Cutting Acrylic

[Baldhead]

I need to cut some 3mm Acrylic sheet for a jig I'm making, will it be ok to cut it with a fine jig saw blade?

Stew

 

[Steve Maskery]

It should be, yes. If you are not getting a clean cut though, you could sandwich it between a couple of pieces of MDF (with your pattern stuck to the MDF, obviously).
But it might actually be easier and quicker to do it by hand. If all the lines are straight, and hacksaw or dovetail saw would do, if it is curved, a coping saw or fret saw.
S

 

[wcndave]

I've cut with table saw, bandsaw, track saw, jig saw, and for the best finish, a router. All worked well.

 

[Billy Flitch]

Stew I just looked up the name acrylic and it also comes out as plexy glass if you cut it with a jig saw you must cut it on a slow speed other wise it welds itself back together behind the cut damhikt I found that a Formica cutter will work well on short pieces. the Formica cutter looks just like a bent nail with a carbide tip hope this helps.

 

[AndyT]

The main problem is that if you go fast enough to build up heat, the acrylic can weld itself to the hot blade, which is why a hand tool is probably the way to go.

As a schoolkid I had a weekend job in a plastics factory. I still remember the most boring days of my life were when I was set to drilling hundreds of holes into sheet acrylic. It was essential to go slowly or else the drill would be welded in place and then snapped.

 

[Baldhead]

Thanks for the replies guys, i wasn't sure if it would shatter when cutting with a jigsaw, fine blade and go slowly seems to be the order of the day.

Stew

 

[Steve Maskery]

Yes, exactly right.

 

[Paul Chapman]

If the edges will be straight, cut it roughly to size then plane it with a finely set block plane.

Cheers :wink:

Paul

 

[Steve Maskery]

Yes, but be prepared to re-sharpen every 5 or 6 strokes, and I am not exaggerating. You will notice the difference in cut between stroke 1 and stroke 2, let alone 1 and 5.

 

[Baldhead]

Thanks again guys, I think on this ocassions I'll use sandpaper, I hate sharpening!

Stew

 

[woodpig]

Acrylic is one of the most brittle plastics and easily broken if you're not careful. It's not a plastic I'd use by choice unless it was free and even then... If you need a clear plastic have a look at Polycarbonate or PETG next time, not as scratch resistant but very much tougher.

 

[oddsocks]

I've got to cut some expensive splashbacks (source is Akril but rebranded by Wren kitchens to 'Tekglaze') next week and akril customer service has recommended specific tooth profiles (the festool blade is the 'special' one that I found for just over £50 (best price) ). For jigsaws they recommended dedicated acrylic blades so I've bought these..http://www.ebay.co.uk/itm/BOSCH-T101A-S ... 1776759313

The also advise using blunt drills for holes to avoid grabbing and shattering the acrylic.

I've not done any of this yet, but at £400 a sheet (kitchen suppier retail price) I have invested in minimising my risk. I did actually negotiate all the splashbacks for free, but will need to buy any replacements.

 

[Lons]

Hey Stew
Just seen your post so you've probably cut it now.
As you know my background was in plastics and as main distributors we provided a cut to size service as well as full sheets of ICI Perspex and GE Lexan polycarbonate as well as styrene, pvc and dozens of other types of semi finished plastic sheet.
For straight cuts,a 64 tooth neg rake blade on a table saw or wall saw produced a decent edge though 3mm acrylic is easy to score and snap if you're brave enough. I wouldn't' plane the edge either, just use a fine flat file but watch your fingers as acrylic is sharp
Jigsaw no problem with a medium to fine blade cut slowly, in my experience a metal blade cuts too slowly and produces to much heat for acrylic. Except for tablesaw, 3mm should definitely be supported with ply or similar or you risk fractures. Can also cut with a bandsaw or scrollsaw. I've used all of these methods and still do! Routing gives the best off the tool finish but a faff imo.
Drilling also no problem as long as you take care as it breaks through, I've drilled hundreds and never had a fracture. If the acrylic is clamped flat or ideally sandwiched it won't flex and ride up the drill bit which is the cause of the fracture. Not sure about the blunt bit idea as I've only ever used sharp bits which cut rather than melt their way through.
Hole saws or router for larger holes. Forster bits ok but flat its don't work well. There are guidelines for drilling close to edges, from memory about 12mm but I've drilled much closer!

