SPP Machine Begins

[BigSwede]

Biggeroots started a thread (http://homedistiller.org/forum/viewtopi ... 50&t=47960) on his SPP experiments, and I rudely jumped in and began a series of posts... my apologies. Here's where it's taken me, FWIW. Biggeroots thread is a good place to start, because this builds on everything we learned there in making this deluxe packing material.

Summary - did a boat-load of experiments, and determined that you need SS MIG welding wire or similar. Dead soft stainless tie or safety wire does not work. All you'll do is make some funky springs, and you may as well buy springs and pack your column with them. And I made a bunch of springs!

I also learned that tension is good, the more the merrier, right up to the breaking point of the wire, which, for a 2" to 3" column, is probably good at about 0.025". Everything I did here was with 0.023" or 0.57mm wire - just a bit light. Thicker wire will lobe out and spread out better than thin.

So, good bits and tension is the key. Can't feed it by hand all day, so I designed a very simple machine to do it for me. And it does not take machine tools to make or use. All you need is a bench drill press that can hopefully be slowed way down by whatever means.

I'll start with the machine, then go to the bits or mandrels that work correctly.

Overall. Yes it's on a lathe, ignore that, it was just for testing.

You start with a pretty heft piece of angle, aluminum is best, it drills and taps easily. This is the only part that might take some scrounging. Find one big enough that you can hang a spool of MIG welding wire roughly as shown.

Ignore the fancy handle. Take your spool of wire, go to the hardware sore, and find either a long bolt or better a big section of all-thread that will mount the spool. There needs to be room for a spring and washers and nuts. The spindle hole of MIG wire spool is pretty hefty, so maybe one could cut a section of copper pipe that would work, and use that over the all-thread.

If you have taps, use them and drill and tap the angle for the spindle. If not, drill through and use nuts on both sides to secure it. Slide on the MIG wire. Add a big washer. Find a pretty stout spring, add that. Add another washer, then two more nuts. Those nuts will be your tension adjustment. Nuts in, more tension on the spool.

I found that adding drag to the spindle was FAR easier than adding drag to the wire, but feel free to experiment. Two things:

1) You want to be able to turn the spool by hand, but it should feel pretty stiff. Play with washers, springs, rubber gaskets, whatever it takes. And it should be adjustable through a modest range.

2) IMPORTANT - be sure that when the spool of wire rotates, it does not move the adjusting nuts at all. That's why there are two, use one as a lock nut. Maybe put a single lock washer between them.

I made mine too fancy, had to add a lock lever to prevent this, because the spool self-adjusted towards higher tension and the wire broke.

The lock lever down and locked - don't need this with correct engineering:

Continued...

[BigSwede]

The wire feeds up and does a 90 degree turn. On the edge of your angle, mount a chunk of brass (or bronze even better) to route the wire. A big brass bolt will work. Solder it, braze it, drill and tap, whatever.

The wire approaches the mandrel. It is very handy to have some sort of clamp that you can tighten to hang onto the wire. The spool wire is under some spring loading, and if you let go, it'll uncoil a lot and make a mess.

Mine is grossly overengineered. This was designed to add DRAG to the wire, but in the end, I use it only to clamp it when cutting the wire or changing bits.

Suggest a single 1/4 x 20 socket head cap screw and a washer. The washer captures the wire against the angle.

Next, this one is important. Find some scrap brass, bronze, maybe copper in a pinch, but copper is very soft and will wear. Drill it as small as you can yet still pass the wire. 1/16" is fine. Mount it to feed the wire onto the mandrel.

That's 80% of an effective SPP machine. Once working, it'll make SPP so long as there's wire. The lengthening SPP strand will begin to weigh a bit, and it'll be rotating along with the mandrel, so what you have to do is mount a tube that is very smooth, no tight radii, to route the strand to where you want it.

I tried copper tube, poly tube, PVC, they all work.

Continued... House boss just came home, must hep with groceries!

[BigSwede]

I made six bits for a final test, numbered 1 through 6. Each varied slightly, but what they made varied hugely. Good news, it's not hard to make a decent bit/mandrel. I'll call them bits.

Start with a hollow-ground, decently hard regular screwdriver bit. For a 2" column, look for 1/4" or 6mm at the base. With some sort of grinder, you have to add a taper from root to tip of about 5 degrees along the edges. The pictures will help. And of course, a dremel to cut the starter notch.

I'm going to give the dimensions for all 6, and show what sort of SPP they made. The good part, most of them made acceptable SPP.

