Whether you are shopping for a production system or considering building your own, here is some information you may find helpful.
Drawer systems can be made from a number of materials, but there are a few that are most prevalent. With all materials there are pros and cons, so let’s take a look at the most popular and see why they may or may not be a good choice for your build.
Here is a table comparing these materials as objectively as possible, rated 1-10 in each category except cost. This is not a result of any scientific process, just an observation from years of fabrication experience. Disclaimer: Some assumptions were made to obtain these results. We are assuming these materials are used efficiently to construct a drawer system using proper techniques, coatings, etc., within reason.
Galvanized Sheet Metal
Galvanized sheet metal is a very economical choice for a drawer system, given you already have the specialized tools and know-how to work wth it. It is an inexpensive material that is fairly robust and maintenance free. Being very thin, it maximizes useful space in the system, assuming proper design. Galvanized metal gives off a very toxic gas when welded, so proper safety procedures need to be adhered to when working with this material. Therefore, it is better for the amateur to stamp, bend, and fasten with mechanical fasteners. While metal does technically expand and contract with temperature fluctuations, it is such a minuscule amount it can be considered completely stable for this purpose.
There are some drawbacks to using galvanized sheet metal. It can become very heavy with thickness, so a thinner sheet with proper construction needs to be used in order for it to be strong enough to carry a heavy load without ‘coke-canning’. Bends, hemmed edges, grooved seams, and flared holes are some ways to stiffen the sheet without adding excessive weight. But this does increase the costs and complexities associated with the manufacturing as well as possibly offsetting any benefits of the thinness of the sheet. It should be coated with a bed liner type material or carpet to reduce rattles, as metal sheet can be very noisy. It can be difficult for the end user to modify and add accessories if they do not have the proper tooling. Damage to the sheet may be difficult for the average user to repair. If the sheet used is thin enough to allow excessive flexing, it can potentially become work hardened and brittle, eventually cracking. And while purely subjective, sheet metal can have a cheap feel to it for some users.
Baltic Birch Plywood
Baltic Birch is a very high quality void-less plywood used in high-end cabinetry. It has one of the highest strength to weight ratios of any readily available sheet material. Unlike construction grade plywood where the inner layers are made of a lesser softwood, Baltic ply is made of many thin layers of solid hardwood (birch). This gives the sheet incredible strength and screw holding power. Given an impact or excessive load, it is very resilient and will spring back to it’s original shape, unlike sheet metal. It is also one of the most stable wood products as far as expansion and contraction are concerned, due to its layers of perpendicular grain. Being a wood product, it should be coated, making it weatherproof and virtually maintenance free. It is easy to repair and modify for accessories with ordinary tools and fasteners. It is very quiet, especially if coated with a bed liner type product. It is a joy to work with, and creates a very solid and high-end feeling product. Not all Baltic Birch is created equal. A good quality sheet will be properly laminated with waterproof glue. You can test the quality of the lamination by cutting a 1” wide strip of the material and attempting to pry the laminations apart. A good glue joint will not fail- the wood fibers will separate first. Baltic Birch is not to be confused with standard Birch plywood found at most box stores.
Like all wood products, Baltic Birch needs to have some thickness to maintain its strength, so it does technically reduce some available cargo capacity. It can also be quite heavy, so steps need to be taken to use as thin of a sheet as necessary for the application. Baltic Birch really should be coated, which does increase the cost. Builds using Baltic Birch normally require a thicker sheet than would otherwise be necessary due to the fasteners used, which increases the overall weight of the system.
Marine Grade Plywood
Marine grade plywood shares many characteristics of Baltic Birch, so we’ll just go over a few differences. Since it comes in many different grades with a myriad of woods used, it is difficult to make too many blanket statements about this product. Normally, it is a relatively strong and light sheet product also made with waterproof adhesives. It is more naturally weather and rot resistant than Baltic Birch, but since both should be coated this isn’t a great advantage. It machines, glues, and holds fasteners well, but not as well as Baltic Birch. It can be lighter or heavier than Baltic Birch, depending on the type. It is usually more expensive.
MDO stands for Medium Density Overlay. It is essentially an exterior grade plywood with a Kraft-type facing. It is used primarily for concrete forms and outdoor signage. There are many products available labeled as MDO, and they are definitely not created equal. A good quality MDO is fairly rigid, strong, and weather resistant but can be quite heavy. It is easy to work with and has average holding power on mechanical fasteners. Like other wood products it should be coated but is then fairly maintenance free. If you have a good inexpensive supply of MDO it may be a good option, otherwise there are better choices.
Standard plywood is quite a broad category. Let’s talk more specifically about the usual 5-7 ply construction grade sheet you would find in a big box store. It is usually comprised of a few layers of softwood sandwiched between a similar softwood exterior skin, or a higher grade hardwood outer layer. It is very inexpensive. It is easy to work with, but only provides a mediocre hold on mechanical fasteners. It is lighter than many other wood sheet goods. All plywood should be coated, but there may still be some maintenance required due to fasteners loosening over time with the vibrations and stresses associated with off road driving. Standard plywood is an acceptable material for the very budget conscious DIYer, as long as its shortcomings are known and accepted.
MDF stands for Medium Density Fiberboard. It is a solid sheet product made from pulverized wood fibers and glue. Due to the lack of grain structure and high adhesive content, it is dimensionally stable but very heavy. It has very poor strength and does not hold fasteners well. Its dense structure makes it very heavy, but it also absorbs sound and vibrations well. It does not like moisture and will absolutely fail if wet. If MDF is used in a drawer system, it must be completely sealed from the elements. Use MDF for jigs, fixtures, and painted interior trim. It is a poor choice for this application.
Particle board is a compressed sheet product made from wood chips and adhesive. It is fairly rigid, but not tough. It has poor weatherability, screw holding power, does not glue well, and is difficult to repair. It also has a low strength to weight ratio. It’s only real attribute is that it is inexpensive. Given the fact that the major costs associated with drawer systems lie in the hardware and labor components, the savings from using this material do not offset its shortcomings. Use it for a closet shelf, not your drawer system.
Regardless of the material you choose, you can count on spending a decent amount of time building your system. Make sure you pick a material that falls within your skill and tool set, and that you will be happy with in the long run.