I’m a big fan of the Grip-it fixings, they are great for supporting large weights on plaster-board walls. And I’ve successfully used them for installing cupboard shelving.
But when I tried to suspend a boxing punch bag, the dynamic load just caused them to pull out the wall. I suspect using a wooden board or battens to spread the load might of worked but in the end we just returned the punch bag as we didn’t have any suitable walls to attach it.
So I was left with some large holes in the wall to fill. Trying to fill these with just filler is possible but needs lots of filler and takes many days as you have to build it up in thinner layers, slowly making the hole smaller and shallower.
To solve this problem, I designed some plugs to go in the holes.
The diameter of the cylinder is the same size as the hole with the spline sticking out a further 1mm. The width of the spline is also 1mm.
Once the plugs were installed the holes were filled with a thin layer of filler which can be sanded down for a smooth surface.