[charkilah]

Since this is my first post, here is a little introduction before my request for help.

I just purchased an Everlast Tig welder and I have never welded before. There you have it, starting from scratch. I have been watching the video's on Welding Tips and Tricks for the last few weeks. I am hoping to eventually weld a bumper for my 1994 Land Cruiser, but I have many smaller projects to hone my skills on before I risk the lives of other motorists.

The first project is a sleeping platform that will be secured behind the second row of seats, in between the wheel wells. When the second row is folded over, I will be able to sleep on a queen sized air mattress.

I have a couple of design goals in mind: 1) keep the weight to a minimum. 2) make sure it is strong enough for both sleeping on and the occasional hauling of junk. 3) as much usable space underneath as possible.

I have drawn up a couple of options in Sketchup to show what I am intending on making. My primary questions involve what gauge of tubing I should be looking at, as well as what thickness of plywood. I am thinking either 1" X 1" in either .065 or .085 wall tubing, and either 1/2 or 5/8 inch plywood. As you can see in the pictures, I will be doubling up in the cross beams (although I am not sure if this is necessary). Of course there is always the option of a center support beam, but that would defeat #3.

I ran some calculations on weight and came up with the following:

.065 tubing = 39.6 lbs
.085 tubing = 50.5 lbs

1/2 inch pw = 25 lbs
5/8 inch pw = 30 lbs

I am hoping to get away with using the .065 and 1/2 for a total of ~65 lbs.

Of course once I have the supplies I will be back asking for settings and help with the actual welding.

Thank you in advance, and any comments or suggestions are greatly appreciated.



EDIT: After posting I realized that there is no scaling on the pictures. The total width is 4'10", the depth is 3'6", and the total height is 10". The wheel wells are 3'8" apart.

[weldin mike 27]

Hey,

Welcome to the forum. Thanks for introducing yourself. There is a specific thread for welding projects, but because you are new we will let you off.

Your project looks good. Its a very good drawing. I couldnt even get sketch up to work.... . The frame should be alright with the thinner wall tube, you may be able to get away with a single section of tube providing you have enough support. As in 2 or 3 legs rather than just 1. This will reduce the unsupported span of your frame and allow you to use lighter material. The main problems come from designing something with a bigger material in mind and trying to make that design work with lighter stuff. Its only for sleeping right . Check out some camp beds and stretchers, they are light and strong.

Hope this helps and isn't too confusing.

Mick

[Nils]

Cool stuff. I agree the .065 should be good. But, I'd think about using a single 1x2 for the three cross members and the vertical upper supports where you've tripled up on the 1x1's. This should help reduce weight and possibly cost. Consider using expanded metal instead of the plywood. The wood will probably not lie as flat as you dreamed it wood. Just throwing out ideas your way. May be good, may be bad, maybe not.

So what kind of machine did you buy and how's the new skill coming along? Doing this project in aluminum would be way cool. Just say'n.

[Mike]

Welcome to the forum.

[charkilah]

Thank you for the quick replies!!

Of course my first post would be in the wrong place... Thanks for letting it slide. I promise to have weld pics up soon.

Mick, Thanks for the suggestion to look at camp beds. after googling some images I think that the .065 will be sufficient. I tend to go overboard with planning for the worst, and since I don't have any real experience with structural engineering (either hands-on or book), I'm lucky I didn't use 1/4 wall tube.

You're right that having more support would solve this problem, but I really want to have a completely open storage area with no supports. If I end up with the supports, I'll probably eliminate the doubling up of the cross beams and just have singles.

Nils, that's another vote for .065. Thanks. Initially I just wanted to use the same size tubing for the entire structure for simplicity, but I'll look into the 2X1 tubing. I purchased the everlast powerpro 256. So far I haven't had any problems with it. I'm watching Jody's videos and then attempting to make some beads. I'll post up some pictures this weekend. So far I'm having a lot of fun, even if I wouldn't trust my welds to hang my coat on.

Thanks for the help so far everyone.

[weldin mike 27]

Hey,

Its a pleasure mate.

If you really want an open space underneath, try rectangle tube for the main spans. say 1"x2" on its edge . Will give more rigidity.

Mick

[Otto Nobedder]

I agree. The double 1X1s are redundant. The two mating faces add weight, not strength. If the structure were side-loaded, it would make a difference, but for a simple vertical load, as a sleeping/light cargo platform, those mating faces do nothing structurally.

I believe single 1X1 will do fine, if the legs are firmly attached to the floor, and 1/2" plywood (CDX for moisture tolerance) is both glued and screwed to the top surface.

If you want more open space beneath, Mick's suggestion of 1X2 should eliminate the need for center legs, or to keep it simple this could be doubled at the access end without much weight penalty.

Can't wait to see what you come up with!

Steve S

[charkilah]

small update. Weighed the 3rd row seat I'll be taking out. Seats plus brackets plus seat belt assembly is nearly 90lbs. I'm not as concerned about weight anymore. Decided to go with .083 wall 1 inch square tubing since I still have the goal of eliminating any central support beam (maximizing usable space underneath platform).

After some more measuring I realized that there was no way to install a fully assembled platform. Won't fit through the rear door. Decided to break into two halves. Works out fine since I needed the double beam in the middle to support the hinged piece of plywood.

Went back to sketchup and here is my final plan. Purchased metal and hope to get started next weekend.

[charkilah]

more pics

[charkilah]

last ones

[Otto Nobedder]

That looks like a winner!

Makes the most of the space available.

Pics, please, when it's more than a drawing!

Steve S

[weldin mike 27]

Hey,

If it ebds up being as snazzy as the drawing ,you're on a winner .

mick