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profqwerty - n/a
4-Dec-07, 09:39 AM
Ideally the fuel tank(s) would be situated under the seat - providing seat support, keeping the CoG in the middle and won't move during use, neater finish.



I was thinking an aluminium sheet bent and welded at each end to form a long thin one.



It would have 2 compartments inside running the long way, so filling/take off for both compartments are at one end. This means I can effectively have the seat resting on the top of the tank, and the filling cap can be at the end where the seat rises up with the handlebars.



I have emailed a few companies/people who do sheet metal fuel tanks, and they are quoting from 180 - 250.



Does anyone here have expereince making one / can advise me on making one myself / sell me one cheaper / make one cheaper at all?



I have expereince welding steel, but never aluminium. It looks difficult, but would be cheaper if it came off well!

ScotsSpeed - n/a
4-Dec-07, 10:53 AM
Toby,

If you want to weld aluminium, then idealy you should use an AC/DC tig machine. You can use the handy migs with special flux coated wire, you can buy it in Halfords. However, i have never found it to be very successful. The one thing is the ally must be clean! Good luck.

jon_curtis - n/a
4-Dec-07, 11:53 AM
welding sheet ally edge to egde with a handy mig, will look rougher than a sack of knackers, and i doubt you will get it fuel tight, on the first second or third try!

assuming you dont have access to a sheet metal giloteen and or press brake, therefore an ally tank cut with a jig saw and folded by hand or on a box and pan folder will be rough as it gets! you also have to think about heat distortion!



250 quid is extremly high price for a fuel tank, used to make them where i work, and sell for around 100 quid, this was based on 20 quids worth of material (excluding fittings) and then 2 hours labour!



unless you have access to proper cutting equipment, decent Tig welder etc i would not even contemplate making a ally tank!

profqwerty - n/a
4-Dec-07, 12:06 PM
i think dangerman has hit the nail on the head.



i have access to a MIG and a jigsaw.



This is going to be a problem...

profqwerty - n/a
4-Dec-07, 02:17 PM
I think I foudn the solution http://hovercraft.org.uk/images/icons/smiley_icons/icon_biggrin.gif



http://www.dureflex.co.uk/



Make custom plastic fuel tanks - rigid and flexible!



they seem to make skirt segments too.



Please forgive me if this is old news http://hovercraft.org.uk/images/icons/smiley_icons/icon_confused.gif

jar2 - n/a
4-Dec-07, 03:00 PM
Hmmm... maybe you should checkout the prices first!



Why not just use a standard plastic boat tank something like THIS (cgi.ebay.co.uk/12-L-HULK-FUEL-TANK-OUTBOARD-ENGINE-BOAT_W0QQitemZ120185531855QQihZ002QQcategoryZ15271 QQrdZ1QQssPageNameZWD1VQQcmdZViewItem)



You can get various shapes and sizes and they are much safer (and cheaper!) than making your own. The other advantage is that they are removable so you can have a spare tank ready filled to just pop in when you get low on fuel. It also means you don't have to re-fill them in the craft - a dodgy procedure at the best of times.

sixpackpert - n/a
4-Dec-07, 03:38 PM
Hmmm... maybe you should checkout the prices first!



Why not just use a standard plastic boat tank something like THIS (cgi.ebay.co.uk/12-L-HULK-FUEL-TANK-OUTBOARD-ENGINE-BOAT_W0QQitemZ120185531855QQihZ002QQcategoryZ15271 QQrdZ1QQssPageNameZWD1VQQcmdZViewItem)



You can get various shapes and sizes and they are much safer (and cheaper!) than making your own. The other advantage is that they are removable so you can have a spare tank ready filled to just pop in when you get low on fuel. It also means you don't have to re-fill them in the craft - a dodgy procedure at the best of times.








I don't think one of those tanks will fit (safely) in a racing craft using the mirage hull.



