DIY truck bed plate

[jaywo]

I am looking at doing a plywood plate for my truck bed (F-150 short bed 67in L, 60in W). The issue is that I can’t find 6’x6’ plywood sheets.
Am I supposed to buy 2 4x8 and join them together? This seems complicated with the limited tools and experience I have.

This plate will be used for a truck camper build. The galley/cabinets will be made of 8020, and that 8020 will be secured directly to the side of the camper thanks to the t-track. But I will still secure those cabinet to the plate.

The plate won’t be secured to the bed (I don’t want to drill the bed), only to the 8020 cabinet (themselves secured to the camper).

 

[Herbie]

Skip the big-box stores for sure. You can check with industrial lumber yards to see if they have alternate sheet sizes (my local one stocks 5'x5' baltic birch, for example), but I don't know that I've ever seen anything that would yield a 6'x6'.

 

[llamalander]

With a little planning, you can make a clean join with simple tools, but you will need to buy 2 sheets if 4x8 is all you can find. The more plys the better, 1/2" is probably fine, no need for 3/4".
Basically plan on joining two pieces near the centerline of the bed, if there is low point on the front-to-back grooves, pick that for the join. Cut them for the length of the bed (67"), then cut 2 strips about 2"x67" long for later, each part is now 44" x67" roughly.
You can freehand or make a template of each half to fit around the wheel wells, cut the pattern with a jigsaw or a coping saw, using the factory edge for the outer walls of the bed. You have some spare wood to use up as you get it fit right--if the first try isn't as good as you want it, try again a few inches back.

Once both sides match the outer bed walls, put one in and the second on top of the first, each tight to the respective outside edge, with a long scrap by the wheel well to keep the top piece in the same plane as the bottom (both parts will overlap by a foot or more).

If you don't mind a screw-hole or two, tack the two parts together outside the line of the cut you're about to make, and you can do the next step on saw horses.
With the other long scrap to level a circular saw, cut a straight line back to front through both sheets at the same time--the groove keeps your blade away from the bed. Pull out the off-cut and the two pieces will fit perfectly together.

If you cut one of the scraps to fill the groove in the bed under the cut, you can glue/screw the two parts together and the fit should be close enough to keep the plate in place with friction alone.

Hopefully that makes sense, done carefully it will make a joint you're proud of.

 

[Beltfed]

I'm not aware of any sheet goods that give you a clear 6'x6' so you are looking at an edge to edge joint with one thickness of material.
Best option is a scarf joint. You could go with a biscuit joint, But easiest will be a lamination and an overlap of two materials.
So what that means if you are looking at a total thickness of 3/4":
- get two 4x8 sheets of 3/8", cut two 6x4 and two 4x2 and join the 6x4 and 2x4 pieces together with joints opposite to each other when you sandwich the sheets together. You'll want to use a good quality carpenters glue and figure out a way to ensure the laminated pieces stay together while it all dries (either mechanically via fastening or clamping or a heavy weight on them on a flat surface.

Good luck with your project.

 

[jaywo]

Thanks all. I am gonna call lumber yards around and then use some of your suggestions. I think I will try to glue edge to edge without cutting some sort of complicated joints because I do not know how to do those and all I have is a jig and circular saw. For some reason, I don’t feel comfortable working with wood but much more comfortable with 8020.

Because the 80/20 is going to be secured to the camper, and to the plate at multiple locations, hopefully it helps secure the 2 plates together.

The wood plate will be under a vinly flooring so I don’t care about the look, so do I need to finish it? Should I buy it normal or pre-finished, and if finish is needed what’s the bare minimum? again the wood won’t be in view, if I have to apply a finish it’s just for durability. Will be inside a dry camper.

 

[rgv]

What’s wrong with tongue and groove plywood? You can even get it pressure treated which is what I’d use for a floor base.

 

[jaywo]

What’s wrong with tongue and groove plywood? You can even get it pressure treated which is what I’d use for a floor base.

What‘s wrong with it? Nothing just did not know it existed.

https://www.ashbylumber.com/p/1932-4-x-8-cdx-tg-plywood/58CDTG

That’s what you are refering to? I don’t understand how you order that: if you order one 4x8 sheet, does it come with one edge female and one edge male? How do you know if it’s on the long edge or short one?
But yeah, this sounds like an easier solution!

 

[llamalander]

Tongue & groove is usually much thicker than you want/need, even 3/4" may be too.

If you're going to be breathing in the back of your truck, it is worth painting all 6 sides of wood you install--or none.

Expect to get condensation inside and wood will soak that up and change dimensions. If only one face is painted, the wood will cup and warp as well as expand.
A good primer is generally fine but you have to plan to fit, then paint and install later when it is all dry.

 

[IdaSHO]

Another option is to laminate multiple layers of plywood and stagger the joints.

This would be far stronger than any scarf, butt, or tongue and glue joint.

 

[rgv]

What‘s wrong with it? Nothing just did not know it existed.

https://www.ashbylumber.com/p/1932-4-x-8-cdx-tg-plywood/58CDTG

That’s what you are refering to? I don’t understand how you order that: if you order one 4x8 sheet, does it come with one edge female and one edge male? How do you know if it’s on the long edge or short one?
But yeah, this sounds like an easier solution!

Yes, that’s the stuff. That pic is a bit misleading as they cross cut it to show the profile. Normal 3/4 or 5/8 sheathing will have male edge on a short and long side and a female edge on the opposite long and short sides.

For your use it won’t really matter, just use some sheathing adhesive on the joint and tap them together.

The milled edges are fragile so trim them off when you cut your floor.

 

[jaywo]

So I got 2 4x8 birch plywood from the lumber store.
Since I will build galleys on each side with 80/20, and because the 80/20 will run the full length of the bed on each side I figured I could just bolt the 80/20 to both pieces of the bed plate and this will secure them enough without needing any glue or joint right?

 

[llamalander]

Yes, 80/20 bolts nicely... if you use a threadlocker; Permatex or Locktite, otherwise the fasteners will rattle loose in no time. Wear gloves, the stuff is not actually anything you wan t to touch, eat or breathe, but it works.

That said, your bed moves and flexes, if you have two parts they will not always line-up.