Tank sheet metal thickness?

[MrFryMoto]

Glue together blue styrofoam blocks to rough shape.

Finish shaping to your heart's desire.

Lay carbon.
Aircraft Spruce probably has fuel-resistant epoxy.
See what they say.
Tell them about the next step:

Dissolve blue foam with acetone.

Seal tank with POR.

Check for leaks.

Paint/clearcoat or whatever.

Run it.

No FHE with this method, but it's what I'd do.

Aluminum and carbon in intimate contact will suffer galvanic corrosion if there's any water.

sounds like the best option to me
i know many "carbon fiber" parts are actually a carbon fiber/kevlar or Fiber glass with a carbonfiber outer layer



inspiration:
http://www.bayarearidersforum.com/forums/showthread.php?t=145975&highlight=carbon+fiber+gas+tank

[Langanobob]

I'm currently working on making the buck for my custom gas tank.

Sounds like a worthy project.  I have a friend of a friend who makes aluminum tanks starting with flat sheets.  I'll see if I can get some feedback from him.  Also see if I can get his opinion on just the carbon fiber over foam technique with  no metal. 

I  made a venturi type vacuum pump for a long abandoned project using plans and parts I got from an internet woodworking site.  It pulled good vacuum although I never got as far as using it for anything useful.

[MotoCreations]

I've made aluminum, steel, copper, stainless and carbonfiber fuel tanks so far.  I also admittedly have more metal shaping tools/machinery than probably almost everyone combined on the DMF.

As for making an aluminum tank and then sealing it and then making a carbonfiber tank overlay on top of that?  Way too much work in terms of hours, potential for leaks, weight (enormous) and long-term I think you'd gain nothing.  If you had to ever fix it --- forget it --- it hits the dumpster.

If you are doing a one-off tank, just carve what you want from foam and pull molds with flanges.  Fastest method to get what you want with internal baffles.  If you are lazy, you can do it without a mold and just overlay the foam and dissolve later. (not as nice internally)  note: somewhere I posted on this forum a BARF thread of someone who has all steps in making of a carbonfiber fuel tank for a SV650 -- definitely a worthwhile read.

My preferance for tanks?  Steel (long term it's worth the effort and strength).  Aluminum (quick / easier to shape but easily damaged).  Carbonfiber (fast construction for a newbie but not necessarily the lightest given a one-off layup)  Stainless -- it's a nightmare to shape/stretch/shrink but welds beautifully.  Copper -- incredible looking but tough to shape as the material thickness needs to be thick to offset its inherent "soft" nature.

With any "metal" fuel tank, you have to have welding skills to make happen properly.  If you aren't a good welder -- find someone who is.

POR15 is just an insurance policy to add incase you miss a small pinhole leak somewhere as part of welding/layup and "pressure testing".  It isn't a "cure" for bad construction.

[MotoCreations]

Metal thickness for tanks?

- aluminum:  .060/.063 for top/sides at minimum. I'd stay away from .050 as it will get too thin real quickly when being formed/shaped.  If the tank bottom as a backbone mount (ala Harley) -- then I'd recommend .080 minimum for the bottom / mounting system.  TIG welding is ok but possibly cracks in the future due to HAZ (heat affected zones) and metallurgy changes thereof. O/A gas welding is best for tanks but very few people do anymore. (I will only do aluminum tanks via O/A)  If fuel injected bike, remember you need to create a thicker flange for the fuel pump assembly to clamp into without disforming everything.

- steel: .040 minimum for lightweight.  .050 is pretty common.  TIG welding is fine. Ditto for the fuel pump flange ala above.

note: if carbonfiber tank, just get aluminum machined for the fuel pump mounting flange and bond into the tank itself. I wouldn't recommend a fuel pump / carbonfiber mounting system as something worth trying for someone who hasn't done carbonfiber layup before.

[TiAvenger]

Thanks for the info.

I think I might be going the pure cf route. I had not realized the weight issue with the Al/CF cap

Im reading through the barf thread now

as for welding A/O is how I learned so should I decide to make a metal tank, that is good news


I will probably make several attempts at this  My best friend (who  does sheet metal and composite work for the army) was supposed to be helping me, but ships out to Iraq on Sunday.  If all else fails (me) he is going to help me when he gets back. 

[Speeddog]

inspiration:
http://www.bayarearidersforum.com/forums/showthread.php?t=145975&highlight=carbon+fiber+gas+tank

Fantastic thread. 

[TiAvenger]

Fantastic thread. 

Just finished it.


Looks like I may be doing a composite tank 

[Langanobob]

I also admittedly have more metal shaping tools/machinery than probably almost everyone combined on the DMF.

Sheeesh.  I think you are underestimating us or overestimating yourself or a combination of all of the above   

TiAvenger, I'm working through the BARF thread and it is great.  Once concern they mention with a carbon fiber tank is what happens when you crash.  I think even adding Kevlar isn't a complete solution but no FHE.

[TiAvenger]

Sheeesh.  I think you are underestimating us or overestimating yourself or a combination of all of the above   

TiAvenger, I'm working through the BARF thread and it is great.  Once concern they mention with a carbon fiber tank is what happens when you crash.  I think even adding Kevlar isn't a complete solution but no FHE.

I'm not to concerned with that. The tank will only be as wide as my frame, so it would take a violent high side for it to come into contact. Plus since I will be making a full mold, I will probably just make two tanks from the start. 

I pick up my foam Friday, to start the plug. 

[Langanobob]

I pick up my foam Friday, to start the plug.  Grin

Excellent.  Amazing amount of information in the last day or so and just thinking about teh interweb.  Without it we'd be on our own and always be re-inventing the wheel, or the tank. 

[TiAvenger]

Next question, do I have to put the fuel pump inside the tank?

[MotoCreations]

Next question, do I have to put the fuel pump inside the tank?

what year / engine displacement / fuel injected or carb'd?  You have differing options.

For fuel injected bikes that I've custom built over the years, I've always used an internal fuel pump (factory Ducati setup or 5.0l Mustang assembly through the gascap opening itself).  note: the pump itself gets hot due to constant circulation and the fuel itself helps keep it cooler strangely enough.  With high pressure fuel pumps you will need a feed and return line plus electrical routing and vent hoses.  If you go do a high pressure external fuel pump -- make sure it has adequate ventilation to keep from overheating.

For carb'd custom Ducati-powered bike's that I've built, I always use either a 3.5psi external electric or vacuum fuel pump. (although technically if the fuel pickup location is higher than the carbs, you can go gravity feed also)  I've used self-regulated pumps here and thus only one fuel line from the tank is required.

[TiAvenger]

what year / engine displacement / fuel injected or carb'd?  You have differing options.

For fuel injected bikes that I've custom built over the years, I've always used an internal fuel pump (factory Ducati setup or 5.0l Mustang assembly through the gascap opening itself).  note: the pump itself gets hot due to constant circulation and the fuel itself helps keep it cooler strangely enough.  With high pressure fuel pumps you will need a feed and return line plus electrical routing and vent hoses.  If you go do a high pressure external fuel pump -- make sure it has adequate ventilation to keep from overheating.

For carb'd custom Ducati-powered bike's that I've built, I always use either a 3.5psi external electric or vacuum fuel pump. (although technically if the fuel pickup location is higher than the carbs, you can go gravity feed also)  I've used self-regulated pumps here and thus only one fuel line from the tank is required.

2002 SS 750ie motor, will eventually be replaced with a 800

[franklin1990]

               Actually you used a very hard metal, my suggestion is you used you aluminum.

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