Measuring stress on angle iron

[aaronsb]

Isn't that a saying? "If you've got wood, then there's a way!"

Originally Posted by nat_ster

Hey man, I hate wood, and vote steel all the way.

I think pork chop already has the plywood.

Nat

[porkchopsandwiches]

What do the critics think of this design to hold the 2 tanks between the frame rails? If the angle steel is, say, 2" x 2" x 1/4" and the square tube is 2x2x 1/4"? Think 1/2" grade 8 flange bolts from the angle to the frame, and one big 3/4" grade 8 flange bolt holding the tube to the angle. This is not dissimilar to how the 60 gallon diesel tank is held, though it uses one preformed piece where I am using 3. Please ignore my sh!t drafting. I am just throwing these out there because that is what I have readily available. I would do 3 or 4 of these to hold the 2 tanks, and have some sort of "cradle" for the tanks made of some smaller stuff.

Originally Posted by aaronsb

Instead of plywood, go buy some lengths of galvanized steel decking. Install it in your pan frame (with hopefully some more vertical supports) so the deck ridges are left to right (the shortest possible span)

You can use the same stuff for supporting the tank walls, as well.

Make sure you treat the edges where you cut the decking, so it doesn't rust. It'll be strong or stronger than the plywood, completely waterproof, and probably lighter.

Don't have to buy it from here, this link is just as an example of what you want:

Galvanized Steel Decking | Metalmart

I'll think about it for the floor. I'd use it for the walls but it is too thick, I only have about 3/4" TOPS on each side to play with.

A 4x8' (32 sq ft) sheet of marine grade treated 1" plywood from the local lumber store here (Seattle, WA) area is $85/sheet.

$2.65 /sq foot

A 12x3' (36 sq ft) 20 gauge 1" form deck panel from a local steel building supply costs $100/sheet.
$2.77 /sq foot

The steel decking, when installed on 5' centers, has a live load rating of 210 lbs/sq foot.

I didn't look up a comparison rating for the plywood, but I bet if you lay it on two centers 5' apart, it's not going to hold 200 lbs in a single square foot in the center.

A 4x8' sheet of 3/4" treated ply, which is what I will use, is $40 here. I am installing this stuff like 18" on center. I hate using wood in a manner like this too, but the fact of the matter is I probably won't own this thing in 5 years, I am 20 and make little money, and I am leaving for a 7 week, 9,000 mile road trip in less than 2 months. Yes, I know, I am a typical capitalist American who thinks in the short term and thinks everything is disposable, haha. I just want to get this done and make this trip happen, that is more important to me right now. Also, this thing gets driven less than that amount a year and sits around 95% of the time where the wood would be dry. It isn't being bombarded with saltwater or anything (not anymore, anyway).

Thanks for the input.

[bansil]

Unless you sleeve the tubing, I would use two or 4 bolts to secure instead of 1 long bolt, this will keep from squishing tube and 2 bolt is just....we'll.... Because its stronger

That is 2 or 4 bolts and nuts per end so they each secure 1/2 inch of material (2x 1/4")

Did that make since???

[porkchopsandwiches]

Originally Posted by bansil

Unless you sleeve the tubing, I would use two or 4 bolts to secure instead of 1 long bolt, this will keep from squishing tube and 2 bolt is just....we'll.... Because its stronger

That is 2 or 4 bolts and nuts per end so they each secure 1/2 inch of material (2x 1/4")

Did that make since???

Yeah. And by sleeve you mean put some galv pipe or something around where the bolt goes through to keep from crushing the walls in, right?

[aaronsb]

You could get away with some thick C channel (1.5x4? Maybe) instead of square tube for the bottom. That way you're not worried about crushing the square tube.

I think if you used that layout with a 48" long tank, the sets of double 2" angle iron would easily keep the sides of the plastic tank from flopping too much.

Copying the cradle for the fuel tank is a great idea since someone probably had to prove to a manager or safety review the design used. I see black plastic ABS fuel tanks on various offroad equipment that doesn't have issues, but has similar strapping layout to your drawing.

I'd say go for it!

Originally Posted by porkchopsandwiches

Yeah. And by sleeve you mean put some galv pipe or something around where the bolt goes through to keep from crushing the walls in, right?

[bansil]

Drill 2x2 tube with a .781 dia drill and get tubing with an ID of 3/4 (so bolt slides in) cut tubing to a length of say 1-1/2" in so it slides inside tubing, and bolts with thick washers 1/8" and it will not come loose, paint all parts and assemble with plenty of anti-sieze so tube doesn't rust around bolt and you should be good to go

[porkchopsandwiches]

Originally Posted by bansil

Drill 2x2 tube with a .781 dia drill and get tubing with an ID of 3/4 (so bolt slides in) cut tubing to a length of say 1-1/2" in so it slides inside tubing, and bolts with thick washers 1/8" and it will not come loose, paint all parts and assemble with plenty of anti-sieze so tube doesn't rust around bolt and you should be good to go

Thanks! This is the idea I am going with / have already started building.