Bending/Forming acrylic

[Franco B]

I have a acrylic part that I would like to reproduce. These are some pictures of the part in question:







Its made from 5mm tinted acrylic and is approx 500mm square

I work with a lot of plastics and the cutting, drilling holes, polishing etc is no problem but I haven't done any bending yet.

I was originally thinking of using a heat gun and a radius form to bend the radii but I don't think it will really be the best method.

I was looking at videos on youtube and I found this one: http://www.youtube.com/all_comments?v=iUTNcQlHiho

Whilst the video is showing acrylic being bent with a heat gun, some of the comments were talking about building an oven with heat lamps in to heat up and bend the acrylic.

I was wondering if this would be a suitable method for forming the item above.

I was thinking of making a positive mould and then lying the sheet on top and letting the heat lamps heat the material up and hopefully the plastic would sag to the profile of the mould.

Does any one have any thoughts on this? Do you think it would work, would gravity be enough for the plastic to bend to the profile of the mould? Any thoughts on oven size and heat lamp power etc?

Thanks in advance for any thoughts or advice.

[kellys_eye]

I would suggest using an old electric fire heating element (the older 'tube' type element) fed through a 'speed control' (for temperature control) as a means of heating along a 'straight line'. I have seen heating done using single wires but this requires a more sophisticated level of controller.

[Franco B]

Thanks for the reply.

I was thinking about heating it from above as its quite a large area that needs to be heated, something like this:



For heating I was thinking about decasing the quartz lamps and controls etc from a couple of quartz lamps like this:



That should give me some degree of heat control. I'm just unsure of what type of wattage I should be looking at. The distance between the lamps and material will affect the performance too.

I just hope the material will sag enough to follow the profile of the mould as I need the finish product to be an exact replica of the original.

[kellys_eye]

Yup, those were the heating elements I was referring to.

If you can get hold of a couple of dimmers rated to handle the elements you will get the best possible temperature control in which case the element wattage would be irrelevant.

[cgw59]

Contact your local college Technology dept who will have a line bender and I am sure if they have time they would heat it and bend it for you, it should take all of about 20mins to do those two bends, it would help if you could make an MDF former prior to going so that they have something to bend it to.