My RF1000 modifications (English)

[rf1k_mjh11]

Primoz,

I don't think epoxy is a good idea.

1. Epoxy won't take the temperatures needed for ABS printing, so you would be stuck with materials that don't require higher bed temperatures. You may be able to use a high-temperature epoxy, but see next concern.
2. PLA may stick to epoxy too good (this is unverified) - then the next printed object might pull out the epoxy and even more of the ceramic bed.

I'll just throw up some suggestions with advantages/disadvantages:

• Silicone - Advantage: can take high temperatures, no filament materials will stick to it. Disadvantage: no filament material will stick to it (if the hole is too large, this would be a distinct disadvantage). Possibly too soft, which would pose a problem during a Heat Bed Scan.
• Cement or tile glue - Advantage: can take high temperatures. Disadvantage: probably a rougher surface than the tile itself. Unknown if the adhesion to the tile will be greater than to the filament material.
• Solder - Advantage: can take temperatures up to 180°, smooth surface. Disadvantage: unknown if you can make it bond to the tile.

Looking at my list, I'm beginning to think high-temp epoxy may be the best option. Maybe someone else has a better idea.

mjh11

[Primoz]

I have this epoxy glue at home: https://www.yuki-model.de/Klebstofftech ... &c=53&p=53
And I might also have some this epoxy putty somewhere: http://www.bison.net/en/products/648-ep ... ua/how-to/
Both claim to be resistant to temperature up to 120°C. I usually don't print that high. Even ABS I print 90-100°C.

I was also thinking about tile glue as I also have it at home, but all their specifications says that is meant up to 75°C. I don't know what happens above that temperature. Maybe I need something that is used for fireplaces/ovens/grills.

Silicone was also an idea, but it might be too soft especially if nozzle would touch the bed at that spot during heat bed scan.

I don't print directly on the bed, I always use something like PrintaFix or PVAc glue. (I tried ABS and PLA directly on the bed, but it didn't work. Thanks god I didn't try that with PETG. ). I have ordered PEI sheet, but it wasn't shipped yet.

And I tried to soak the part with the peace of ceramic into soapy water and it didn't came off. So I assume that PETG has adhered directly to the ceramic bed with similar effect as is mentioned here at 3rd dot: http://reprap.org/wiki/PETG

[Primoz]

I finally decided to fix my ceramic bed. At first I used UHU epoxy kit to fill the hole, but it was very hard to get exact amount of epoxy into it, because it was very shallow hole and it was hard to get epoxy kit that thin. After it dried I saw that I didn't completely fill the hole and that finish on epoxy was very rough.
Then I used 30 minute epoxy glue to completely fill the hole and to make nice and even surface.

I have also ordered PEI sheet from Prusa. It was 30€ for two sheets including shipping, therefore it was 15€ per sheet, which I think is quite cheap. It came in cardboard envelope, so it isn't very protected during shipping, but it was not damaged at all. It is not the same dimensions as ceramic bed, but is close enough. The shorter side is a bit too short and the longer side is a bit too long. I had to cut off cca. 8mm on one side and you can see on picture that it doesn't cover whole bed.





For now I only printed a couple of pieces, this one on the picture is quite long and thin and with small contact surface with the bed. This would be very prone to warping, but with PEI sheet there is absolutely no warping. It was printed with ABS. It was stuck to the bed when it was heated, but when it cooled down to 30°C it was very easy to remove it.



I have yet to print bigger pieces and see if it works, but for now I am very satisfied with Pei sheet.