Propane tank mounted against frame rail

[r0meboards]

So I finally got the undermount RV propane tank mounted to the chassis behind the drivers seat and between the front and rear axle. It just barely fit into the space, and is now up against the frame rail on one side. I placed some thin rubber mats between the tank and the rail but now I'm stressing that this could be potentially disastrous down the road – wondering what folks think and if its possible that I'm overly stressing about this?

[Timeline]

Not liking that install, rubbing is not good, and it looks like the tank is the lowest thing on the bus just inches from the ground. That set-up is dangerous.

[r0meboards]

Originally Posted by Timeline

Not liking that install, rubbing is not good, and it looks like the tank is the lowest thing on the bus just inches from the ground. That set-up is dangerous.

Thanks for the response. To clarify, that photo angle is deceptive – the clearance is higher than the driveshaft and the exterior shell (see photo). Its at least 12-14" from the bottom of the tank

[Timeline]

Thanks for that photo, I'll be able to sleep tonight!
Does the tank rub on the frame without the rubber pad?

[r0meboards]

Originally Posted by Timeline

Thanks for that photo, I'll be able to sleep tonight!
Does the tank rub on the frame without the rubber pad?

Yeah, it would be touching the frame without the pads which is why I put them there. I think I have probably 1/4" - 1/2" that I can move it away (which of course requires new nylock nuts, redrilling holes, etc) but I'm very short on time (moving out of our house) so trying to see if this install will buy me some time/miles until I can get back under there and tweak it some more

[DeMac]

Wow. Great looking tank & install so far

You can rehang the tank, using the awesome mount which you've already installed.

Just need to offset the mounting holes.


You could use two short pieces of strut, cantilevered
over the top by two inches.
Then hang longer althread/bolts)

OR

If height/space is a concern, purchace four of Unistruts "T" Shaped 4-hole Connector Brackets
amazon.com/Genuine-Unistrut-P1031-EG-Connector-Bracket

You could use them to offset the hangers for similar results. Surely other will suggest additional options. I'm looking forward to seeing more.

You can redo stuff for peace of mind. I do that alot.

[r0meboards]

Originally Posted by DeMac

Wow. Great looking tank & install so far

You can rehang the tank, using the awesome mount which you've already installed.

Just need to offset the mounting holes.


You could use two short pieces of strut, cantilevered
over the top by two inches.
Then hang longer althread/bolts)

OR

If height/space is a concern, purchace four of Unistruts "T" Shaped 4-hole Connector Brackets
amazon.com/Genuine-Unistrut-P1031-EG-Connector-Bracket

You could use them to offset the hangers for similar results. Survey, other will suggest additional options.

You can redo stuff for peace of mind. I do that alot.

Thanks for the kind words! Yes I went with the (crazy expensive) ASME undermount tank after months of deliberation. I will probably remount it (drill new holes 1/2" or expand the current ones and move the strut over) and try to move it a little further away from the frame. My only issue now is time, we need to hit the road so I'm hoping this solution with the rubber pads might be good enough for the next few months, or if its pressing enough that I should redo it before plumbing in the propane lines.

[Timeline]

I'd drive it that way for a short while.

[Rucker]

Originally Posted by Timeline

I'd drive it that way for a short while.

It's an ASME tank of steel, against a steel rail. Could likely go indefinitely like that.

If the rubber mats fall out the primary reason you might move it is because of the rattle, not anything having to do with safety.

[r0meboards]

Originally Posted by Rucker

It's an ASME tank of steel, against a steel rail. Could likely go indefinitely like that.

If the rubber mats fall out the primary reason you might move it is because of the rattle, not anything having to do with safety.

Thanks. Yeah I'm sure the tank itself is quite sturdy (that why I got it) I guess the fear was more from any extra vibrations / rattling from its contact with the frame and any potential danger from the propane inside.

[HamSkoolie]

Looking at your pics it seems to me that the easiest and probably best solution would be to bolt two sections of 1/4" x 3-4" plate to the bottom of and perpendicular to the unistrut you've already mounted and then bolt the tank to those plates.

Kudo's for going with the ASME tank. We did the same and went with the Flame King 29.3 gal tank. If we mount between the frame and outer skirt I'll cut an access but I'm considering between the frame rails with a remote fill on the skirt.
I like the idea of the tank being protected by the frame rails and it would leave more of the frame to skirt area for storage box or liquid tankage.

