After 1 year of usage, the PEI coating of the J1’s glass print bed starts getting lots of holes, so I wonder - is there a cheaper alternative to a new bed than the official 50$ replacement part?
I would even go to extreme measures like cutting something to shape if it doesn’t come in 33 x 22,5cm 
For me $50 for a years use is cheap.
You can use the other, flat side of the plate coated with capton foil. It gives an excellent adhesion and can be renewed as often as it is necessary.
Hi FlashErase,
I experimented with painters tape in the past, but sometimes run into problems where warping forces were simply lifting the tape from the plate, or also trying to remove an object after print would more often than not lift the tape from the plate. What is your experience with capton tape?
I’ve good experiences with this foil (click the link “capton foil” in my posting above).
I applied the foil using water with dishdrops for bubblefree positioning and a squeegee to press the foil on and to remove the water.
Kapton is the registered trade name of a polyimide tape by the inventors, Du Pont.
‘Capton’ is one of the names used for similar tapes and films.
The Chinese are very inventive when it comes to naming their clones. I have also read “Coptan” several times.
The fact is that the clones are much cheaper than the original but are sufficient for our purposes. For our private gadgets, it doesn’t necessarily have to be the expensive original.
This is the closest I could get for a cheaper bed replacement:
for 23 Euros you can get a 5mm glass sheet of 33x22,5cm size, which you can then post-process with sandpaper to make it more sticky without ruining your original build plate. I will yet have to test how good PETG sticks to sanded glass, but first tests look promising. There are even full 3d-print-beds with pei for this price on the market, but none of them in the required dimensions.
Has anyone else already tried sanded glass?
2 cheap alternatives to consider:
Hi Rwide,
thanks for your ideas!
G10 is no option: at 5mmx25x35 it already cost around 50€, so I could just buy a new print bed.
PC plate looks promising, you can get one for 12€ cut to the size of the print bed on Amazon :-). But I fear it will be more prone to scratches or damages, in case you mess up your leveling. And of course its lower stiffness compared to glass could be a problem.
Can you share any experience you have with it?
@Dumblefox I believe you can adjust the thickness of the buildplate so perhaps a 3 or 4 mm G10/FR-40 could work… Not sure wich materials are compatable with it though. I only use it for Nylon…
PC buildplates are great for PLA. Much better than PEI in my opinion (if they are flat).You have to sand it though. Otherwise it will stick too good and you might damage the plate when trying to remove the part. One of the downsides is just like you said the lower stifness. I have a 5 mm PC plate that I use sometimes on my J1. It works ok but the center is a tiny bit higher than the edges. But it works…
i got an aluminum plate machined to size and a magnetic sheet to put a PEI spring steel sheet over top. worked great until the aluminum warped
Hi,
Here my full solution to save you from hassle to figure out all details:
Howto
This way, you get:
This is not just a replacement. This is an upgrade 
