Reflow Fred Style! :-)

[Fred]

A few pics to illustrate just exactly how hot it got in there...















So I decided to make the baking tray for the PCBs out of the alloy (this is where Abe got all upset).















But it didn't fit properly, because I'd put too much glass fibre insulation in between the layers.

And the heat made it bow from expansion anyway, so I "fixed it" (pun intended) with a couple of screws.



And called it good. Tune in next time for the high-tech electronic side of the modifications! :-)

To be continued...

Fred.

[Fred]

As you may recall, I baked the thermocouple IC first, by feel.



First I dismantled the thermocouple and recorded the polarity of the cable going
into the plug by orientation of the printing on the shrink sleeve.







Then I loaded up the schematic and started getting artistic with components! :-p























Things seemed to be going well, so it was time for the first cold-on-hot-off-cold test! :-)





The circular thing on the little circular PCB is a piece of solder so I could tell when it was hot enough.
I didn't actually get a reading from the thermocouple this time around, so I killed it before it got hot.

To be continued...

Fred.

[Fred]

After some scratching of my head, and chatting to DeuceEFI on IRC, I realised that I had
simply been ignorant and ignored a crucial but unimportant-looking part of the schematic.









In the process my thermocouple wire got shortened a significant amount :-)

But, it was time for another test!





This was the noisy test that I posted earlier, but largely a success.

The thermocouple wire insulation showed signs of being plenty hot.



And the noise meant that I thought I'd follow the schematic even more closely and add some filtering.





Plus, the expansion forced the door partly open from about 200C up, so I fixed that too.





It must be time to control it! :-)



I don't have the rest of the pics handy right now, but I'll try to find them and do another post soon.

To be continued.... but not today! :-)

Fred.

[Fred]

viewtopic.php?f=9&t=1621 < johntramp, now it is! :-p

[Fred]

How many people bugged me about these pics? How many of those commented at all? Poor form.

Today the oven baked another tcouple IC. Tonight I have two working and tested. Tomorrow I might do some experiments!

[ToxicGumbo]

How many people bugged me about these pics? How many of those commented at all? Poor form.

I was skeptical about the need to insulate and double plate the unit, but you sure as hell have it down to a predictable state, which is nothing short of impressive.

You need to come up with a logo, such as:



Oops...wrong image. Maybe more like this:

[johntramp]

Classic. Do you think the insulation helped much? And have you tried your slice of bread heat distribution test again with the alloy plate?

[Fred]

Do you think the insulation helped much?

Yes, a LOT. You can almost touch the top and back with the inside @ 300C now. Before you couldn't get closer than about 10cm from the back - the radiated heat was too much.

And have you tried your slice of bread heat distribution test again with the alloy plate?

No, but that's a stellar idea! If we obtain another bimbo for thorough use, I will commandeer some for this purpose.

[Spudmn]

Hey Fred. I thought that you might like this.

http://hackaday.com/2012/06/18/toaster- ... overboard/

[Fred]

LOL :-p

The actual link, for those wishing to short cut Aaron's trickiness ;-)

http://hobbybotics.wordpress.com/projec ... ler-v8-03/