How much pulling force will this plug withstand in gypsum bricks?

Question

I have these plugs that I mounted on a 70 mm (2.5”) thick gypsum brick wall.

The goal is to mount a rail for hanging coats. I have the sizes and I can calculate the required pull-weight, but I don't know how much the plugs can withstand before being pulled out of the wall (the force applied is axial to the plug).

The plugs are 31 mm (1.25”) long, diameter 5 mm (3/16”) (the same of the hole I made). I used a screw 40 mm (1.5”) long with diameter 3,5 mm (1/8” or #6) as recommended by the manufacturer ("3-4 mm"). The hole was well cleaned from the dust before applying the plug.

How much pulling force can these plug withstand? should I use longer plugs and screws? like 50 mm (2”) long, same 5 mm (3/16”) diameter.

The plugs: TOX. In the PDF (page 3 and 4) I see various materials, but I don't know which one is equivalent to gypsum bricks.

The geometry. As you can see, the lower plugs (there are multiple ones) act as the fulcrum of a lever, resulting in a pulling force applied to the upper plugs. This is why I need to know only the force to pull out the plugs, not the force parallel to the wall.

Answer 1

Is it really worth engineering a coat rack as if you're building a bridge?

Do this as an experiment. Choose a spot that will be behind the coat rack but not where you'll put an anchor. Install one of the anchors, screw in the screw, and see if you can get it out with a medium pull on a claw hammer. (Put a scrap of wood between the wall and the hammer so you don't damage the wall.) If you can pull it out without a lot of force, use a stronger anchor.

My guess - in soft gypsum brick, you'll want something longer.

Answer 2

exact strength depends on the construction of the wall and correct installation procedure.

What strength does the maker promise?

data on the bricks says strength is under 6 kN which seems pretty soft