So as I transition from my handy little CM column to a modular design, I’ve decided to build a CCVM head for my new 2”column. I’ve read around the site, and it seems like there have been two materials of choice for the coil:
1/4” copper tubing — it’s always nice to have a bit more copper in my stainless rig, but my missus the artist tells me that copper is surprisingly unforgiving. She says “it’s all soft and pliable. And then it isn't.” I’ve seen some interesting things about avoiding kinks by filling with salt, but…
3/8” CSST - I gather that the corrugation adds some surface area, bit I wonder about the sizing — is 3/8 gonna wind to fit in a 2” tube? It also seems that the only tubing I can find in that size is coated. Is it as easy to skin it as the videos suggest?
So what’s the collective wisdom these days? I reckon they can both be outfitted with pressure fittings adapted to my standard coolant plumbing, so that’s good — I’m a miserable solderer (and a worse welder).
Dr Griz wrote: ↑Thu Jul 01, 2021 5:11 pm
- 3/8” CSST - I gather that the corrugation adds some surface area, bit I wonder about the sizing — is 3/8 gonna wind to fit in a 2” tube?<— It will. In fact, it’ll be easier to fit than the 1/4” soft copper.
It also seems that the only tubing I can find in that size is coated. Is it as easy to skin it as the videos suggest?<— Probably not. Some have tried peeling it off and some have even tried to burn it off. I suggest keep looking around for corrugated stainless steel tubing that isn’t covered with a coating.
So what’s the collective wisdom these days? I reckon they can both be outfitted with pressure fittings adapted to my standard coolant plumbing. <— The copper tubing will have brass compression fittings and some copper sweat/solder fittings. The CSST should have special brass compression fittings.
Dr Griz wrote: ↑Thu Jul 01, 2021 5:11 pm
- 3/8” CSST - I gather that the corrugation adds some surface area, bit I wonder about the sizing — is 3/8 gonna wind to fit in a 2” tube?<— It will. In fact, it’ll be easier to fit than the 1/4” soft copper.
It also seems that the only tubing I can find in that size is coated. Is it as easy to skin it as the videos suggest?<— Probably not. Some have tried peeling it off and some have even tried to burn it off. I suggest keep looking around for corrugated stainless steel tubing that isn’t covered with a coating.
Thanks for the good info, even if it’s bad news: uncoated CSST is superior to copper but harder to find. I guess I’ll have to keep looking. Anyone have thoughts about where to source it?
My CSST came from a flea market, so I don't know its actual source. It had the yellow coating that stripped off fairly easily. Here's a pic:
I would suggest looking around for it at hardware or big box building supply stores. I think I remember seeing it at Lowes. If it's sold by the foot, buy a foot and take it home and see how difficult it is to remove the coating.
About hose connections - I use clear silicone hoses and attach them to the CSST using hose clamps. Buy hoses that have an ID that matches the OD of the CSST. You may have to heat the hoses a bit to make them pliable enough to slide onto the CSST. The concentric corrugated ridges make for a good seal.
Good luck with it.
Every new member should read this before doing anything else:
OtisT wrote: ↑Fri Jul 02, 2021 6:00 am
IMHO, if you have the build skills make a copper coil. If you just want it done w/o another project, use the CSST. Otis
I’m sorely tempted to go with copper, not because I have the build skills, but because I’d like to build my skills.
That being said, I reckon I’ll try CSST to start, so that I can get to playing with CCVM goodness while I play with copper on the side…
In a fit of inspiration, I popped into a venerable plumbing supply business — turns out that they had a big roll of the gas tite csst, just gathering dust in the basement. Seems that 3/8” isn’t all that in demand and the old easy-to-strip coating isn’t as good for its intended purpose of insulating gas lines. They were pretty happy to get rid of it.
My daddy always said it’s better to be lucky than good…
cob wrote: ↑Fri Jul 02, 2021 8:30 pm
Did you end up with a lifetime supply?
He gave me more than I figured I’d need, so I reckon so. But I didn’t want to clear him out, in the off chance that one of you fellas might get the same idea…
Thanks again to everyone for their advice -- the bit about running a screw driver through the loop at the end was particularly useful. It's all leak-tested and cleaned, and I'm looking forward to my first CCVM run!
But now I have a problem -- I reckon I got a hang of the technique just with the last few twists. I may have to make another just for the sake of craftsmanship!
Good job! I reply late but both copper and CTSS will give excellent results, they are very different in malleability, CTSS generally folds more easily (if small diameter) the copper has the advantage that if you have a stainless steel column add copper will do well to your product. A greeting!
I think I may have to play around with making a copper coil, too, now that I have something that ought to be serviceable for getting my new build running. I’m really curious to see how the difference in conductivity between SS and copper that Tiramisu pointed out play out in this context.
I’ve seen some interesting things about avoiding kinks by filling with salt, but…
