Guys, the Lulzbot support has been fantastic and have shipped me out a replacement bed as the heater became detached on the original one. As the old bed has to come off anyway and I have to wait for the replacement, I was wondering if there is any way to reattach the heater, so that it can be used as an emergency spare.
I can find lots online about changing the bed, but nothing specifically about the heater, has anyone had a go?
Cheers
Les
I have no idea what you are actually asking, but here you go:
https://itworks3d.com/product/silicone-heater-24v-170mm-x-170mm-pc-bd0029/
I don’t think he wants another heater; I think he is asking how to re-attach the silicone heater to the glass. (In another thread, he posted about the heater coming loose and having a large “bubble” between the glass and the heater. He is getting an entirely new replacement bed/heater assembly to replace it, but is asking if it is possible to salvage/repair the old one to have as a spare.)
I imagine the same 3M adhesive used for the PEI would work. But the big job would be removing the heater where it is still stuck (without damaging the silicone), then cleaning off the old adhesive (again, without damaging the silicone). That could be challenging.
I’ve used limonene with great effect to remove the adhesive from the GLASS. But I don’t think limonene is entirely safe for silicone.
In any case, that would be the first step: Get the heater off the glass, and clean up the old adhesive. Anyone know a good way to do that without damaging the heater?
I tried that about a year ago - good luck with that. Mine lasted about 30 minutes hot and then it just fell off. 
I do not recommend it but - I use to use black high temp Automotive gasket adhesive, but it gets everywhere and stinks while curing.
I did some searching on the heater supplier’s web site, and they mention using high-temp RTV for bonding the silicone pad heaters. Probably very similar to the automotive gasket adhesive you used.
Thanks for these answers guys. While I was waiting for the new bed to arrive, I messed around with the old one to see what i could do.
I was wary of removing the old heater, as I wasn’t sure if I would break the heater in doing so. As a result I decided to try and see if there was some way of keeping the heater mat in contact from below. The first problem though was to get rid of the bubble, which was full of air. In the end, using a new scalpel blade, I made a small incision in the mat between where the heater wires obviouly go, and then pressed the bubble until it was all back in contact.
I then used a bit of 2.5mm thick rubber foam sheet, and cut it to size and lay it under the bed. The rubber I used is able to take up to about 150deg C so it was safe. The result is that while you can see that the heater is not in 100 percent contact, as there are small areas that are still showing bubbles, it does keep enough contact to work and keep a stable temperature.
Not perfect, but at least I can use it as a back up.
Of course, now the PEI film has started to bubble too (maybe due to local overheating?) but as the new bed came complete with PEI film that’s no issue, especially if used as a backup
Cheers