Tender Tank

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kenrinc
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Re: Tender Tank

Post by kenrinc » Fri Jun 30, 2017 11:45 am

I used 22 gauge sheet steel for my slopeback A3 tender. It's built the same way as Kozo shows in his book although, since I burn propane, I didn't need the coal bunker so I was able to gain another gallon and half or so of water for a total of 9 gallons. I also don't sit directly on the tank itself. I have a removable seat assembly that sits on the tender frame. I used POR for sealing originally. I had sandblasted and roughed up the inside parts before assembly but less than a year later the POR was coming off. I scraped it all out and tried a product from Goop called "Coat It". So far I've had no issues with it. I've used Flexane and Aircraft fuel tank sealant in the past. Both work great. You always want to use a 2 part product for sealing. $.02

Ken-
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Greg_Lewis
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Re: Tender Tank

Post by Greg_Lewis » Fri Jun 30, 2017 12:02 pm

Jbt68 wrote:I used 20 gauge CRS for the tender of my little 0-6-0 switcher. It has a custom-made plastic insert tank with a baffle. The tank holds about 13 gallons or so. This relieves me of all the corrosion-related maintenance issues and no peeling tank sealer to deal with. Another benefit is the open side legs in the tender that I will use for the battery to power lights, etc. It's an extra expense for sure, but it will more than pay for itself in reduced maintenance costs and aggravation from having to disassemble the tender periodically.

- Bryan
An advantage to this is that you can do what you want to detail the tank without worrying about leaks. The plastic inner tank will last forever and is easy to make. You can get a cheap plastic welding heat gun from Horrible Fright Tools.
Greg Lewis, Prop.
Eyeball Engineering — Home of non-interchangeable parts.
Our motto: "That looks about right."
Celebrating 30 years of turning perfectly good metal into bits of useless scrap.

Glenn Brooks
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Re: Tender Tank

Post by Glenn Brooks » Mon Jul 03, 2017 10:15 pm

Here's my out of the box thought for the day... Iam thinking of using Dolphinite marine bedding compound when I build my tender. Composition is a bit softer than plumbers putty, and contains a fungicide to stop mold and dry rot. This stuff has been around the boat building industry for over a hundred years, and is superb at keeping water from penetrating deck joints, and preventing rot from forming between two pieces of wood, such as structural timbers, or decking and beams. It skims over and is tough on the outer surface, but stays absolutely flexible inside the joint, so can move a bit, and fill voids. Cleans up very easily with paint thinner. You can also paint over it, once it skims over.

Shelf life is well over 30 years once applied. I've replaced planks and beams in boats that were 45 years old and found this stuff was still soft and pliable when scraped off the matting surface.

Now, one downside. Probably wouldn't work if you welded or brazed any part of the tank. As the heat wild probably melt it out of the joint. Ok, two downsides: can't be applied retroactively, like a paint on tank liner... but, for original construction, I suspect this stuff would be great to use.

The modern synthetic alternative is butyl tape. Lay the tape between the frameing and tank sides, then drive the assembly home with screws or Rivets. Supposedly this stuff lasts as long as
Dolphinite. But 40 years? Iam skeptical,,because I've always found rubber in other applications always eventually hardens and looses seal. Dolphinite won't do that. Plenty of internet discussion on marine/boating forums concerning both products. Might be worth looking into...

Glenn
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Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

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Fender
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Re: Tender Tank

Post by Fender » Tue Jul 04, 2017 1:54 pm

Rather than putting a liner inside of a rivetted steel tank, why not make the tank from TIG-welded stainless, and put a thin wrapper of plain steel with dummy rivet detail? This won't leak or corrode.
Dan Watson

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johnpenn74
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Re: Tender Tank

Post by johnpenn74 » Tue Jul 04, 2017 3:09 pm

Guys I am hearing a lot of suggestions for building a tender that leaks and then sealing it with sealant, solder, welding, etc. Is it that hard to make water tight riveted seams?

Didn't the real guys do this on just about every tender, boiler, tank car for almost 100 years?? Has anyone actually made a tender that is riveted and holds water? I once thought it would be impossible to make water tight welds without leaks and inclusions, then after a little practice I actually achieved this. Can't say that I have achieved riveted water tanks, but am pretty certain I will try. Any body else have a go at it?
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Bill Shields
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Re: Tender Tank

Post by Bill Shields » Tue Jul 04, 2017 3:15 pm

POR tank sealant and or DEVCON FLEXANE

Glenn Brooks
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Re: Tender Tank

Post by Glenn Brooks » Tue Jul 04, 2017 3:30 pm

johnpenn74 wrote:Guys I am hearing a lot of suggestions for building a tender that leaks and then sealing it with sealant, solder, welding, etc. Is it that hard to make water tight riveted seams?

Didn't the real guys do this on just about every tender, boiler, tank car for almost 100 years?? Has anyone actually made a tender that is riveted and holds water? I once thought it would be impossible to make water tight welds without leaks and inclusions, then after a little practice I actually achieved this. Can't say that I have achieved riveted water tanks, but am pretty certain I will try. Any body else have a go at it?

John, try this link:

https://www.boatdesign.net/threads/supp ... -ii.34290/

These guys discuss two primary methods: hot riveting seams with closely spaced rivets, and imparting a sealing/caulking compound between each plate at the seam. The hot rivets would contract upon cooling and exert tremendous pressure upon the seam-particularly when double or triple riveted and closely spaced - making them water tight. The rivet holes were also punched to specific tolerances and dimensions to ensure a tight, water proof fit after cooling.

I think we tend to forget that locomotive boiler and tank work and old time shipbuilding were very, very similar processes.

Glenn
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....

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Fender
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Re: Tender Tank

Post by Fender » Tue Jul 04, 2017 5:33 pm

Boilers were sealed by "caulking" the joints (deforming the edge of the overlapping plate with an air hammer). I suspect that tender tanks were sealed the same way. I don't think this is feasible on our small tanks with thinner metal.
Dan Watson

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