Tinsmith's in frame gas tank for cantilever Schwinn.

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Tinsmith

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May 15, 2009
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Tim,

Go for it and if you can post some pics so we can see what you come up with. When SB's tank is finished I plan to get back on my second build. When that is done I would like to make a tank similar to what you are describing for my chopper. Good luck, Dan
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
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In the time since our last session Dan cut out a second tank slightly smaller than the first one and came up with a better way of assembling the tank. I have misplaced a photo disc and may return to the business of assembly later when I can better illustrate what I'm talking about, but most basically he fits the tank sides and top long piece together, sandwiches it between two wooden forms, clamps it together with large C clamps and solders it together. I don't have the photos to show the removable tin spacers he has placed to the inside of the tank to help it keep it's shape under the force of the clamps. As I said, I'll return to this idea later when I have the photos to show. It is a great idea and does two things. First, it aligns everything together for a perfect, symmetrical fit. Second, it leaves both hands free for the business of soldering.
Another improvement over tank number one is the bung for filling the gas. I have been using a simple and inexpensive 3/4" male copper plumbing fitting on my V8 gas tanks with a brass hose cap and it has worked fine. The threading is slightly off, but it works and seals up. Dan was going to pick up an extra fitting at his local old time hardware store since he wanted to cut down the length of the fitting and remove the first few threads, thinking it would look better. The elderly woman who owns the hardware wondered why he wasn't using a brass hose coupling to go with the brass cap. She showed him one, Dan brought it home with him and the threading of course is perfect. This makes a great and inexpensive gas tank bung and cap. It needs to be modified, however, so that the hole it fits in to can be snug against the bung. Using a belt sander, Dan removed the threading from half of the coupling. It only took a couple of minutes and did a nice job. Brass bungs made for gas tanks are pricey. This home made one is less than ten bucks including the cap. I like it.
One of the photos shows the tank with the forms on it and it is being drilled out for the filler bung. Dan is using a cone shaped bit/grinder and we did the final grinding with the more precise Dremel tool. The final pictures show the bung being tinned to prepare it for soldering to the tank. This is an important step. The difference in how much heat it takes to bring the brass up to temperature compared to the tin it is going to be soldered to is considerable. The tin heats up in no time while the thicker brass will take much longer. If Dan were to try to bring the brass up to the temperature it needs to accept solder flowing into it... by then the tin around it would be so hot that his other soldering of the nearby seams would be coming apart. The tinning of the brass solves this problem. Here's how. Dan heats up the brass by itself to the point that it can be coated with tin (fluxed first of course) which penetrates down into the brass. This isn't just a glue on the surface, it goes into the brass on a molecular level. He then puts the brass bung into the gas tank hole. Now when he goes to solder the bung to the tank what he is doing is just heating it to the point that the solder flows into the tin and into the tinning on the brass bung. All it has to do is flow into the solder on the brass bung. If this isn't clear, maybe Dan can explain it better. This allows you to join the bung to the tin gas tank without all that extra heat which would wreck your soldered seams. This is an important thing to understand and will make the difference between success and failure. Thank you, Dan!
(cont.)
SB
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
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The photos below show Dan heating up the brass bung with a large electric iron... 250 watts worth big. It is the electric one in the last photo where an array of the old copper irons are laid out. "Big Bertha" is needed for heating up the brass more quickly than the smaller 100 watt iron he has used in soldering the seams of the tank together. He has to heat the solder through the bung since there is no room to maneuver with the iron. (please note that the bung could be added to the top piece before joining the sides to it) If I remember correctly Dan used acid core solder for this little operation. It could be done with liquid flux, but I believe Dan was trying to control the flux so it did not flow out around the bung and mess up the outside surface with flux and solder where he does not want it (cosmetics). With the bung solidly connected to the tank, Dan flips it over, gives it a careful border of liquid flux with the small paint brush and runs a bead of solder around the bung to make it look nicely finished. Note that he is back to using the smaller hundred watt iron for this step.

