ways of making a bobbin

[black_labb]

hi guys, i am in the process of making a strat style pup but need it as small as possible to fit inside the neck (the neck extends into the body), and i also want the top to be very thin so that i can put it inside a wooden cover and have the polepieces popping through and not having the actual coil too far from the strings.

what i am trying at the moment is putting the alnico magnets into a temproary bobin, with tape on it to prevent it from getting stuck itself (think it happened anyway) and then filled between the magnets with 5 minute adralite (an epoxy). i stopped it from running under the magnets by sticking tape to the bottom to create a barrier.

do you guys think this will work well, or have any better ideas? i will post back later when it has dried (im sure it has now, but im not at home)

[Spence]

you can use Polymorph such as in this link:

http://www.maplin.co.uk/images/Full/n14at.jpg

Just embed your magnets in it and either mold the bobbin or machine it after it's set.

[black_labb]

you can use Polymorph such as in this link:

http://www.maplin.co.uk/images/Full/n14at.jpg

Just embed your magnets in it and either mold the bobbin or machine it after it's set.

that stuff looks great, ill see if i can get it easily in australia. the epoxy is still drying due to the thickness, the time given wouldbe for an extremely thin layer between glued surfaces, its part way there though, butits been 24 hours. im glad its "5 minute" stuff not the full cure time. ill see how this turns out anyway.

[jonson]

Hey Spence. Don't know if you are using this stuff and if you buy from Maplins but at nearly £20 for 500grams. Typical of them. Try these people At £21 odd per kilo much better. I have dealt with them. Very quick and no probs.
://www.mutr.co.uk/catalog/product_info.php?products_id=550&osCsid=ae772dcd86218ada 521ce06f5c9ce79e

[Spence]

That's a much better price. I did use it for a couple of things such as making formers for vacuum moulding as suggested by Maplins. It is useless for that as the hot plastic sheets melt it's surface immediately. I would imagine that Fields metal would be just as hopeless.

[jonson]

Iv'e cast white metal into silicone rubber before Spence which should give you a permanent buck to form onto. The people at that site also do the sheets for vacume forming as well but worth looking at the dental suppliers as it is used for things like gum shields as well. These guys are handy and prompt on delivery http://www.tiranti.co.uk/index.asp

[Joe Gwinn]

that stuff looks great, ill see if i can get it easily in australia. the epoxy is still drying due to the thickness, the time given wouldbe for an extremely thin layer between glued surfaces, its part way there though, butits been 24 hours. im glad its "5 minute" stuff not the full cure time. ill see how this turns out anyway.

The hardening time for epoxy shold not vary with thickness at all, unless the part is too thick and so the center is getting too hot (the cure reaction is exothermic).

[David Schwab]

sounds like it wasn't mixed right.

[black_labb]

The hardening time for epoxy shold not vary with thickness at all, unless the part is too thick and so the center is getting too hot (the cure reaction is exothermic).

i have a feeling i didnt mix it correctly. i think ill just make the top of the bobbin from wenge, as the strings are quite low on the guitar im making, so you wont be able to see far underneath the cover. the cover is going to be about twice as large as it needs to be, even though it is just a strat style single coil. i just like the look of large covers. if nesesary i can always glue a piece around the side to get the correct look. it wont be long before i post the guitar up with the homemade coils. its been a while, but it will be there soon.

[Spence]

Iv'e cast white metal into silicone rubber before Spence which should give you a permanent buck to form onto. The people at that site also do the sheets for vacume forming as well but worth looking at the dental suppliers as it is used for things like gum shields as well. These guys are handy and prompt on delivery http://www.tiranti.co.uk/index.asp

Appreciate what you're saying. I actually use a dental vacuum former. That Fields metal melts at 61 deg C too. I may give it a try though as I currently use Chemical Metal which can be a pain to ge the air out of.

[David Schwab]

it wont be long before i post the guitar up with the homemade coils. its been a while, but it will be there soon.

I have to make my own bobbins. You don't see them though, because the pickup is covered.

I think I'm going to try and make a silicon mold and cast them. Making the coil forms is the most work I have to do with my pickups.

[Spence]

Iv'e cast white metal into silicone rubber before Spence which should give you a permanent buck to form onto. The people at that site also do the sheets for vacume forming as well but worth looking at the dental suppliers as it is used for things like gum shields as well. These guys are handy and prompt on delivery http://www.tiranti.co.uk/index.asp

This link shows what Fields metal, an alloy of 51% Indium, 32.5% Bismuth, and 16.5% Tin does in hot water.

http://sci-toys.com/scitoys/scitoys/...loy/drips2.gif


Woods metal has a slightly higher melting point.

[jonson]

Just read the stuff on that Spence. Wonderful material but what a price so would have to be a reusable jobby. Think i'll stick to Machining and welding at mo cus i'll probably be pushing up daisies afore I got through a kilo of that. Trying to locate a pourable metal being used by the punch and die maker guys at mo as the stuff has a fairly long life and can be reworked to make another die once a project is finished. Couple of companies come up lately that laser work dies for punching out sheet materials Cardboard and the such but whether it would work on harder stuff remains to be seen.

[Spence]

Actually, that reminds me that the box company I use makes up the cutters with flexible blades. They'd be able to make something to cut out flatwork I would imagine.

[jonson]

These guys may be worth a call just to find out the costs of knocking out a sheetfull. They list Fibreboard as one of their stock materials allthough that could be anything, but, their site does make claims of doing almost anything.
http://www.gpwaterjet.co.uk/die_cutting.htm I don't do strats teles etc but could be worth a look anyway.