Experiment 'upside down' heat block

I had a bed adhesion issue on my Prusa a while back, I learned a lesson look really carefully at downloaded STL files. The first layer was not actually touching the bed. I digress.

I ended up with the a mess, blobs on everything. I pulled the J head and started cleaning, when I went to pull the heater cartridge out and Thermistor I found the grub screw hole filled as was the allen recess in the screw holding the heat block. I fought with this for a while and decided to cut my losses and replace the block and parts.

The I reassembled I got to looking at it and thought if the grub screw hole was facing up it would not fill so easily. So i have mounted the heat block upside down.

This changed the relative Thermistor and heat cart. positions but as I tend to prefer brass blocks, I am hoping this will not make a difference. Thermal mass and all. I am still using a X nozzle and it needs a bit extra time to heat up so the changed positions in my mind will not make a difference.

I have very successfully printed 3 replacement fan shrouds in ASA (first time with it. why was I ever printing ABS??? No more, ASA printed flawlessly)

Has anyone else tried this?

1 Like

Cant say ive heard of this hack, but if it makes sense then awesome. I’ll keep it in mind.

If your waiting on the nozzle in particular anyway, moving the heater cartridge to a different orientation should make only negligible difference. Though it would be interesting to see how much of a change it does make. By anychance do you have a separate thermometer or thermal camera?

Mind posting what your setup looks like? im also trying to wrap my head around how the allen key is “upside down”… Looks over at my prusa mini which the hotend is caked with charred filament. Hmm i guess i can kinda see how, that with some designs could be an issue XD.

I’m not looking forward to trying to replace my heater block if i ever do. Though my other printers have near mint heater blocks just by good luck.

I have an old thermal camera, I’ll see if I can dig out the old phone it connects to. It will take a while I am heading away for a week tomorrow. I will take regular pics and I can easily do some details with parts kicking around.

1 Like

Ok no thermal yet. I will need to find an old phone still.

This is the correct orientation.

This shows a brass heat block with the throat attached upside down. There is an well used aluminum one correct beside it.

This is a old dirty block. The hex hole is clear but it took cleaning to dig out melted plastic the grub screw hole also was filled.

I am not sure I would attempt this with an aluminum block. The heat cartrage so close to the throat and low thermal mass might lead to issues. My thought is brass is slow to heat and slow to cool. It is more likely to promote raven heating. In the upside down orientation the grub screw comes from the top down, as does the pinch screw for securing the cartridge.

This might mean changing the cartridge mean removing the whole hot end but in practice I always do anyway. In my personal case the only time I have had to replace either cartridge or thermistor is because I broke a wire changing a nozzle. At that point there is no issue removing it anyway.

I’m curious to see what you all might think. Cons I have yet to think of? It has printed about 11 hours of ASA which printed like butter. Smooth and perfect.

1 Like

Should be fine putting it upside down also good job on printing ASA


if it works it works. the problem i could see is in order to remove the thermistor or heat cartridge you need to heat the block up before loosening screws. with them on the top you wont be able to service or replace without disassembling your extruder. And prusa extruders arnt designed for easy dissassembly.

1 Like

I have yet to need to disassemble the extruder. the X nozzle is not wearing so there is no need at this point. The prusa the fastest way to get the extruder open for service is to remove the bolts and disassemble it. I have large hands and can’t fit from the underside. It ,made no difference. To be honest it has been a successful experiment.