I started with a feasibility study of making a clamp from PVC pipe here: https://www.instructables.com/id/DIY-PVC-Clamp/
When I published that I'ble, I found there were other Instructables about PVC clamps, but they all required 2 hands to use the clamps. That's not always an easy option, since your other hand is holding the pieces you want clamped.
This is my third version, and it only requires 1 hand to use. Let me show you how it's made.
Step 1: TOOLS & SUPPLIES
Hack saw, Sawzall, or chopsaw
1/8" & 3/8" bit
Large bench vise
4" PVC pipe 1.25" long with 1/4" wall thickness
2 - 3/8" steel rods 7" long or longer
Epoxy or equivalent to secure 3/8" rods in holes (may be necessary if the holes are a little too big)
Step 2: CUT PIPE
Cut the 4" PVC pipe into a 1.25" band. I used a chop saw.
Step 3: CUT SLOT IN BAND
You can use a hack saw or Sawzall. I used an air reciprocating saw.
I have some 1/8" rotary blade air saws, but I wanted a really narrow "cut" (AKA the "center").
Step 4: DRILL HOLES IN THE BAND
I measured 1" from the center and drilled a pilot hole with a 1/8" bit. I then measured 4.5" from the center and drilled another pilot hole. I repeated this on the other side of the center. I now had 4 pilot holes.
I tightened the band in the vise, aligning the pilot holes drilled on one side of center with the top of the vise. OK, that's rather confusing, but I needed to align the hole drilled !" from center with the hole drilled 4.5" from center, so I could insert one rod for a handle.
I then drilled through both holes with a long 3/8" bit. I repeated this on the other side for the other rod. No bolts, no rivets, no pop rivets......and the rods are strong.
Step 5: FINISHED
I put a tape in the first photo for perspective on size.
2nd photo shows some metal to be clamped.
Last shows pieces clamped together.
This clamp is quiet strong, but can still be opened with one hand.
If you have any questions, just ask in comments.
Step 6: MAKE THEM STRONGER
I found I could add 2 - 1/2" bands to increase the clamping power of the clamps. This 2" clamp now has more holding power than a 4" clamp.