Tinsmith's in frame gas tank for cantilever Schwinn.

Discussion in 'Motorized Bicycle Welding, Fabrication and Paintin' started by silverbear, Jan 23, 2011.

  1. Tinsmith

    Tinsmith Member

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    J.P., As far as a finish on the tank, if you are able to get tin electoplate and want to paint it you should probably scuff up the surface with a 3-M plastic pad to allow a primer coat of paint to adhere better, then spray on the finish color. If you desire the shiny finish I would wash it with soap and water to get any fingerprints off and spray with a clear finish. SB got some clear finish that is supposed to be resistant to gasoline, but I don't recall what it is. It's important after you get the surface clean of any fingerprints not to handle it with your bare hands. Probably should wear latex gloves. The natural oil from your fingertips will remain behind and over time will show up on the tin. Now it'll take a long time, but many of the tin patterns I've used over the years are are covered with my oxidized fingerprints. Hope this helps. Dan
     
  2. silverbear

    silverbear The Boy Who Never Grew Up

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    Jose,
    I sprayed the tank with a clear coat called Top Flite which was recommended by member and moderator 2door, who knows quite a lot about such things and whose opinion I value. This clear paint is for remote control airplanes and is supposed to be resistant to fuel... a good idea it seems to me for a gas tank. I like the look of the bare electroplate tin, shiny, without being like chrome. So I wanted to see over time how it behaves with small spills of gasoline. I did not know enough to wash it with soap and water before painting, but hopefully the surface is sealed so that oxidation can't happen. Wanting it to be shiny, I did not scuff the surface. I tried doing a little polishing with mag wheel polish ("Mother's" brand) and discovered that the tin plating is very thin and in no time can be removed with the fine grit in the polish, so that is not a good idea. Clean it, handle carefully and cover it with clear coat unless you plan to paint it a color. This was done on tank a#2. I left tank #1 alone with no clear coat to see what will happen with gas spills, dirt, etc. It is on the bike I've been riding and still looks pretty nice. I'm expecting to paint this tank someday when the bike's frame gets repainted.
    SB
     
  3. silverbear

    silverbear The Boy Who Never Grew Up

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    Dan and I had another shop session yesterday and made progress on both my solo tin tank and his first try at a copper tank. I wanted to show a picture of the tin snips which we used a week ago to cut out the side pieces with all the curves. Dan used the Weis which has wider cutters and is designed for making straight cuts. I used the other one which has narrower jaws or cutters and is intended for curved cuts. Dan likes the feel of the Weis in his hand, so generally uses it for everything. In other words it will also cut curves fine, but might require a bit more skill to do so. The pair of snips I used will also cut straight lines fine, so in the end it is more a matter of what feels comfortable in your hand and is also sharp enough to make clean cuts. Neither of these tools has serrated edges on the cutters which would leave a rougher edge on the cuts.

    The other pictures are of the brass hose coupling we used as a bung on these tanks. You may recall earlier in this thread that Dan removed the threading from one half of the coupling using a belt sander so that it would fit snugly in a 3/4" hole. We later cut that coupling off inside the tank to be shorter once it was soldered. On these two tanks we decided to cut them shorter before soldering to the top piece. I
    I believe it was sportscarpat who mentioned the need to either shorten or drill a hole in the side of the bung which is inside the tank, else a dead air space will result at the top of the tank. I think in future tanks I will remove the threading as we did on tank #2 and drill a hole in the side of the bung rather than cutting the bung short. I think the soldering will go a little better that way. I used a small rotary tool with a cutoff wheel to make the cuts.
    SB
    (cont)
     

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  4. silverbear

    silverbear The Boy Who Never Grew Up

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    Once again Dan uses the burring machine to create the flange on a side piece. Once the long runs are done the short ones are done as well as they can... in the middle of the short run the burring machine will still work, but toward the ends of the short run the burring machine no longer works as it runs into the flange already formed. What to do?

