Choosing a suitable power supply

deckingman

@pedromelim In addition to what others have said about thermal fuses, be aware that MOSFETs which are on the board itself, can fail the same way as SSRs. That is to say, they can also fail in such a way that full power would be supplied to the heater.
Duet firmware does a good job of detecting heater faults but of course, it should not be relied on.
Having said all that, if you aren't comfortable about using a 220v heater then don't. But the risk of electrocution is probably higher than the risk of fire (but both can be mitigated).

snoozer

Just to add, heater pads with adhesive may not hold up as well as factory bonded heaters. I have read in a number of places that the adhesive can be an issue at higher temperatures. So for a 24V bed I would try to get a PCB heater type, for a mains powered bed a factory vulcanised heater on aluminium.

Jan.

snoozer

@pedromelim

Just out of curiosity, what Hotend are you planning to use ? I am just interested in anything regarding the V-Core. I have a topic here that I extend as it go along.

https://forum.duet3d.com/topic/9465/core-xy-based-on-rat-rig-v-core-and-duet-2-ethernet

THX
Jan

mrehorstdmd

@phaedrux said in Choosing a suitable power supply:

Here's a good example bed build from @mrehorstdmd
https://drmrehorst.blogspot.com/2017/07/ultra-megamax-dominator-3d-printer-bed.html

I don't recommend mounting the TCO on the bed plate as I did in the page you linked. The adhesive that holds the heater on the bed is starting to let go after about 2 years. If the heater ever falls away from the bed plate the TCO won't do its job. I'll be moving the TCO soon...

I recently put a kinematic mount and new bed in SoM and mounted the TCO on the heater using a blob of high temperature silicone. That's the safer way to do it, I think. When I rework the heater in UMMD I'll probably stick the heater to the plate using the same high temperature silicone.

wilriker

@mrehorstdmd said in Choosing a suitable power supply:

I recently put a kinematic mount and new bed in SoM and mounted the TCO on the heater using a blob of high temperature silicone. That's the safer way to do it, I think.

That's also the way how Keenovo does it if you order the heater with a TCO. Or actually they put it under another layer of silicone but that's essentially the same.

Phaedrux

@mrehorstdmd Right. Good warning. Was that with the 3M adhesive sheets or was it bonded with RTV silicone? I can't remember. I've bonded my heater pad with RTV silicone, that should last a lot longer than a sticker sheet. I remember seeing your post about the PEI sheet lifting when the 3M sheet lost it's bond.

snoozer

@phaedrux

Hi, could you elaborate regarding RTV Silicone ? I am suspicious about adhesives and would be interested to know more. Do you by any chance have a link to a product ?

Thanks
Jan

Phaedrux

I used this: https://www.amazon.ca/Rutland-600-Degree-Silicone-2-7-Ounce-Super/dp/B004YEBWTG/ref=sr_1_34?crid=1ESRUA3CQI4NP&keywords=rtv+silicone&qid=1552499348&s=gateway&sprefix=rtv+sil%2Caps%2C171&sr=8-34

But there are many options and types. It's also called gasket maker.

I cleaned both the aluminum and heating pad thoroughly, then applied a thin layer of the silicone, then used a rolling pin to slowly roll on the pad. Added a bead around the edges of the pad to seal them in, and then placed it on a flat surface with a flat board over it and several rolls of filament on top to press it down. Left it to cure for a day. It's been going fine for about a year of daily use.

You can see pictures of it in the link in my signature.

mrehorstdmd

@phaedrux I used the adhesive that came on the Keenovo heater- it's 3M 468MP. It holds with temperature cycling for about 2 years then seems to dry out and let go.

@snoozer You can get high temperature silicone at auto parts stores for about $5-6 for a tube.

snoozer

I figured out by now RTV is an abbreviation lol, I thought its a brand so. Have found a number of brands and types...... Thanks for the responses however !

Jan

Phaedrux

@snoozer room temperature vulcanization is a mouthful.

pedromelim

@snoozer im gonna use a spare e3d v6.1 i think...the ones used on the original prusa...got a spare one hehe

After much thought and some more research, i decided to go 24v instead of mains (220v).

For both safety and the simplicity of everything.

The RSP-500-24 will do just fine, as i found that is used on the lulzbot taz 6wich used a silicone heated bed rated at 360w.
The heated bed will probably be the same as the taz 6.

Difference in price from one way to the other is around 25€ and i much prefer paying a bit extra for the simplicity of the system.

Tks everyone for the input on the matter.

snoozer

@pedromelim

After much reading and a bunch of good an plausible advice I also give a silicone heater under a substantial aluminium plate a go. I stay with 230 AC, I am qualified electrician (in a former life) so no worries about mains. Did you order the V-Core including the printed parts ? the hotend mount is designed for a v6 I think. I have spend all last WE to make a Titan Aero mount, only done it in PLA with little infill as test. Still don't have the kit to put it on actually. I like to have it detachable and keep the belt tensioner attached. I split the mount. Intend to be able to manually change between hotends and also service it easy. Maybe able to use a laser as well.......... that's for future.

Jan

PuterPro

@snoozer said in Choosing a suitable power supply:

I split the mount. Intend to be able to manually change between hotends and also service it easy.

I did a rework of this mount, in Fusion 360: E3D V6 Hinged Extruder Bracket & Clamp for my little Monoprice Select v2. It's pretty kludgy so I didn't post my rework, but I have all the wires on plugs and can change the v6 clone on it in about 30 seconds. (Went with genuine v6 Gold for my CR-10S)

Kinda cool to have a hinge.

@pedromelim - Good luck with your project, keep us posted!