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Discussion Starter · #1 ·
Is there a tolerance for how flat the bottom aluminium platen of a heat press is?
I recently purchased 16" x 20" swing heat press and the bottom aluminium platen has nearly a 1mm belly in the middle down from the sides.
Is this acceptable or should it be dead flat.
For reference this is the press i just bought.
Heat press

Thanks
 

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Discussion Starter · #3 ·
It depends on how the press is made, and what you are pressing.
For t-shirts 1mm is not a problem.
I am pressing white cast acrylic A3 panels, using a silicone mat, i have done 8 panels and not 1 turned out, they all seem to be faded towards the center, I have tried making the pressure much harder but that doesn't seem to make any difference across the tests, all seem to have the spot where it doesnt transfer properly, yet if i do say a cake topper sized piece of acrylic its fine.
I have included some pics of it with a metal ruler across the diagonals
Automotive tire Rectangle Wood Bumper Floor

Wood Bumper Rectangle Font Flooring
 

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Discussion Starter · #5 ·
Any gap on the upper platen? You shouldn't have an issue with that small a gap on the lower, especially using a pad and thick acrylic. Try placing a smaller sized, 1mm high pad in the middle to compensate.
Yes there is a little in the upper heat platen, not as much as the bottom platen tho, the problem seems to start when the acrylic is around 30cm(11.5") long, I was wondering if ithe bow was helping to create an air pocket so the ink doesn't transfer properly to the acrylic
 

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Yes there is a little in the upper heat platen, not as much as the bottom platen tho, the problem seems to start when the acrylic is around 30cm(11.5") long, I was wondering if ithe bow was helping to create an air pocket so the ink doesn't transfer properly to the acrylic
The smaller pieces span less of the dip, as well as having less surface area pressing against the pad, so they sink a bit more into the pad and/or deform more for a given press pressure. Opposite for the larger pieces, which would sink in and deform less.

For soft things, like garments, not an issue unless the dip is large. I use a GK, which has a slight curve to the top platen, for my garments with no issues at all. For stiff/hard substrates, I would go with a press that was as dead flat as possible.

At least with GK presses, one can adjust the curvature of the top platen to some extent. I believe the bottom is supposed to be flat already. Perhaps your brand is also adjustable ... but I wouldn't bet on it.
 

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Discussion Starter · #8 ·
Is that a bottom silicone pad, or a a silicone cover sheet?
Using a felt bottom pad shoult fix the issue.
I have a bottom silicone pad I bought for it, which seems much like wet suit material, as the press came with the t shirt pillow pad, which was good for mouse mats but terrible for acrylic.
Ill have a look around for a felt pad and give that a go.
 

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I have a bottom silicone pad I bought for it, which seems much like wet suit material, as the press came with the t shirt pillow pad
Silicone pads are good for absorbing small bumps and protrusions (ie buttons), but don't work well for larger areas like pockets and side seams.
Just try pressing the pad with your finger, and then try pressing it with your palm. You will notice a huge difference.
Now imagine trying to compress it with an A3 size panel.

You need something soft enough to absorb the giant (in surface area) gap of the platen.
Alternatively you can put a piece of flat plywood bellow the silicone pad.
A flat piece of thick aluminium or steel plate will be a more permanent solution.
 

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Discussion Starter · #13 ·
A flat piece of thick aluminium or steel plate will be a more permanent solution.
This sounds like a plan, as the press is only a month old, Im going to contact the place I bought it from, if I have no luck with them, i also have a cnc machine, I may get carried away and surface the aluminium platen flat, I have some aluminium sheet here so Ill see if that helps too.
Appreciate your input and help thank you
 
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