A dz mod :)> ....Ok pdib too

[dhomes]

I'm curious about this, did you test with a firing pin that was pointy (like robs) made out of brass? What metal is Rob's firing pin made of, Aluminium; steel? I was seaching for the most conductive/least corrosive metal and I found this chart and it shows that brass is not a very good conductor, and is less conductive than aluminium (but more than steel). For you guys that are running sub-ohm setups, I would think that what helped reduce the voltage drop the most was surface area. I believe that dhomes also took the point off the firing pin and made it flat.

I would venture to say that an aluminum shim may be *slightly* better and just as easily obtainable. Normally the metal of choice would be copper but it may corrode faster than aluminium when heated, or if it were to arc. That being said, I am not sure there would be any noticeable difference between the metals used, I have a feeling it only attributed to the 0.05V gain if Robs pointy pin was made from steel. (Sure would be nice to get everything silver plated for $5 )

This is just a theory, I'm not a metallurgist and its been a while since school, so I may be way off base.

Awesome looking pin mod pdib, thanks for all the pics!

the required equivalent area graphic is very interesting, i didn't think of that!

So compared to brass, it's like I'm using ~ by sheer luck ~ 4x the contact area

I do have a pointy bar, I wanted it flat, but it's not what I got, since, I have flatten the tip a little bit (it's now about 1 mm wide at its flattest point)

Instead of going through such extremes at the +, I think you all should focus in better ~ yet secure ~ options at the bottom - contact, that's were the main drop is.

Once you start getting into the tenths of a Volt between one material and configuration and the other you really aren't making much of a difference.

Except off course, for maintenance (oxidation and the like)

Rob's is made out of Aluminum I think, isn't that the whole point of Noalox? (No Aluminum Oxide). That'd be my guess.

 

[pdib]

Kay, so . . .. here's the deal. Rob's pins are SS. They represent about a .15V drop. Some of us (sub fellows) have arcing issues at the pin. This particular thread is all about whether different shapes (contact area, attack, areas almost but never touching, areas sometimes touching - sometimes not) can help to reduce arcing/sparking → oxidization → reduced fire power.

This bit of "science" will take some time as sparking doesn't always become apparent for days, or a week or two.

I happen to have been playing with the voltage drop theme, so I was measuring stuff. Here is what I measured.

Rob's SS pin: 0 (baseline)
Rob's SS pin sheathed in brash shim (still pointy): +.15V in power getting to atty posts
My rounded SS pin sheathed in brass (larger contact area): +.2V in power getting to atty posts

Gdeal contributed #s from a solid copper pin with rounded (like mine) tip (but we don't know the smoothness/detail of the actual contact area): +.10V

If I recall correctly . . .

dhomes' silver pointy pin: +.15V

 

[dhomes]

Kay, so . . .. here's the deal. Rob's pins are SS. They represent about a .15V drop. Some of us (sub fellows) have arcing issues at the pin. This particular thread is all about whether different shapes (contact area, attack, areas almost but never touching, areas sometimes touching - sometimes not) can help to reduce arcing/sparking → oxidization → reduced fire power.

This bit of "science" will take some time as sparking doesn't always become apparent for days, or a week or two.

I happen to have been playing with the voltage drop theme, so I was measuring stuff. Here is what I measured.

Rob's SS pin: 0 (baseline)
Rob's SS pin sheathed in brash shim (still pointy): +.15V in power getting to atty posts
My rounded SS pin sheathed in brass (larger contact area): +.2V in power getting to atty posts

Gdeal contributed #s from a solid copper pin with rounded (like mine) tip (but we don't know the smoothness/detail of the actual contact area): +.10V

If I recall correctly . . .

dhomes' silver pointy pin: +.15V

Ok, let me contribute my two cents regarding arcing

This is from Structural Engineering

3 things come into play, so it's a balance of the material & the thickness of the flat bar

There is the Yield stress (Fy) , this is the stress (measured in kips/in^2 or also psi, after which a material won't go back into place)

There is the Elastic Modulus (E) also called modulus of elasticity, this is the amount of stress generated by unitary deformation in the material

E is measured, for metals in Ksi (for psi just multiply by 1000)

