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How are they making reproduction gas tanks for the less common cars like ours?

Started by TJ Hopland, January 21, 2018, 01:15:27 PM

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TJ Hopland

A couple recent threads got me wondering how it can be practical to make gas tanks for something that isn't a Tri5 or Mustang?  Those cars sure, sales volume will be high so if it cost a few bucks to tool up I'm sure they can make it back and profit.   This raises the question how can it be practical to make new tanks for something that has such a limited market as just about any model Cadillac?   Gas tanks are perhaps a unique item.   They usually last the typical lifetime of a car so the OE's don't plan on selling more than a few to cover the odd damage here and there.   They are not that attractive to aftermarket because by the time they need to be replaced in many cases the number of cars still on the road that may need them is limited.

I presume originally they were made in some sort of a stamping press.  I assume it took a very expensive die/mold sort of thing that fit into a very large machine.  I also imagine they had an idea how many they had to make so they made the die only just good enough to last through the original estimated production run so even if they kept it it may not be making the best quality parts.   Then after a few years the machine changes for one reason or another and the old tooling won't fit the new machine so no more old parts unless the demand is high enough to make a new die for the current machine.   I know in some cases the die and machine get bought and shipped off and in many cases someone keeps making parts in the likely worn machine but I think that again is for the more popular models.  Anyone know were things like tanks usually made at the main assembly plants?  I would think maybe since they would be kinda bulky to ship and store if they were made offsite.   You think of how many tanks you could get out of a rail car of flat sheet metal vs a rail car of finished tanks.   The space and transport savings is likely well worth the floor space for the machine in or near the main plant. 

Even offshore these days I would think it would be expensive to build, maintain, and store such dies.   So how are they doing it?    Can they 3d print a mold and then hydroform them?  I totally see how smaller parts can be done small scale or by an offshore manufacturer but bigger semi complex stuff like a gas tank really has me curious. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

chrisntam

Don't ask, just be thankful someone is making them!   ;)

I'm thinking about getting one for my '70 and just storing it for when/if I need it.
1970 Deville Convertible 
Dallas, Texas

bcroe

I have been taking tanks to RENU for a lifetime guaranteed remake.  I guess
that means, if it leaks in your lifetime and burns down your building, they will
refund the rebuild cost.  But they do quite a job on it, which takes a week. 

I have rarely been happy with after market repros of anything.  There are
some tanks for my cars, but they are the gasoline version.  Yes there is a
diesel version, but its just the same tank.  My cars have real diesel tanks,
which have up to 4 extra gallons, for quite a long range.  Put in gas pickup
units, all my diesels died.  I collected them in the era, there is a rack of
spare tanks in the shop. 

One more option, a place at the edge of this village makes 304 stainless
tanks.  Not an exact copy, but really tough.  They had one on display that
survived a pretty serious rear end collision.  Bruce Roe

TJ Hopland

I can totally see someone welding a tank out of sheet metal product that more or less fits and works but being a largely hand process isn't going to be cheap.   You could do water or laser cnc to cut the parts but I don't think CNC welding has got affordable yet.

I'm hoping someone knows.   I tried some youtube searches and didn't really come up with what I was looking for.   There must be some modern machine / process that allows them to do it cheap. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason