Firstly, for DC voltage, a threshold of around 30 volts is often considered relatively safe for brief contact. This is based on the concept that at low voltages, the body's natural resistance limits the amount of current flowing through it to levels that are unlikely to cause harm. However, depending on the current source it can be dangerous if the output is shorted in that it can cause severe burns. e.g. an automobile battery output is 12 volts with a current capacity > 200A and it can literally melt metal and if you're in its path then you'll be severely burned. Likewise, AC voltage can be more dangerous than DC voltage of the same magnitude due to its ability to induce muscle contractions, potentially causing the victim to be unable to release from the electrical source. For AC voltage, the threshold for safe touch is generally considered to be lower than for DC voltage. Around 50-60 volts (25v positive and then 25v negative) AC is often cited as a threshold for safety, again for brief contact. These are well established safety margins. I learned these margins long ago early in my career as an electrical engineer in the aerospace business. Secondly, the cork method will likely work fine but be aware that you're adding height to the bed and some printers may not allow you to compensate for that added height easily. You may be able to compensate in the firmware but many don't have the skills or wherewithal to know how to do that. So be cautious when doing this kind of modification and have a plan to compensate for any deviations from the original machine physical characteristics.

Excellent video, and an extremely good point about SSRs most commonly failing closed!

I just picked up an old folger ft5 myself and one of the first things i thought to do was sort the 12v bed heating out. Perfect vid tyvm 👍

Excellent Video!! Great explanation of the different options. Thank you.

very concise and to the point--left me with minimal questions

Take it from a EE and use a power switch that switches the live and neutral. The switch is called a DPST switch. For the AC ground I would attach it to the aluminum plate that the silicone mat is sitting on since most beds have leveling springs or silicone standoffs.

Recently found your videos through my bad experience with my Tronxy. Still working on upgrading but I love the informative nature of your videos and delivery. Keep it up!

Thanks. Mainly focus on security. I'm looking for the safest AC hot bed possible and this is probably the only video that mentions using the hot line and ground details on the SSR.

Useful info, Im building a X350 x Y700 x Z450 bedslinger and was going to double up but buying a cut to size stand alone sounds good.

great video man.. i extended my ender 3 v2 recently to 300x300x400 and this is exactly what I was looking for to upgrade the bed heater

Ive watched loads of these guides and done the upgrade a few times the one thing no one ever mentions is that the mat heating to temp quickly isn't the same as the heat propagating to the top of the bed you need to allow time for this

Well explained.

Great video

Excellent tutorial, thank you! I believe 'uxcell' is just a generic Chinese retail brand. Meaning other generic Chinese retail brands likely sell the same SSR's as uxcell.

holy crap what a good video

Hey a fellow FT-5 owner! Great video. What about using a large heat sink for the SSR instead of the print frame?

Thank you!

wonderful video, so in the end which is best, the Mofset or SSR? thanks

How are you sending your bed temps to home assistant and what relay are you using to switch off power to your printer. Are you querying moonrakers api in home assistant?

Hi. I wonder why i can not find any 48v silicon heated bed's? Everywhere i look i only can find 12v, 24v, 110v or 220v bed's. Does anyone know why i should not use a 48v silicon heated bed? I have a Mean Well 48v 13A powersupply.

So I can hook up the silicone heater to my mainboard? I don’t mind how long it takes I just want something simple for now.

Thanks for your video. I was wondering if the silicone heater of 200x200 I wanted to buy would be a problem for my 225x225 aluminium bed. I do have some feedback regarding your safety disclaimer. It came across with me as if only Voltage matters when it comes to safety risks. In fact, although it's relevant to account for all factors, the real danger lies in the amperage. Voltage will just determine how likely your body's resistance will be enough to prevent becoming a neutral or ground. High voltage will easily arc thrugh the air and reach your body, but if the current is low, you will just feel a pinch. That's how some domestic 5000 V electrified fences work. They carry a very small current and will only scare you if get near it. Now I'd rather take 240 V shock from my a circuit in my house than (which I have), than 12V shock with 600A from my car's battery. Not sure I'd survive that easily as the times I got stung manipulating the 240 live without shutting it down.