A word about the copper irons. Some of these pictured have removable tips and some do not. Some have been filed to a different shape for a particular job. They come in different sizes, so will hold heat for different lengths of time. Roofers used to use these for the copper flashing and had a pot of some sort for heating the irons with one or two being heated while another was in use. Plumbers also used them for joining copper pipe together. The plumbers pots I have seen are heated with propane. I'm planning to make a small one to use with a propane torch for my own use in making gas tanks. The copper irons can often be found at auctions for a couple bucks each and will work just as well as electric ones. Cleaning the tip and tinning it with sal amoniac and solder is the same. I used copper irons years ago in making leaded stained glass windows when I lived in a Mandan earth lodge with no electricity. I heated my irons at the open door of my wood stove. Heat is heat. Not so very long ago copper irons were the only ones used. Just so you know...

Coming up... joining the bottom section with petcock and mounting nuts to the tank... nearly done!
(cont.)
SB
 

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silverbear

The Boy Who Never Grew Up
Jul 9, 2009
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Now Dan needs to cut the bottom piece which will close off the gas tank. He measures carefully so that there is an additional 1/8" or so of lip showing on the side pieces flanges to give more surface area for the solder to flow into. I forget the name of this cutting machine, but it is a little like a big paper cutter except that the blade cuts through the metal evenly all at once, else the metal would want to curl if it cut like a paper cutter. He marks the length and cuts off the excess. Then he marks the two spots with an awl where the mounting bolts will attach to the tank. Acorn nuts will be soldered from the inside, so the holes need to be bigger than the bolt and smaller than the outside edge of the acorn nut. You and I would use a drill probably, but the problem with a drill bit is that it can grab the metal and want to tear it. Dan uses a metal hole punch instead of drilling. You can see the blue box next to the tank which holds different sizes of punches which fit inside the punching tool. Pretty slick.
(cont.)
 

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MarkSumpter

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Now Dan needs to cut the bottom piece which will close off the gas tank. He measures carefully so that there is an additional 1/8" or so of lip showing on the side pieces flanges to give more surface area for the solder to flow into. I forget the name of this cutting machine, but it is a little like a big paper cutter except that the blade cuts through the metal evenly all at once, else the metal would want to curl if it cut like a paper cutter. He marks the length and cuts off the excess. Then he marks the two spots with an awl where the mounting bolts will attach to the tank. Acorn nuts will be soldered from the inside, so the holes need to be bigger than the bolt and smaller than the outside edge of the acorn nut. You and I would use a drill probably, but the problem with a drill bit is that it can grab the metal and want to tear it. Dan uses a metal hole punch instead of drilling. You can see the blue box next to the tank which holds different sizes of punches which fit inside the punching tool. Pretty slick.
(cont.)
I have a Leslie shear I use for trimming that works well and I like his old Whitney punch. My personal opinion would be to use a regular threaded female bung with a lip on them and solder them into holes from the outside so that they can be repaired if the develop a leak or break loose from vibration later.
 
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silverbear

The Boy Who Never Grew Up
Jul 9, 2009
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670
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northeastern Minnesota
The brass acorn nuts now need to be tinned in the same way the bung was tinned. The bolt is threaded into the nut to guard against any solder getting into the nut's threads. With that done the nut is secured to the bottom and again the bolt is attached. Nuts are soldered to the bottom piece and then the piece is tacked at the upper end of the tank. Note that the petcock has already been soldered to the tank in the photo (which is tank #1).
(cont.)
SB
 

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silverbear

The Boy Who Never Grew Up
Jul 9, 2009
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Mark,
You could well be right about the female threaded bung soldered from the outside being better. I don't know. Part of what is driving this version is economy. I just picked up a brass hose coupling from Lowe's for the next tank and it was less than four dollars. The brass cap was less than two dollars. My thought is that if there is a weak point subject to vibration stress it would be at the mounting points. On this tank #1 it fits the 51 frame so snugly that the little vibration coming from the four stroke is hopefully not going to be a problem. I guess I'll find out. I figure for the smaller tank #2 that shimming it snug with rubber pads or harness leather should keep vibration down. But there is always room for improvement.
Yes, that's what Dan called the cutting machine,: a shear. Cuts like a guillotine. I wouldn't want to get a finger in the way...
SB
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
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northeastern Minnesota
Dan finishes the last of the soldering and gives the tank a good look over to see that the soldered joints look sound and leak proof. At the machine shop where he works he made up a couple of steel fasteners to attach the tank to the two frame members under the tank. These will be a pattern for others to be made of hard plastic or similar which can be more easily worked by hand. The fit is perfect. A job well done, my friend!
(cont.)
SB
 

