To hear the laminations of their women

[Dave Kerr]

I was thinking about how Kinman laminates his shield in the stacked humbucker when I mentioned the loaf of bread/Marmite approach - those look much like a stick of staples - certainly more effort than I'm willing/able to put into this. I'll try making one pickup with solid 1/8" blades, another with laminated ones, and see how they come out.

[David Schwab]

Yeah, his laminations run that way. What he's doing is pretty interesting. He wanted to increase the inductance on the dummy coil. Apparently this improves the tone. DiMarzio follows this approach also. The dummy coil will have steel slugs, and steel screws between them.

Now I'd imagine if you made a steel bobbin, it will really muddy thing up. So Kinman got the idea to use laminated steel.

Kevin Beller, the engineer over at Duncan got a patent on a real interesting stacked pickup, # 7166793. Page 9 shows a laminated steel bottom bobbin.

The Kinman patent is: 7189916

[jonson]

Run some tests this morning. 15thou shim, paper and glues.
Superglue worked and no shorts but probably the weakest of the three. I do use a fair bit of the stuff as I find it handy to spot glue to hold things together while the real glue works if there is an awkward clamping problem.
24hour epoxy no shorting but was still not fully cured as I heated it to speed it all up. Acrylic structural rock solid in an hour and again no shorting out so you should have no probs Dave. I cut all 3 pieces with snips after to see if any burrs would cause a prob allthough I presume you will do your shaping and plating first.Still no probs got no readings side to side at all. so good luck hope it all works.

[Dave Kerr]

Thanks a bunch. I'll be using an abrasive cutoff wheel, anyway - why snip when you can throw off a bunch of sparks?

[jonson]

Hi Joe. been using both types of permabond till recently but my glue man has come up with another one now no difference in quality but a few pounds cheaper. he has his own label so where this one is from I dunno. Permabond is good.
http://www.permabond.com/en/en-acrylics.htm

[Joe Gwinn]

Hi Joe. been using both types of permabond till recently but my glue man has come up with another one now no difference in quality but a few pounds cheaper. he has his own label so where this one is from I dunno. Permabond is good.
http://www.permabond.com/en/en-acrylics.htm

Yes, Permabond is good.

One thing that strikes me is the viscosity (30,000 cP; for comparison honey is 3,000 to 10,000 cP) and the cure time (30-90 seconds). This combination may make it hard to squeeze the excess glue out from between the laminations (steel, paper) fast enough, and yet get the pieces aligned properly before things set up. One also wants to ensure that the paper is saturated with resin. A thinner mix and longer set time may be helpful.

How sensitive to grease and oil is the acrylic? This can be a real problem for epoxy. In any event, things must be really clean for good bonds.

One solution is to make up sheets of laminate, and later cut pickup pole assemblies out of the larger piece. This amortizes the labor cost of making the laminations. If one can do the cutting without causing too much delamination.

[jonson]

Gonna try this again Joe , but everytime I type a reply this site tells me I am not logged in and then loses the reply and I have to start again?????.
I have never had a setting time like that stated usually 3 to 5 mins setting and 10 to 15 mins curing so had no probs. Not sure with the bead on bead stuff about doing large areas as I normaly mix the same way as epoxy and apply it to one surface but I would have thought that using the liquid hardener on the paper and the resin on the steel would give all the time needed. I just coated up and pressed between waxed paper, Mdf and a solo clamp and that came out as tight as a drum can't get a razor blade between the laminations. I recut them all afterwards and the only signs of any delamination or weakness was on the superglue job. I wouldn't worry about soaking the paper all through as I dont think this will give at all. I allways wipe glue surfaces with acetone so have not had any failures in that area yet. I will run a test this week in the press and see how big I can go with this stuff without getting failures and will give my glue wizard a call and see if he has any thoughts on the subject.

