Exposure Unit Hot Foil Stamping Screen Pad Printing Plate Die Making Tool DIY

I had great hopes for this UV Exposure Unit for making photopolymer plates for letterpress printing, as advertised on the Amazon website. It is compact, accommodates an A4 sheet, has 6 bulbs, and includes a built-in timer. I was sorely disappointed.This device uses compression to ensure close contact of the negative to the plate. Although the unit seems generally well made, out of the box, both latches were bent and needed adjustment to easily open and close the lid.The timer, labeled "Solarize Minute" is set by a rotating knob for between 0 and 5.5 minutes. Timing to the second for letterpress photopolymer plates is not critical, but the times that I observed were all about 10-15% less than the position on the dial.Ok, but can this unit make a useable photopolymer plate? Using a Stouffer 21-step Sensitivity Guide, I started to try to find an acceptable exposure. I use Toyobo KF95 plates from Boxcar Press with a recommended exposure to step 17-18. With the Epson-printed negatives I make, with other exposure setups I have only been able to push the density to step 14 without serious infill.So, how long would I have to run this unit to achieve a solid step 14? I tried 3, 5.5, 11.5, 14.3, 22.5, and 42.3 minutes, and finally, I started to get step 14 mostly filled in-that is, after punching the run button 10 times and enduring the shrieking alert that the machine emits at the end of a cycle.Conclusion, this exposure unit has too little wattage to be useful in my shop for making photopolymer plates. It is going back.