Test Fit and Assembly
Table of Contents
With pan head screws, assemble the form using the layout lines as a guide. Check that everything is square, fits tight, and there are no gaps.
If there are any variations with each assembly, you may need to try different part combinations to see what fits together best.
I apply several coats of Polyurethane Finish, lightly sanding between coats.
I used four coats of this durable flooring finish. Wet cement is very corrosive so you want to protect the wood to get the most life from your concrete forms.
Pipes and Wire
Cut the PVC conduit down to length.
Cut a section of Concrete Reinforcing Mesh to size with small bolt cutters and have it ready to lay in the wet cement.
This will make the concrete panels very strong.
This is where I remembered that not all 3/4″ plywood is fully 3/4″ thick. Most is now slightly undersized and I laid out the parts for actual 3/4″ plywood. It’s an easy fix by adding a few slim shims.
Once assembled, the molds need to be made water tight. I use a small bead of Latex Caulking to do this.
Latex works well as it’s not overly strong and will allow you to disassemble the mold easily once the concrete sets up. Don’t use regular silicone for this. It’s too strong and will be difficult to remove later. Latex caulk is all that’s needed.
Place the moulds on a strong and secure surface and level them in both directions.
Once the caulking is dry, spray the mould with a releasing agent to keep the concrete from sticking. I used Vegetable Oil Cooking Spray for this.
UPDATE: Cover the pipe and pipe wrap wire with a cloth to keep the oil spray away from it during this step.