    The tool for making small bends is in the three pictures which follow. They are hand powered miniature versions of a brake and you can see in the design of a couple of these that there is a longer run in the front of the tool and also a shorter run on the end. I forget what Dan called them, but they are something like running pliers in glass work. While these are the right tools for the job, you and I will need to figure out how to accomplish the same thing, maybe not so easily or quickly, using what we have... pliers?... don't know, but will give it some thought. If you run across a pair of these at a farm auction... now you know what they are and can pick them up.

    The tool in the last photo I also don't know the name of, but it is pretty neat. I think Dan called it a "nibbler" and I want to call it "nipper" after a similar tool in glass work. Whatever it's name what it does is take a very clean square shaped bite out of the sheet metal. You may have noticed on our side pieces that at the corners this little bite has made it easier to fit the pieces together. You can do something like it with tin snips, but this is the tool designed for the job.

    Specialized tools are interesting and I often think of the unsung shop heroes who have made our lives richer by designing tools, machines and processes to make the job go better. I salute all of you backyard geniuses, past and present, whose names we may never know... the first pliers and saw, the T square, claw hammer... so many bright and inventive minds have given us so much.
    SB
    (cont)
     

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  5. timboellner

    timboellner Member

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    Nice tutorial.

    I'll be taking your advice on cutting down the filler "bung"

    We call the tool hand tongs in the trade, but I think their official name is hand seamers.

    I have that same pair of Wiss snips Dan uses.

    I've had them for 24 years and use them almost daily. They'll still cut paper, and they've never been sharpened.

    Wiss makes the best tin snips, I don't care what others say, Klenks, Kleins,
    off brands will never touch Wiss.
    No other snips can cut into corners half as well.

    TiM
     
  6. MarkSumpter

    MarkSumpter New Member

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    Most commonly these are called hand seamers and are available as a modern version from Wiss who makes a full line of sheet metal tools for about 50-60 dollars, I think Harbor Freight has a straight pair for around 25 bucks:
    [​IMG]

    Link to Hand Seamers

    As for a Polish for Plated tin look into a product called FLITZ, It is a non abrasive and will clean and protect uncoated metals well. I don't think I would try to put a clear coat over Flitz without washing it well though and maybe following that with a wiping of denatured alcohol to remove its protective coating.

    Another thing to keep in mind if you are using Top Flite Airplane Dope is that if there is extremely high humidity like on a rainy day it can cloud up and look milky when applied. It is best to cure it under a heat lamp if you are using it under these circumstances, just don't let it get too hot or it will blister especially on metal.
     
  7. silverbear

    silverbear The Boy Who Never Grew Up

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    We have cut our long top pieces on the sheer and then mark the spot where the gas filler will go. Dan is going to the right side of the tank as the others have been and I'm doing mine on the left side. He punches a hole for the brass bung, but doesn't have a punch large enough. The ideal would be to have a 3/4" punch and in a few seconds a clean hole would result. Instead he uses the largest punch he has and then reams it out to size using a cone shaped metal bit. While he opens his to 3/4" I do the same with a Dremel type rotary tool and a grinding bit.
    Dan tins the brass bung where it will be soldered to the tank and also tins the copper at the hole it will fit in to.
    He places Big Bertha on the top of the brass bung to heat it up to the point the solder flows... and waits...
    As we wait Dan talks about how the copper is different from the tin. His area of expertise is tin work, but has worked with copper off and on a bit through the years and knows the soldering process is different due to the difference in metals. The tin heats up quickly and allows you to get in and out quickly enough to get the job done before too much heat migrates to other areas of the tank, possibly melting previously soldered joints. The copper tends to suck the heat out from where you want it and kind of generalizes the heat. It is one reason we are doing the bung on the top piece before it is joined to the side pieces. You can see the logic in that there is no danger in melting seams if the seams have not yet been made.
    We are still waiting for the solder to flow as Dan remarks on another difference between copper and tin. The tin bends are more crisp while the copper makes a more rounded bend, I'm guessing because it is more malleable and is more willing to stretch.
    Dan decides that Bertha is not up to the task of heating the solder enough to flow... the brass is dissipating the heat before it can get to the lower portion of the bung and make a union with the tank.
    This is the one time in this tank making that Dan fires up the propane torch and applies the flame directly to where the bung joins the tank. Done in a few moments with a solid joint.
    Now we can start putting the tank together... coming up.
    SB
    (cont)
     

