PSYBRID Phase II . . . . . . . splat!

[pdib]

So, I got the centerpost(s) from Dizzie. They are beautiful! It's very difficult to bore a ~1+mm hole through 28mm of threaded rod. I know, I tried it like 5 or 6 times. Anyway, darkzero took on the challenge and nailed it (of course). He tried brass; but found it to be too soft, methinks . . . so stainless was the other option (methought). I got my rig all set up with the SS post and a little wire trap that I ground down from a nut. In there are: a nylon bushing, a solid brass pin and an SS nut (+assorted gaskets/insulators) . . . as well as the copper wire filler to join the ss atomizer base to the REO aluminum (if it offers a better path than the 510 female).

Here's what it looks like . . .

So, the brass tube (Psybrid I) got me about where my previous setups (w/ 510) got me . . .~.15V drop on a 1Ω load.

Where, you may ask, dear Reader, Fellow Reonaut, did this setup put me? . . . . . allow me to mention that I was rather careful to make good strong connections, to clean everything . .. I took my time . . . . . . . ~0.4V drop on a 1Ω coil.

Be happy, my friends; no need to venture down this road. (not to say that someone else won't come up with a different approach; but I'm done with this one.)

Dizzie, thanks again for your work. Spot on! My work . . . . spot off.

 

[lizardnipples]

Valiant effort my friend! I love seeing what you guys come up with! If anyone is going to come up with something badayus it's you and DZ! Oh wait, you guys are already the reason Rob is coming out with a sub ohm kit! Mission accomplished!

You guys rock!

 

[thinkingaboutit]

Hey, at least you tried

 

[turbocad6]

that is slick, I tried and tried and tried but the greatest length I've been able to drill through successfully is like 1", DZ's got some awesome tooling though.

question, how are you measuring voltage drop? I would think to measure at the battery while firing, then measure at the atty while firing and compare?

 

[pdib]

I'm just measuring the battery on the bench, and then at the posts while firing. Although I can't say what that tells me, I can compare to other setups that I test the same way.

Yeah, I kept breaking out the side, or breaking off the bit at about 9/16" or 5/8". I managed to get most of it by going in from each end (although I wanted the top solid); but, even there, I couldn't meet in the middle.

 

[turbocad6]

but how do you know how much drop is caused by the actual load and how much is caused by loss in the mod? could you try under load at the battery then under load at the atty? I think you'd see exactly what the actual mod loss is, your way is showing mod loss plus the drop of being under load, so you don't really know how much of that is just from the mod alone I think. I bet you see much less than .4

 

[Filthy-Beast]

Wow, that drill work by DZ is just amazing!

 

[turbocad6]

also I don't see how you are getting max contact between the post and the firing pin, I only see one nut, not even another at the top and one side of the brass is contacting the insulator up top. I would suggest double nutting the firing pin above and below the brass and tightly compress/clamp with the nuts for best contact, even a dab of nolox in there before tightening so the connection doesn't oxidise and deteriorate with time

 

[Xobeloot]

Bummer my man. Looked like it would be a solid build plan. Should put my FIMO cap-reducer-pluggy-thing in there to seal the deal!

 

[MamaTried]

i'm sure dibby is taking in all these suggestions, but i have reason to believe he's been distracted lately by giving aid to the elderly and disabled...

 

[turbocad6]

I think that post should be better than you're thinking it is, it is completely eliminating one iffy connection and reducing the problematic connections of a mech from 3 points to just 2. the 3 biggest potential losses for a less than perfect connection on a mech are batt neg, batt pos and 510 to atty.

this is assuming you don't have any additional losses though like from the firing pin to the brass contact, double nutting and tightening that should eliminate that as an additional variable I think

 

[Filthy-Beast]

I think its the resistance of the SS screw you used that cause the unexpected high leakage. I know it would not last very long but wonder what results you get with copper post and bar for the battery.

Aluminum is 2.82 x 10-8
copper is 1.17 x 10-8
SS is 6.89 x 10-7
Brass is 3.5 x 10-8

 

[ChrisEU]

The stainless steel doesn't have THAT much resistance, whole mods are made out of it =)

I think it's the contact between the brass firing pin and the new rod, with the nut on top. The contact area between the brass and the screw threading is tiny. Could you please try some noalox on the surface of the nut where it meets the brass and some more on the rod threads where the nut rests?

But then again, you're done with it! =)

 

[Xobeloot]

But then again, you're done with it! =)

Bah! He's out in the shop ...... on it more as we speak!

 

[turbocad6]

I wonder how much of a difference there would be between a brass pin and a ss pin considering it's only the 1" length there. I would have guessed not that much if any, but honestly don't really know for sure. i think the pin has so much mass that there really wouldn't be a higher resistance with the SS over brass or even copper, if were talking about a very thin wire of brass vs a very thin wire of SS then yeah I would expect that to be measurable but something like this I would guess not so much really

 

[ChrisEU]

Can't let this idea go to waste! If ...... helps, here, have a Will Bräu with a fitting slogan from back when I was young:

"Will in Motten, unerreicht, eins gesoffen, drei geseicht!"
"Will (brewery) from Motten (little village somewhere around Fulda), unsurpassed, drank one, ...... three"

 

[pdib]

So, I know the pictures didn't tell the whole story. I will add some detail. There was noalox on the cheek of the SS nut (the whole surface where the flat of the brass pin meets the nut was buttered). What happened as I was trying different parts, and fitting things was . . . . . . . . . I discovered that that exact setup (combination of parts) was ~1/2mm bigger than perfect . . . . . meaning . . . . . when I jammed the delrin cover in place, and pried it tight while I screwed it down, It put a substantial amount of upward pressure on that there stack of parts. Above the nylon bushing, is just post and gaskets, it doesn't slide around, but with a dash of force, you can pull it up or push it down. So, the delrin cover was cramming the whole assembly up (shoving the nut REAL tight against the brass pin which was being shoved REAL tight against the nylon bushing, which was being shoved REAL tight against the REO body/opening).


It was tight.

 

[pdib]

And, there's a lot less SS left of that threaded rod than you think. Between the hole up the middle, and the outside being threads (worthless for current), there's no more metal there than that brass pen tube on V.1. . . . . I do think it was the SS.

BTW: my AGA-T had a long pos. post too; and it had some mo-fo v-drop.






not to mention that this was hardware store, screw bin SS . . . . . not rocketship to the moon SS

 

[Xobeloot]

 

[darkzero]

Good to see that it worked, sorry to hear it didn't get you the result you wanted.

IMHO, the way to get the lowests results you're after, you have to reduce the number of contact points. Yes the conductivity (electrically) plays a role as we all know but there's also other factors. Like a excellent conductor usually would be a much softer material which affects areas of strength where needed & corrosion resistance. It might be great to have a bare copper center post with great results when first installed but you have to think about maintenance & how quick it will oxidize. Specific metals will also increase in resistance when heated.

Contact area also plays a big role. If the contacts were pretty clean to begin with, applying an antioxidant like Noalox isn't going to do anything but of course it doesn't hurt if used sparingly. Noalox is to help prevent oxidation, it will not make a material conduct any better than it's capable of. Noalox works for many others & I'm sure it's a great product as it was designed for but I don't use it in small electronic devices, too messy & no noticeable difference for me.

Pdibz, if you can find a way to go bigger in diameter we can take another stab at it with brass or copper. The tiny little screw was....well tiny & too thin! I usually cuss at stuff that small when machining & usually end up just taking a BFH to it.

BTW, for what it's worth, with the stock SS firing pin & the SS material I used for firing pins, I only measured .02Ω from the the 510 center post to the end of the firing pin.