Reflow Master Pro housing for Ninja toaster

Having become thoroughly frustrated with my T962 ‘reflow oven’, I decided to take the plunge and build one myself. After doing some research, I found that the Ninja toaster/air fryer seemed like a good bet for a donor oven, and I scored a used one on eBay for not too much. 

Controlling the oven would be the amazing Reflowmaster Pro from Unexpected Maker. This great little board has integrated wifi and web UI for editing protocols, and uses really nice and flexible thermal control logic. 

My goals for the build were to have it be well insulated, tidy, robust, and to give me the ability to control as much of the functionality of the toaster as possible.

There are two main elements to this build: the electronics insert, which contains most of the AC components and organizes them inside the existing toaster electronics compartment; and the display housing, which holds the RMP.

I'm so tired

This project has fully engaged my ADHD hyperfocus for the last week, and so I regretfully am not going to have the spoons to do a full step-by-step how-to at the moment. So here are a few thoughts and lessons learned while they're fresh in my mind, in case you should like to give it a shot yourself.

Toaster disassembly

I mostly followed the instructions above for basic disassembly. In addition, I found that popping the sheet metal top was a really good move for insulating, and definitely should have done it sooner. To do that, you need to remove the rivets holding it down at the top of each end. On the left side I was able to easily drill it out; on the right side, I loosened the screws attaching the front control panel assembly enough to shimmy it out a little, and was able to get a Dremel cutoff disk in far enough to cut off the rivet head. 

Toaster wiring

The link from 84ace doesn't really explain the AC layout super well, and my wiring didn't really match anyway, so please only attempt if you are fully qualified to reverse engineer and test yourself. 

On my toaster, the elements all shared a common (white) neutral tied in to the left side, while the top elements shared a red and the bottom elements a blue live side. I tied the live sides together to the SSR output using a 10AWG-capable Wago connector. 

 There was also what looked like it might be an overtemp protection element of some sort screwed to the lower right side, with a blue insulated and a yellow insulated wire going to it. I capped those off and left them disconnected. 

I added a DPST power switch to cut L and N AC power between the cord (input) and the 5-terminal Wagos I used as AC distribution bars.

To power the DC side, I used a 5V/2A power supply module from Amazon. 

To control the AC convection fan, I used a 5V relay module. 

I replaced the existing 12V electronics cooling fan with a 5V one.

The inside-toaster electronics should be mostly assembled and wired on the printed insert outside the toaster, then the whole thing installed into the toaster. You'll need to break off a couple plastic fins to get it to fit, but when that's done it should slide right over the standoffs for the original PCB, and you can fasten it in with the same screws. 

RMP wiring

I soldered leads onto the five interface buttons of the RMP so I could use fancy external switches – these 8mm ones for the four control buttons, and a 12mm lighted one for the on/off button. (There's also a printed adapter if you want to use an 8mm switch for on/off too.)

I added a spot for one of the auxiliary fan controllers from Unexpected Maker in the display housing. It attaches with 2 M2/M2.5 self-tapping screws into the plastic. Currently it's operating the 5V cooling fan, but in the future I might try and rig up a cooling air fan pushing through the oven light port controlled by this module.

The housing has spots for smaller 5-position Wago connectors to act as the 5V power bus, as well as zip-tie attachments for cable management. I strongly recommend pre-inserting the zip ties before install the RMP!

The RMP is attached with M2.5 screws and standoffs through the display into the plastic part. I had to swap the existing F/F standoff for a new M/F standoff (5mm with an additional nut threaded on as a spacer to make it 6mm). Then the main board plugs in to the SPI header and is screwed into the standoff on the other side.

I drilled small holes near the top of the right and left sides of the toaster to feed the thermocouples.

Printed parts

The printed parts assemble with M3x4mmx5mm brass threaded inserts and FHCS and SHCS screws of various lengths. The two exterior_ (lower and upper) parts can be connected together with M3 FHCS before installing to make things easier, if you want. The display housing is held onto the the exterior_upper using the retainer part as a clamp, with M3 bolts tightening it against brass threaded inserts in the exterior_upper. 

The USB cover just friction fits, and can be removed to flash new firmware. If you tilt the display to point vertically, you can fit a normal USB-C cable into it over the top of the toaster.

The exterior parts fit into the hole where the plastic handle goes on the stock toaster. To remove it, just unscrew the little phillips head screw holding it in at the bottom of the side panel, and slide it down and out. The printed parts assemble together with the interior part on the inside and M3 screws clamping it to the brass threaded insert in the exterior_upper and exterior_lower parts.

I've included highlights parts that can be imported together with the display housing and/or the exterior_lower part for use with MMU multicolor printing. 

Insulation

I more or less followed the recommendations from this guide from Whizoo. I used high-temp RTV silicone to seal the internal seams of the toaster, then added ceramic fiber insulation around the oven chamber. Care must be taken on the left side so as not to interfere with the lid hinge mechanism. By taking the sheet metal off, I was able to lay one piece front-to-back and one piece side-to-side, then tuck some additional pieces behind the electronics compartment to help keep it cooler.

Finally, I used reflect-a-gold on the inside of the door and oven sides and some floor and tunnel shield in the top and bottom of the oven.