[jonson]

Dave if you want to run aquick one on this without recutting then cut all your bits of steel and paper to size and get a couple of bits of mdf or ply and pin some strips tight round the pattern onto the mdf as a base. Cut one pice the same size as your blade and then heavily wax (furniture type will do) all the mdf or ply. Coat it all up with a long cure 2 part epoxy like David (araldite or equivilent) drop the bits in place and clamp the small bit of mdf etc on top. That will hold it all in line till it cures oh! and I didn't use fish paper I just used brown craft paper and you can't even see it between the laminations.

[David Schwab]

One solution is to make up sheets of laminate, and later cut pickup pole assemblies out of the larger piece. This amortizes the labor cost of making the laminations. If one can do the cutting without causing too much delamination.

So why not buy some laminated steel sheet? Then you just need to cut the stuff. McMaster-Carr has it. Granted it might be cheaper to make it, if your time isn't worth much.

[Joe Gwinn]

Gonna try this again Joe , but everytime I type a reply this site tells me I am not logged in and then loses the reply and I have to start again?????.

They want you to register.

I have never had a setting time like that stated - usually 3 to 5 mins setting and 10 to 15 mins curing so had no probs. Not sure with the bead on bead stuff about doing large areas as I normally mix the same way as epoxy and apply it to one surface but I would have thought that using the liquid hardener on the paper and the resin on the steel would give all the time needed. I just coated up and pressed between waxed paper, Mdf and a solo clamp and that came out as tight as a drum can't get a razor blade between the laminations. I recut them all afterwards and the only signs of any delamination or weakness was on the superglue job.

OK. What's the shortest distance to air, about 1"? How do you cut the laminated stack?

I wouldn't worry about soaking the paper all through as I don't think this will give at all.

Unsaturated paper is weaker than saturated, and vulnerable to sweat as well. More to the point, if one saturates the paper, one can use any kind of paper, not just fishpaper, and can use much thinner paper as well. Circuit boards can be made of epoxy-saturated paper. One can saturate the paper in advance one assumes.

I always wipe glue surfaces with acetone so have not had any failures in that area yet. I will run a test this week in the press and see how big I can go with this stuff without getting failures and will give my glue wizard a call and see if he has any thoughts on the subject.

Acetone is good. As is washing one's sweaty hands before starting. What I find to be very effective is to wet-sand surfaces with TSP in water, rinse, dry. This gets any surface scale et al off as well, and roughens the surfaces up a bit. Not to mention removing any greasy layer. This can be done in advance, with acetone used just before gluing.

Also ask about how to ensure paper saturation.

[Joe Gwinn]

So why not buy some laminated steel sheet? Then you just need to cut the stuff. McMaster-Carr has it. Granted it might be cheaper to make it, if your time isn't worth much.

Are you thinking of laminated shimstock? If so, the glue is intentionally weak, so layers can easily be peeled off.

[David Schwab]

Oh now that I look, it is shim stock...

I guess what we need is this stuff?

Cold Rolled Motor Lam Steel (CRMLS)

Or roll your own...

[jonson]

David I'm Not sure that will be any good for Dave as that will be all steel and no paper layers so I think Dave's gonna have to make it or get it made.

[David Schwab]

David I'm Not sure that will be any good for Dave as that will be all steel and no paper layers so I think Dave's gonna have to make it or get it made.

I figured it was like transformer core laminated steel. That's the stuff you want. It's insulated with glue between the lams. Doing it with paper will work too. I hadn't even though of laminating it myself... that's a good idea.

Bartolini used to make a pickup with laminated steel blades.

[jonson]

Sorry Joe I missed that post but yes I will ask the man lots of questions he's over next tuesday. Will also ask unless someone on here knows what glue is used for what David is talking about on transformers. I've tried that both with clamps and in my presses but they are set at mo for 6000lb per sq in. all to no avail. With just glue the laminations short out allthough probably not if I was to coat and let dry and then glue them together. Will have to find answers cus this stuff could be pressed in big sheets and then cut to size afterwards.