Bending Perspex

[KAM]

I need to put a permanent large radius bend in 15mm perspex. I was going to build a temporary oven. Has anyone tried this. Any tips appreciated.

 

[pvb]

I've bent thinner perspex by clamping pieces of ply both sides of the perspex, and on both sides of the bend, leaving the bend area exposed. Then applied gentle heat with a hot air gun until the perspex would bend. Might work with 15mm perspex.

 

[rogerthebodger]

Try suspending the sheet of perspex over a bar type electric heater but not too close. The perspex once heated may sag to the large radius you require.

If the sag does not happen just move the electric heater closer.

 

[pvb]

Try suspending the sheet of perspex over a bar type electric heater but not too close. The perspex once heated may sag to the large radius you require.

If the sag does not happen just move the electric heater closer.

It's quite difficult that way to control the area being heated. With my project, I wanted the perspex each side of the 90 degree bend to remain perfectly flat, hence clamping ply both sides of it to shield it from the heat.

 

[rogerthebodger]

I agree with you method when a sharp bend is needed but the OP specified a " large radius bend " so need heat over a larger area.

The trick is to have the heater not too close to heat the whole area that he needs the radius over.

 

[Spuddy]

Use your temp oven - errm, 160 C I think. Then drape form over a male former knocked up out of bits....but smooth bits. 15mm thick will take a while to heat through as acrylic is a good insulator. I've used this method on smallish bits - about A4.
Cast acrylic has a reasonable plastic band. Extruded acrylic has a narrow one so less cooperative.

 

[colind3782]

Drifting slightly but does anyone have a source for 15mm perspex. I want to make a new washboard from it. All the searches I've done come up with prices in the range of £150 for a washboard sized piece of the tinted stuff.

 

[nimbusgb]

I have a 12 mm perspex washboard. It weighs a bloody ton and can do serious damage to fingers, toes and anything else if it get loose in the cabin. 15mm even heavier. 12mm will hold back water well beyond even a green wave over the boat!

 

[Daydream believer]

I would go for 9mm polycarbonate

 

[Tranona]

Drifting slightly but does anyone have a source for 15mm perspex. I want to make a new washboard from it. All the searches I've done come up with prices in the range of £150 for a washboard sized piece of the tinted stuff.

No need for that thick and heavy. 9 or 10mm is normal, and yes, it will cost.

 

[prv]

Drifting slightly but does anyone have a source for 15mm perspex. I want to make a new washboard from it. All the searches I've done come up with prices in the range of £150 for a washboard sized piece of the tinted stuff.

I used 12mm polycarbonate, more to fit properly in the frame and accept the lock mechanism than for strength, though that's a bonus. Cost £110 from an outfit called Liv Supplies.

Pete

 

[davidpbo]

I recently replaced my windows.

2 relavent posts on the subject.

Bending Acrylic:
http://www.ybw.com/forums/showthread.php?398649-Bending-Acrylic-Sheet&highlight=

The 10mm sheet I used bent to the radius I required easily but it was only two months ago so not long enough to see if there is any problem long term.

I would not use interscrews again if any pulling to shape is involved.

Acrylic sheet suppliers

http://www.ybw.com/forums/showthrea...ons-for-Perspex-Polycarb-suppliers&highlight=

Sorry on mobile so limited format options.

 

[charles_reed]

When I put a 40 degree bend in 9mm acrylic, I used a Black & Decker hot-air paint remover gun on the outer radius with one side clamped in a wood vice. Constant movement of the air-stream and pressure on the free end did the trick.. width of the strip was 200mm.
I'd not like to try the method on anything much wider.

 

[pmagowan]

You can vacuum form it by creating a male mould of the desired shape on a small table with holes in it attched to a vaccum. You heat up the plastic until it is starting to sag and then stick it in your vaccum former, turn on the vacuum and hey presto. There are lots of youtube videos of it. An alternative is to make a male mould, set on the plastic sheet and then put the whole lot inside a clear plastic bag. Tape a vacuum onto the bag opening with masking tape and then remove the air. You can heat with a hot air gun and the plastic bag will keep permanent pressure on, acting like a large clamp. Edges and areas where the plastic becomes a little clouded can be treated by wafting a blow torch over them.

 

[DownWest]

Done this: For a spiral staircase. Fabbed up an oven from sheet metal with an 1500wt element in the bottom. Covered that with a sheet of metal, so no direct heat and put a fan to circulate the heat. Temp needs to be 120C. Used formica to cover the mould, and it has to be really clean. Any dust will dink the surface and show up. Pièces were around a meter long and as it was a spiral, were helical, not simple curves. But that was in the mould. Steep learning curve, but it worked out with minimul wastage.

Edit: It was with 10mm, but for 15, just a bit more cooking time, as long as the temp is controlled. i.e. kept at 120C.

 

[colind3782]

No need for that thick and heavy. 9 or 10mm is normal, and yes, it will cost.

Just thought about 15mm as that's the size of the channel and plywood board that I've just made. I never thought about the weight so I'm not sure it's necessary.

Thanks all

 

[pmagowan]

Just thought about 15mm as that's the size of the channel and plywood board that I've just made. I never thought about the weight so I'm not sure it's necessary.

Thanks all

The plastic can be made thicker at the edges to fit the channel which will cut down on the weight overall.