How Tom tell the difference

[888guitars]

is it possible for me to figure out what type of bar magnets are? I have a drawer of about 10 magnets that I'm not sure what they are. I know they are alnico but not sure if 2 or 5? How can I figure this out?

[Antigua]

Maybe buy a known A2 and A5, and use a cheap magnetometer such as a WT10A to figure out which of the two the magnets you have on hand are more similar to.

Or if you have an LCR meter like the DE-5000 that measures inductance well, AlNiCo 5 bars will read slightly lower inductance than AlNiCo 2/3/4 when mounted in a PAF style humbucker, but again, you'd need a known frame of reference to compare against.

[copperheadroads]

Are They magnetized ? the A5 will be stronger than A2 ,

[John_H]

An easy way to compare magnets if you have no test equipment is to count how many paper clips, brad nails, BB's, or any other small item you can lift with each magnet. The A5 will be the stronger. Are they short, or long? 2.25/2.50? I think most short magnets are A5. They can also be A2, but aren't as common.

[Helmholtz]

The A5 will be the stronger.

Only if fully magnetized.

I think most short magnets are A5. They can also be A2, but aren't as common.

I analyzed about a dozen of short Gibson magnets from the 60s and found A4, A2 and A5.
In the 70s and 80s Gibson used mostly short A5 and rarely A2 magnets sometimes sintered not cast.

[mozz]

The owner of Throbak pickups had a lot of older paf types analyzed and said a lot of A2,A5 but has yet to see a A4. On the other hand some other pickup makers said they saw original Gibson invoices and saw A4 listed, but no proof was ever posted.

[Helmholtz]

The owner of Throbak pickups had a lot of older paf types analyzed and said a lot of A2,A5 but has yet to see a A4. On the other hand some other pickup makers said they saw original Gibson invoices and saw A4 listed, but no proof was ever posted.

Well, a couple of years ago I partnered with a German PU maker in a PAF magnet reengineering project. We had about 20 long and some short (dated) Gibson magnets from 1956 to early 60s analyzed by 2 independent labs using 3 different scientific methods. Results were that all long magnets were positively a variant of A4 without any exceptions. (Recent Arnold A4 is somewhat different. A4 samples I bought on Ebay were no A4 at all.)
We found not a single A5, A3 or A2 magnet from the 50s.

Results were also published in a German guitar magazine.

I do have the labs' data and charts but agreed not to make them publicly available. My partner found a European cast magnet manufacturer who now reproduces the original formula magnets for him. Have some samples of different lots.


BTW, who is Tom?

[the great waldo]

Well, a couple of years ago I partnered with a German PU maker in a PAF magnet reengineering project. We had about 20 long and some short (dated) Gibson magnets from 1956 to early 60s analyzed by 2 independent labs using 3 different scientific methods. Results were that all long magnets were positively a variant of A4 without any exceptions. Recent (Arnold) A4 is somewhat different.
We found not a single A5, A3 or A2 magnet from the 50s.

Results were also published in a German guitar magazine.

I do have the labs' documentations but agreed not to make them publicly available. My partner found a European cast magnet manufacturer who now reproduces the original formula magnets for him. Have some samples of different lots.


BTW, who is Tom?

Tom is probably a typing error !!
Cheers
Andrew