The rest of this post is just all six bits, and the SPP they made. The dimensions are in mm, and are width at the root, length, and thickness, and the SPP diameter from the given bit. Note how some do very well, others not so well, and there are trends which I will summarize.

They uploaded in reverse order, for whatever reason.

#6 The best, IMO, if a bit large. Diameter of the SPP is 7.4mm. Got consistent lobe stagger and coil spacing. Remember, quality SPP will have both. If the SPP is closed, no space between turns of the wire, effectiveness suffers.

#5, Good SPP, better than average.

#4 Acceptible, looks funky, but I think it'd be very effective. Smallest diameter of the six, at 5.4mm.

#3, Crap. VERY finicky, didn't wind well or consistently. It's too short! And too thick for its size!

#2 is a longer version of #3. It's slightly better, but not something I'd be happy with.

#1, An average size, very acceptable SPP in every way.

SUMMARY:

Note how the best (#6) in terms of ratio is by far the thinnest of them all. It is wider at the base, longer than any of them, and thinner to boot. This is the ticket. Think thin and long. SPP diameter is of course closely tied to the root of the bit, so in terms of ratio of base width to SPP diameter, they are all reasonably close, vary between 71% to 81%, i.e. base width divided by final SPP diameter. If you want SPP that is 10mm, create a bit that is between 7.1 and 8.1mm.

Thicker wire will not expand as much. This is for 0.023" wire.

If the bit is too short relative to base width and thickness, the bit may act like #3, and barely make SPP without a struggle. Look for a minimum length to base width of 1.25 or better.

Thickness: I'd go again replicating #6 of a thickness that is 20% or less than the root width.

So let's say you want SPP that is 9mm diameter... I'd go for a root width of 6.7mm, a thickness of (6.7 x 0.18) = 1.2mm, and a length of (6.7 x 1.25) = 8.4mm


Again, simplified

Bit root width = Desired SPP diameter X 0.75 (this will definitely vary with wire diameter)
Bit length = root width X 1.25
Bit thickness = root width X 0.20 (or less)

One last thing - don't create a concave area at the root where the wire can snuggle and cause subsequent turns to overlap and go haywire. That's where the sliding washer comes into play. There must be a continuous taper from root to tip.

More to come, if you can stand it!

[Bob Loblaw]

Very informative (and Cool!). Thanks for sharing. Looking forward to the rest of the story

[corene1]

Do you think you could make these out of copper wire, or would it be too soft? I have been looking for a place that sells copper pall rings in small quantities for using as packing but have not found one yet. We use stainless pall rings for packing in some foam guns we make for the oilfield industry. I was thinking they would make great packing for a column. Very low pressure buildup with lots of contact area. Looks like some experimenting is in order.

34.jpg

[BigSwede]

Do you think you could make these out of copper wire, or would it be too soft? I have been looking for a place that sells copper pall rings in small quantities for using as packing but have not found one yet. We use stainless pall rings for packing in some foam guns we make for the oilfield industry. I was thinking they would make great packing for a column. Very low pressure buildup with lots of contact area. Looks like some experimenting is in order.

34.jpg

It'd be possible, but in my limited experience, the soft copper wouldn't expand or have lobe stagger off the mandrel. Some sort of "upset" / contact device right at the end of the mandrel would pop it open and stagger the lobes a bit, and while I've tried different methods and it can be done, it's super-twitchy, and just a hair to much will wrap the entire output into a tangled ball. Too little does nothing.

I've seen GOOD copper SPP, so it obviously can be done. Just don't know how at this point.

I've often thought you could make a decent packing by cutting thousands (it'd be super-tedious) of copper rings from say a 1/4" tube, then taking a punch and flattening one half of the ring perpendicular to the original tube axis, if that makes sense. Basically upsetting, mangling each ring a bit. Maybe it could be done in bulk by the simple expedient of a ball peen hammer into a pile of copper rings. Poor man's pall ring.

But would it out-perform copper scrubbies, or stranded copper wire? Probably not.

Idea - some sort of female die. Stick thin-wall 1/4" Cu tube in. Say the die is about 6" long. Press hydraulic, or hammer, or squeeze in a vise. Portions of the die might punch, deform, or othewise make that 6" section into a pall ring imitation. You cut the 6" segment of say 16 pall rings in a row, then clip them.

It'd be interesting.

[Tokoroa_Shiner]

I've often thought you could make a decent packing by cutting thousands (it'd be super-tedious) of copper rings from say a 1/4" tube, then taking a punch and flattening one half of the ring perpendicular to the original tube axis, if that makes sense. Basically upsetting, mangling each ring a bit. Maybe it could be done in bulk by the simple expedient of a ball peen hammer into a pile of copper rings. Poor man's pall ring.

