Coil encapsulation

[samsearcher]

Got some coil shells! wondering about spray 'builders foam' for coil encapsulation??? The expanding, lightweight stuff.....any good?

[Carl-NC]

White's used to use expanding foam for encapsulation. I would be concerned about things moving around as it cures.

[KingJL]

"... I would be concerned about things moving around as it cures."

I unsuccessfully tried expanding foam a while back. That was exactly the problem.

[dfbowers]

MG Chemicals 832b or Max MCR bkack a/b. Sticks well to ABS and will not melt your shelks.

[samsearcher]

Thanks chaps, .....this looks like a worthwhile mod to the TGSL coil..... https://youtu.be/XnrStRklcUQ?t=539

[Koala]

Thanks chaps, .....this looks like a worthwhile mod to the TGSL coil..... https://youtu.be/XnrStRklcUQ?t=539

not sure the difference in coils at the end will be down to shielding.

make two coils and they nearly always preform slightly differently


love how he got it to all fit in a slimline box.

[waltr]

White's used to use expanding foam for encapsulation. I would be concerned about things moving around as it cures.

I unsuccessfully tried expanding foam a while back. That was exactly the problem.

Foam would reduce coil weight but can have the issue Carl & KingJL stated.

This should be an issue if you first use a small amount of epoxy to fix the coil into the housing.

I did this when building a DD coil to ensure the balance didn't move before encapsulation the entire coil. I use just enough epoxy to anchor the coils into position. Then recheck balance.
If balance needed tweaking I could have cut away a little epoxy to move a coil.

[samsearcher]

It looks like he is flexing the Rx coil to achieve the final null point.

.........not sure the difference in coils at the end will be down to shielding.

[Koala]

correct the screw just flexes the wires slightly. Bit of over kill as you get just as good results by sliding and temporary gluing in place

at the end of the video he depth tests two coils with different shield method's aluminium poor graphite good. I suspect its more to do with the coils than the shield unless they used kitchen foil.

[samsearcher]

I suppose that spray 'builders foam' would be OK for the Minipulse coil though.....?

[Hyena]

correct the screw just flexes the wires slightly. Bit of over kill as you get just as good results by sliding and temporary gluing in place

at the end of the video he depth tests two coils with different shield method's aluminium poor graphite good. I suspect its more to do with the coils than the shield unless they used kitchen foil.

I tried this difference on one coil. Coil unshielded, with thin aluminium kitchen foil and with adhesive copper tape. No difference in possible deepest null, detection depth or shift. Only difference was that unshieded coil detected my hand. Did not tried graphite spray, I use only for shielding plastic enclosures. And I hate it

[Koala]

I tried this difference on one coil. Coil unshielded, with thin aluminium kitchen foil and with adhesive copper tape. No difference in possible deepest null, detection depth or shift. Only difference was that unshieded coil detected my hand. Did not tried graphite spray, I use only for shielding plastic enclosures. And I hate it

thanks

[waltr]

I suppose that spray 'builders foam' would be OK for the Minipulse coil though.....?

No issue at all for a Mono-coil.

It is only with IB coils that there can be an issue.

[Teleno]

Thanks chaps, .....this looks like a worthwhile mod to the TGSL coil..... https://youtu.be/XnrStRklcUQ?t=539

Can anyone explain why the nulling point must not be at the minimum but a little bit overcoupled?

[Koala]

Can anyone explain why the nulling point must not be at the minimum but a little bit overcoupled?

Good question.

I know from experience if it just the wrong side of null it preforms badly. But don't know why.