Why not just get Ken to make one, then you know it'll fit, it will have the correct baffles in it etc etc.

profqwerty - n/a
4-Dec-07, 05:58 PM
Yeah i looked at those on ebay (and there's an official site/vendor). They *just* don't fit in the seat!



max height is 19cm, width 25cm at the bottom, 20cm at the top (tapered).



Really annoying as they were hardly expensive, and would help support the seat as well!



I never thought about asking Ken, I'll do that right now http://hovercraft.org.uk/images/icons/smiley_icons/icon_biggrin.gif

jon_curtis - n/a
4-Dec-07, 07:11 PM
i appear to have been in france earlier today! Odd.

team black - n/a
4-Dec-07, 07:40 PM
i appear to have been in france earlier today! Odd.




It's a secret thing we're working on behind the scenes here at Hover Central, don't be alarmed, but DO buy a phrase book http://hovercraft.org.uk/images/icons/smiley_icons/icon_lol.gif

Jeremy - n/a
5-Dec-07, 06:57 AM
I've made aircraft fuel tanks from alloy, using pop rivets and sealant. It's a very well proven technique - hundreds of aircraft are flying around with tanks made this way.



You just bend the sheet up (making sure that the last panel to be fitted is big enough to get your hands in) with flanges about 1/2" wide or so where edges join. Pop rivet the flanges together, then liberally apply 2 pack fuel resistant sealant (the best stuff is PR1422, see here: http://www.lasaero.com/article/a-pr1422).



The final panel is best fitted "wet" with sealed pop rivets (ones with no hole right through) and a liberal smearing of sealant on the mating faces.



The sealant is horrible stuff, but is exceptionally good at both bonding the tank together and sealing. At least one aircraft has it's wing skins just glued on with this sealant.



Jeremy

profqwerty - n/a
5-Dec-07, 08:20 AM
At least one aircraft has it's wing skins just glued on with this sealant.

Jeremy




We live quite near White Waltham and get lots of light aircraft over us. I'll keep a look out.

nickyd - n/a
5-Dec-07, 08:58 AM
Hi mate,



I made an ally fuel tank for an Eagle Sport earlier this year, to go under the seat.



My first attempt was using those aluminium welding rods you can buy that just use the heat from a blow torch. Verdict - totally rubbish for making fuel tanks!



In the end I cut and bent the ally sheet at home to the size I wanted. I made a fairly crude metal bender out of some lengths of 4 x 2. I was well impressed with how well it worked!



I ordered bits like filler cap and quick release valves from a place on the internet (can't remember where just yet, will look it up) All cool anodised ally stuff.



I then drilled the holes required for these fittings and swaged the hole for the filler cap. (This was the most pleasing bit coz it looked wicked!)



Then I took it to a local welder to weld up. Bit of a jobsworth, but did it for 40 cash.



Took it home, chucked an airline in it, found a couple of leaks, took it back and he fixed the leaks. Job Done!!



Hope this helps, PM me if you want any more details



Nick

Jamie Lewendon - n/a
5-Dec-07, 12:00 PM
You need to talk to Roger Clark in Reading 0118 9507735. Just off the Oxford Rd)

He is the daddy when it comes to TIG welding. I have used him many a time, and he has done lots of stuff for me, ranging from RS250 crankcase (after its argument with a conrod), ali engine frames, and ali thrust frame. He can probably recommend a local sheet metal place also.



Jamie

Nick Long - n/a
5-Dec-07, 02:14 PM
If you want a tank to fit a specific and awkward shape, then using composites is the most versatile method. Vinyl ester resin resists fuel nicely.



Nick



Edited to add: Hi Dangerman, I really am in France, I'm posting from the Cote d'Azur.

profqwerty - n/a
5-Dec-07, 02:28 PM
It's not that awkward shape really, just has to be exact!



I've spoken to Roger Clark, and he is happy with welding it, said I should go to Higgin's Engineering to cut metal.



The only issue is where to get a filler cap / neck from!



