I started with harbor freight #42708 - 870 Lb. Capacity Utility Trailer, 40" x 49". It was $219.99 and with a coupon I got it shipped to my door for around $160. In addition to the trailer kit here is what I used for this project –
10’ 11ga 2” square tube
14’ 1/8” 2” angle iron
2 6’ pieces of 1.25”od round tube
4x8 sheet of 1/2” treated plywood
2 12’ 5/4” deck boards
2 8’ 5/4” beck boards
4 10’ 2x4s for bunks
7 eye bolts for tie downs
6’ wire for harness extension
Front braces are 3/4” steel bar that was already bent that I got from a scrap pile
For those who don’t know the above picture is what the manufacture intended it to look like.
First I started by assembling the kit to have a starting point, make sure you square the basic frame and check several times while you tighten since the entire build is based off this. After you are happy with this point throw away the instructions because now the fun begins!
I wanted to add a brace to connect the tongue directly to the spring hangers so I added this. It is a piece of the 2” angel iron lined up with the front spring holes. I turned the frame around so the axle centerline would be farther forward since I will be extending the front. This will make weight distribution better and be easier to pull and track better.
Now grind off all the powder coat on the joints then some welding. I wanted a longer bed to haul all my camping gear and coolers so added some extensions. These are 2’L each and are made from the angle iron. This will make the bed 6' long. Tacked everything in place ready to square, used the original tongue for the front brace since I won’t be using it for its intended purpose. I then Burned everything in and hit the welds with primer, I welded all connections together including the spring hangers to the brace I added and the rear hangers to the frame.
Tongue bolted with grade 8 bolts and welded on, if it is worth doing it is worth overdoing. Started welding all metal to metal connections but I ran out of welding wire so this is a good stopping point and hit with a light coat of primer to protect from rust until I can finish
Day 3 started with a trip to tractor supply to get some welding wire then I figured I would do a little cosmetic work filling all the holes I'm not going to use. This is optional but I wanted it to look good
Now it's time to put the front upright on using some scrap I had laying around, Bolted on with grade 8 and then welded. Also added a sleeve over the tongue to beef up where all the weight will be (this is optional but it was scrap I had so might as well use)
Okay, let’s get this thing finished
More grinding, sanding and priming and welded on front uprights. Let the primer cure for a few hours and time to start paint.
Bottom primed and painted, I hit this with oil based black for the best protection. Shot this paint everywhere that won’t be color (places you don’t see)
Now to work on the top side, shot everything that will be blue with a base coat of metallic silver to really make the blue bright
I put 3 coats of blue on and 2 of clear.
Coupler on with grade 8 bolts, added front eye bolt tie down and starting wiring
Now time for the floor
Got carried away and didn't take any of side rail and axle installation but it is pretty straight forward (might have to refer to instructions for axle setup) here is the kids enjoying the "almost" finished product, we run up and down the road several times to seat the bearings.
Total price is $363. And it weighs right less than 350lbs
Here is the finished product all loaded up, I have three kayaks on here (my daughters 6’ sits in the bed) a grill, firewood, tent and other camping stuff loaded.
I am very happy with how this project turned out. I pull it with my 4cyl escape and have had it to 70mph+ on the interstate with no problems. Since it is so light weight I can hardly feel it behind the car, and I have less invested than most put into converting a jetski trailer and everything is new. The only thing I might change is making the bunks moveable so I can put 3 full size yaks on top.