Filler for Coil shells, or filler for any coil

[Matt_Rowe]

thought i would post this as i have used it before for other projects, but never heard of anyone mentioning it in the forum here, it is a light weight, sand able epoxy filler called Micro Balloons,
im going to try it on my shells i have coming from Don

Micro Ballons

[Matt_Rowe]

Or, how about these plastic bbs used for air soft kids guns.

https://www.amazon.com/2000-Pcs-Plas.../dp/B01MYD332G

[ionut_mtb]

I once used micro glass ballons mixed with epoxy. It reduces a lot the weight and it is also good dielectric. You have to put as much as possible but without harden the mix to much, because is hard to fill the coil after. For my coil i put 100% this mix. Others use 75/85% epoxy/micro ballons first and the rest only epoxy to have more strength (because no coil cover).

[Matt_Rowe]

Thats what i was thinking, i only have the tops coming from Don, and thought of these while on my pc. In all the coil threads ive been looking at, i have never heard of anyone using these as fillers.

[waltr]

Yes, I also use micro-ballons with epoxy in Dons' coil shells.

The epoxy I use Don recommended and is:
http://www.polymercompositesinc.com/...-mcr-black-ab/

[Matt_Rowe]

Thanks for the link, ill save it.

[dfbowers]

That stuff is probably the best I have found. A little pricey though.

[MartinB]

That stuff is probably the best I have found. A little pricey though.

Hi Don
I have read in various posts that filling the shell with epoxy degrades the performance of the coil. Have you any experience of this?
Also, I have read that graphite dust can be mixed with the epoxy to provide shielding. Again, have you any experience of this?
Thanks

[SVEN1]

I use the same epoxy. No bubbles like some others. It is heavier as it does have filler mixed into it. Very easy to work with.

[eclipse]

Hi Don
I have read in various posts that filling the shell with epoxy degrades the performance of the coil. Have you any experience of this?
Also, I have read that graphite dust can be mixed with the epoxy to provide shielding. Again, have you any experience of this?
Thanks

A commercial coils use these methods I got one - NEL BIG it's called and it's pile of s**t. Very light but also not very working. If you make your own coils with these methods you can at least adjust the amount of filler so you don't get coil that's not nulled properly after few hours of work on the field.

[dfbowers]

Hi Don
I have read in various posts that filling the shell with epoxy degrades the performance of the coil. Have you any experience of this?
Also, I have read that graphite dust can be mixed with the epoxy to provide shielding. Again, have you any experience of this?
Thanks

I have never noticed any change in performance after potting but I have heard strange things happening when used on a really cold day, almost like the contraction rates are different between the wires and and the potting compound. On more than one occasion. A fellow builder (Cyril) has had PI coils just quit working only the have them work again when they warm back up. I never checked any of my IB coils..

[MartinB]

I have never noticed any change in performance after potting but I have heard strange things happening when used on a really cold day, almost like the contraction rates are different between the wires and and the potting compound. On more than one occasion. A fellow builder (Cyril) has had PI coils just quit working only the have them work again when they warm back up. I never checked any of my IB coils..

Thanks for your reply. Looks like it will be potting compound rather than epoxy.

[dfbowers]

Thanks for your reply. Looks like it will be potting compound rather than epoxy.

Yes, Epoxy, auto body fillers and boat resins are a really bad idea. They get hot in large masses, can melt your project and generally don’t stick to plastics very well. Another possibility is acrylic. Don’t have any personal experience with it but I have heard of others using it successfully.

[MartinB]

Yes, Epoxy, auto body fillers and boat resins are a really bad idea. They get hot in large masses, can melt your project and generally don’t stick to plastics very well. Another possibility is acrylic. Don’t have any personal experience with it but I have heard of others using it successfully.

Thanks Don. Just got some jobs to do around house for the next couple of weeks and then I can start building again

[WM6]

Yes, Epoxy,They get hot in large masses, can melt your project and generally don’t stick to plastics very well.

True.

But there is solution:

- pot epoxy in layers (especially first two or three layers)
- spray plastic coil housing and inserted coil with so called "plastic primer" (available in spray can too).