[LargeMargeInBaja]

'Yes', you are stressed... and I would be, too.
.
One of my hobbies is walking wrecking-yards aka 'dismantlers', investigating all the ways a homicidal vehicle can get you dead or decapitated.
.
For some odd reason, drive-line U-joints are indestructible.
Until they are not.
After they let go, the two sections of the drive-lines go every which way.
With the engine powering one section and the rear axle powering the other section, those flopping steel tubes show zero remorse for their wanton behavior.
.
An aside:
In some fUSA military vehicles, after the U-joint goes, the drive-shaft drops to the pavement as a steel pole-vault, rolling the vehicle into the ditch or on-coming traffic.
Fatalities occurred, but fortunately, those were cheap and easily replaced by the next truck and next driver.
.
As you might imagine, instead of fixing the problem, they fabricated straps to catch falling drive-shafts.
.
For your rig, at minimum, I would fabricate catcher straps.
I think I might fabricate a shield between the rotating parts and the explosive stuff.
.
.
Note to new conversion folks:
.
Although tons of water, tons of propane, tons of photovoltaic, tons of framing and pipes and wires with their associated gizmos look good on paper...
... your Real-World use may be a fraction of that.
.
In your earlier conversion attempts at crafting the ultimate rig, you might come at it from your experiences living in a stand-still house.
I think your blank space is a gift.
You can go any direction... even duplicating a stand-still house on wheels, complete with dedicated spaces behind multiple doors -- this's the galley, this's the head, this's the entry, etcetera -- if your heart's desire leads you there.

[Ross]

What is the tank size? Weight when full? I'm skeptical of the Uni-Strut hangers.

[HamSkoolie]

Originally Posted by Ross

What is the tank size? Weight when full? I'm skeptical of the Uni-Strut hangers.

Our Flame King ASME tank is the largest we could find for a mobile install. It has a capacity of 29.3 gallons. Since you can only fill to 80% of capacity it will have a max of 23.44 gallons which is only 96.3 pounds. Add the weight of the tank which is less than 50 pounds for our big tank and you're looking at less than 150 pounds suspended.

25 gallons of water is 200 pounds and who's got any tanks that small?

[Ross]

Thanks, HamSkoolie, for the reply. I have a similar tank to yours, Armebe 29.something gallon. I'm fairly unskilled at using this forum, so I may have unwittingly directed my questions at you, but I was asking r0amboards about his tank installation.

[HamSkoolie]

Originally Posted by Ross

Thanks, HamSkoolie, for the reply. I have a similar tank to yours, Armebe 29.something gallon. I'm fairly unskilled at using this forum, so I may have unwittingly directed my questions at you, but I was asking r0amboards about his tank installation.

It's all good. I was responding to you over the skepticism of the mount being sufficient.
It's strong enough, I'd have just wanted it up higher and with some steel caging on the outside. Those little four wheelers tend to go right through that sheet metal skirting and I want my propane tank protected. I'm going to try to get mine up between the frame rails. Which would also leave me more skirt to frame room for tanks or storage.

[DeMac]

Originally Posted by Ross

What is the tank size? Weight when full? I'm skeptical of the Uni-Strut hangers.

------------
Nah, good stuff.

I use Unistrut in medical treatment facilities, every day. I am not skeptical about the Unitrut hangers' capabilites.

Per the Unistrut specs, the 5500 series maximum allowable load limit is 3,270 pounds.









The empty pipes weigh 49lb ea.

Each pipe contains 4 strands of 400 mcm Cu, adding another 48lbs to each pipe. 36 pipes per strut hanger amounts to 3499lbs. Not including straps, couplings, nuts, washers, 7/8" threaded rod, plus my own weight.



Over 3500 pounds split between two to four unistrut hangers & repeated every 10 feet.

[Joerg]

I've installed like this, see picture. Works well since many years. Installed beside the fuel tank.

[Rock-N-Ruth]

Originally Posted by r0meboards

Thanks for the kind words! Yes I went with the (crazy expensive) ASME undermount tank after months of deliberation. I will probably remount it (drill new holes 1/2" or expand the current ones and move the strut over) and try to move it a little further away from the frame. My only issue now is time, we need to hit the road so I'm hoping this solution with the rubber pads might be good enough for the next few months, or if its pressing enough that I should redo it before plumbing in the propane lines.

If the tank is empty, you should be fine driving with it. Just give it a good inspection when you move it and plumb the lines.

[Iceni John]

Just bear in mind that Unistrut is intended for houses and buildings that don't usually move at all (except in California...), and its load ratings are for static loads. In a moving vehicle the loads are dynamic, and can briefly exceed the static loads by a factor of two or more. All hangers, mounts and attachments should be designed and made accordingly. If in doubt, over-engineer! The Victorian engineers usually did this (e.g. the Firth of Forth railway bridge in Scotland*), and their achievements are still going strong after almost two centuries.

Isambard Kingdom John

* The Forth road bridge built in the 1960s has already been taken out of full service due to unanticipated fatigue- and corrosion-related weakening, requiring a new replacement road bridge to be built recently. I suspect the rail bridge will still be in use long after the new road bridge reaches the end of its life.