Having a home gym is a convenient way to stay consistent with your workout routine, especially if your schedule makes it hard to make a daily run to the gym. But purchasing equipment for a home gym can be expensive, about $2 per pound.
That’s why we (my girlfriend and I) decided to build our own sets of 35, 45, and 65 pound concrete free weights. The weights turned out great, and I’ve been using them daily.
I did learn that shortening the grips of each set would make them easier to balance, and I’m also planning to coat each dumbbell end with more rubber sealant since some of the weights have crumbled slightly on some sections.
Also, I should have mixed the concrete more thoroughly because proper mixing means less cracking and crumbling down the road.
Overall, we spent $120 on the weights, not including the time we spent building them. The same set of premade weights goes for around $300, so we saved about $180.
Note: A list of materials, costs, and YouTube video influences will be listed at the bottom of this article.
Step One: Calculating Dimensions and Picking Materials
To avoid mistakes and ensure the dumbbells were the correct weight once finished, we used this handy online concrete calculator, specifically the circular slab or tube section.
Here are the calculations for one side of each set of weights:
Picking Handle Material
To mimic the grip size of a standard olympic barbell, which ranges between .98 inches and 1.26 inches, we decided to purchase a 1-inch-by-10-feet schedule 40 PVC pipe. This PVC has enough tensile strength to accommodate all of our weight sizes and can be manipulated with heat so we could attach galvanized spikes to help bind to the concrete on both ends of the weights.
Molds for Barbell Ends
To save money, we looked around the house to find plastic containers that could serve as molds for the ends of each weight, but nothing we found could provide the adequate dimensions for the barbells we wanted.
Instead, we purchased 8-inch-by-48-inch concrete mold tubes that could be easily measured and cut to our specifications based on the calculations above.
After watching similar YouTube concrete weight videos, we decided to insert ⅜-inch-by-6-inch galvanized steel spikes into the ends of each PVC cut, then stack ½-inch-by-6-inch rebar cuts on the spikes for extra reinforcement.
The type of concrete needed for this project must bind well and not easily crack or chip, so we decided to go with 80-pound bags of premixed fiber-reinforced concrete. The fiber reinforcement, along with the galvanized spikes and rebar, should make the barbells last longer.
Rubber coated barbells are the standard at most gyms. The rubber coating allows the weights to be dropped, offering protection to toes, ankles, and the floor. While our weights do not have the same rubber coating thickness of standard dumbbells, the rubber spray we selected will help keep the weights from chipping and degrading with daily use.
My beautiful girlfriend allowed me to use her garage space to construct the weights, and we wanted to make sure we weren’t staining walls or the concrete floor, so we purchased a 10 foot by 25 foot, 3.5 millimeter plastic sheet to act as a staging area for the project.
Now that we have covered the measurements and materials, let’s get started.
Step Two: Measuring and Cutting Rebar, Spikes, and PVC
To fit inside the concrete molds, we measured and made 6-inch cuts of the galvanized spike and rebar pieces. We used a miter saw with a steel cutting blade we already had in our toolbox. If you don’t have access to any cutting tools, most hardware stores will cut rebar for you. Call ahead to see if your local hardware store offers these services.
After that was completed, we measured sections for each weight set and used a standard blade to cut the PVC sections. (You can use a hacksaw for this part)
We intended to have 7-inch grips on each PVC cut, but we somehow muddled the measurements and ended up with 8-inch grips instead.
Step Three: Reinforcing the PVC Cuts
With the old eyeball method, we cut two holes on the ends of each PVC cut where we could insert the galvanized spikes and attach rebar for extra reinforcement.
Once the holes were drilled, we applied heat to each PVC end with a blowtorch and then inserted two spikes.
After the PVC cooled, we attached the rebar to the spikes using extra zip ties we had in our toolbox.
Step Four: Cutting the Molds
Using a tape measure, black marker, and rubber band, we measured the correct lengths for each barbell end and cut the cardboard mold using a boxcutter. The process took more time and forearm strength than we anticipated, and a hacksaw would have worked better.
Step Five: Mixing Concrete and Setting Molds
This part made us sweat, and it could have been far easier if we’d purchased a cheap drill mixing attachment. Instead, we mixed the fiber concrete in a five gallon bucket with a standard garden trowel. We added the concrete mix slowly to water, ensuring that it was the correct consistency.
If you’re not sure what consistency is needed, the concrete bags have specific mixing instructions printed. Next we placed the rebar and spike reinforced ends into their proper molds and filled them with concrete, tapping them to release air bubbles.We also used a tape measure and level to center the PVC in each mold.
After about 24 hours, we removed the concrete molds and set the other end of the reinforced PVC into the proper mold and propped them against the wall so they wouldn’t fall over while setting.
After removing the molds, we allowed the weights to cure for another 24 hours before I started the next step.
Step Six: Sealing Weights and Taping Grips
Using a rubber spray, we applied three coats to the concrete on each barbell, specifically the corners and edges that are prone to cracking and crumbling.
After the rubber coating had dried completely, we covered the handle grips with a few rolls of electrical tape we had lying around. This was a cheap and easy way to provide more grip during daily exercises, and can be reapplied anytime in the future.
What We Would Have Done Differently
We are pleased with the final result of our homemade dumbbells, but if we could somehow travel back in time, we would have made the handle grips smaller and applied more rubber coating to each end.
We can still buy and apply more rubber coating, so it’s not the end of the world, and we plan to use the weights on rubber matting so they don’t chip and crack when we set them down. The idea for the weight came from watching several YouTube videos, and it was fun creating our own design from materials found at any hardware store.
– 1 inch by 10 foot Schedule 40 PVC (1): $3.75
-11 ounce Plasti-Dip Spray Cans (4): $23.92
– ⅜ inch by 10 inch HP Galvanized Spikes (24): $16.32
– ½ inch by 10 foot Rebar (2): $13.94
-80 Pound Premixed Fiber Concrete Bags (4): $28.80
-8 inch by 48 inch Cardboard Concrete Molds: $22.80
-HDX 3.5 millimeter 10 foot by 25 foot Plastic Sheet (1): $10.98