Best wood to construct cargo box/drawers out of?

[The Adam Blaster]

I've been helping a buddy build a box for a couple drawers to go in the back of his Jeep JK.
We built the exterior box out of 3/4 MDF, and the drawers out out 1/2 plywood, with both sides sanded smooth. (I'm not sure if there's an industry term for that type of plywood...)
We are also using a dozen or so 3"x3"x1.5" wide metal L-brackets to help connect the sides to the top and bottom panels.
For the center support between the drawers, we sandwiched 2 pieces of the MDF to make a solid 1.5 thick beam. We also used a good amount of commercial grade adhesive - PL4000 at all the joints.
We chose the MDF because it's cheap and easy to work with, but I am not going to use it when I build a box for my own XJ.
I don't like how it splits when you try to drill into it's edge. We even drilled pilot holes, and tested it several times with some extra chunks, but it split every time. I tend to try to over-build my stuff, and currently, the MDF box is pretty solid, but not up to my normal standards.


So, I'm curious what specific materials others have used, what you might stay away from based on your experiences etc.?
I'm wondering if a standard 3/4 plywood would be a good compromise between ridgity and flexibility vs. using actual lumber, like 1x12's or something?

 

[nwoods]

1/2" aircraft grade plywood made out of spruce is considerably lighter than 3/4" ply or MDF, and very strong. It supports my 300 lbs weight when kneeling on one knee and supports are 48" apart.

 

[xcmountain80]

Baltic birch is a furniture grade plywood that is hard and will hold up over time.

A

 

[The Adam Blaster]

Where do you buy these products?
When my buddy and I were shopping at home depot, I was looking through their stock, and didn't see much anything that was any different that standard plywood.

 

[xcmountain80]

No no no these are not home depot woods. Try asking a cabinet maker where he purchases stock from.


A

 

[The Adam Blaster]

I drove by a plywood specialty place this evening, they advertise a lot of furniture and cabinet wood products, I'll start there.

 

[R_Lefebvre]

with both sides sanded smooth. (I'm not sure if there's an industry term for that type of plywood...)

Both Sides Good or BSG. You can also find OSG.

When my buddy and I were shopping at home depot, I was looking through their stock, and didn't see much anything that was any different that standard plywood.

They usually have a selection of other plywoods near the millwork department. Just go look for their solid woods. I don't think they have real "baltic birch" plywood, but they usually have at least a veneer plywood.

 

[southpier]

spruce and birch are not moisture resistant woods.

admittedly, spruce is used in boatbuilding, so use it if you must. but there are better, more moderately priced and readily available, alternatives around.

the plywood you used was probably stamped "PTS" meaning plugged (boat shaped patches to elimenate voids on the surface veneers) & touch sanded. that's done to any number of types of plywood.

MDF will swell like a sponge when it gets wet. several coats of finish will just postpone the process, but not indefinitely.

the philosophical question to ask: what is my time worth?

that may drive your budget toward the end result. materials can be only a small portion of the job cost if you assign a $$$ to your time.

another consideration is the strengths of materials - & fastenings. how will they react in a crash or roll? will you be pummelled with wrenches and extrication gear if the carcase of the casework fails? or a loved one?

MDO 2S is a decent plywood which fills most criteria. [MDO 2S = medium density overlay 2 sides] it's A-B grade plywood with kraft paper saturated with phenolic resin as a top layer (2S = both sides). resist saving a couple of bucks with 1S - it will absorb humidiy from the uncoated side & has warp potential. also makes cut offs harder to use because they may not be reversible. sometimes if you spend, you save.

the inteweb is a great tool and there are untold sources of plywood information available. figure your cut list, and it may even be practical to have it shipped to your door.

fasteners: use through bolts where at all possible. screws work loose in a shorter time

 

[xcmountain80]

So don't get it wet? DId I miss something is this going on a trailer? You can always stain and then varnish it (like a boat) and never worry about it again. AL is always good but then you need to know how to work metal.

A

spruce and birch are not moisture resistant woods.

admittedly, spruce is used in boatbuilding, so use it if you must. but there are better, more moderately priced and readily available, alternatives around.

the plywood you used was probably stamped "PTS" meaning plugged (boat shaped patches to elimenate voids on the surface veneers) & touch sanded. that's done to any number of types of plywood.

MDF will swell like a sponge when it gets wet. several coats of finish will just postpone the process, but not indefinitely.

the philosophical question to ask: what is my time worth?

that may drive your budget toward the end result. materials can be only a small portion of the job cost if you assign a $$$ to your time.

another consideration is the strengths of materials - & fastenings. how will they react in a crash or roll? will you be pummelled with wrenches and extrication gear if the carcase of the casework fails? or a loved one?

