Interesting plastic drilling

[GrahamRounce]

Interesting? A disc of perspex, 8mm thick. I drilled a 2mm hole all the way through, then a shallow 3.5mm one for the screw head. Put a drop of superglue into the bigger hole and pushed the screw through so it sat flush.
Then noticed all the junk that seems to have penetrated and spread into the perspex itself! Note especially the hair-fine slivers apparently floating several mm into the bulk! Any ideas?

 

[Lons]

Hi Graham

Drilling acrylic (it will be cast acrylic at that thickness) is never a clean hole as it slightly fractures as it cuts, normally not a problem but putting superglue into it affects the acrylic and penetrates the cracks. Superglue also turns white in that situation and I'd suggest the brown marks are from residue off the drill bit and or screw if you inserted that while the glue was wet..

You shouldn't really use superglue on acrylic unless it's one of the specialised varieties as it reacts chemically and weakens it.

 

[niall Y]

Hmm .... I used to work with Perspex, but in the days before superglue. In this instance I would have drilled , threaded and countersunk. the screw .
The problem is obviously the superglue which is a form of Acrylic itself, though it doesn't seem to have reacted very well with the Perspex disc. You might have done better with "Tensol" with some Perspex swarf dissolved into it
I am far from being an expert on the chemistry of Perspex, but I seem to recall that flat sheet - as opposed to components like thin tubes, have slightly different formulas. They certainly smelt different when you cut into them, with the tube having that rather unpleasant smell that is more akin to superglue.

 

[Vulcan]

You have to work with what you’ve got but I always avoid Acrylic. PETG is much nicer to work wit.

 

[GrahamRounce]

I should have said there could have been (apparently was) crud on the drill and also the wood supporting it while drilling.

It's the way tiny pieces have migrated into the perspex - or you think those are fractures, not pieces? But "floating", disconnected ones?

PPS, I'm not complaining, it's not a problem. I'm just curious.