Suppressing Stains on Light coloured Perspex
Posted: Thu Jul 19, 2018 3:36 pm
Hello All,
I've been looking into improving the quality of my cuts for perspex jewellery. Sure, I can get a nice cut quality, with a 60W tube on 75% power, at about 20mm/sec, but on light coloured perspex there's staining on interior angles where a hole is cut out. There's no staining on the convex side of a cut - the stain only sits on the interior acute angle.
This is a very, very picky thing - on most perspex you just won't notice - but look at a white, cream or yellow, and you can see slight discolouration. This doesn't really matter, except with jewellery, where it has to be PERFECT.
I have tested a huge array of chemicals, including acids and bases, solvents and soaps to try to remove this discolouration, to no avail. It does seem that the perspex is chemically changed and the stain is embedded.
I've also fitted a bigger air pump (with double the flow rate). More air equals less stain? While it may make the issue a little better, it doesn't definitively solve it.
Other strategies I've tried include thoroughly cleaning the bed before cutting perspex. This doesn't seem to help. (How about soaking in a bath of 10% sodium metasilicate cleaner overnight, then pressure washing for 10 minutes, then repeating the whole soak, wait, pressure wash process with new cleaner. Did I say clean?)
And how about this - suspending the perspex to be cut 30mm above the bed by balancing it on spacers. Surely, that'll help? Maybe a bit - but not enough.
There's only one strategy I've found that works, and I don't like it. Slow the cut RIGHT DOWN (1mm/sec) and turn the power down as low as I can get away with to get a convincing cut (35%?). This produces beautiful results, but far too slowly for my liking.
Any advice? I was wondering whether there are other settings (tube frequency perhaps?) that might avoid this problem. Or perhaps sodium metasilicate is EXACTLY the wrong choice of cleaner. Or maybe... I don't know! Double cutting perhaps? First time to cut, second time to clean?
All the best,
James
I've been looking into improving the quality of my cuts for perspex jewellery. Sure, I can get a nice cut quality, with a 60W tube on 75% power, at about 20mm/sec, but on light coloured perspex there's staining on interior angles where a hole is cut out. There's no staining on the convex side of a cut - the stain only sits on the interior acute angle.
This is a very, very picky thing - on most perspex you just won't notice - but look at a white, cream or yellow, and you can see slight discolouration. This doesn't really matter, except with jewellery, where it has to be PERFECT.
I have tested a huge array of chemicals, including acids and bases, solvents and soaps to try to remove this discolouration, to no avail. It does seem that the perspex is chemically changed and the stain is embedded.
I've also fitted a bigger air pump (with double the flow rate). More air equals less stain? While it may make the issue a little better, it doesn't definitively solve it.
Other strategies I've tried include thoroughly cleaning the bed before cutting perspex. This doesn't seem to help. (How about soaking in a bath of 10% sodium metasilicate cleaner overnight, then pressure washing for 10 minutes, then repeating the whole soak, wait, pressure wash process with new cleaner. Did I say clean?)
And how about this - suspending the perspex to be cut 30mm above the bed by balancing it on spacers. Surely, that'll help? Maybe a bit - but not enough.
There's only one strategy I've found that works, and I don't like it. Slow the cut RIGHT DOWN (1mm/sec) and turn the power down as low as I can get away with to get a convincing cut (35%?). This produces beautiful results, but far too slowly for my liking.
Any advice? I was wondering whether there are other settings (tube frequency perhaps?) that might avoid this problem. Or perhaps sodium metasilicate is EXACTLY the wrong choice of cleaner. Or maybe... I don't know! Double cutting perhaps? First time to cut, second time to clean?
All the best,
James