Welding rod for pole pieces?

[peskywinnets]

Anyone familiar with welding rods? (I'm not), but I stumbled upon them as a 'possiblity' during an Ebay search for 2mm mild steel rod.

Basically, I want to make a very small humbucker ...I'm thinking here about 12mm wide for the whole pickup. (1/2") therefore just under 6mm width per bobbin (1/4")....working backover, I reckon the pole piece diameter size that'd be a good start both a workability aspect & dimensioning aspect is 2mm.

There doesn't appear to be a lot of 2mm diameter mild steel rod easily sourceable?!!! Welding rods only cost about £3.00 ($5.00) delivered for twenty 12" lengths, whereas plain 'bright' mild steel costs about £9.00 (about $15) for just three 12" lengths!

So welding rods - presumably they all come with that outer coating of flux, which I dare say could be whacked off, then cleaned up with steel wool? Do-able? or not worth the bother?!

Also are they more likely to have a vintage 70s sound or perhaps early 90s tone? (just kidding! That said, they ought to be great for 'heavy metal' )

[Folkcafe]

You should be able to go to a welding supply company and pick up plain copper clad welding rods of various widths.

These are typically used with Tig welding. They come in all the sizes that pre-fluxed rods do. I can't tell you what they will do for your sound or even how the copper is going to affect things. I have a Tig welder along with a gas welding/cutting set and use this stuff for both.

[Magnut]

How about dowel pins. I'm not sure what the material would be. I glanced at these at one time as a possiblity for experimentation.

[Folkcafe]

One possible advantage for the welding rods is you can get a variety of steel mixtures. Like carbon steel and carbon/moly alloys.

[belwar]

I think the dowel pins is a far superior idea. You would really have to know what you're getting into alloy wise to make it work with welding rod.

I use 1/16th aluminum welding rod as fret position markers on my acoustics. nice looking stuff :>

[automan]

I use brass rods for my side dots. If you stop sanding at 220 grit, the sanding lines left in the brass look luminescent when stage lights hit them.

[Possum]

...

Dowel rods are high carbon steel and would be real bright sounding. I looked at welding rods at one point but none are made in actual slug diameters, they could make real interesting slugs if they were the right size as some are a nickel-iron alloys and could work well. Anything is worth a try. I have some tool rod I never got around to trying, even though its very high carbon, some day I will.

[David King]

I've gotten welding rod in 3/16 dia in both mild and stainless steel and used it for truss rods. It's very inexpensive that way and most towns of any size will have a welding shop or welding supply place that will carry a good variety.
The 3/16" is the largest stick size made and might be a special order unless there's a ship yard in town.

[peskywinnets]

Ok, tks for your comments - I guess I'll just have to suck it & see...to this end, over the next few days, I'll likely design/make my own 'micro humbucker' (actually it won't be as micro as I'd hope, as the only 'welding rod' I have to hand is 3.2mm dia - which means my bobbins will need to be a tad wider than I'd hoped)

So then, the sequence of events...

1. A quick bit of CAD (ie to design the required 'small' bucker bobbins)
2. Cut the bobbins out of scrap acrylic (I have a homemade CNC - which is itself made out of scrap!)
3. Wind the bobbins (I knocked up a CNC winder out of ...erhm you guessed it - scrap!). I'm thinking about 2,000 turns of 0.05mm gauge

http://pickups.myonlinesite.com/pick...t=2000&avo=5.5


4. Design a bucker shaped PCB to 'secure' both bobbins onto underneath (I'm using Neo mags)
5. Cut the PCB on the CNC
6. Pot 'em
7. Solder 'em up to the PCB (& glue them down)
8. Hook 'em up to a preamp
8. Try em out!

If I get time I'll take some piccies throughout the process.

[defaced]

I'll preface this, I'm a welding engineer. In the US, welding consumables do not come in 2mm (0.079). Typical sizes are (diameter in inches) 0.020, , 0.025 (maybe), 0.030, 0.035 0.045, 0.052 (maybe), 0.062, 3/32 (0.093), 1/8, 5/52, 3/16, and upwards to 1/4".

