Check this out! Initially, my idea was to build a cement base for a patio umbrella, but it was so easy that I decided to make a set of two weights. Never having much time to travel to a gym, I prefer to workout at home. But during the summertime, it's just too dang nice to not get some exercise outdoors.
-2x6 lumber for the form/mold (Old deck boards were used for mine). You might note in the picture that they are pressure treated but this isn't necessary, do whatever is cheapest/easiest.
-Plywood- any scrap will do as this will be used for the base of the form
-Ratchet strap (maybe not necessary)
-Cement (80lb bag of quikcrete was used in my case)- If you're creative, loads of websites offer various dyes you can add to wet cement to give it some flare.
-2" PVC pipe (or smaller to match a different bar)
-bar/pipe (I used a 2" galvanized pipe- I believe it was an old steam pipe, this is very close to what the 'olympic style' weights will fit. If you can't scavenge something this may be a bit pricey as I've heard a 5 foot section of 2" steel pipe will run upwards of $50.
Step 1: Build the Form
I wanted hexagonal weights so I took my 2x6 lumber and cut it into 6 sections with a 30 degree miter on each end. It's important that they are all the same length, so set up a guide or jig so that everything is uniform. I'm not a mathematician and the person who described the angle to me went over my head, here's a picture that might help?
*Note the interior side of each hexagonal piece is 11" long
-Next, put the pieces together.Regular old 2" wood screws were used in my case. I carefully matched all the ends together to give me a pretty decent hexagonal shape. Once everything was screwed in place, I also used a ratchet strap to tighten everything up. I left the strap in place throughout the pouring process and was just careful not to make a mess/potentially ruin the strap. I'm not sure this was entirely necessary, but I didn't want my form to fall apart mid pour.
-Next I used a piece of scrap plywood, traced the shape of the sides, cut it out and screwed it to the bottom of the form/mold.
Step 2: Pour the Concrete!
Placing the form somewhere level, that won't have huge issues with any mess of concrete, get ready for the cement pouring process. I first cut some wire mesh to fit the interior of the hexagon and ideally prevent cracking. Then take your 2" PVC and place it in the middle of the mold. To find the center, I ran 3 strings across the middle and where they intersected I put the pipe in place.
-Now your ready to mix the concrete. For simplicity sake, I didn't want to weigh designated amounts out so I just used a whole 80lb bag for each weight. I think some stores also sell 60lb (Same type as 80lb bag, just easier to manage) bags and 50lb (Fast curing) bags. I mixed it all up with a bit of water and a wheelbarrow, then slowly began to fill the mold, starting around the PVC pipe first. Once I had about an inch of cement in the bottom, I placed the wire mesh in and finished filling the mold. This was really a bit of trial an error, in general it seems like concrete should be at least 2" thick to prevent cracking, so if you use less mix you might want a smaller form.
-Once the mold is filled, tape the edged gently with a hammer to get out excess air bubbles and fill any voids around the edge. This isn't super critical but it might make cleaner edges.
*Note: I didn't caulk the seams of the form just because I didn't know how difficult it would be to get the concrete out without taking the mold apart. I wanted to be able to just flip it over and dump it, but in the event that I would have to take the whole thing apart, I didn't want to have to go to the trouble of re-caulking everything. This worked fine for me.
-A few hours after you pour, use a nail or stick to write the weight in the surface of the wet concrete. Then let it sit covered for a day or two.
Step 3: Remove From Form
I loosened the ratchet strap and flipped the form over on the grass and knocked it a bit to get the weight out. I cut the PVC so that it was flush with the cement and added a bit of silicone caulk to the seam to keep it in place.
Step 4: Repeat the Process...
Repeat the process to get the next weight finished...
Step 5: Lift Your Weights! But BE SAFE!
I think making the weights 80lb was a bit ambitious. Lifting on a level surface in a gym/weight room with nicely contoured and gripped weights with nice racks is totally different then heaving concrete in your yard. Please be safe and listen to what your body is telling you! Also make sure your base is stable, I think uneven dirt is a bit uneasy to lift heavy on. I think this set may be retired to the garden as stepping stones/permanent umbrella stands in exchange for a 60lb set.
I used some hose clamps to make sort of a weight 'stop' and prevent them from sliding inwards. The fit isn't as tight as the olympic type weights, so I tried a second set of hose clamps to keep them from moving outward, but it seemed a bit cumbersome to go through that process every time i used them. I tried to smear some caulk around the bar to make the weights fit a bit tighter and that actually worked quite well. I can't verify the strength of the weights or the pipes so I tend to avoid lifting it above/over myself (ie. overhead press, etc.), the 2" bar is great for deadlifting and really works your forearms like crazy. Plus, the ability to exercise outside/leave the weights outside without ruining everything is nice in the summer time!