And... As suggested, polycarbonate is more forgiving.

If you're having problems with it, give me a ring.
Cheers
Bob

 

[marcros]

I was advised to score and snap when I had a bit to cut.

 

[zodiac]

I was advised to score and snap when I had a bit to cut.

for thin stuff I've always believe this will work. I've got some 1.5, 2 and 3mm and it's what i'd try, otherwise slow speed with blade or bit sounds sensible !

 

[Distinterior]

I've cut plenty of Lustrolite, which is an acrylic sheet material, 4mm thick. I use it for full height splashbacks in kitchens and shower cubicles.

All the cutting to size was done with a Festool TS55 and rail on a sacrificial board (an absolute necessity IMHO).

The blade I use is also a Festool one, their "Special" blade, specifically for plastics & aluminium.

 

[oddsocks]

Distinterior - do you just use a sacrifical board underneath the acrylic or did you sandwich it? Also what did you use (e.g 6mm mdf, ply, shuttering etc?). I've not yet cut my Akril (unplanned family events keep taking the weekends!) but also part of the reason is they are 3.6m long so I need good weather to do it outside and thought I'd need to make a full length support first.
Did you let the saw cut right through the sacrificial lower board or just into it?

Thanks

Dave

 

[wcndave]

I cut some today for jigs for drawer handles. Table saw did great job, on cross cut sledge. Then router for slots. Plunge and go with a board underneath, only went an eighth into that. U would say sandwich not necessary

I filed the sharp edges however for a great edge a router is the way, just taking a tiny bit of table saw cut.

I've also cut with bandsaw no problem, no special tools, it's only getting a nice finish that needed some effort and thought.

 

[oddsocks]

thanks for that Dave - hopefully I'll cut mine next weekend using your technique (but with festool rail rather than tablesaw due to the 3.6m lengths)

 

[Eric The Viking]

I've had the weld-behind-the-blade thing happen in the past, on a motorcycle windscreen (which was expensive!). Hand tools are the way to go, and sand, don't attempt to plane.

Decades ago, I had a summer job in a light engineering factory. We made a lot of small parts - scales, verniers, etc. - from Perspex (= Plexiglas = acrylic). We always finished the edges with a slow-running linisher (belt sander). You can get a really good finish by ending the sanding with Jif-type cream cleaner, followed, if necessary, by toothpaste. There's also some special polish called Novus which you can find on eBay.

You can theoretically melt the edges to be smooth by running a blowlamp along, but use a butane one as it's cooler, and don't hesitate anywhere. I struggle to make this work well though. I'd guess you might try a domestic iron and greaseproof paper, but it might not be hot enough. There's a very fine line between melting and burning the stuff.

I've had equipment cases made up in 3mm and 6mm in the past (for exhibitions). I used an architectural modelmakers, who were happy to do it. They had a special Perspex bonding system with UV curing glue: you put a few drops along the joint, then hit it with a really strong UV source (with a fibre-optic light pipe, I think). The UV helped the glue spread and cured it, so the joint became almost invisible, and with no bubbles. Bubbles are almost impossible to avoid otherwise. the UV curing glue doesn't spread beyond the joint (usually) so the result looks really good, but isn't quite mechanically strong as the unjointed material.

I've recently seen other Perspex glue on eBay. The original formula was chips of perspex dissolved in Chloroform - highly inflammable, quite nasty to humans, and with very limited shelf life. I don't know what the current stuff is like, but I have to get some soon to repair a crack in a windscreen.

Hope you succeed, but I think it's one of those jobs where hand tools really win over power. As mentioned, a backing board may be a good idea too, to mimimise breakout.

Hope it goes well,

E.