Gina

Testing TEC1 12703 only in the rig shown above. Starting temperature with camera powered = 29°C. Trying the observatory supply voltage of 13.8v first then I'll see if it's better with a lower voltage. Now waiting while the camera temperature drops and settles.

This is the only one I can find that meets my spec in RS-online. Not cheap so I shall try the TEC1 12703 first and only buy this one if I find I need it.

It seems to have settled at 10.5°C - 8.5°C drop. The previous result for the single TEC1 12703 was much better but I'll check that again.

Running on 10v and it seems better. Now down to 12.5°C a drop of 6.5°C. I'll leave it running for a while and see what it stabilises at.

In fact the rig was still on the table from when I tried the new TEC this afternoon. I now have the dual stack with the two TECs connected in parallel to the 13.8v supply. Temperature fallen from 19°C to 18°C a mere 1°. Now trying 12v which I think is about the optimum voltage for these TECs. Temperature has dropped another half degree!

I can certainly try it with the test rig I used before.

I though I had ordered a better quality 40mm x 40mm Peltier TEC but it arrived today and it turned out to be 30mm x 30mm and less efficient than the TEC1 12703 I already had. It was my mistake so can't argue! The TEC1 12703 was a lot cheaper. There are no other 40mm x 40mm TECs on either Amazon or ebay so if I want something better it will have to be Farnell Element 14 or RS online - I don't know any other suppliers.

Been reading up more on Peltier TECs. Seems stacking is very inefficient. I think stacking only works in astro cameras because they are only cooling the image sensor. With my ASC I am cooling the whole camera including all the electronics which is generating heat and therefore there will be far more heat to get rid of. From this I conclude that double stacking is not going to work for this application. Another thing I've learnt is that the TEC wants to be as big as possible as larger TECs are more efficient, so going from the 30mm x 30mm TEC I used before to a 40mm x 40mm should give better cooling. For anything bigger the cost becomes astronomical! The information also confirmed what I already know and that is that efficient cooling of the hot side is of prime importance, which is why I went for water cooling earlier. The latter is still a possibility if I find forced air cooling insufficient. Alternatively, I could go foe a bigger heatsink. Meanwhile I'll stick with the present design and see how it goes.

WAKEFIELD SOLUTIONS TEC-30-36-127 PELTIER THERMOELECTRIC COOLER, 3A, 15.4V NW for my all sky camera.

I run at 80mm/s with 0.8mm nozzle. Volcano hotend with 60W heater.

Very nice.

Magnificent!

I use 240°C for PLA and 260°C for PETG except that I tried 280°C for PETG where there were steep overhangs but not sure it helped - I have some more experimenting to do. I didn't realise a bigger nozzle wanted a higher temperature. I tend to use a 0.4mm nozzle for higher precision parts and 0.8mm or 1.2mm for bigger, lower precision parts. Though on my Giant printer I've been up to a 3mm nozzle plus various smaller sizes and my own design hotend.

Yes.

260°C

I tried a PEI sheet - total disaster! Filament sticks better to clean glass when hot and releases nicely when cold. The hot nozzle burnt the PEI when Z homing using the Precision Piezo Z probe. I ended up removing the PEI sheet and then struggling to get the goo off, though I managed it in the end. Unfortunately, before the PEI disaster on the 300mm square bed I bought a PEI sheet to attach to the aluminium bed of my Giant printer when I get back to upgrading it but I probably won't be using Precision Piezo Z probing. I tried using glass on top of the 500mm square aluminium bed but guess it was too thick as it didn't get hot enough. I haven't decided if I shall use the 500mm square PEI sheet yet.

Made up a second hotend for my Concorde printer to take 2.85mm filament of which I have quite a lot that I got in a sale. So now I can print final versions of the ASC parts in white PETG. Currently printing the "roof".

Ooohhh pricey!! The timber sizes are fine though mostly bigger than mine. I got my timber from a timber merchant just outside Hemyock in Devon. I had already tried Wickes, B&Q etc and the timber yard was about half the cost for better quality timber. You beat me to it in ordering - I didn't think you would proceed so rapidly. Sorry about that. I bought pre-treated timber (tanalised I think they call it). I did give all the timber more treatment after cutting as well.

Having fixed the hotend cooling fan it now sends too much vibration to the Precision Piezo Z probe sensor and causes triggering before the bed reaches the nozzle. I thought of trying a different mounting method which meant work but then though of turning off the fan just during the Z homing - shouldn't warm up too much in that time. M106 P1 S0 should turn the fan off but doesn't. Nor does M106 P1 S0 I0 or M106 P1 S0 I1. Thought "I'll ask the GCode gurus on SGL" and went and did my grocery shopping. Meanwhile, my brain had been active - M106 P1 S1 I0 F500 H1 T45 turns on thermostatic control so that the hotend fan runs when the hotend is above 45°C so I thought "Maybe if I set the temperature well above normal range the fan will turn off" so tried M106 P1 S1 I0 F500 H1 T300 and it worked. My homez.g code now reads :- ; homez.g ; called to home the Z axis ; G91 ; relative positioning G1 Z5 F6000 ; lift Z relative to current position G90 ; absolute positioning G1 X150 Y150 F6000 ; go to first probe point ********************************** M106 P1 S1 I0 F500 H1 T300 ; Set fan 1 value, Thermostatic control is above normal range to turn fan off G4 S2 ; Wait for fan to stop G30 ; home Z by probing the bed M106 P1 S1 I0 F500 H1 T45 ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned on Still wonder why M106 P1 S0 didn't work as the Duet web page says but found a fudge so that'll do.

Don't think my saw cost that much but OTOH it was some years ago! I found EDPM easy and quick on both ROR and warm room roof. I did it on my own too.

Designed a "roof" to go over the outer housing and cover the air vents to keep rain out. Any resemblance to a "flying saucer" is purely coincidental 🤣

Air vents in the outer housing.

New design - now printing.

Tried the air intake bracket against the roof and it needs altering a bit, as expected.

Well, I printed a toilet roll holder when the wooden one broke some years ago 😄