I have about 2m of 6mm copper tube that I mangled trying to wind a condenser for my boka build. Was planing to straighten it out and cut it with bench shears, turning 90* every cut.

[BigSwede]

I think ANY small, weird copper pieces with a reasonable surface area to volume ratio will work well. The question always becomes, will it work better than copper or SS scrubbies? In most cases, the answer is probably no, but I'm just guessing. Someone would have to test.

If we could make mini copper pall rings or some other known packing material, then yes I think it'd be better. But that's either expensive, or hard to do.

Overall, I think a small volume of copper might help those with otherwise all SS rigs.

[DAD300]

Beautiful machine BS...I used PVC and PEX to route my SPP Tubes off the work bench.

You tension devices will make it very easy to change wire dia's and mandrels.

[Odin]

Congrats Big Swede! Nice to see you doing this!

Tokoroa, this SPP is not so much about surface area. Corene, copper SPP will work, but will rust very soon. Special treatment is needed.

Regards, Odin.

[BigSwede]

I think I've made and tried 30 bits. The goal here was to bring consistency and math into it. The machine creates some consistency, and hopefully the numbers I came up with will take some of the voodoo out of it, because of those 30 bits I made, at least 12 wouldn't even come off the mandrel, they'd hang and wrap overlap. Five more would produce a coil, but inconsistent, or would fall off, or not open, etc.

Of these 6, I'd use numbers 1, 2, 4, 5, and 6, and probably get good performance from all of them.

Keep in mind that the wire diameter can and will affect in a big way what happens, but any MIG wire between 0.021 and 0.026" - and that's where most of us want to be anyhow - should follow the "math rules" decently.

Got to find more of those rubber-backed convex washers. And come up with an auto-cut system.

Close up #6:

[corene1]

Congrats Big Swede! Nice to see you doing this!

Tokoroa, this SPP is not so much about surface area. Corene, copper SPP will work, but will rust very soon. Special treatment is needed.

Regards, Odin.

Why would copper wire rust? We use copper for our still structures all the time. Would it be different than using copper mesh for the packing? Or did I miss something?

[Odin]

Hi Corene,

Copper SPP has a relatively high surface area. And SPP works best in semi-flooded conditions. High energy inputs, lots of reflux. What I see happening all the time, is that if I don't treat my copper SPP correctly, the rust quickly prevents reflux dripping down. Blockage & column flooding are the result. Or turning down the energy input, and thus lowering the overall packing efficiency.

Regards, Odin.

[corene1]

Hi Corene,

Copper SPP has a relatively high surface area. And SPP works best in semi-flooded conditions. High energy inputs, lots of reflux. What I see happening all the time, is that if I don't treat my copper SPP correctly, the rust quickly prevents reflux dripping down. Blockage & column flooding are the result. Or turning down the energy input, and thus lowering the overall packing efficiency.

Regards, Odin.

I am still missing something, I have never seen pure copper rust. Why would a shaped coil made from pure copper wire rust while a screen type copper packing material not rust? I need to read more on SPP.

[Odin]

I'll try to post some pictures about rusted SPP. Not sure if it should be in this thread, since I don't want to hijack it.

Regards, Odin.

[DAD300]

Corene, Odin...I think the word should be something other than rusted. Corroded, worn, oxidized,...

I think what the pics will show is very thin copper wire, eroded by ethanol vapor to the point the weight of the stacked column breaks it. If you want to see rusted SPP, I'll show you some I heat treated to roughen the surface.

Odin probably remembers that I tried to heat treat SS SPP...

So that it would have a rougher surface, hold more liquid. Looked beautiful until it got wet...

Rust.jpg (32.59 KiB) Viewed 10973 times

Then it looked like this Russian experiment gone wrong. Amazingly, a lot of people said,"so what?" Use it and the rust will wear away and not hurt your ethanol.

Later I used ferric chloride to etch the surface of SS SPP and SS Scrubbies. It doubles the liquid retention, good or bad...

[BigSwede]

After seeing those pictures, I'm not going to do any surface treatments to my SPP, and I'm tempted to use only 316SS wire. Wow - never would have guessed such corrosion, even after etching, from only ethanol. It is a good demonstration of the potency of hot ethanol as a solvent, and why we must be very careful with our choice of materials.

I wasted a good 3/4 of a day today trying to make square profiled bits work. Couldn't get even one of them to wind correctly. It was some YouTube video that prompted this, the guy had a square bit and it worked for him.