There is the moment of inertia (I), that's a property of the cross section, for a rectangular section (6 mm wide, don't know the height but it's certainly less than a mm) I = b (base) * h (height)^3 / 12, in this case we are talking about the Ixx of the section (in a cross section the imaginary horizontal axis that goes through its 'middle' -it's a bit more involved, but for simplecity) is the X-X axis, the vertical on is Y-Y

(I) is the reason I required my bar to be 2 ~ 3 thicker even though I knew it would be harder to push

With E & I you get EI, the bending stiffness of the material Bending stiffness - Wikipedia, the free encyclopedia

E is a property of the material (Elastic modulus - Wikipedia, the free encyclopedia)

I is a property of the geometry

You can see that EI would increase to the cube power as you increment the height (thicness) of that bar

Rob's though may not arc as it's using Steel. I don't know his specific type of steel but for the structural kind its E = 29000 ksi

silver is 11000 ksi if i recall pcorrectly (is in my thread)

stainless steel also has a much higher yield point as most other metals, it's the reason we use it in construction (well, for concrete rebars it's also because concrete is worthless under tension, so the rebars take care of that)

I'm oversimplifying all this, but either your play with the material or you increase the height / thickness of the bar

for the more adventurous: here is beam theory: Euler (that bar is working as a cantilever beam btw)

 

[gdeal]

Gdeal contributed #s from a solid copper pin with rounded (like mine) tip (but we don't know the smoothness/detail of the actual contact area): +.10V

If I recall correctly . . .

Correct you are on the v pickup on a .7ohm coil. My copper shims look like this:

Original Copper tip only on SS firing pin:


Most recent copper shim full length (ala DZ/pdib) of SS firing pin, similar tip contact area:

 

[pdib]

Sorry, dhomes. This arcing is the one like electricity jumping, not arching or bending. I just looked it up. In Spanish, arcar means: to bend.

 

[dhomes]

Most recent copper shim full length (ala DZ/pdib) of SS firing pin, similar tip contact area:
View attachment 252407

With this design you would get the most arcing, the top 'wraps' is under tension while the bottom half under compression

As they are non continuous, one would slip back and forth over the other every time you fire that button

 

[dhomes]

Sorry, dhomes. This arcing is the one like electricity jumping, not arching or bending. I just looked it up. In Spanish, arcar means: to bend.

oh good deal, I thought you were all having problems with the bending of the bar

it's something someone pointed at in my thread (expecting Silver to give me a permanent deformation) so i jumped to conclusion, disregard

p.d: it's arquear in spanish and the non-permanent deflection is called pandeo

p.d.2: that wraping of the bar, as in the last pic, may give you a problem in the long run though, you are slipping the material horizontally a tiny bit back and forth every time you compress it

 

[darkzero]

oh good deal, I thought you were all having problems with the bending of the bar

it's something someone pointed at in my thread (expecting Silver to give me a permanent deformation) so i jumped to conclusion, disregard

That was me......

The stock firing pin is stainless steel & I suspect it's spring tempered for being so thin. The stock firing pin is .006" thick. I have some .010" SS sheets laying around & they don't have even close tonthe same spring tension as the stock firing pin. I went with .007" thick stainless steel, also spring tempered. I did not want to compromise the spring tension (arching) & my main goal in my experiment was to reduce or eliminate arcing (sparking).

Since the much thicker SS sheet did not have nearly the same tension as the spring tempered, aluminum, brass, & copper certainly wouldn't provide nearly the same amount of spring tension at that the same thickness or close. Purity silvers are even softer & is why I brought that up (for safety). Of course going much thicker with those materials may make up for the tension somewhat but it still won't be the same. Also soft non ferrous metals can not be heat treated for a spring temper. Overtime they can easily fatigue as they are worked back & forth (like bending a paperclip back & forth until it breaks). It sounds like you are well educated in metalurgy so I trust you know what you are doing so all good.

Reducing resistance in the firing pin was not a concern for me (I only measure .02 ohm through the stock firing pin as well as my new one).

 

[dhomes]

That was me......

