Regarding a steel tank; a simple question

That mold could easily cost more than $150k. Easily.


I'm thinking about making a spank die for Roadster tanks. But I'd still be into it over $70k. Just the material is over $10k.
You'd have to sell a lot of tanks to even brake even...

pbmw said:

That mold could easily cost more than $150k. Easily.


I'm thinking about making a spank die for Roadster tanks. But I'd still be into it over $70k. Just the material is over $10k.
You'd have to sell a lot of tanks to even brake even...

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What Gary doesn't realize is that the plastic isn't "poured" into a mold. It's injected.

The current low cost options are aluminum and fiberglass (with modern resins). There are also the Indian/Pakistani steel tanks, although they may require a slight amount of work to be perfect. But a used tank may also need work.

That's a lot of reasonable options. Pick one.

I've thought about making a tank. I have the tools to get what I need done, but the time is another thing.
There are about 60 hrs I think in making an alum tank. Evan Wilcox charges about $1500. That's $25/hr. That is cheap in anybody's book

Obviously the subject line on this thread is wrong, this is not a simple question. We have overlooked the obvious solution. Take a 5-gallon red plastic gas can and strap it on the frame in place of the tank! Tap in some threads for fuel fittings and off down the road!
OK, so maybe that is such a bad idea that it makes the price of a new tank seem a little more reasonable! I don't know who makes the Novil alloy tanks but 800 bucks doesn't seem all that bad to me for an Interstate tank.
Russ

OK, ok, ok!

So, I am now eductaed on the cost of the mold, that plastic is 'injected' not poured, etc!

Darn it, what's it take for a guy to enjoy a little venting around here, huh?

Seriously... I had thought a plastic mold could be made in the garage for a couple hundred dollars, and at that, just for the materials.

So, ok, guys... thanks. Guess I'm back to the drawing board, sigh.
I just figured picking up a steel tank would resolve the issue... didn't expect the sealer to turn into goop that'd foul the plugs.

Anyone simply run straight steel tank, perhaps throw in a little (pinch) Marvel Mystery Oil each fill up, as our Oz brother suggested? I guess I can see where that might alleviate some rust issues, while if only a pinch amount is used, wouldn't effect the cumbustion.

eh??
Again, just frustrated.

Gary said:

OK, ok, ok!

So, I am now eductaed on the cost of the mold, that plastic is 'injected' not poured, etc!

Darn it, what's it take for a guy to enjoy a little venting around here, huh?

Seriously... I had thought a plastic mold could be made in the garage for a couple hundred dollars, and at that, just for the materials.

So, ok, guys... thanks. Guess I'm back to the drawing board, sigh.
I just figured picking up a steel tank would resolve the issue... didn't expect the sealer to turn into goop that'd foul the plugs.

Anyone simply run straight steel tank, perhaps throw in a little (pinch) Marvel Mystery Oil each fill up, as our Oz brother suggested? I guess I can see where that might alleviate some rust issues, while if only a pinch amount is used, wouldn't effect the cumbustion.

eh??
Again, just frustrated.

Click to expand...

You do not need to seal a steel tank unless it is already rusty.

If the rust isn't too heavy you can clean it out by washing the tank out with phosphoric acid (Home Depot sells it) or by electrolysis. Phosphoric acid leaves a phosphate coating inside the tank that helps inhibit rust. That's been working fine on my 850 tank so far. If the rust comes back I'll do it again.

Over on the Ducati forums, the prevailing opinion is that the tank warping is caused by reaction to E10 USA fuel. Owners in other countries are reporting no problems. I suppose sticking vent check valves are a possibility, but that doesn't seem to explain the problems people are seeing.

Debby

I was just going to sugest phosphoric acid to protect a new tank.
I ground my Harley tanks till they were nice and smooth. then pressure tested. A little more welding and smoothing and it was done. I lined it and have not had any issues. But if I do, I'll remove it and go with phosphoric acid.

Maybe I am not being clear about what I meant. Why can’t you just inject the plastic (like the stuff they make gas tanks out of), right into the tank. The tank is the mold. It’s free. Who care about rust, splits, etc. I would think it would work on any type of tank, fiberglass, steel, or the stuff they make beer cans out of.

I could be way off base here. I am WAY over my head on the tech of plastic injection, but it seems to me with so many people having trouble with the tanks and with a fixed number of stock tanks available, at least a few calls to the people who make stuff like plastic tanks would be in order. If they laugh, at least ask “Why”.

