Tips for working with plexi/acrylic
Common terms
- Plexiglass, Perspex, plex, plexi, acrylic, all refer to the same chemical compound (Polymethyl methacrylate - PMMA). wich hence forth in this document shall be refered to as plex or plexi. Another compound known as lexan has a simaler appearance to plex however may handle diffrently. this document is intended for use with PMMA based products only.
Please note these tips are a in my own words summery version from what i understand of what was said all over the net. A link will be at the bottom to some conversation about this
*******Cutting*********
i have heard success using the folowing :
Drimel - use the cutting wheel. typicaly you hear that you should use a low rpm to cut as a high rpm has more of a tendancy to melt (so they say). i have recently heard otherwise so if you have some scraps test out whatever way you prefer to see what suits you best. Drawbacks of using the drimel is that the cutting wheel on this device works like a very fine grind stone and thusly cuts by friction resulting in the plex getting very hot and melting a little so cut a little wide of your lines. also due to this abbrasion meathod the edges of your cut will be not very clear. very scratched up and a pain to polish.
jig saw - I have never used one for this but from what i hear you need to use a fine tooth hacksaw blade. the edges left over will likely be alot less rough then with the drimmel. from what i can tell with this cutting meathod you could potentially chip the surface of your peice when the blade retracts. so make sure its a sharp blade. beyond that you should be carefull of the vibration here as if your blade binds up it could cause cracking.
score and break - This meathod is exatly what it sounds like. you make a cut on the surface of the plex i would say 1/4 of the way through should be enough to make sure it stays on the lines you want. then put one side of the plex on something like a table and press on the side that remains hanging over to flex that cut open. doing this in a sharp and abrupt mannor should cause the plex to snap roughly allong the lines you have cut into it. this leaves a more clear edge (except for the little bit you cut).
hack saw - yes the tried and true old school meathod. works ok but if you have alot of curvs ... well lets just say its time consumeing. again make sure your blade is very sharp. has about the same finish as with the jig saw meathod.
scroll saw - like a band saw, except the blade isn't continuous. This allows you to do piercing work - like a custom fan grill. The blades can be incredibly thin.
**********Cleaning ,polishing, scratch removal**********
Cleaning - Plex has a very soft surface as it is just plastic. Unfortunately this lends itself to scratching easly. it is best to wash and then wipe if there is some dirt on it. rather then just wipe. DO NOT use alcohol based cleaners. i have heard that this can make the plex crack. personaly i just use soap and water with a very soft cloth. try to use a clean cloth to wipe it down with. if you use a dirty one you may find soemthing stuck to it may scratch the surface of your plex.
Scratch removal - lets say you do manage to scratch the surface area of your peice. dont dispare. you might could recover. apparently there is some products for plex that you can use to remove scratches and polish it back to being clear. They have diffrent numbers associated with them depending on what they do. Try using Novus #2 (scratch remover) then polish with novus #1(...polish..) for a perfect finish.
Novus#2(RED) is the scratch remover
Novus#1(blue) is the polish
check it out
http://www.tapplastics.com/shop/product.php?pid=113&
Polishing - Again you can use the same compounds as you did in the previous section. it also works on the edge peices too after some sanding. you need to use a very high grit sand paper to flatten out and smooth the edges over. i hear once you think your done with the sand paper that you can use toothpaste to give it an even nicer finish. or instead you can use the stuff from the previous section Novus #2 then polish with novus #1. There is another method to polish the edges. this is called flame polishing. this can be tricky so i strongly suggest trying it on scraps till you get the hang of it. essentually what it entails is using the heat from a flame (not the acctuall flame itself) to soften and melt the flat part of the edge and allow it to melt down into the scratches you made while cutting out your work. best tools for this seem to be propane torches butane torches, or any other device that does not have a yellow / orange flame (leaves icky carbon on your work). you want this flame to be controled so propane torch / butain torch is perfect. WARNING! do not use flame polishing on edges that you wish to join to something else. The melting process typicaly mildly deforms the edge so it is not flat anymore makeing it more diffuclt to glue and get a good seal.
********* Glueing and afixing your plex**********
Fixing to other plastics - if you are trying to stick some plex togeather to create a complex shape you will need something to glue it togeather properly. forget crazy glue guys. here is what you want to use. IPS Weld ON #4. there is also an IPS Weld ON #3 and it is fast drying. probably best to take the longer drying kind though. most likely it does a better job.
http://www.tapplastics.com/shop/product.php?pid=131&
fixing to wood - dont know whats the best for this if i find it iw will edit this document
fixing to metal - i have experimented with epoxy and it seemed to work ok to a particular extent. the problem seemed to be when the steel flex. plex is more rigid then the lite steel used on case sideings and thusly seems to break the bond to the steel when and if the steel tries to flex. perhaps the gauge of plex i used was too thick. i think it was 1/8 inch. anyways if you do decide to glue to steal its a good idea to sand the steal with rough sand paper as well as the area of plex that will acctually be glued. this allows the glue to get a better grip on both peices. again if you know something i dont ( and you most likely do ) please share with us and i will add it to this document.
Rivoting - if you need to rivot plex to lets say steel it is better if you can use aluminum rivots. they tend to not take as much pressure to crimp and snap the end off as steel rivots. this should prevent your work peice from cracking while you apply nessasary force to pop your pop rivots. also please remember that it is a good idea to not put rivots in on the very edge of your peice. good practice is to leave a healthy area between the edge of your plex and the hole you make to rivot. for example
if this is how thick your plex is | | then you should leave about this much space | | before putting a hole to rivot. this should ensure that you dont ruin your work at its last stages and have to start all over.
Bolts - lots and lots of diffrent shapes types and sizes here folks. find one that suits the look your trying to get best. Concider countersinking your holes so that the bolt heads dont stick out. the Benifit of bolting rather then glueing or rivoting is that your plex can be removed and washed if required. i supposed you could remove the other types mentioned here but it would only create alot more work for you (have fun drilling out those rivots and not scratching your plex). one remaining thing to say is that if the excess threads on the bold stick out alot you may want to concider marking them, removeing the bolt and cutting off the extra.
********Shapeing********
preform shapes - if you heat plex up it will become plyable enough to mold it onto diffrent shapes. probably the esiest way of doing this is with the element of your electric stove at home or other simaler device(space heater maybe?, basebord heater? heat gun? my fingers after typeing this much?). essentually try to keep the parts you want to bend warm to the point that they can bend fairly freely. i tried this for the first time last night so i am not an authority on it but it seems fairly easy. i heated up the plex by holding it over the element (not touching) untill it was somewhere between rigid and playdoh. keeping it at this state allows you to form your shapes without haveing to worry about the plastic drooping too much or getting bubbles in it. by heating it, while bending it should prevent little stress cracks that later could show up as little white lines. once its warm enough you can use other objects to help you mold the shape you want. be ware of heavly textured surfaces as i think that could imprint a pattern on the surface of your plex if its hot enough. Finaly, once you have accieved the desired shape you can dunk(if its small enough) your work in cool water to harden the plex again.
this about sums it up for now. i will likely be updateing this with any new info or experiances i come accross. if you see something that is in correct or have another / better way of doing something you see here feel free to comment. if you have a tip or a trick please try to make an obvious heading at the top of your post denoteing what it has to do with for example
****** glueing******
this way people can more quickly find the things that pertain to them.
thank you for your time
here is the link to the thread i found
http://www.twistedforums.com/forums/...hp/t-1354.html
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Originally Posted by jdbnsn
