Acrylic is widely known as Perspex (tm). Sold mainly as a clear glazing sheet, it must be worked correctly to avoid cracking and breaking.
Acrylic is much cheaper than twinwall polycarbonate, and looks very like ordinary glass, but lacks twinwall's insulation.
Acrylic is also available in colours, though not from diy [[suppliers]].
==Common uses=*Secondary [[glazing]] *[[Shed]] glazing *Tanks for fish & vivariums *Display cases, racks, stands etc *Gardening bells *Decorative [[lighting]] with [[LED]]s
==Thickness=4mm is rigid, and suitable for secondary glazing, shed glazing, tanks, stands etc. Its not recommended for use as the sole layer of domestic glazing, as it melts & burns in a [[fire]].
2mm isn't fully rigid. Its usable for shed windows, but less secure than 4mm. It can be used in a frame as secondary glazing for little windows, but doesn't give the [[noise]] reduction of heavier stiffer glazing. 2mm can be used where it won't lie entirely flat, such as non- frame type shed windows, and mildly curved applications. Curving increases rigidity.
Acrylic provides less [[noise]] reduction than the same thickness of glass, due to lower rigidity and less weight.
=úilure=Acrylic is much more able to survive stray footballs, bricks etc than glass. Acrylic goods are more likely to survive falls than glass.
Cloudiness occurs eventually.
Acrylic scratches & clouds if rubbed repeatedly. This includes [[cleaning]] with unsuitable materials, such as scourers.
It melts readily in [[fire]], creating a [[security]] issue when used as the only layer of [[glazing]].
==Cutting=Breaking and cracking often happens due to wrong cutting technique. The usual problem is basically applying too much force, or using a [[saw]] with too coarse teeth.
There are several effective ways to cut it, including: # Score and snap. Fast, but a little risk of it going wrong. # Electric [[saw]] - always take it easy, don't use a coarse blade, and remove the blade from the work as soon as it stops # Hand sawing - Use a fine tooth blade and be gentle-ish. # [[Die grinder]] - use a small flat abrasive wheel to melt your way along. # Hot wire cutter
Sawblades should have at least 3 teeth in the work at any one time.
==Drilling=Use a regular [[Drill bit|twist bit]], don't push much, and keep speed moderate. Be gentle when the bit breaks out.
Its also possible to make holes with a small pointed grindstone in a [[die grinder]]. These just melt through. Withdraw the stone as soon as it goes through, or it won't then withdraw.
If you work with acrylic more than just occasionally, its worth regrinding a [[drill bit] or two to zero rake angle.
==Machining=The same basic principles apply to all types of machining. Use [[tool]]s with nonaggressive cutting angles, keep pressure low, speed moderate, and avoid vibration.
=íge finishing=Edges can be filed, sanded, or routed gently. Once suitably shaped, the simplest way to get a good finish is to wipe once with acetone. This restores shine. Don't wipe it a 2nd time, the plastic goes temporarily gooey.
==Gluing=Acetone or cellulose thinners dissolve acrylic. Solvent can often be used alone. Dissolve some shavings in the solvent for a quick drying [[glue]].
=¾nding=Boiling [[water]] softens the [[plastic]] for bending.
==Refinishing= If the surface is scratched or cloudy, either grind & polish, or wipe once with acetone.
==Safety=Acrylic has no specific safety issues, other than melting and flammability in a fire, which limits its use as [[glazing]].
Acetone is highly volatile, expolsively flammable and mildly toxic. It has a habit of the vapour igniting from distant flame, which then flashes back to the acetone container. Hazards are addressed [http:// www.jmloveridge.com/cosh/Acetone.pdf here (MSDS)].