MacGyverS2000
Electrical
- Dec 22, 2003
- 8,504
A number of fellow associates are having issues with warping of colored acrylics, and we'd like to narrow down the exact cause (and solution). It is believed humidity is the issue, but unfortunately the effect does not appear to be transient.
The sheets are 4'x8' in size, and I believe are mostly extruded (I cannot say if any of the sheets are cast, though it may be possible with some colors). They are often ordered from suppliers cut down to 12"x24", and even over that small size have a bow in them of up to 1/2" edge-to-edge. We have ordered full sheets directly from the manufacturer, they show up straight as an arrow, and remain that way while sitting on the shelf... within 24 hours of removing the protective plastic the damn things are warped beyond use.
My question(s):
1) If humidity is the problem, how can we prevent it from warping the sheet (tests have been run in areas with dehumidifiers)?
2) Why does the warp occur? This happens with solid color sheets (it was initially believed the two-color sheets warped because one color absorbed more moisture), so shouldn't any expansion/contraction happen at equal rates on both sides? I assume if it's extruded there is a grain to the polymer chains, but that would be a length-versus-width change, not up-versus-down.
3) How can we avoid the warping in the first place? At least one has tried baking it in a drying oven, and it appears to work to a small degree, but it's not perfect, and few of us have such large ovens to play with.
Dan - Owner
The sheets are 4'x8' in size, and I believe are mostly extruded (I cannot say if any of the sheets are cast, though it may be possible with some colors). They are often ordered from suppliers cut down to 12"x24", and even over that small size have a bow in them of up to 1/2" edge-to-edge. We have ordered full sheets directly from the manufacturer, they show up straight as an arrow, and remain that way while sitting on the shelf... within 24 hours of removing the protective plastic the damn things are warped beyond use.
My question(s):
1) If humidity is the problem, how can we prevent it from warping the sheet (tests have been run in areas with dehumidifiers)?
2) Why does the warp occur? This happens with solid color sheets (it was initially believed the two-color sheets warped because one color absorbed more moisture), so shouldn't any expansion/contraction happen at equal rates on both sides? I assume if it's extruded there is a grain to the polymer chains, but that would be a length-versus-width change, not up-versus-down.
3) How can we avoid the warping in the first place? At least one has tried baking it in a drying oven, and it appears to work to a small degree, but it's not perfect, and few of us have such large ovens to play with.
Dan - Owner
