This seems very difficult to get in this size. Springs come to mind but I'm looking for something with longer grooves in between each rib.

a pulled apart spring?
Stretch a spring lengthwise until it gets the wanted measurements when you let it relax again ?
Another option is to wind thin copper wire tightly around a suitable steel rod or nail and then gently pull it out to get the desired distance between the wires/ribs.

Have you got an image of the real thing somewhere?
/ Robin

Try;

Prime miniatures
MFH
Tuner model manufactory
Hiroboy
Detail Master
KA Models

Ian

I Googled for pictures to figure out what corrugated hose looks like.
If I were to try and make this in 1 mm size I would get soft copper wire, 0.8 mm in diameter and take two thin copper wires, 0.1 mm and wind a double coil around the 0.8 mm wire. Make sure that the thin wires don't cross each other or get mixed up.
When the spiral is long enough it is time to carefully unwind one of the thin wires to leave grooves between the ribs.
Fix the remaining spiral in place by carefully applying CA-glue.
If you are an EXPERT at soldering you might try but I wouldn't trust my soldering skills to do it good enough ...

/ Robin

Miwa,
It might help if we knew what you are using this for-- NBC or oxygen hoses perhaps? I make mine out of fine solder and wound copper wire per the method someone mentioned above-- but there are other ways too. One I've used before is to use Ka-dee coupler springs (a model RR product) slipped over fine brass tube.
VR, Russ

I have some plastic corrugated hoses from some of the brands mentioned above and they're very useful. Primarily intended for car modelling: radiator hoses, air hoses, etc. I got mine from BNA Model World in Australia while I was ordering some other things. Have a look at their site. I'm sure there are other sources: I think the brands are all Japanese, so someone like HLJ might have them. Model Factory Hiro is another brand that comes to mind.

Also, don't overlook guitar strings - especially bass strings for larger diameters. They won't give the effect you're looking for here but are very useful for ribbed cabling or ducting in many scales. There are at least 10 diameters available. The only down side is that they're quite stiff and can be awkward to bend to shape. If you know a guitar shop, tap them up for offcuts from re-stringing: I used to steal my son's offcuts and old strings before he moved out. But budget brands aren't expensive to buy considering what you get.

MDC makes excellent flexible resin oxygen hoses in a couple of thicknesses, one of which is around that.

links:

http://www.modeldesignconstruction.co.uk/mall/productpage.cfm/ModelDesignConstruction/_mdcdt08/54274/Oxygen%20Hose%201.5mm%2F2mm

http://www.modeldesignconstruction.co.uk/mall/productpage.cfm/ModelDesignConstruction/_mdcdt07/54274/Oxygen%20Hose%201mm%2F0.8mm%2F0.6mm

Miwa,
Here's a method I have used with some success:

Start with a length of wire with a diameter that matches the inside diameter you want. Wrap that very tightly with very fine wire to get the right outside diameter. Now set a knife edge in the groove of the fine wire at one end and start rolling the whole thing across a flat surface. The knife blade will slightly space out the fine wire (you may have to gently slide it off the core first if it doesn't want to space out properly). Finally, use some CA glue to hold everything in place.

Good luck!

Guitar string? I have used bass/guitar strings to make cables before and liked the result. And they come in various sizes.