What is the max safe bed temp for stock V2.4r2?

[evo_grind]

Printer Model

Voron 2.4 r2 300mm

Extruder Type

Clockwork 2

Cooling Type

Stealthburner

TL;DR: What is the maximum safe continuous bed temp for the stock voron 2.4r2 design using magnetic PEI sheet and adhesive that comes with the bed heating pad?

I was unable to find this on voron 2 guide.
I got a voron 2 300 kit from voronkits.com and trying to print ASA (polylite) in an enclosure. This stuff will not stick to the bed unless the bed is AT LEAST 110C. I started reading a few things that has me concerned, namely the adhesive on the bed heating pad (The kit came with Vivedino 110V 450W, NTC100K B3950) can break down at 100c, and it did have adhesive I used to stick to the aluminum plate, even though I also secured it with high temp RTV silicon.

Second is the adhesive for the magnetic sheet which somewhere on voron's website claims many can have a max temp of 70C. I really want to be able to print a variety of filaments without worrying about dangerous fumes.

So far, I have not smelled anything and have been printing at 115 / 110C for a few days now, but still want to make sure I'm not exceeding limits.

 

[IBCrazy]

If the adhesive is not high enough temperature on the magnet bed, you can pull the magnet up and clean it off with a solvent like Xylene. This will remove the adhesive and give you a fresh starting surface. Then to adhere the magnet base you can use a different contact adhesive to adhere it. Just be sure to thin out the contact adhesive 2:1 with solvent so you can be sure the magnet is perfectly flat.

As far as the 70C rating, I don't know why any would only go to 70C. Voron is really an ABS machine and that requires 90C.

Just keep printing with the bed at 115C. I doubt you are doing any harm.

 

[Yaaj]

What adhesive is it ? The LDO bed comes with a mag mat, coated with 3M 300LSE double sided adhesive. Rated 150°C.

 

[mkl]

The magnetic sheet from the formbot-kit works fine until 115°C (on the print surface, NOT on the underside of the heating pad...), above that the magnetism decreases permanently.

The heating pad itself should withstand at least 150°C.

There are more heat resistant magnetic sheets out there and print beds with embedded, high temp magnets.

 

[evo_grind]

Ok thanks for all the replies. I do notice my bed only reading 86C or so with a laser thermometer when the bed is reading 110C. Is this just normal with a magnetic bed? I'm guessing heat is lost with the thick magnetic sheet... not sure though

 

[Yaaj]

There's a temperature gradient between the thermistor and the buildplate surface (aluminium, magnetic mat, springsteel sheet and two layers of PEI).
Also, the reflective surface does not give reliable readings. Readings depend on material emmissivity.
Better stick a thermocouple or a thermistor (glass bead type) on the buildplate with some Kakton tape. This will give you a reference for the readings you get later with the infrared thermometer.
You could try after sticking some matte black adhesive on the buildplate, and measuring on the sticker. Electrical tape for example.
Some infrared thermometers can be compensated for emmissivity.
I wouldn't bother too much...
Having an even temperature is more important.

Emissivity Table for Infrared Thermometers

Emissivity chart for different materials, including metals, concrete and plastic. Find which emissivity setting to use on your infrared thermometer.

thermometer.co.uk

How to Get Great Results with an Infrared Thermometer

Infrared (IR) thermometers enable you to measure temperature quickly, at a distance, and without touching the object you're measuring. They are so useful, easy, and even fun to use that they have become as common in kitchens as they have on factory floors. Infrared thermometers are often used to...

www.fluke.com