TIG rod (36" long straight lengths) and MIG wire (spools from 2lb up to 1000lb pay off packs, 30 lb most common) will be a different composition from stick electrodes. Welding consumables typically have more deoxidizers (silicon, aluminum, titanium, etc) in them to tie up nasties in the weld pool. This may or may not be a good thing for you guys. Steel welding rod is also typically very cold worked, so the grains are going to be long and highly deformed as compared to an annealed wire.

ER70S-X (2, 3, 6 are the most common) is the most common solid steel TIG/MIG wire - typically supplied with copper flashing, but you might be able to source some bare but I doubt it. E7018 and E6010 are the most common steel stick electrodes. You'd have to clean the flux off them, but that's not hard.

These rods/electrodes are dirt cheap. Buy them from a local welding supply store, not from someone on eBay. Oh, ER70S-X and E7018/E6010 are AWS designations, they don't mean a whole lot, so don't think every ER70S-X is the same as the other - they're not. Once you find something that works, keep buying from that manufacturers and that trade name.

And like someone already mentioned, you can get compositions out the wazoo in welding wires. Not all will do something for you, but they're out there.

[peskywinnets]

I finally got my backside in gear tonight, & designed my own 'slim' humbucker bobbin in CAD ....then cut it out of acrylic (alas, I only had transparent acrylic in the right thickness!) - the bobbin is two 'halves' glued in the middle.

Since I know you guys are partial to a bit of bobbin/pickup porn, here's my offering to get you through...



Standard string 'span', but only 6mm wide (I need to make a partner coil for it over the weekend) & 8mm tall. I used 2000 turns of 0.05mm - which I think you guys stateside would call 44 AWG (probably not the best wire to have my first pickup winding attempt with!)....ziegler pickup calculator reckons will be about 2,000 Ohms (I've not checked as I want to get it mounted onto a PCB base before dicking about with the start/end wires ...they're impossibly small!) ...I'll be mating it with a preamp.


To get a sense of scale, here it is next to a std strat coil...


I've already cut the (defluxed & wire wooled) welding rod slugs, but they need deburring (& even then, I think the fit might be too tight - I measured the cleaned up welding rod @ 3.15mm thick with digital cailpers ...I had a 3.2mm drill so I just used that, but it probably needed a bit more diameter.)

I'll post more updates as & when I have them.

[David Schwab]

Nice work. I like clear bobbins.

I would have used a blade in that. That way you can keep it thin, and don't have to worry about drop outs when bending away from a small diameter pole.

[peskywinnets]

Thanks for the blade heads up. I'd considered it, but there's the issue of getting a magnet on the bottom of the pickup. (nice work by the way!)

Basically, I want this pickup to mount on top of the guitar surface (no routing), I'm restricted to 7mm thru 8mm 'headroom' (about 5/16" in old money). I can't find a suitable slim long thin bar magnets (dimensions would have to be approx 12mm x 50mm x 2mm deep - it ain't out there).

At least using pole pieces I can attach a small neo to the bottom of each pole. The string bending shouldn't be a big issue as this is going right against the bridge - it's unlikely a string would ever be bent outside the 'hot spot'.

[Steve Conner]

Defaced's info is all very good, except that the compositions and code numbers for welding materials are all different in the UK and Europe.

[Folkcafe]

I looked at welding rods at one point but none are made in actual slug diameters, they could make real interesting slugs if they were the right size as some are a nickel-iron alloys and could work well.

In a chapter I was skimming through about soft magnetic materials today, I found a reference to Invar, a nickel-iron alloy. I had remembered this post so thought I would add a reply. I dug a little deeper into it including an old bulletin from the department of standards (believe me some of this old material gets incredibly detailed). Finding an alloy might be the easy part. Finding it in the shape and size you are looking for is another thing. I did find a company in TN that stocks various nickel-iron alloys. Unfortunately they jump from 1/8" to 1/4" skipping 3/16" round stock but to try a handful of slugs it would be a small matter to cut them in a lathe as the alloy is said to be very machinable. The site does however state that they specialize in small to medium volume custom sizes if that were to become a consideration.

They also have sheet stock which is what I was looking for. From what I read it has magnetic properties similar to annealed iron sheets but malleable and you can drill and tap it. Made me think of some of the blade pickup and transformer de-lamination threads.

I previously looked into welding rod that is nickel-iron and found there is often Al, Ti plus some others elements added to enhance welding properties that may have other unwanted affects in this application.