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silverbear

The Boy Who Never Grew Up
Jul 9, 2009
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And that's it for now. Next Saturday Dan will attend to his Worksman 4 stroke build and I will attempt to make a cantilever tank in tin on my own... with Dan nearby to ask for advice. A bit later we will make the same tank out of copper and later yet I want to make a tank for a Schwinn Panther either of tin or copper or both. I have mounted Tank #1 on my daily rider, a 51 Schwinn with a Greyhound engine and Q matic transmission. No leaks...
Pictured below is tank #2 on what will probably be my entry in the 4 stroke build off next year. It has a Tomos moped suspension fork and will get those vintage Schwinn rims laced to moped drum hubs with heavy duty spokes. I think the paint will follow the original Hornet pattern with the same colors, black with white trim. Tank will be clear coated and left alone. Headlight is from Harbor Freight and needs to be drilled for side mounts. Engine will probably be another 79CC Greyhound with EZ transmission, hopefully the 2 speed version. Tinsmith's tank sure looks nice in that frame. Thanks, Bud...
Silverbear
 

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buzbikebklyn1

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Jun 3, 2009
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A work of art in tin... beautiful, functional, elegant, and its got that hand made look that you just cant buy.

I'm looking for a set of soldering irons and a flanger.
I especially like the brass hose connector as a gas cap, very cool.
Brass Fuel valve as well?
I cant wait to see how it looks with the fuel valve installed and it all finished.
Excellent work!
BBB
 

Tinsmith

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May 15, 2009
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Bairdco, Yeh, working with brass is nice. I enjoy working with it at work in the lathes. This was the first time in nearly six years I have been back in my shop. It been a storage room. Worked in there nearly 20 years most every day all day. It's been nice to work with the machines and see if I still have "the touch". Heck I enjoyed the smell of the flux and lead solder. Even though I'm a bit rusty I think the project came out well for the most part, and Silverbear and I are enjoying a new friendship. Any suggestions from any of you guys would be welcomed. Dan
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
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northeastern Minnesota
Yes, I am a lucky guy. This forum has been very good to me. I've learned a whole lot here and made some very good friends. A lot of talented and big hearted people frequent this site and I'm glad for an opportunity to give back some by sharing what I have learned from our own Tinsmith in the past few weeks.
I'm excited at the prospect of trying my hand at tank #3, putting into practice some of what we have learned here. Today I went shopping for hardware for the next one. Pictured is a hose coupling in the package and a couple of bushings which are used with the 1/4" brass petcocks. The petcock is one I have had and ran across in my stuff today, just like the ones used on the other tanks. I'm not sure where I bought it. The bushing is what Dan soldered to the tank which allows for the petcock to thread in to it, making it removable. The petcocks come with a little filter, but I remove them since I have no intention of fooling with the petcock once it is in place. I prefer relying on an inline filter which is easier to replace.
I've shown a few more pictures of the second tank and today drilled the small vent hole in the brass cap. Without some kind of vent the fuel would eventually starve out due to the vacuum which results from not being vented. Thanks to Ferbal who was kind enough in a much earlier thread to share how he modifies this same cap...
http://motorbicycling.com/f3/pvc-tank-how-21154.html The very first post shows the inside of the cap where he places a spacer to keep fuel from sloshing out when you hit a bump in the road.
SB
 

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curtisfox

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Dec 29, 2008
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SB Maybe you might want to make a small washer type bafel to go inside of the cap with a offset hole. Like lawn mower tanks have to keep the gas from splashing out My thinking anyway.........Curt
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
113
northeastern Minnesota
SB Maybe you might want to make a small washer type bafel to go inside of the cap with a offset hole. Like lawn mower tanks have to keep the gas from splashing out My thinking anyway.........Curt
Yes, that's what Ferball shows how to do in this link...http://motorbicycling.com/f3/pvc-tank-how-21154.html
I made one today and it works nicely. We're having a warm break here in Maryland so I've been getting in some nice rides... put around 25 miles on the new tank and cap today with no leaks... woohoo! I hear that even northern Minnesota was balmy today in the mid fifties... weird, but nice.
SB
 

curtisfox

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Dec 29, 2008
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Wonderfull that is a neet little bafel. Yes it been awesome the last 4 days melting like crazy. Bad thing is march is comeing and always get big snow.......Curt