Diablouph said:

Maybe I am not being clear about what I meant. Why can’t you just inject the plastic (like the stuff they make gas tanks out of), right into the tank. The tank is the mold. It’s free. Who care about rust, splits, etc. I would think it would work on any type of tank, fiberglass, steel, or the stuff they make beer cans out of.

I could be way off base here. I am WAY over my head on the tech of plastic injection, but it seems to me with so many people having trouble with the tanks and with a fixed number of stock tanks available, at least a few calls to the people who make stuff like plastic tanks would be in order. If they laugh, at least ask “Why”.

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There is nothing wrong with asking "why". Innovation comes from people asking that very question.

I've already listed what I believe are the alternatives. If you want to investigate this further please do. But do some more research on manufacturing processes (Youtube is a good start) first. You can learn enough from some simple videos.

Diablouph said:

Maybe I am not being clear about what I meant. Why can’t you just inject the plastic (like the stuff they make gas tanks out of), right into the tank. The tank is the mold. It’s free. Who care about rust, splits, etc. I would think it would work on any type of tank, fiberglass, steel, or the stuff they make beer cans out of.

I could be way off base here. I am WAY over my head on the tech of plastic injection, but it seems to me with so many people having trouble with the tanks and with a fixed number of stock tanks available, at least a few calls to the people who make stuff like plastic tanks would be in order. If they laugh, at least ask “Why”.

Click to expand...

Because the plastic is not "sprayed" into the mold. It's pumped under pressure. It would just fill the tank...
There is the process of blow molding which is taking a sheet, heating it and using hot air pressure, forcing it into a mold. But the mold opens and closes...so a tank wouldn't work.
Roto molding spins the mold as the plastic is once again pumped in under pressure. But those molds also open and close. They have plugs...
I'm going to just line mine, and ride it while I wait for the money to get a nice alum one. The price of a Pakistani one is not bad...

I recently read an article about an English company that was having brand new plastic tanks disolve. This leads me to think it is a problem all over.

I have a plastic tank on my Bultaco that seems to be holding up just fine to the evil E10 fuel. It doesn't fit on my Norton though. Besides, it only holds about 1.5 gallons - even less than a Hi Rider tank!

I took a snow day today so I was just out in the garage looking around. I can tell you that a 1974 Yamaha TY250 tank also will not fit, and likewise for a 1975 Suzuki GT550 tank (just trying to be creative!)

The general problem is the Commando backbone is so wide, and you need an extra wide and deep area at the back of the tank to clear the area where those tubes flare out. I took a quick look on Clarke Mfg's website (they made the tank that I have on my Bul) and they have some universal tanks that are about the right length to work with a Roadster seat, but they do not give the cutaway dimensions. I don't think they would fit. Some time ago I tried fitting a Vesco SkinnyFat tank that I had on the shelf. Same thing, tunnel too narrow. Oh well.

One of many dubious ideas I've had was to build a dual sport Commando, complete with plastic tank and fenders. It could have SS pipes and a big skidplate. It would be awesome! But finding a tank that would fit appears to be an impossible task.

Sorry for the digression. These are the sort of things I think of when I get bored.

Debby

Debby, a late 70's 900 GTS tank would look the part, might even fit the frame?????

graeme

No, to my original post: I do not think there was ANY rust in this steel tank. Hence my disgust, as it appears to have been added 'just in case'... yet the crap is dissolving into an electrode fouling goo, same as a bad 'glass tank.

Sigh.

I'll be cleaning it out, keeping it nothing but straight steel. At least, I can then rule everything else out! Per the original question... that crap is the only thing it CAN be that's fouling the plug...

~Gary

I'm expecting the chemists to come though with some new good sealers soon.

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There are good sealers out there. They are in use in aircraft tanks and storage tanks. They are also designed to be applied with a brush or spatula or spray gun to a properly prepared surface. The problem we have is trying to dump some magic goo into a tank we think is clean enough and slosh it around and expect it to stick. It only takes a tiny uncoated surface in a fiberglass tank to allow the fuel to wick under the liner and dissolve the polyester resin in the fiberglass. Then the liner loses adhesion and begins to flake. I'd guess that the goo found in the carbs on a failed lining isn't the lining, but the dissolved polyester used in the fiberglass layup.

The small companies like Caswell, Hirsch, and POR-15 actually offer a decent product for the price. Commercial tank liners sell for up to $250/quart and will still not perform any better if the entire surface is not covered and the surface is not clean enough to provide good adhesion. There are a lot of chemical storage tanks out there coated with technology similar to the Caswell material and have been in service for over 40 years.

http://www.aircraftspruce.com/menus/ap/fuel_tanksealants.html