The stock firing pin is stainless steel & I suspect it's spring tempered for being so thin. The stock firing pin is .006" thick. I have some .010" SS sheets laying around & they don't have even close tonthe same spring tension as the stock firing pin. I went with .007" thick stainless steel, also spring tempered. I did not want to compromise the spring tension (arching) & my main goal in my experiment was to reduce or eliminate arcing (sparking).

Since the much thicker SS sheet did not have nearly the same tension as the spring tempered, aluminum, brass, & copper certainly wouldn't provide nearly the same amount of spring tension at that the same thickness or close. Purity silvers are even softer & is why I brought that up (for safety). Of course going much thicker with those materials may make up for the tension somewhat but it still won't be the same. Also soft non ferrous metals can not be heat treated for a spring temper. Overtime they can easily fatigue as they are worked back & forth (like bending a paperclip back & forth until it breaks). It sounds like you are well educated in metalurgy so I trust you know what you are doing so all good.

Reducing resistance in the firing pin was not a concern for me (I only measure .02 ohm through the stock firing pin as well as my new one).

Not metallurgy, but i have a degree in structural engineering, it's play between the mechanical and geometrical properties of the material / section you use

 

[gdeal]

With this design you would get the most arcing, the top 'wraps' is under tension while the bottom half under compression

As they are non continuous, one would slip back and forth over the other every time you fire that button

I'm not sure why you think I would get arcing. I havent seen any yet.

I believe any movement is non-consequential. The single strip of copper is wrapped around the SS firing pin and has much greater surface area to contact the battery top. The copper (.01mm thick) retains its shape at the battery contact. It is secured by the positive atty pin on top and the silicon sleeve on the bottom. While there is probably slight micro movement between the two firing pin materials, it would more likely effect contact erosion of copper material at the largest stress point which would be at the point in contact with the tip of the SS firing pin, (I did not change the shape of the SS firing pin).

If this does create a wear point over the long run. ie: the SS tip comes through, I would just redo the mod. It took less than 5 mins.

 

[dhomes]

I'm not sure why you think I would get arcing. I havent seen any yet.

I believe any movement is non-consequential. The single strip of copper is wrapped around the SS firing pin and has much greater surface area to contact the battery top. The copper (.01mm thick) retains its shape at the battery contact. It is secured by the positive atty pin on top and the silicon sleeve on the bottom. While there is probably slight micro movement between the two firing pin materials, it would more likely effect contact erosion of copper material at the largest stress point which would be at the point in contact with the tip of the SS firing pin, (I did not change the shape of the SS firing pin).

If this does create a wear point over the long run. ie: the SS tip comes through, I would just redo the mod. It took less than 5 mins.

not referring to wear, mostly permanent deformation in the long run (not that it's hard to replace) due to residual stresses from the movement / slippage between the two contacts

just pointing to something that came to my mind, most likely nothng will occur but you may want to check in two / three months

 

[SeaNap]

NOALOX is used to prevent oxidation that occurs when AL contacts Steel (or copper). When two dissimilar metals contact there is a much greater rate of oxidation (specifically Galvanic corrosion). There is another type of oxidation that occurs in our mods from High Temperature caused by Arcing (sparking).

There are two steps to prevent oxidation; Dielectric Compound (NOALOX), and reduce arcing.

Summery of thread so far (for my sanity ):
Primary objective is to prevent arcing (sparking) of firing pin. Secondary objective (not OP's) is to reduce voltage drop under load.

DZ: .oo7" spring tempered stainless steel, rounded, progold pen, No Arcing, No reduction in resistance

pdib: stainless steel with brass shim contact, rounded, .2V gain, ~90% reduction of arcs

pdib: Robs SS sheathed in brass shim, pointy, .15V gain, ~90% reduction of arcs

Gdeal: Robs SS sheathed in .01" Copper, rounded, .1V gain.

dhomes: Robs SS pin silver plated, pointy-ish, .15V

Hopefully I got all that right. Being electrically minded, I tend to think of MOV's when the issue of excessive voltage (arc) suppression comes up. A simple RC snubber circuit across the switch would eliminate arcing. This would require a modification by adding a + battery connection terminal and wiring in an off the shelf snubber.

