shut up? Even Al mentioned an alternate source of tin plate while Brett recommend the K&S tin.

I don't own a Weller gun, mine died and never replaced it, instead I use a Weller 40 watt pencil iron with a 1/4 inch tip. If the guy doesn't have a Weller gun but happens to have a 30 or 40 watt pencil iron that will work just as well, why can't someone give an alternate solution. When I take tanks apart I don't use a torch, soldering iron or the stove, I use an Unger heat gun. Clean, safe and doesn't screw up the tin plating.

So because I don't do it exactly like Brett using the exact same tools my methods are wrong and I shouldn't tell anybody that they might have other options..

Please enlighten me so I can better under understand when it is politically correct to offer and alternate opinion.

PS: In the 60's when I worked for Hughes Aircraft I was a NASA certified soldering instructor. How many of the "Experts" have one of these in the shop.

If you're into Slow Combat or like to use a hard tank in Speed Limit (masochist!), or are just too cheap to buy K&S tin plate, an article that was published in the MACA Newsletter some years back talked about how to make tanks. The author said that tin can material was good, but you needed the unpainted, unvarnished variety. Pineapple comes in such cans. The inner surface isn't polished, so you see the tin crystals, but it works great. Leave the corrugations alone - they serve to make the tank stronger to withstand those crashes better. Another source is 1 gallon cooking oil cans - get them from your local Chinese restaurant, they go through cooking oil like nothing else. This stuff you have to burn the paint off, but the sheets you get are large. And they look cool if you just burn the paint off the seam areas. A blowtorch, and then some steel wool, will quickly do the job, said the article.

Auto body shops may have some laquer thinner cans around. These are gallon cans it is already clean. (Hey, it has been cleaned with lacquer thinner.) I used to use old mimeograph cans in the early years. Ah, the good old days, when the cans were cheaper than the product inside!

>I don't own a Weller gun, mine died and never replaced it,
>instead I use a Weller 40 watt pencil iron with a 1/4 inch
>tip. If the guy doesn't have a Weller gun but happens to
>have a 30 or 40 watt pencil iron that will work just as
>well, why can't someone give an alternate solution. When I
>take tanks apart I don't use a torch, soldering iron or the
>stove, I use an Unger heat gun. Clean, safe and doesn't
>screw up the tin plating.

Of course you can use those - I hope I didn't suggest otherwise. But I do think you need to have more skill and experience to know when you have gotten it hot enough. You might be able to have good results, I might be able to have good results. But for raw neophyte a stronger iron gives them more margin. I prefer it because I can just pull the trigger and run the tip down a whole seam at high speed, and finish it completely. Heck, I *can* do tanks with a torch - but what you can get away with, and what is a good idea, are two different things.

In any case, soldering technique is the crux of most problems. I emphasize that the solder must be hot enough to flow like water no matter what heat source you use, or the joints will be weak and the tank will start leaking pretty soon.