But not for me. The flat bits work fine and are much easier and more forgiving.

[DAD300]

The corrosion is from being left wet, water...but I agree it is better not to etch.

[BigSwede]

The corrosion is from being left wet, water...but I agree it is better not to etch.

Hmmm. Is it possible that there was an electrolytic action going on with them? Stranger things have happened. If you have one metal soaking inside a container of a dissimilar metal, you can sometimes get plating, oxidation, reduction, all sorts of oddities. It almost looks like those stainless SPP have a coating of copper, or a salt of copper, maybe a sulfide?

Stainless simply doesn't do that by itself unless the liquid/electrolyte is exceptionally aggressive.

[DAD300]

Much simpler than that...if you overheat (cherry red) a piece of SS (even 316), iron impurities comes to the surface and rust.

[BigSwede]

After the gross failure of the square bits, I went back to the ones that I know work well.

Mounted the machine on a very simple drill press, and re-verified it would work. In fact, it works in ways better than when it is on my lathe, as the SPP feeds down, gravity assisted, right through the center hole. Down there, it can be routed into a very long, smooth tube, and you should be able to get some long lengths. Or, it can ideally be fed into a cutting device.

About the only thing I might suggest is to use a SLOW drill press, or modify with pulleys if needed. Slow is more comfortable, but I verified it'd create good SPP even at speeds that any off the shelf small drill press would do.

The crazy pulleys were mounted to see if I could get a smoother feed. It helps, but the original setup was perfectly acceptable.

Next came a number of tests of both speed and tension. Came up with some interesting results.

WIND SPEED - 5 tests from ultra slow to scary fast. Sorry, no actual RPM. Slow was probably 50 RPM, fast was several hundred. I ran off a length, weighed each one, and came up with a gram per inch value. Why bother? LOW mass per inch equates to a more OPEN SPP... this is good.

Slow: 1.46
Standard: 1.45
+1: 1.35
+2: 1.26
+3: 1.26

At the "+3" speed, it was a bit scary in the sense like I felt the wire was close to breaking. It would spin off 6 inches in about 20 seconds.

The numbers indicate faster spindle speeds produce more open SPP, but only up to a point... the effect levels off.

Next came tension tests. Interesting results. At a VERY low tension, so low that the SPP was rather ugly and definitely not consistent, the coils opened WAY up, got a mass/length value of 1.10. Worth exploring more. But it's got to be more consistent than this picture shows, the low-tension SPP is at the bottom. It's not even straight.

Low tension very definitely produces looser SPP and also larger diameter SPP.

Summary: As wind speed increases, SPP opens longitudinally, to a point. As tension decreases, SPP opens longitudinally in an extreme manner, and also increases in diameter.

Why am I doing this? For fun, but I'm mainly waiting on an order for some copper I cannot find locally, and I need it to finish my build. May as well do something useful.

This is going to sound dumb, but wound lengths of SPP are quite beautiful. They reflect light in a kinetic way. Wife wants an SPP necklace!

[bellybuster]

Oh man, haven't been around in awhile and come to see this. Impressive crap. Yet another project that I must start and probably never finish. Thanks BS

[Bob Loblaw]

50RPM? Just checked, my cheapo HF drill press goes down to 760RPM. Oops. I wonder if I can slow it down with a router speed controller?

[Johnny6]

I'm really enjoying this thread. BS, you mentioned rigging some sort of automatic cutter. My brain has been racing to try to imagine how that might be rigged, without crushing a lot of the SPP in the process. Thanks for all the details. I'm going to try to set up my drill press and wind some up.

[BigSwede]

50RPM? Just checked, my cheapo HF drill press goes down to 760RPM. Oops. I wonder if I can slow it down with a router speed controller?

Bob, I'll try to get a real rpm reading for you rather than just guessing. 50 RPM was crazy slow and I did it just for fun. Most of the tests were done at a few hundred RPM. Don't think a speed control will work with that sort of motor.

These drill presses are very easy to modify - remove the motor, measure the shaft diameter, figure out what belt it uses, then get the smallest pulley you can find, something smaller than what's already on there. And route the belt on the largest spindle pulley available. I wouldn't mess with the drill press spindle pulleys.

Most hardware stores have racks of those zamac pulleys, they work well.

I'm really enjoying this thread. BS, you mentioned rigging some sort of automatic cutter. My brain has been racing to try to imagine how that might be rigged, without crushing a lot of the SPP in the process. Thanks for all the details. I'm going to try to set up my drill press and wind some up.

