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    [3.4.0rc1] I think the bed heater is overheating?

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    • zaptaundefined
      zapta @Phaedrux
      last edited by

      @phaedrux said in [3.4.0rc1] I think the bed heater is overheating?:

      Maybe so, but I'd still be more inclined to follow Keenovo's own recommendations.

      Is the high temp RTV method preferred over that 3M double sided sheet? I have 3M as the main adhesive and RTV around, heating the bed up to 110C nominal.

      Phaedruxundefined 1 Reply Last reply Reply Quote 0
      • Phaedruxundefined
        Phaedrux Moderator @zapta
        last edited by

        @zapta said in [3.4.0rc1] I think the bed heater is overheating?:

        @phaedrux said in [3.4.0rc1] I think the bed heater is overheating?:

        Maybe so, but I'd still be more inclined to follow Keenovo's own recommendations.

        Is the high temp RTV method preferred over that 3M double sided sheet? I have 3M as the main adhesive and RTV around, heating the bed up to 110C nominal.

        It would be preferred for me. From the specs I've been able to find of the 3M sheet it's not really meant for long term high heat use or repeated heat cycling. Eventually it deteriorates. Adding RTV to the edges to seal them at least keeps them from peeling away, and perhaps through suction would keep the center from releasing.

        IMG_3487.JPG

        Here the 3M has given way at the center of the mat. It's not a good design as there is no strain relief on the cabling and at temp the 3M has let go from the gentle pull of the cable.

        There have been other cases where pockets have formed and the heater has burnt up from lack of contact causing hot spots.

        Given the low cost of 500c RTV silicone ($10) why not?

        Z-Bot CoreXY Build | Thingiverse Profile

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        • zaptaundefined
          zapta @Phaedrux
          last edited by

          @phaedrux said in [3.4.0rc1] I think the bed heater is overheating?:

          Given the low cost of 500c RTV silicone ($10) why not?

          Yes, it's sounds as the right thing to do. In my case I already have a bed with the 3M adhesive and RTV around the edges as you recommended in an old thread. Will add it to my TODO list. Not sure how easy it is to clean the existing RTV from the bed.

          The reason I am looking into is is a thermal fuse blowout I had a few days ago. It's a 115C fuse with a bed I heat to 110C (originally I planned going only up to 100C). Everything looks good and I ordered a 135C thermal fuse but may go the full RTV route down the road.

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          • Gixxerfastundefined
            Gixxerfast @Phaedrux
            last edited by

            @phaedrux Yes, you are of course right. More safety is never wrong. In my case I bought the variant which goes right to the edge and only leaves < 5mm either side.

            If you want to go full RTV one have to either remove the 3M glue from the heater or buy the version without 3M tape.

            I have this idea of making a thinish clamp in aluminium. Sort of a skeleton frame which is hold to place by small spring loaded screws in the extra three holes which the Voron beds usually have to be compatible with the 1.8/Trident models. It wouldn't have any other purpose than give some peace of mind and maybe a stress relief for the heater/thermistor cables.

            Well, we'll see. It's not stupid expensive to send out for laser cutting.

            Voron V2.4 (#1317) with Duet 3 Mini5+ Wifi and 1LC v1.1 Toolboard
            Voron V0.1 (#637) with Duet 3 Mini 5+ Wifi and 1LC v1.2 Toolboard
            Ender 3 Pro with BTT SKR-2 + RRF

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            • Phaedruxundefined
              Phaedrux Moderator @zapta
              last edited by

              @zapta said in [3.4.0rc1] I think the bed heater is overheating?:

              Not sure how easy it is to clean the existing RTV from the bed.

              Not easy. The 3M tape can be dissolved with a citrus oil solvent, but the RTV silicone would need to be cut away with a blade. Not likely worth the effort.

              Z-Bot CoreXY Build | Thingiverse Profile

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              • zaptaundefined
                zapta @Phaedrux
                last edited by

                @phaedrux said in [3.4.0rc1] I think the bed heater is overheating?:

                Not likely worth the effort.

                I got a nice 250mm bed from a european vendors that doesn't ship anymore to the US. Will need to find another source. 😉

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                • Velviaundefined
                  Velvia @zapta
                  last edited by

                  @zapta Is it possible to attach a bed with only RTV? Why is this not the norm? The 3M adhesive kinda sucks for anything over 110 C. Does Keenovo deliver pads with no adhesive?

                  Homegrown, grass fed and organically built 350mm delta

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                  • Phaedruxundefined
                    Phaedrux Moderator @Velvia
                    last edited by

                    @Velvia said in [3.4.0rc1] I think the bed heater is overheating?:

                    Does Keenovo deliver pads with no adhesive?

                    You can custom order from them.

                    Z-Bot CoreXY Build | Thingiverse Profile

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                    • zaptaundefined
                      zapta @Velvia
                      last edited by zapta

                      @Velvia, I read that this is the recommended way now, but I don't have any experience with it, my heater is attached with that 3M high temp adhesive. I just added RTF along the edges.

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                      • mrehorstdmdundefined
                        mrehorstdmd
                        last edited by

                        The bed plate acts as a heat sink/heat spreader for the heater. If part of the heater separates from the bed, that part gets extra hot. Here's what happens to the heater when the 3M adhesive starts to let go:

                        alt text

                        https://drmrehorst.blogspot.com/

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