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How to deal with very hot and cold temperatures when using 3D printed and metal parts? Answered

As the title states...
Currently struggling a bit with my cooling tube project.
I finally got a prototype that is both usable and printable.
And when I thought I can somehow deal with the limited air supply of my compressor I got hit by total parts failure :(

The obvious idea beind this old invention is to have one side of the tube freezing cold and the other rather hot.
To the problem at hand:
1. Resin based glues with activator don't like to bond anymore once you go below zero.
And once getting over about 80°C they go soft and fail as well.
2. Putty like glue is impossible to apply properly and suffers from simial temp rpoblems unless you go the special purpose route.
3. Silicone seems to be the way to to go but it is simply impossible to cure when sealed in with basically no air and moisture reaching the still uncured areas.
4. ABS goo as my last result but ABS itself does not provide the properties required to print in the fine details needed :(

I am currently experimenting with a PLA blend that has some ABS in it.
Chemical welding with Acetone works similar to just ABS.
However it goes soft at even lower temps than either ABS or PLA.

Possible solutions I still try to avoid:
1. Using screws.
2. Using threaded connections for the pipe and fittings (just a pain to print).
3. Single print for the entire construction.
Number three would be still possible on a well calibrated printer but would also mean that there is no easy way for mods, like using a different vortex generator.

Right now my desing went down from over 15 parts and the need for well over 20 screws to just 4 printed parts for the generator end and 2 parts for the hot end.
Plus of course length of aluminium round tube.
But I can't finetune the design to match the tube if my parts constantly blow apart LOL
Embedded printing would work great and result in a properly closed generator end with no need to glue or screw anything.
But it is not for the beginner and certainly not the easiest way out for everyone.

What I would need:
1. Can you recommend a glue that works well with PETG (my prefered option for the final design) while also keeping full bonding strenght between -20 and +100°C ?
Preferably with the option to fully cure quickly and in enclosed spaces.
2. Is there such a thing like these air hose quick connectors that work with aluminium pipe?
I have seen collar like inserts that claim to provide a pressure secure fit but they are permanant things and it is not possible to get the rod out again...
3. If you have some easy and simple way to make an airtight connection between a printed part and an aluminium rod then don't keep it to yourself please!!! ;)


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12 months ago

It's not clear what you are trying to build. Can you provide a picture or CAD image? PM if you like.


Reply 12 months ago

It is a relatively simple Ranque-Hilsch cooling tube.
Just imagine you want to get a smooth aluminium rod into a smooth bore to fit and stay there - without using screws.
Will see if I can upload some pics of the current design on the weekend, now I first need a few hours of sleep.