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  8. silverbear

    silverbear The Boy Who Never Grew Up

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    Thank you both for the clarification on the hand seamer and I will remember the tip on doing the top coat in dry conditions. I will also look for that polish and try it on the unpainted tank I'm currently using. Maybe it is a better option than clear coat if the tank is to remain natural.
    SB
     
  9. curtisfox

    curtisfox Well-Known Member

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    Just a note if you use any kind of polish like Mothers you need to clean it off before paint...........Curt
     
  10. silverbear

    silverbear The Boy Who Never Grew Up

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    The following photos are out of order in what we actually did. You will notice that the bung has not been soldered on yet in the pictures. But the test fitting is something that happens more than once in this process of getting things right. Pay particular attention to the last picture as it is key to making the soldering go well with hands free. Sportscarpat mentioned in an earlier post how much better his welding of tanks went once he figured out a jig for holding it in place as he tacked it together and did the final welding. I don't know if what Dan has come up with qualifies as a "jig", but it does the same thing... holding the work in position so that you are free to use your hands for joining it together.

    Dan thought about this problem long and hard and in the middle of the night a while back he got the idea you see in the last picture. He has made spacers of the same width the finished tank will be and bends them as shown, placing them inside the tank. I apologize for not having the next series of photos, (battery ran out in the camera and I didn't realize it) but next week I'll take more pictures and will make clear what I will just describe now...

    So picture two things. There remains an open space on the bottom of the tank which will be the last thing in finishing the tank. It is through this opening in the bottom that the spacers will be removed once the sides have been joined to the top piece. So they are used in the "jig" but do not remain inside the tank.

    Dan has two pieces of wood the same shape as the sides of the tank. You may remember them from earlier in this thread. He places these wooden pieces on each side of the tank while the spacers are inside the tank. He holds it together with C clamps, effectively pushing the sides snug against the top piece, while the spacers inside resist the sides being pushed too far, crushing the tank. So now the tank is together and both hands are free to do the soldering. There's a little more to this which will be made more clear next time when we have the photos to go with it. Dan's tank is just about ready to solder up and is going to look super. Mine is not as far along and is going to be acceptable. See you next time in the Tinsmith's Shop.
    SB
     

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  11. bairdco

    bairdco a guy who makes cool bikes

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    on my newest copper tank i did a similar spacer method. i've had some tanks not fit exactly right, and have low spots in them when you look at them sideways.

    my problem was having the top and bottom keep it's shape with the large flowing curve of the closon frames.

    i cut 7 or 8 strips of copper, about 1/2" wide, and folded the top and bottoms over and soldered them inside the tank down the middle, basically making a spine to keep the shape.

    didn't bother trying to remove them, i figure if they come loose they're too big to go anywhere, so i could fish them out if i had to.

    your tank is more of a box compared to mine, so looks like you wouldn't need a spine...
     
  12. LS614

    LS614 New Member

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    Very cool, now I want to attempt to make one. Hopefully I can get tips from Dan. Do you NEED to have the other irons? or can you do this with just one or two electric irons? I would definitely need a good pair of snips. What an amazing tank. One like that would look SO good in my Schwinn. Ignoring man hours, what does it cost to make one. Finally, any kind of tank sealer? Sorry if I missed any of this information, I tried to read carefully
     
  13. Tinsmith

    Tinsmith Member

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    LS, If you want to try to make a tank out of tin electroplate (the shiny stuff) a 100 watt electric iron will work. The copper will take alot more heat. The old style soldering coppers will work fine with practice and you have to use a propane source to get them up to temperature. The electric one I use is 350 watts and they are pricey of you buy a new one. Probably around $200. The cost of the tin electroplate shouldn't be that much. I haven't bought any in many years and of course when I had a working shop I bought it in large quantities. I would think you could get a sheet (20"x28") for under $10, but you'll have to find a supplier to sell it by the sheet. There is some real poor quality stuff available at some of the craft stores, but I wouldn't go there. I'll see if I can find a source. The copper will be more . You might be able to get some at a roofing shop. They may have some drops that aren't large enough for a project they might sell you. If you do that, make sure you know how much you need before you go there. Dan
     