Good luck with it! My initial thought was a solenoid from Zoro tools, about $30, but their stroke is pretty small. It'd require some sort of custom cutter.

I found a really nice cutter that I've been using manually - did some tests and found it took 6 lb of force and a 5 inch stroke to actuate if I rig the cutter to some device. Makes me think "pneumatic actuator", but a solenoid would be easier to set up for repetitive cuts.

A 555 timer driving a solid state relay would work. Or, an industrial timer using an octal socket like an Omron would be perfect. I have one of the latter from an earlier project... it'd be expensive to buy just for this.

My thought is you can adjust the wind speed, or adjust the cut interval timer. Maybe both. A 12" length of SPP feeds through a tube into the cutter mechanism, the cutter is actuated, and the momentary stress of this on the wind shouldn't cause any problems back up at the bit.

I cut a small amount of actual SPP last night by hand... NOT fun.

[DAD300]

LOL...cutting by hand not fun...I've now cut 4 gallons by hand and watched way to much tv while doing it! I hate TV!

Others have used washing machine gear solenoids as a cutter. There are videos around of it. I think the actual blade and anvil is the hard part.

I imagine a pvc tube, followed by a steel tube with the SPP projecting through it. As the SPP exits the steel tube, which acts as an anvil, it hits a switch that triggers the solenoid. Blade chops off SPP and action starts over. The length of the SPP bits is changed by physically moving the switch further down line from the blade.

My idea of automation is usually KISS...I suppose a simple timer would do the same.

BOB, my lathe is running at 375 rpm when winding. I think most drill presses will easily slow to 375. It makes an inch of SPP approx every three seconds.

As a side note...I have cut the SPP coils without stopping the winding. A momentary crimp on a coil, say a foot from the mandrel, does not pull the winding off.

[BigSwede]

Bob, I re-checked my speeds.

The "50 RPM" was really more like 100. The machine made nice SPP up to at least 450, but that speed is a little "exciting" IMO. Didn't test faster than that. The formed SPP tail can really start to whip, and that will put stresses on the coils forming on the bit and maybe make the whole thing pop free.

A nice sedate 200 RPM is a good number, FWIW. 760... hmm, dunno about that!

On the cutter - good timing BTW Dad, we're posting at the same time.

I'm staring at a big piece of annealed A2 stock, and a bigger piece of brass rectangle. Mill two pieces of A2, one a chisel, the other a sharp hole. Mount the latter in the brass, create a brass bridle to hold the moving chisel piece. Attach chisel section to solenoid. I think it'll work, all it needs is about a 1/2" stroke.

That said, I need to study your notion. GREAT idea of having the SPP itself trigger the cut! Heck you don't even need a micro-switch, have the SPP itself complete a circuit, energize a cheap solid state relay with low voltage DC. Don't want 120VAC in there.

This is going to be fun while I wait for my copper.

[FullySilenced]

there is a russian video showing them using meat grinder blades in a variable speed drill to cut the spp as its unwinds off of the mandrel... Only saw it once but it as kinda interesting...

[BigSwede]

From a physics POV, having the SPP emerge from a solid and strong tube area, and having the blade slice across that tube very quickly (solenoid would be ideal) - should be able to knock off SPP with ease. A 30 degree angle will see the blade sneak right between 2 loops and pin the far wire against the hole for the cut.

I can see some sort of rotary blade/cutter rig do this, but Dad300's idea of having the SPP itself trigger the cut is just too awesome to not use. Simple length adjustment, speed independent. Love it.

I really cannot see any reason why a standard solid state relay, SSR, of the DC voltage input type, wouldn't work perfectly.

Get a 12V wall wart DC transformer. The SPP machine, all metallic parts, become ground. For the cut sensor, I'm seeing a leaf of spring steel cannibalized from a cheap feeler gauge set mounted on a plastic insulating column. Washers stacked between SPP machine and the plastic adjust for length. The leaf becomes positive in the DC circuit.

Position the leaf so that it contacts the SPP on the upper half. 12VDC energizes the SSR. SSR powers the 120V solenoid. <CHUNK> As the SPP falls away, 12VDC circuit is opened. Solenoid resets. Repeat.

The only thing that may go wrong is if the cut SPP hangs up and won't allow the solenoid to reset. Inbound SPP gets jammed up against the blade. Maybe some sort of "kicker" can be mounted on the blade itself so it will forcefully move the SPP out of the sensor path.

[DAD300]

A kicker on the top of the blade is perfect...even just a piece of wire would work.