Making some 2mm laminate?

[dvddvd]

I'm trying to build some wooden bobbins for a guitar pickup.

I tried some 2mm thick hardwood and cut the shape out but when I tried to put in the 5mm metal slugs it split the wood. They need to be a tight fit.

So I thought of using the same hardwood and use 2 x 1mm pieces and glue them together, but have the grain running at 90 degrees to each piece to stop the wood splitting.

Any advice on doing what I'm trying to do?

I was looking at a 6 tonne press to clamp the pieces together or which other way would work?

The pieces would be around 100mm x 500mm and I'd cut multiple pieces out once it's all dried

Thanks

 

[Ozi]

I don't know if this is relevant but ply mostly has an odd number of layers as this is supposed to make it more stable.

I have a mental image of you trying to work with 0.67 mm sheets thinking "Ozi is a *""!%!!!.

 

[Agent_zed]

Do the pole pieces actually need to be that tight? The just need to not move around. Easiest way would be to make them just tight enough that they don't fall out.
If you are wax potting them then the pole pieces aren't going to move, and if you aren't and you really want to be sure they don't move just put a bit of CA glue around them (you might want to wait until you're happy with their final position). It's not going to make a blind bit of difference to the sound.

 

[MikeJhn]

Have you thought about casting them in Epoxy resin and Carbon Fibre sheet?

 

[dvddvd]

Thanks for replies..if I managed to get a tight fit without spliting the wood, could it split in the future? Just thinking in damp weather could it push it over the edge and split in the future?

I did look at carbon fibre sheets in either .5 mm or 1mm stuck to the back and then cut them out. Would that stop them splitting?

 

[MikeJhn]

If genuine Carbon Fibre sheet it would be very difficult to split it without it physically being bent first, saying that anything can be split if forcing something too large into a hole.

 

[dvddvd]

How strong would 0.5mm carbon fibre be?

 

[MF1000]

Carbon fibre sheet strength is very dependant on the orientation of the fibres with the force applied and the resin quantity. In your case I’d guess you would use a disc on either side of the wooden bobbin as a strengthening washer …glued with epoxy - strength shouldn’t be an issue.

 

[dvddvd]

Thanks, so how's the best way to clamp two thin pieces together?

 

[MF1000]

I would use a simple spring clamp and some baking paper to stop the clamp sticking to the disc etc

 

[niall Y]

If one is laminating up ply, then the grain of the alternate layers, does not have to be at 90 degrees to each other.
There used to be available a special drawer side ply, where the angle of grain in each layer was only slightly displaced. This worked well for stability, didn't look too stripey, and was well behaved when being planed.

 

[Inspector]

Could you use birch plywood? It comes in 2mm with 3 or 4 layers of veneer.

Pete

 

[Fergie 307]

Mercedes use of aluminium sheet behind the real wood veneers in their cars, specifically to prevent the wood splitting and splintering in the event of an accident. They typically use a plywood body for the part, then a layer of aluminium sheet, typically about 0.5mm thick, then the veneer on top. The whole lot bonded with some kind of resin. Might be worth a try.
I use old fashioned long setting araldite when repairing them. The interior of a car can get very hot, some other glues soften in these conditions and can allow the veneer to move.
If this method is suitable for what you are doing then it should handle anything you can throw at it.

 

[the great waldo]

Pete's suggestion is good. You can get very high quality plywood from a radio control airplane shop. I get verythin plywood form a local shop here in Vienna
https://kirchert.at/collections/sperrholz
You should be able to get something similar in the UK or you could use thin vulcanised fibre
https://www.dictum.com/en/materials...-basis-cg/vulcanized-fibre-black-04-mm-719641
or use some printed circuit board laminate. I pressume your'e making strat pickups or similar single coil types. If so so I would go with the vulcanised fibre (forbon) as it has a tiny amount of give when you push the magnets through. >Slightly chamfering the magnets helps to get the magnets through (otherwise they tend to work like a cookie cutter and cut through the forbon. The magnets have to be tight in as when winding there is a surprising amount of pressure on the bobbins as the coil is wound.
Cheers
Andrew
ps.there is plenty of information here https://music-electronics-forum.com/forum/instrumentation/pickup-makers
on pickup making.

 

[MikeJhn]

Look here: https://www.easycomposites.co.uk/high-strength-carbon-fibre-sheet

 

[MikeJhn]

Or two of these bolted back to back: https://www.amazon.co.uk/Mirthobby-Steering-Futaba-MG996R-Airplane/dp/B08SC5B6YJ