String pickup alignment on closed cover pickups

[sirmuppet]

Hi guys.

This one has eluded me for a while and I can't come up with a decent solution. Of my basses I have two that both have closed cover pickups. One is a Gibson Thunderbird and the other is a Hybrid bass with a Musicman style pickup by Kent Armstrong. Both basses are passive and both have pickups where the pole pieces are cover by a plastic cover and then sealed with epoxy. 

So my question is this, when setting up the basses how do you make sure the strings are going over the pole pieces? The only solution I can even remotely think of is getting something magnetic and trying to manually mark out where the poles are and go from there. Surely there must be a better way? Any thoughts?

Thanks,

Edited November 14, 2017 by sirmuppet

[Hellzero]

Try this : https://www.amazon.co.uk/first4magnets-F4MFP4-1-Medium-Field-Paper/dp/B003N1LZXO/ref=sr_1_2?ie=UTF8&qid=1510661746&sr=8-2&keywords=magnetic+field+viewing+film

You'll certainly find it cheaper by eBay...

[Manton Customs]

Those type of pickups don't usually have individual pole pieces for each string, they have a flat bar pole pieces which span all strings.

Edited November 14, 2017 by Manton Customs

[sirmuppet]

1 hour ago, Hellzero said:

Try this : https://www.amazon.co.uk/first4magnets-F4MFP4-1-Medium-Field-Paper/dp/B003N1LZXO/ref=sr_1_2?ie=UTF8&qid=1510661746&sr=8-2&keywords=magnetic+field+viewing+film

You'll certainly find it cheaper by eBay...

Perfect. I'll get some of this. Thanks!!!

1 hour ago, Manton Customs said:

Those type of pickups don't usually have individual pole pieces for each string, they have a flat bar pole pieces which span all strings.

I did wonder but I know the Gibson Thunderbird has had the poles exposed on the new models. Also the Kent Armstrong has a description which states pole pieces. Suppose I could only get the above and try it?

[Hellzero]

Yes, and you'll also see the strength of the magnetic field by the concentration of metal particles. It's an interesting little tool.

[Manton Customs]

Below is the description of the MM pickup. I've done quite a few builds with them.

CERAMIC / D.C. =13K- Our Music Man Stingray replacement is an answer to may prayers. The Stingray is a modern classic, but until now, finding a suitable replacement has been difficult. With far less magnetic pull than the originals, ours has full length bar magnets to get every bit of string vibration, no matter how hard you play. Having similar output and tone to the original unit, this improved version has enough output to be used passive, without a preamp. For the authentic Stingray however, a low impedance buffer preamp is recommended. We also strongly suggest series/parallel switch or push/pull pot to get two distinctly different tones made available by the widely spaced coils in this pick-up. Includes wiring diagram and mounting screws. 

[dyerseve]

or place the body flat horizontally and use a metal ball-bearing on top of the pups and see where it rolls to?

[Norris]

On 15/11/2017 at 10:22, dyerseve said:

or place the body flat horizontally and use a metal ball-bearing on top of the pups and see where it rolls to?

Or a cheap map reading compass?