My First Leak...

 The FEP/PFA film on the bottom of the tank is a consumable. It gets pulled on every layer of every model, and eventually wears out (and I strongly suspect using metal tools on it will make that happen faster). What happens when it wears out?

You get a leak.

Early signs of a leak

I had noticed a bump in the PFA film previously, and I guess this was a leak in the making. There were no scratches or whiting of the film besides that.

Is it worth replacing the FEP/PFA film at the first sign of a leak about to appear? My current thinking is no. I got quite a few prints out before the leak actually developed, and the effort and money probably comes down on the side of waiting - if you have a screen protector.

Printing with a leak

This is what I got. There should be two octagonal towers, and some other bits. The tower on the right is fine, the one on the left, not so much. It stuck to the base plate and the supports are fine, in fact by the end of the print is was looking okay again.

Aftermath

It is not as much of a disaster as you might envisage. I actually got some good prints from elsewhere on the build plate, and not much of the resin leaked out. What does leak out gets cured, and tends to seal the leak, at least to some degree, so you are not mopping up resin from the floor or anything like that. In fact, after the run, I could lift up the tank, and nothing was dripping out of it.

NOTE: This is my first leak; whether this is typical I cannot be sure.

Resolving

It was harder to get the tank off, as the resin was be stuck between the film and the printer itself, and you need to be careful not to jerk the tank as it releases. You might want to empty the tank first, but I had a feeling that would be more messy. I found it easier than getting prints off the build plate can sometimes be.

There will be cured resin on the printer.

The easiest way to remove that is to have previously put a screen protector on it. Pull off the screen protector, and the printer is clean. The screen protectors are not that cheap, at around £10 each, but I consider them consumables like the FEP/PFA film.

Instructions for replacing the film here. It is quite laborious because of he number of screws involved (over fifty), but the part that is most difficult is getting the protective film off the PFA film.

The video assumes you have a foam spacer; I do not know where that is supposed to come from but I did not have one. I used a strip of 2 mm foam - about the thickness of the metal sheet. I have seen people recommend using things as thick as 8 mm, and I feel that is wrong. The film needs to be supported in the centre at the same height it is round the sides. That said, at the next stage, the film gets stretched over the other part of the tank, and mine ended up very taut!

I did a print that more-or-less covered the build plate, but was fairly fast, to confirm it was okay. I did not re-level the base plate, and it printed okay.

Edit: It is now August 24, over 14 months later (and doing about two prints a week), and no more leaks so far, so making it taut seems to have been a good thing in that regard. i thionk it is about a year since I last levelled it too.