Metal Sublimation - Help!

[Glitterbomb]

I am relatively new to sublimation and mainly done slate, glass and mugs on my 3D press. I have recently wanted to start using aluminium metal sheets but can't get a good result on large pieces. (A5 size). I have attached 2 photos, one of a metal sheet sent to me for testing - it's 10cm square. Good results at 190 degrees for 420 secs, which is what the press manufacturer says in their instructions. Ironically even better, glossier finish if I accidentally leave the plastic coating on the sheet - was a bit more difficult to peel off but was noticeably better! (Won't do it again though!).

so the second photo shows the exact same settings on a larger piece - about A5. As you can see, the few mm round the edge is ok but the rest is not. It's not smooth and shows the tape marks. I get the same result when dropping a min off the time and when I add a min. The sheets are EXACTLY the same in thickness (a few mm) - they only differ in size.

Before I waste any more pieces I thought I'd ask here in case anyone has some experience or advice that could help?

[UK Printed Mugs]

Good morning. We sublimate onto sheets around this size as well but only at 190c for 60s which is a lot less time than you are doing. Anything more than this then the ink starts to burn onto the metal and get the same type of results you are getting. Maybe worth a try. Kind regards, Olly.

[spongerobinson]

Yes I would definitely say your heating that for way too long. I would also try 190c for 60s, and tape from the back, so that your tape isn't actually over the area your trying to print.

[Glitterbomb]

Super, thanks. Just to confirm, are you using a 3D press too?

[UK Printed Mugs]

Using a flat bed press.

[Justin]

I do my metal at 180c for 50 secs

[Quinsfan]

I do metal sheets but place kitchen roll over it as well as this seems to help with a nice finish. I also press with the transfer under the metal.
So from bottom to top
Kitchen roll, transfer paper, metal sheet, Teflon sheet.

[UK Printed Mugs]

That's a unique tip, will try the kitchen roll tomorrow! Olly

[mrs maggot]

I do metal sheets but place kitchen roll over it as well as this seems to help with a nice finish. I also press with the transfer under the metal.
So from bottom to top
Kitchen roll, transfer paper, metal sheet, Teflon sheet.

yep thats how we do ours here as well, although i use teflon sheet at the bottom, just incase as i print a lot of white shirts, and don't want to ever have a shadow on them

[GoonerGary]

The temperatures will vary from press to press but my Insta is 190 degrees C and 60 seconds using Chromaluxe. Medium pressure, a sheet of supermarket greaseproof paper either side to protect the press.