MDO 2S is a decent plywood which fills most criteria. [MDO 2S = medium density overlay 2 sides] it's A-B grade plywood with kraft paper saturated with phenolic resin as a top layer (2S = both sides). resist saving a couple of bucks with 1S - it will absorb humidiy from the uncoated side & has warp potential. also makes cut offs harder to use because they may not be reversible. sometimes if you spend, you save.

the inteweb is a great tool and there are untold sources of plywood information available. figure your cut list, and it may even be practical to have it shipped to your door.

fasteners: use through bolts where at all possible. screws work loose in a shorter time

 

[nick disjunkt]

spruce and birch are not moisture resistant woods.

I have pretty extensive experience of birch plywood in all sorts of applications and can safely say that decent birch ply with WBP glue is definately waterproof. I have left untreated pieces in salt water and freshwater for extended periods of time with no delamination and no significant warping.

In my opinion slow grown WBP birch plyood represents one of the best durability and strength to weight ratios of any material.

I'm not sure whether there are homegrown birch sources in the US but in Europe the scandinavian stuff is the best. What you are looking for is birch grown in cold countries where the trees grow slowly and the wood is denser. Finland makes great birch but latvia and russia are also good and a fair bit cheaper. The far eastern (chinese, indonesian, etc) is crap and usually comes with more voids than wood.

Decent birch plywood is lighter than MDF although nowehere near as light (or as flimsy) as spruce.

In Europe there a few companies manufacturing birch plwood sheets laminated with various hardwearing surfaces. They work perfectly as the basis for hard wearing furniture in utility vehicles. They get used in the UK in van, truck and trailer floors and walls, flightcases, kids playgrounds, outdoor signs, etc.

I have used a few of the products from:

http://www.advancedtechnicalpanels.co.uk

 

[ersatzknarf]

How about King Starboard ?

I have been going back and forth and back and forth over material to use for the interior build-out. Plywood is nice (would like to put Formica on most surfaces, too), if good materials can be found, but agree that there are concerns about moisture and if something "very unpleasant" should happen while driving.

From all I can find out about using KS, it seems that it is heavy and needs (more ?) support ? It's completely recyclable and won't be much affected by moisture... They build boat interiors (cabinets, lockers, etc.) and exterior parts (ladder steps, swim decks, etc.) out of it. Is it so bad ? Heavy seems to be the worst part, that and it is not as thermally dimensionally stable as the other choices.

So don't get it wet? DId I miss something is this going on a trailer? You can always stain and then varnish it (like a boat) and never worry about it again. AL is always good but then you need to know how to work metal.

A

 

[The Adam Blaster]

Unfortunately, my knowledge and skill set is quite limited when using metal.
I have plenty of tools, and a pretty good working familiarity with wood, so that's why I'm going to use that as my primary building material.

I haven't thought about getting it shipped to my place, shipping to/within Canada is quite a bit more expensive that the US, but I wouldn't rule that option out if I found a deal on a quality product.

When I'm finished this box will be anchored in the rear cargo area of my Cherokee. As per my past experiences with water, I will need it to be moisture resistant. I've had water come in through all four door seals, and through the seal around the rear hatch. I've also had water come in through the open window, large bow wave on that one. lol
If my XJ was a dog, it would likely be a Burmese Water Dog.

I've heard of marine-grade plywood, and presumably it would have a pretty high level of water resistance, but I have no idea where to look to source such an item. I will be starting my local search today, as I mentioned in my previous post.

Regarding keeping the occupants safe -- hopefully my wife will let me/us take our son on some trail rides soon, he's almost 2, but she's a bit of a worrier when it comes to his safety.
I want to build some sort of mesh structure to attach at the front of the box, right behind the 2nd row of seats and go all the way to the ceiling of the XJ. I have to figure out a way of securing it to the roof. I might make some sort of large metal "cage" that emcompasses the whole cargo area and secure it to the floor, and that way I would have a way of hanging light and loose objects in a mesh cargo net from the roof.
I've also thought about having someone build a single rollcage hoop that would go just behind and above the rear seat to add a large attachment structure, and provide an extra level of safety if I was ever to roll. But, I'm really not planning on taking it on any "crazy" trails, especially not with the little guy in the back seat. Might be a future mod...

 

[Scott B.]

MDF Screws

McFeely's has a specially designed screw for fastening MDF. MDF Screw

You can see from the picture, it is not tapered. You pre-drill for it (again, non-tapered) and the screws drive right in.

I always had the same problem of MDF splitting when I drove a screw in it - I found these several years ago, and used them building a buddy's speaker boxes in his Pinz. They work great.

Of course, MDF does absorb moisture, and we are going to have to rebuild the boxes...

 

[The Adam Blaster]

Thanks for posting that link Scott.
And if anyone has other links to buying the supplies, please feel free to post them up as well!

Scott, when you use those screws, do you really predrill as per the instructions?
(They say use a 5mm then a 7mm and finally a 10mm drill bit.)
It would take me a year to predrill all my screw holes 3 times!

I'm not a quick builder... lol

 

[R_Lefebvre]

Adam, at the very least, use common plywood for the box instead of MDF. Not only will it be slightly water resistant, there's no way MDF will hold up in a crash. At least you have a chance of a plywood box keeping your stuff in place.