Can I use hard tubing with these fittings?

[ch3w2oy]

I got a great  deal on a cooling setup and the fittings the guy is sending me are these. 

 

I made a thread about it, as I'm searching for a case now. 

 

Anyway, these fittings I linked to above, the dude is sending me soft tubing that he bought for them and I'm curious if I can use it with hard tubing instead? The website says it's 3/8 ID and 5/8 OD. Please don't take my word that they are for soft tubing as the guy could have been wrong about them, please confirm this for me as this is my first loop.. Thanks! 

 

Does 3/8 ID and 5/8 OD hard tubing exist? If not, can I use elbows to clean up the soft tubing to make them appear straight or will they have a heavy sag to them no matter what?

 

He wants to sell this as a package so the only way I get a great price is to get the fittings with it, so I'm trying to make it work with the ones linked above. Unless someone tells me 3/8 ID will impact performance, then I won't get them.. 

 

Thanks a lot, any advice or tips are welcome! 

[Dissitesuxba11s]

6 minutes ago, ch3w2oy said:

Anyway, these fittings I linked to above, the dude is sending me soft tubing that he bought for them and I'm curious if I can use it with hard tubing instead?

No, these compression fittings are made specifically for soft tubing.

7 minutes ago, ch3w2oy said:

Does 3/8 ID and 5/8 OD hard tubing exist?

No, only soft tubing.

10 minutes ago, ch3w2oy said:

If not, can I use elbows to clean up the soft tubing to make them appear straight or will they have a heavy sag to them no matter what?

You can, if you can cut the soft tubing at an exact length that there is no slack.

13 minutes ago, ch3w2oy said:

Unless someone tells me 3/8 ID will impact performance, then I won't get them.

 Tubing ID doesn't make a difference performance wise.

[ch3w2oy]

2 minutes ago, Dissitesuxba11s said:

No, these compression fittings are made specifically for soft tubing.

No, only soft tubing.

You can, if you can cut the soft tubing at an exact length that there is no slack.

 Tubing ID doesn't make a difference performance wise.

Thank you! That helps!