Demon tweaks do one at 15, but it has no vent.

I guess not a problem - could just run a hose from a pipe stub welded on to a higher point?

nickyd - n/a
5-Dec-07, 03:23 PM
Try Think Automotive www.thinkauto.com



They do all the fuel unions, filler necks (about 16) and stuff. That's where I got all mine from.



They also do roll over breather valves. Means the tank can breath, but when you 'roof rack' it (roll the craft) then the breather hole shuts off and then your pride and joy doesn't end up in a ball of flames!!



Nick

Gayle Spedding - n/a
6-Dec-07, 09:19 AM
Nick



Perhaps you should take more care when you race, then you wouldn't have the need for roll over breather valves........ or did you get it for Jimmy?!?!!

Jamie Lewendon - n/a
6-Dec-07, 11:48 AM
SOunds like a useful crimbo prezzie for scuba storm Kev!!!!!!!!



Jamie

profqwerty - n/a
6-Dec-07, 11:54 AM
I have decided to go with Ken. he has had experience with tanks in a mirage hull and explained to me a much simpler way of doing things, for that i am grateful http://hovercraft.org.uk/images/icons/smiley_icons/icon_cool.gif



he says he would machine the filler neck himself, using a cap off of an existing fuel tank i think, then put the neck through the seat so it's very easy to fill up.



sorted for real i think!



Those roll oer valves are pretty expensive. I seem to remember the regs saying something about if t he craft turns over it shoudln't leak. not that i'm planning on it http://hovercraft.org.uk/images/icons/smiley_icons/icon_rolleyes.gif

profqwerty - n/a
6-Dec-07, 11:59 AM
on a side note - I have an interview at oxford for engineering on monday so shall now have to concentrate on that.

nickyd - n/a
6-Dec-07, 02:02 PM
Make sure you choose carefully where you have the filler cap sticking out! Could be a tad painfull un a plough in if you know what i mean...........

sixpackpert - n/a
6-Dec-07, 02:57 PM
Make sure you choose carefully where you have the filler cap sticking out! Could be a tad painfull un a plough in if you know what i mean...........




Seconded, smoothness is where you're at. I have a good mate, who will remain nameless, that had that problem. We were both in the craft doing a fair rate when there was a bit of a ploughy moment, he slid forward and crunched his nuts on the filler cap. http://hovercraft.org.uk/images/icons/smiley_icons/icon_eek.gif



To add insult to injury the petrol that accumulates around the vent hole on the cap came into contact with other downstairs blokey bits and caused a slight burning sensation! http://hovercraft.org.uk/images/icons/smiley_icons/icon_eek.gif http://hovercraft.org.uk/images/icons/smiley_icons/icon_redface.gif



As Nick said, smooth seat, or filler cap half way up between seat level and handlebar level.

profqwerty - n/a
6-Dec-07, 03:52 PM
I was going to put padding ontop of it, which would probably be thick enough to be above the filler caps.



Failing that, I might put the filler at the back of the tank / seat nearer the engine. As long as i'm careful filling up it shouldn't blow up or something. That would stop crunching onself on it.



Do you mean on the side of the seat or on the sloped bit between sitting part / handlebar part? I was going to put some guages there ad it's not very big http://hovercraft.org.uk/images/icons/smiley_icons/icon_confused.gif

bryan - n/a
6-Dec-07, 03:55 PM
Smooth filler cap is the key........and yes John i am still dabbing the savlon cream to cool that spot!

sixpackpert - n/a
6-Dec-07, 04:07 PM
Smooth filler cap is the key........and yes John i am still dabbing the savlon cream to cool that spot!




http://hovercraft.org.uk/images/icons/smiley_icons/icon_lol.gif http://hovercraft.org.uk/images/icons/smiley_icons/icon_lol.gif

Kevin Eastwood - n/a
8-Dec-07, 02:10 PM
Just a snorkel will do for me!! Jamie if you are getting one for yourself I'll have one as well