  14. LS614

    LS614 New Member

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    Thank you so much! I was looking on ebay at 300watt American Beauty irons and other 300 watt irons today. you can get them for as low as $20 buy it now price. I plan to use tin electroplate but it would be great if you could find me a source :) If I were lazy and less adventurous I'd just pay you to make me one, but I'm the adventurous type, and although my soldering job will not look as nice as yours :D I will give it a shot :)! I look forward to seeing the copper one in completion, that will look very cool.
    -LS
     
  15. silverbear

    silverbear The Boy Who Never Grew Up

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    I found the missing photo disc today from the work session two weeks ago and thought I'd share as few even if they are a little late. First is a photo of the petcock, the reducing bushing it fits into and the petcock in the bushing. Dan soldered the bushing into the tank and later on the petcock is threaded into it.

    Second photo shows the two filler bungs used on tanks #1 & #2. One is a male 3/4" copper plumbing fitting and the other is a brass hose connector, also 3/4". Either will work, and neither is very expensive. The brass one is maybe twice as much. The copper fitting has a slightly different pitch to the threading, so a brass hose cap fits the brass coupling better than the copper one, although it does thread on and seal up. I used the copper on tank #1 and now wish that I had drilled a small hole in the smooth part which fits inside the tank. I didn't and that means I'm not able to get the full capacity of the tank since there is a dead air space from the bottom of the filler tube to the top of the tank. So you either want to cut off much of the bottom portion or just drill a hole in the side of the fitting. On tank #2 I did cut off most of the tube which is inside the tank. Important!

    The other three photos are of tank #2 when it was being readied for soldering. Dan has fitted the sides to the long top piece and then placed the two wooden forms to each side before clamping it in place. Note the spacers inside the tank which Dan removed after the soldering was done. Keep in mind there is still an open space in the bottom at this point and that is where the spacers come out. You might need to twist them a bit to bend enough to fish them out. Now the tank is solidly together and it is simple enough to solder on the bottom piece, tacking it at the corners of one end and then working a bead around the whole bottom piece. This jig (if that's what it is) means Dan can solder with both hands free. Pretty neat.
    SB
     

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  16. silverbear

    silverbear The Boy Who Never Grew Up

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    LS,
    I'm glad to hear you have plans for making a tank.
    Bairdco,
    I was wondering how you managed to hold it together while soldering. Pretty clever!
    SB
     
  17. LS614

    LS614 New Member

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    Yeah, if I fail miserably, I'll pay tinsmith to do it, but I'm a smart kid, so I'll try to figure it out for my self first :D This thread is a wealth of information, so I won't be completely in the dark with trying to figure it out :)
     
  18. corgi1

    corgi1 New Member

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    SB,is the opening in the fuel neck big enough to put a dremmil cut off wheel (even a worn down one),down past the tank surface in the fuel neck and cut an air bleed slot so the tank can be filled to the top?
     
  19. corgi1

    corgi1 New Member

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    I went back to the pic of the tank on the bike and so I also wonder about a small brass tube to add a breather tube forward mounted 1-1 1/2 inches ahead of the filler neck to remove the air bubble,,,like a piece of antenna from a old car
     
  20. silverbear

    silverbear The Boy Who Never Grew Up

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    Corgi,
    Those are both good ideas. I'm figuring at some point to dismantle the bike that tank is on (to repaint it) A slot in the filler tube is a good idea. As you say, a worn cut off wheel would work and I also have some dime sized diamond embedded metal cut off wheels I got at Harbor Freight. One of those would work nicely... then flush out the tank well to remove the filings. I would think that a small brass or even copper vent tube would be fine with a lot of care given while soldering it in place. I think I'd opt your cutting a slit approach. Thanks!
    SB
     

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