Cutting Acrylic

[Quandary]

The main hatch board in our boat is 10mm. smoked acrylic with a stainless vent cut in to an aperture near the top, it is heavy and awkward to handle and stow.
Our last yacht had a similar acylic board but it was in two parts with the joining faces cut at about 45 degrees to the surface to discourage water. There was a neat and secure little stowage rack just inside the cockpit locker where it was very accessible.
So I am tempted to cut the existing board in half with the cut angled as above, repondents to a Google search say that acrylic is easy to cut with either a hand saw or a powered jig saw but I am dubious because once I start there will be no going back. I favour the hand saw as guiding a jigsaw, even along a lath when the blade is angled could easily go wrong and I am more adept with hand tools. Obviously it would be easier if the cut was at right angles to the surface but if the angle cut was practical I would prefer to do it, it does mean that the material depth will be greater. I could cut a thicker wood lath first to the angle using a circular saw and clamp it either side of my cut as a guide?
So has anyone tried anything similar, how did it go and what advice would you give?

 

[yachtorion]

Whichever route you go - make sure you have the piece very well supported and clamped. Acrylic can be very brittle. If the saw sticks it may bend and fracture the material if is isn't well restrained.

Personally I'd go the jigsaw route. I'm assuming your jigsaw is like mine and you can angle the cut relative to the base plate. Keeping the base plate flat on the surface and guiding it with the lath you mention would be my method. I've had a lot of luck with that in the past cutting windows. I'm certainly more accurate that way than by hand.

 

[Tranona]

Contemplated doing it myself, but bottled out and had a carpenter do it. Not sure whether he used a band saw or a table saw but end result was perfect. Then screwed a teak batten on the upper board to cover the joint when both boards were in. I split mine 60/30 as the bridge deck was rather low on that boat. Usually left the lower part in place when sailing. The two bits still fitted the chocks for stowage down below.

 

[halcyon]

Have a look locally for a laser engraving firm, ask them to cut it for you, accurate and a polished edge thrown in.

Brian

 

[geem]

If you do it yourself get the acrylic warm before you start. They occasionally break if very cold. I cut a complete new one out of 10mm. I cut it with a hand saw then used an electric plane to square up the edges. You can then use a blow torch to gently heat the cut edges and you get a perfect even, clear appearance that looks like you have never cut the acrylic at all.
With the 45deg cut you require I might be tempted to get somebody else to do it!

 

[Lomax]

Having recently looked for instructions on how to cut and bend acrylic, I eventually found this excellent resource which you may find useful: http://www.bcae1.com/plexi.htm

 

[Bobc]

I cut mine as you describe. I would recommend using an Exakt saw to cut it. It's a tool that's so useful for so many things, you'll wonder why you never had one before.

 

[Quandary]

I cut mine as you describe. I would recommend using an Exakt saw to cut it. It's a tool that's so useful for so many things, you'll wonder why you never had one before.

After building a house extension and a 2 storey garage (sail loft over) and justifying a plethora of power tools on the 'Its cheaper than paying a man' argument, I am reluctant to buy any more, as well, I am not sure how that gadget manages angled cuts? it seems limited to straight and vertical cuts in light material?

 

[Martin_J]

Hi

I cut mine in half horizontally about three years ago.. also on the slight diagonal since I wanted dampness to drain ouwards.

Prior to cutting with a simple handsaw, I did mark with masking tape both sides of the washboard and both sides of where I wanted the blade. This gave me an indication to maintain the cutting angle.

A quick wipe over with (I think) 1200 grade wet and dry then left the surfaces like a mirror.

I am pretty confident at straight cuts with a saw though.. and didn't want to use a jigsaw for two reasons.. 1) heat and 2) blade going off at an angle all by itself..

Decide how good you are with a handsaw first..

Washboard cut horizontally

If you get the cut in the right place, you might even be able to stow the boards either side of companionway steps like the picture below..

Washboards stowed whilst still attached to boat.

One thing to note.. the top board will sit lower in the slots.. firstly by the width of your cut and secondly it will drop slightly outside the lower board as the diagonal cut edges slide past each other

 

[Aja]

Take it along to Midton Acrylics who I believe are local to you. They should be able to cut at an angle and also polish the edges.
If not QD Plastics in Dumbarton (01389 762377) will do it for you if you phone ahead and are prepared to leave it with them for half an hour.
Donald

 

[Quandary]

Hi

I cut mine in half horizontally about three years ago.. also on the slight diagonal since I wanted dampness to drain ouwards.

Prior to cutting with a simple handsaw, I did mark with masking tape both sides of the washboard and both sides of where I wanted the blade. This gave me an indication to maintain the cutting angle.

A quick wipe over with (I think) 1200 grade wet and dry then left the surfaces like a mirror.

I am pretty confident at straight cuts with a saw though.. and didn't want to use a jigsaw for two reasons.. 1) heat and 2) blade going off at an angle all by itself..

Decide how good you are with a handsaw first..

Washboard cut horizontally

If you get the cut in the right place, you might even be able to stow the boards either side of companionway steps like the picture below..

Washboards stowed whilst still attached to boat.

One thing to note.. the top board will sit lower in the slots.. firstly by the width of your cut and secondly it will drop slightly outside the lower board as the diagonal cut edges slide past each other

Sounds encouraging, I think I am okay with a handsaw, my paternal grandfather was a cabinetmaker who is reputed to have worked on the Titanic, (I still have some of his tools) and as an architect who worked on a drawing board for much longer than I used a computer I am used to precision.
Just one question, was there anything special about the handsaw you used and did you oil the cut?

 

[grafozz]

I use a good jigsaw to cut mine then orbital sander 200/ 400 paper and a slight chamfer on the edge .
I used an old window to make a nice curved flyscreen for my Vespa (where the edge was polished down to 1200 paper )

 

[waynes world]

Myself I use either a Jigsaw or better still an angle grinder with plasma disc, only if your good with one and keeping it square or at correct angle you want cut though.

 

[DownWest]

Built a spiral staircase a few yrs back in acrylic. Cut it with fresh sharp blades in the jig saw, lubricated with water + washing up liquid. Edges were then cleaned up with a router and polished with 600 w&d. Also cut it on a table saw with out probs. Key is, smooth feed and no pinching or twisting of the blade. So, guide battens and a sharp wood blade with the jigsaw + a bit of lube. If no lube, the swarf fills up the cut behind the blade and sticks it together, so, keep it cool.
DW

 

[wiggy]

Have a look locally for a laser engraving firm, ask them to cut it for you, accurate and a polished edge thrown in.

Brian

I teach D&T in a secondary, here are my top tips:
Circular say will chip the edge on the bottom surface.
Band saw is great if you have access to one, nice new fine tooth blade is best.
Jigsaw will work fine, a fine tooth again and don't rush.
Laser cutter is fantastic but you'll be luck to find a cutter that can do a 45 degree cut.
If you cut by hand I recon you would struggle to get a nice straight edge.
Once cut file the edge then either wet and dry then polish or file then run a blow torch across the edge to give a mirror smooth finish.

 

[wully1]

Go talk to Midton Acrylics in the 'Gilp ,I'm sure if you went to see them they'd help. They made me some bits for me for a previous boat.