For those looking for a ready made solution to getting SSR switched 110v heating, and PEI coated print surface, this is $300 but may be what you’re looking for. It was out of stock, but it now available again. I had (sometime back) asked to be notified, and just this morning got word they have more. It’s compatible their Sidewinder X1 printer, but likely you could figure out how to use it with MP3DP.
Someday … Looks pretty nice. I am still unusually nervous about jumping to 110VAC. I am using 24VDC now and it works. But this would be a nice upgrade.
The 110v AC was an option I chose to do when doing the “Ender Extender 400XL” kit on an Ender 3 v2, and I’m always glad I did. Works perfectly, and the fast heat up is so nice.
I only worry about how it will fail. I am sure it will work well. I might be underestimating how nice it will work in the nominal case.