Lacrosse Rebounder

My son wanted a lacrosse rebounder for practice, but when we asked around, we discovered they were very pricey and had mediocre performance. I looked around for ideas and found a few, but didn't like the execution, so I decided to make one that would be durable, mobile and fairly easy to construct. My son wanted a large surface so that he can come up with some target designs for the face (still to come). It's 6 1/2 feet (78") tall and ~4 feet (48") wide. The rebounder surface is 48"x48". He's loving it!

1 sheet 48"x96"x1/2" exterior plywood (try to get the flattest sheet you can with at least one good side--minimal blemishes or holes)

5 pieces 2"x2"x96" exterior pressure treated lumber (aka green lumber)

2 tubes exterior construction adhesive (I used Loctite Heavy Duty, but see what's available. You might want 3 tubes, but 2 tubes was sufficient)

Wood glue (I used the exterior wood glue on the leg cross braces because I ran out of construction adhesive)

1 box 2" exterior decking screws

2 pieces 5/16" or 3/8" x 4" galvanized carriage bolts, with 2 nuts, and 6 washers (the extra washers is to place 2 washers at the joint where the wooden legs would fold)

~1/3rd gallon exterior house paint (I chose white latex paint because we had a can in the basement)

Clamps (or weights or screws or all three, which is what I did. Make sure you have a flat surface to place the plywood on when you glue the 48"x48" pieces together because you want the rebounder as flat as possible)

Jigsaw with wood blade (Optional, but then you'll really need to sand the plywood corners and top of the back leg (see step 5))

Drill with drill bits and countersink bit

1 pint can Bondo All Purpose Putty (optional step to fill the screw holes after the clamping process if you used screws. You can use wood putty or just forget this step)(I like to use Bondo because it dries in a few minutes and you can sand it after about 15 minutes. It works a lot better than wood putty). You'll also need a putty knife and a throwaway flat piece of wood to mix the Bondo and the activator.

Sandpaper (I used a 1/3rd sheet electric finishing sander to speed the sanding process along)

When selecting the plywood, make sure you have a fairly clean side (reasonably smooth and with minimal holes/blemishes) to be the front of the rebounder. Cut the plywood in half to make two 48" x 48" pieces. It would be easier to have it done in the lumber yard if they do that; otherwise, you'll have to do it yourself. You need to be a stickler to make sure the pieces are as close as identical sized as possible to minimize the sanding later.

Make sure the clean sides are facing out on either side and align the pieces so that you know the orientation of how you want to glue them (I marked a corner on both sheets just in case). Then cut the nib of the construction adhesive about 3/8". I put a a crisscross pattern and then beads along the edge and in the other areas (see picture), but you decide how you want to glue the pieces (squiggly lines, straight lines, dots, etc...). One thing to be careful about is making sure is that you minimize gaps between the pieces.

Align the pieces together and clamp them. I used weights as well as clamps and then decided to put some screws in to secure the two plywood pieces to minimize air gaps.

After the requisite time has passed (check the construction adhesive curing time, which for me was 24 hours), then unclamp and sand the edges so that you won't get splinters later when you move it around. You might want to round the corners, which I did by using the paint can bottom to trace a curve at the 4 corners of the plywood. I then used a jig saw to cut the rounded corners. Sand them down.

I used Bondo at this point to fill in the various screw holes I made in the clamping process. I also used it to fill in any voids in the plywood edges. When using Bondo, only mix a small amount at a time because you'll only have about 3 minutes to mix and work with it as it hardens quickly (which is pretty awesome). Try not to make a mess with the Bondo because you'll have to sand it down (so start small and build if needed). Make sure you have ventilation in the area you are working because Bondo emits a lot of fumes, but it works great and is very hard (heck, they use it in car body work).

Sand things down to your satisfaction. I used a 1/3 sheet finishing sander with medium sandpaper.

Clean the surface of any debris or dust/dust and then paint it. I did 2 coats of paint on each side and 3 coats along the edges. This takes about a day because of the drying time.

I made the rebounder 6 1/2' (78") tall based on my son's size and in discussions with him. So the two front legs were cut 78" and the two back legs were about 4" shorter because I didn't like the look of the knots in the wood. I then made sure the back legs protruded 6" beyond the front legs, and marked off on the front legs where I needed to drill the holes (so the hinged part wasn't at the tippy top, but rather about 10" below the front top part of the legs (which would be behind the rebounder).

Because the top of the back legs would be behind the rebounder and needs to swivel out, I rounded one side of the top that faces the back of the rebounder or else the top of the back legs will dig into the back of the rebounder (see picture)

Make sure to align the legs and drill the holes for the carriage screws. Try to get this on center. For the back legs, think about how the legs will swivel out and drill the hole accordingly. Once you drill the rounded back leg, align the leg with front leg, clamp it and use the drill hole to drill the front leg hole for the carriage screw.

Position the plywood side that would be the rebounder surface facing up on the workbench and then marked off the centerline 6" from the two edges on either side where the front leg would be screwed in. Mark off 5 places where you intend to drill and screw the rebounder to the front legs (I made sure I placed a screw 2" from either edge; the other 3 screws were evenly placed along the centerline). Position the front legs underneath the plywood (you'll need to elevate the plywood) and make sure the carriage bolt screw holes are appropriately positioned (parallel to the plywood sheet). Drill and then screw in the deck screws (you might be tempted to use glue at this time, but resist that temptation because you might later want to make the rebounder higher or lower and gluing it would make this latter action very frustrating). Repeat for the other front leg.

Align the back legs (inside) to the front legs (be mindful of the curved top part should be facing towards the back of the rebounder) and then put the carriage bolt in, put two washers where the legs would hinge, and then a washer where the bolt screw end protrudes and screw the nut on. It might help to use a hammer to push the bolt through the holes. Tighten the pieces so that the square part of carriage bolt head securely bites into the side of the front leg. Repeat on the other side (see picture).

Measure the front and back leg span and cut two cross pieces of 2"x2" wood to secure each set of legs. This is an optional step but I think it adds stability to the rebounder. Predrill the holes and countersink them (which will avoid cracking the wood legs since the screw would be near an edge). Apply the exterior wood glue (or exterior construction adhesive if you have any left) and screw the pieces together. Notice the placement of the front and back stabilizer cross pieces in the picture.

You might want to touch up the front of the rebounder with some paint to hide the screw heads and the two penciled centerlines.

I was considering a chain on one or both sides (with appropriate hardware) of the legs to prevent the legs from sliding and provide potential demarcations (with a sharpie pen) so that the desired angle of the rebounder face remains static even if we move it. Since the rebounder is going into the backyard, the dirt is soft enough to secure the legs from sliding, so I'm not seeing a need to do this but you might want to do it if you have the rebounder on a hard surface.

My son is considering some target patterns to draw/paint on the rebounder, so that's another project once he decides.