Coil enclosure proposal

[ivconic]

It is always hard to find good coil enclosures, for us diy'ers. After many years of making various coils i find out what is most suited for most of my needs. Best compromise between size, shape and functionallity would be coil with sizes between 20 and 24cm. Turned to be most effective in 90% of cases. Another good thing would be possibillity to use same enclosure for both; DD and coplanar coil. Why making many simillar models, why not use one universal enclosure and cover most of coil types?
So here it is, my proposal.
Dimensions in this case would be 24cm for outer circle and 13cm for inner circle. All other dimensions must be adapted to those.

[ivconic]

And here are main dimensions...

[perdica 2]

hi

hi , ivconic

as i know you are from serbia where are made Yugo's

if you can find the PVC plastic(thin,hard and durable) ,like on the dashboard from older Yugo you can easy form your profile , useing mold-quarc heater-and vacum(from ordinary vacum cleaner)

[beachbum]

DIY BigFoot coil

As a newbe I love the many posts here and the tech questions answered.

My question: Does anyone know how to make a replica of the BigFoot coil. I would like to make one for my White's Prizm IV. You guys seem to have all the answers to most of my quetions so i thought I would through this one out. Thanks ahead of time

Beachbum

[ivconic]

hi , ivconic

as i know you are from serbia where are made Yugo's

if you can find the PVC plastic(thin,hard and durable) ,like on the dashboard from older Yugo you can easy form your profile , useing mold-quarc heater-and vacum(from ordinary vacum cleaner)

Yes i inderstand you. But this shape is rather complex to make it that way. This is prepared for vacum extruding plastic machine to make huge serie of enclosures. Hopefully it will be ok. When finished i will know.

[ivconic]

As a newbe I love the many posts here and the tech questions answered.

My question: Does anyone know how to make a replica of the BigFoot coil. I would like to make one for my White's Prizm IV. You guys seem to have all the answers to most of my quetions so i thought I would through this one out. Thanks ahead of time

Beachbum

I dont know any details on BigFoot coil. But..this forum is best place to ask such question. I do beleive somebody will answer you.

[beachbum]

Bigfoot coil

thanks ivconic. I think your right. Some one will come up with the correct design. I have seen your many postings and have learned a lot from them. Keep up the good work for yor friends and the MD world. Next endever is to find a schematic for my White's prizm IV and my Viper Trident. Nice to have schematics when things go wrong.

Thanks again for the responce
Beachbum

[Carl-NC]

The Bigfoot is a Figure-8 coil. The TX is wound around the perimeter, and the RX coil has the shape of a figure-8. Tweak the position of the middle crossover to null.

- Carl

[beachbum]

Bigfoot coil

Thanks Carl. You are the first one I have spoken to that seems to know the configuration of Bigfoot. Your discription sounds plausable to me. Now all I need is someone who can discribe details (wire size & turns, etc) of construction to me.
I want to try to make one. I have the skills just not all the knowledge.

Thanks again guys

[Carl-NC]

Use whatever turns give you the right inductance (trial & error). Wire size is not critical, maybe 26 for TX and 30 for RX.

[kt315]

Next endever is to find a schematic for my White's prizm IV and my Viper Trident.

Viper Trident seems is full Fisher 1280's clone. I do not agree opinions I see in Net that Viper is cheap China junk. it is very good done and has best PCB SMD quality I could see.

respect Ivconic too.

[Carl-NC]

Here is a variation of your shell... I got rid of the two crescent holes. To keep it lightweight you don't want to fill the whole thing up with epoxy so use foam block fillers where you can.

[Tinkerer]

Filler for coil enclosure

Mixing a low viscosity epoxy resin with glass micro balloons, makes a very solid, but very light filler to cast into the coil enclosure.
Tinkerer

[ivconic]

Here is a variation of your shell... I got rid of the two crescent holes. To keep it lightweight you don't want to fill the whole thing up with epoxy so use foam block fillers where you can.

Yes, that looks better! I like it! Simplier with less elements to worry about, but even better and more nice than my proposal! I will adopt this one instead previous, thanks much!

[ivconic]

Oh yes, epoxy is hevy weight! Good only to apply on critical spots where windings must be tenable with no relative movements. Enough good is to cover whole windings with epoxy layer and later cover with foam, and again thin layer of epoxy on top to isolate it good from outer influences like moisture, stress and direct outdoor temperature changes.
One thing bugs me for long time; i "disected" much original coils so far. Was pretty confused at older Cscope coils (other manufacturers also). Usually those are filled with hard foam. Excellent material! And light weight! But... i experimented with foam (2 components; foam liquid and hardener) and it must be exposed to air to dry. Once closed in enclosure good (top and bottom plastic covers) it can not dry, stays semi liquid!!! Need a open air to dry good. And i tried many methods...drill small holes on enclosure...this and that...and no good results at all!
So i am wandering; how they succeded to close foam in enclosure and dry such good!? Are there any special chemicals or something else?

If i had good method to "curb" foam so far, i would never used epoxy, or i would use it just for last, thin, final layer...