SpudFiles

I am making a plunger for a shock pump and I boght som liquid hardener and I don't want to screw this thing up when you screw the top off of the bottle the place where there would be a hole is covered over with a disk of plastic it is bonded on. Do I just poke a hole in the disk of plastic? This may seem like a stupid question but I don't want to screw up the measurments.

Sounds like maybe it's the kind with two plungers (syringe looking tube)?

Usually there's a line on the plastic where to cut the tip off at with a razor or knife.
It's still a good idea to apply it onto a a flat surface and look at each side before mixing them to get the right ratio. 8)

That's not correct I must have exsplained it wrongly the little sqeezy bottle used with fiberglass resin It is called mek peroxide aka
methyl ethyl ketone peroxide.

Adding a pic would certainly help.
If you want to get it out, you'll probably have to make an hole.