February 8, 2012
Because we both have smallish cars, we knew we would be using the trailer to transport materials. This meant before we began work on the base for the trailer, we would need to purchase all of the larger items - meaning everything that came in a 4x8 sheets. These items included 1/4" plywood sheathing for the roof, ceiling and interior walls, 1/2" plywood for the floor and 1/2" marine grade plywood for the exterior. But more on that later. Once the items were purchased and brought back to our assembly area, the base needed to begin.
The majority of the framework including the base will be built out of 1x2 pine which will be easy to work with as well as lightweight. We started out by building a rectangular framework of 1x2's on their side around the perimeter of the trailer which were glued and screwed together using pocket holes. The long sections of the frame were inset 1/2" so that the 1/2" plywood of the exterior walls could sit flush on the metal trailer and we would be able to screw straight into the wood frame.
I should mention that I was given a Kreg Jig for Christmas. This tool allows you to drill accurate pocket holes and create strong joints in wood. The kit comes with a special drill bit that fits into a standard power drill and is easy to use on any thickness of wood. So far we have only used it to make these frames, but it results in strong rigid connections and I would highly recommend it for any project!
After the exterior frame was completed I added additional wood framing on the flat at each of the of the interior cross members of the trailer as well as the front and rear cross members. These are what will be bolted through to secure the frame to the metal trailer base. They will also act as a support for the 1/2" plywood that will become the floor of the trailer.
With the wood frame complete, the next step was bolting it to the metal trailer with 9/16" bolts. First I pre-drilled each hole and created a recess for the bolt to sit in so that it would be flush with the wood frame. Since the trailer wasn't exactly level, we decided to use shims to make the wood frame level and make a better surface for the plywood floor to sit. I simply bolted directly though the shims then cut them flush after everything was done.
You may have noticed that the front two sections of the the trailer frame have additional 1x2's on the flat against the frame. This is for two recessed compartments that we are designing to give us some more storage!