Helpful video! two questions: are you using a zero-crossing SSR? Are you using PID control on your SSR controlled bed? Is so what switching frequency? From what I understand a Zero crossings SSR can’t switch nearly as fast as a mosfet I’m just wondering if that causes issues with PID control.

Beware that lot of SSR's do not go well if PWM controlled, they will just fail / melt.. When using a SSR, keep the heating control to "BANGBANG" (Marlin) or "Watermark" (Klipper) which just turns the SSR on or off without using a destructive PWM signal

I gotta ask, how much additional time was added to your o to 120°C temp drag race, putting an insulator between the Keenovo and 6160 plate? I too was a bit concerned, but my solution was to add one more layer of the High Temp 3M double sided affixing tape. Negligible increase, as I'm still sub 50 seconds to 120°C. I did use cork though, but as the final layer in my hotbed sandwich 😋😅😁 ... Reason being, I've got a 500watt PTC in the chamber, and one of the high velocity 120mm always seemed to wabble the bed temp 5°or more when it kicked ok. Not anymore with a cord finishing piece tho! As always, gr8 vid my friend! ...And if you have a spare minute, lenigma1 has sent more than 1 email since Christmas 😉😉

This is awesome. Sub'd

Hi, I got a 110v 220v 650w heating mat that has a total of 5 wires coming out, 2 small wires for the thermistor and then 3 red wires with no markings or instructions on how to wire this to 110v and or how to add a thermal fuse in-line, any help would be appreciated

Wait. What? 14:25 you said you have a solder joint on a mains heated bed? Umm. Am I misunderstanding what is being said. I have always been told that you should never, never have a solder joint on a heatbed connection anywhere. Can you please explain this for me... Thanks.

Great info. What thickness did you use for the cork tile?

I have a question, lets's say I want to put 3 Ender 3 V2 Beds all together, at 220W per bed I will need at least 660W. If I buy a 1000W power supply, will the mainboard be able to accept the wattage and high amps?

Your ac silicone bed is very different from mine apparently. You’re showing just over 4 minutes to reach 95c while I did with mine (750 watts while yours is 700 watts) in just under 2 minutes.

which type of cork to be used natural or rubber cork?

Any recommendations for an SSR from a reputable source? I am very sketched out seeing 10 dollar relays on Amazon/eBay.

thanks impotent information

bro I need help, the more I look at yt the less I understand ... I'm afraid I'm going to screw something bad with the heater connection. I took myself (skr 1.2 pro motherboard) with a few upgrades that I plan to apply ... but the more I look, the more insecure I am about the security of everything. I need a heat bed, a nozzle heater, a chamber heater (80C max) and maybe a filament heater for drying. I plan to connect 5 stepper motors (no 17, 3x32mm, 1x40, 1x48mm) Probably 8-10 fans 2x chamber fans 3x housing 1x power supply 2x cooling of the print 1x hot end 1x filament dryer + screen, bl touch and other little things if I left something out I currently have a 12V 360w (30A) power supply, I think I will need another 24v power supply to connect it all. Besides ... how many fuses do I need .... 60? How much mosfet do I need?

Voltage doesn't kill. AMPs do.

great informative video. thanks so much making and sharing your knowledge. for future you try and normalize your audio little better. it's something i haven't done well myself for my videos. but a quick right click on your video, launch the `stats for nerds` and you'll see the audio for you video is normalized around ~ `-9db` get that sucker closer `0db` so i dont have turn my volume on youtube to 100%.

12v Will Never give you a shock! even with water on you hands. Perhaps some people can feel 24v with wet hands i cant!

Hello im working on a printer with a dual bed combination do you have a contact mail? i have few questions to ask

"ac ssr" is a simple thyristor circuit. There is nothing to pay $50-60 for.

Nice shirt. Pretty sure it would take at least 2 people. Maybe 3.

im hoping that shirt is a letterkenny reference haha

So, the cork sit on the top of the aluminum bed, the heater pad sits on top of the cork and the glass sits on the upside-down heater pad with the 3M sticky side still covered??

How many people does it take to #*^# an ostrich?? 🤣😂

we heard it was a sick ostrich

12 to 24 can't shock you heck even 84vdc can't

so much babbling and overthinking ... 220v heated bed with a cheep chinese SSR is just fine .. no fuse bullshit or grounding wires to frames and other crap like that ... juust keep an eye on the printer when you print .