Thanks for the kind comments guys!
Will try and remember all the questions......
I was a machinist for 15+ years, but now I work at Toyota doing quality verification (portable CMM measurements) on new bodyweld equipment. And yes Dave, that's definately a lathe & mill, although they're just cheap ones from Harbor Freight. My last project was doing a 2 axis CNC conversion on the mill. It's in a varying state of incompletion.
The tubing is 316, I bought two 5' sticks of it for $135. It's .065 wall, so my effective gap is about 1.5mm or .060" Scotty, I seriously doubt you can find any "standard" ss tubing with any thicker wall. You *MAY* be able to find some workable combonation of inch & metric size tubing that will close the gap, but I'm not sure where you'd find the metric tubing at. Truthfully, I really don't think it needs to be any closer than what it already is.
BTW: good luck with your move! It's really difficult to keep up with a project like this in the middle of a move.
The bigger cell will fit inside a 4" PVC pipe. I've got a housing already made for it. Unfortunately I don't yet have an ammeter (although I see they have one on sale at Harbor Freight for $4.99, so I'm there!). I also haven't configured a LPM gauge yet either. I can tell you that it worked scarry good though! I ran it straight off my car battery with about a tsp. of baking soda, and it bubbled like crazy. It bubbled at least as much as some of the really high-output units I've seen on Youtube. BUT, it also drew big-time current, melting the nylon nuts I had on the electrodes. That's when I built the smaller cell, because I didn't know if I could tame-down the big unit enough. I bet it was pulling well over 30 amps.
Actually I do have an ammeter, but it only reads up to 20 amps. My smaller cell was pulling around 18 amps, but I was running it open-top, so I can't guestimate the LPM. I don't have the housing for it complete yet. It will fit into a 3" dia. PVC pipe.
Here's a pic of the small cell taken apart. I drilled & tapped 3 holes radially in the top & bottom of the inner tube, then put in 6-32 nylon screws and machined down the heads so the outer tube would fit over them. I also wanted a design that would pull apart easily for occasional cleaning.
The tubes are the same that a F-16 might use.... 1/2 round with a 5/16 SS bolt in the middle. I ran zip ties between the bolt and tube to avoid shorting out. It's pretty strong stuff.
HomeGrown If you configured the tubes differently to use a few neutrals it may tone down the amp draw or use distiled water only.
I ordered my 316L tubes tonight I'll have a .060 space between tubes also. To incorporate neutral tubes we'll need another way to get the electricity to the tubes
It's kind of ghetto but I put a radiator clamp around each tube and put wire under the clamp and then hooked them up to the -...
I suppose I could try and use 1/2" tubing inside the 3/4" inner tube... I will give that some serious consideration. It's definately doable...
EDIT: I was just about to order the 1/2" tubing but then I started thinking..... The 1/2" tube will have only have a little more than half the surface area of the 1" tube.
Is that going to be an issue?
1/2" tube = 1.57" circumference
1" tube (.87 i.d.) = 2.73 circumference
EDIT 2: Maybe I should try a 1/2" bolt for the center electrode, since it would have more effective surface area....
How about 1 1/4 pipe on the outside?
Logistics and cost keep me from using 1.25". My current setup lends itself to really easily put in a smaller .5" dia. electrode. Plus, the place where I get the seamless 316 tubing only goes up to 1.00" dia. I imagine the cost of 1.25 dia. 316 tubing would be
The price for a 6' stick of .5" dia. tubing is $38.
Type Stainless Steel Seamless Tubing
Metal Stainless Steel
Shape Single Line
System of Measurement Inch
Outside Dia. 1-1/4" (1.25")
Inside Dia. 1.084"
Wall Thickness .083"
Type 304 Stainless Steel Material — -425º to +1,500º F Operating Temperature Range
36" 89895K179 $81.35
12" 89895K279 39.44
6' 89895K65 123.26
Type 316 Stainless Steel Material — -325º to +1,500º F Operating Temperature Range
36" 89785K179 $80.94
12" 89785K279 36.29
6' 89785K85 139.56
I worked inspecting tube heat exchangers for many years most of which are made from SS and other alloys.
www.tubesalesqld.com
This place is located in Houston and supplies most of the exchanger shops in the area. They have minimums but they also have tube sizes in Metric and standard. You could actually start at 3/16 and continue to 8" with just minimal gaps between sizes. I think they are also a sources for Copper/Nickel and other alloys that are much better conductors and very close to being as resistant to corrosion as SS but may be a bit pricey.