Copper clad electronic board

[DIYASTRO]

Havnt been on the boards for months! Still fabricating stuff and have hit small problem!

I need some single or double sided  copper boards for etching tracks. Have got some from Maplin to try but the copper is not very thick, I want to make a pick up plate for a focus motor / Crayford which also has a camera rotation facility. (pick up plate to provide power to focus motor without leads becoming tangled.)

Anyone know of supplier of heavier copper board? Must be 200mm sq or larger.

I will try and find one of my threads later (multi lens astro camera and post some pics of what I am doing)

[Tinker1947]

These people may have want you want.......

http://uk.rs-online.com/web/c/pcb-prototyping/printed-circuit-boards-pcb/

[DIYASTRO]

Thanks Tinker,

I have had a look at RS and they only have the standard 35um copper type (1.6mm thick with the fibre glass board)

These boards, like the ones I have just brought, will work but not too sure for how long with a carbon or soft brass pick up on the track.

I will post some images here latter to show what I mean!

[Gina]

Maybe you could use solid copper sheet?

[DIYASTRO]

Hopefully you will see from the pics that a simple gear train from dc motor gearbox drive the Crayford clockwise or anti.

The motor gearbox on the Crayford needs a power pick up from the copper plate (yet to be etched to provide tracks) This prevents any tangled cable when the camera rotation is used.

Thicker copper track would be the order of the day, if not available commercially I guess I will have to make a resin / copper tracked plate myself but trying to avoid that!

This is part of a filter wheel/camera rotate/focus system for the 10"SCT

[DIYASTRO]

Gina, sorry, didn't notice your reply must have posted at same time as I did!

Thought about solid copper plate until I looked at the cost of 200/300mm sq 2 or 3mm!!!!!

I think this will eventually be a fabrication job with thick copper wire and resin cast in a mould and then faced off in the lathe to give nice flat copper tracks.

would just be so easy with a thicker copper clad plate and photo etching it.

[Lonestar70]

Hi,

Try this one...

http://uk.rs-online.com/web/p/photoresist-boards/4184168/ all ready to apply the tracks using a positive mask. (black tracks on a transparent background)

Only trouble with using copper tracks for sliding pickups is it will quickly oxidize unless it is plated... the same would apply to brass pickup springs.

The best option would be carbon plating and gold wipers.

Hope this helps.

Sandy.

[DIYASTRO]

lonestar,

thanks for that.

Yes I have seen these but still the copper is only .07mm thick.

I know that is double the std. but still not quite robust enough for the purpose.

They are also presensitised which means pre machineing is difficult.

Think I will continue for the present with std board and see how that works, but ultimately make some copper resin pads and machine those.

[keithatrochdale]

You could make the focuser self powered?

[2stroke]

I pick my copper plate up from hobby shops here in australia. They may not have the right size cut's though chances are they will get what you need from there suppliers. I think this is where i got my last peice http://www.hobbyman.com.au/ though you will find simalar UK hobby shops stocking it or that can get it in for you.

[Lonestar70]

Try these people, they do single and double-sided board of various thickness and up to 4oz copper thickness.

They may be able to supply a non-sensitized panel of the correct size.

http://www.screenbond.co.uk/capabilities.html

You will find it difficult to get heavier than 4oz copper in the UK... it is made though... see these people in the USA

http://www.pcbuniverse.com/pcbu-products.php

They do board thickness up to 8mm and copper up to 11oz (0.383mm)

Good luck.

Best regards.

Sandy.

[Davey-T]

May be a silly suggestion and not sure what diameter circle you need, but what about model railway track ?

Dave

[DIYASTRO]

Hi Dave,

Thanks for your input, and to all others that have had a look into the problem!

I have thought about 'N' scale track which is about the smallest gauge available and concluded that it is an option but still need soldering to a copper etched board for stability and electrical connection.

Havnt ruled it out though!

I intend to get going with the etching of the copper clad board tomorrow. the photo dev and ferric chloride arrived today!

Will post up results asap.

Thanks again to all for your very constructive ideas.

Boyd

[JohnC64]

Have you tried a jewellery supplier?  They sell  copper sheet and will cut to size required.  

Take a look here http://www.cooksongold.com/Sheet/-Alloy=Copper_Sheet/-Thickness=0/-Type=0/&prdsearch=y

HTH John

Edit: copper is expensive though :-(

[dtokez]

Try ebay, I've always got my copper clad from there, not sure how thick but seems pretty thick to me once etched

[DIYASTRO]

Had a go at etching the copper clad board today, wont win any awards but looks intact and worthy of soldering up to test it out.

Will try and find time to do the pick up for this today and get it fitted / tested.

Couple of images to show the double sided etched board and its location on the filter wheel / focus / rotator.

[DIYASTRO]

Found some time to etch the pick up board etc.

Posting images on my other thread ( SCT modifications; 26-july-2014 DIY astronomer)

[rfdesigner]

Nice project.

Have you considered getting the tracks gold plated.  Gold plating is commonly used in the electronics industry as it aids soldering and prevents oxidisation so maintains contact impedance over time.   There are different grades available with some being specifically for contacts, not just soldering.   It needn't be expensive.

Derek

(electronics R&D by day)

[DIYASTRO]

Derek,

No... I hadn't!

I will look into that... Quite possible that the reason I didn't think along those lines is that the price of solid copper sheet was frightening enough!

I can instantly see the advantages that you point out and oxides are potentially a huge problem when operating outdoors.

Many thanks.

Boyd

[Gina]

Since ball bearings were mentioned somewhere as a possible alternative to slip rings, I tested one of mine.  The resistance varied from around an ohm up to 4 ohms.  Could be a possibility for signals but too high for power.  Myth busted

[rfdesigner]

Since ball bearings were mentioned somewhere as a possible alternative to slip rings, I tested one of mine.  The resistance varied from around an ohm up to 4 ohms.  Could be a possibility for signals but too high for power.  Myth busted

When I had my own lab I used to measure the resistance of the ESD hand straps to confirm they were working.. sometimes I'd get an open circuit as the connectors were not too good, so I used a spot of graphited grease on them and the contact was much better, perhaps with ball bearings using a graphite grease would also help to improve consistancy.

just a thought