 

[darkzero]

DZ: .oo7" spring tempered stainless steel, rounded, progold pen, No Arcing unless cycled repeatedly, No reduction in resistance

To clarify, the arcing when cycled repeatedly was with no ProGold. After applying ProGold no more arcing whatsoever as the ProGold always does for me.

When I first installed the new firing pin I got no arcing whatsoever with nothing applied to it. Used it over the weekend with nothing applied to it. Since some very minor arcing developed I suspect eventually oxidation will build up but at a much slower rate than stock. My guess is the width of the tip across the top of the battery is not perfectly flat unless I really give it a firm press. But sometimes I forget or don't pay attention when I'm out & about. I'd like to test this one more but I don't see a need to. Out it comes when I get the chance & on to the next shapes I have in mind.

I wad reading on snubbers & wad thinking how I might be able to build one for the Reo. Then I thought not worth it. I never seen a real snubber though. Have you used them before?

 

[pdib]

I'm glad you can think of other shapes. I've been passively mulling and haven't thought of any. Bear in mind, I've got plenty experience with Rob's pin shape filed down quite a bit . . . so I've tried more contact area in that sense.

 

[darkzero]

I have three more shapes in mind, whether I can manipulate the material to achieve what I want is a different story. Two shapes in mind requires a die of some sort. I could machine a die but not sure if it's worth it but I think I will try anyway.

Update on my last post. I was just looking at the pin closely comparing the sparking to my other Grand. I decided to compare cause I noticed the arcing when firing repeatedly looked different than the stock pin (cleaned off with no ProGold) & the arcing doesn't occur every time. I noticed that it's not arcing between the point of contact between the firing pin & battery. It's arcing at the rolled edge inside my tip against the "arm" (flat section) of the firing pin. There's a slight gap there so whenever I fire with enough pressure that these two points meet it arcs. That explains why it doesn't do it all the time. At first I thought why but then again it makes sense, electricity will always flow through the shortest path or least resistance. Electrons were taking a shortcut....

To add, some one contacted me on where to get ProGold. I searched & didn't get many hits either. Then I discovered that it's now called Deoxit Gold. Before Deoxit was just the deoxidizing product & Progold was the contact enhancer (with like a very small percentage of Deoxit in it). I seriously swear by this stuff as I have been using it on everything for years but it's not cheap & even more expensive now.

 

[SeaNap]

I wad reading on snubbers & wad thinking how I might be able to build one for the Reo. Then I thought not worth it. I never seen a real snubber though. Have you used them before?

I was thinking the same thing, adding a snubber would require far too much modding for what you seem to have solved with your pin/progold. I just figured I'd throw it out there since it would accomplish the same thing.

Yes I have used snubbers before, however I've never designed/created one. I did VFD repair for a number of years in a previous life, and if there was a major voltage spike (lightning strike) the MOV's would always pop and need to be replaced (along with many other components). They are great for small arc protection on switches like relays, as well as taking care of voltage transients on high frequency IGBT's , but lightning or a short between phases can take them out.

There might not be a better shape than the rolled design you have now without completely changing the button (again absolutely not necessary) or having some very precise CNC machined pin. I would think that the DZ/pdib/gdeal design is a winner at form, function, and versatility.

 

[pdib]

Well, I've managed to catch a few tiny little sparklets on my 3 (nominally same as each other) versions. I also have to fiddle with it and almost flutter the button say 5-6 times, and I can catch a sparklet. If a spark/arc on my traditional pin could be given a value (for size and brightness) it would be 100. The size and brightness of my current sparklets would then be . . . . . .10, say. They are tiny, and dim, when I can produce them. They seem to occur on release. It's too early in the game yet, for me. 4-5 more days for a somewhat fair comparison.

 

[pdib]

So, my first pin post looks to be about from 9/14, and today is 9/24, so 10 days.

3 pins in 3 mods, all ~.4-.5Ω . .. . .. No sparks, No arcs. Lookin' good.

 

[studiovap]

Been watching, will be watching. Still awaiting my Reo delivery. The poor thing has no idea the delights in modifications it will experience within moments of its arrival

 

[pdib]

Been watching, will be watching. Still awaiting my Reo delivery. The poor thing has no idea the delights in modifications it will experience within moments of its arrival

If you end up making solid Australiantium firing pins . . . . . .. make a couple for me!