Sourcing gold plated contact material - Page 1
Forum section: electronics / projects

author: Glug
author_rank: Contributor
timestamp: January 19, 2013, 09:41:19 pm
content: I need to make some small custom contacts, and I am having trouble sourcing raw gold plated material.I doubt I can justify having them produced, so I plan on forming them myself. They are fairly simple - just a few bends. Size is approximately 1.0mm x 5.0mm. In some cases they will be sandwiched, in other cases they will be a leaf spring style contact.In one instance the contacts will inteface to a gold plated surface, and in another they will interface to nickel plated brass. The contacts will carry audio signals.I can find plenty of vendors to make custom parts, but I haven't had any luck finding sources for raw materials. For example, sheets of gold plated copper or brass. I can buy pieces of plain brass at the corner store, and that is useful for prototyping.Help on finding a source and selecting appropriate materials would be appreciated.It is also possible that I am dismissing the viability of short run production. So any insight on costs there would also be helpful. If things work out, I could see needing maybe a hundred a year, ballpark. Hopefully more.Thanks for any help!

author: marshallh
author_rank: Unknown
timestamp: January 19, 2013, 10:11:46 pm
content: Take a look at digikey's connector selection. You can spend days on there.Unless you want to spend $10-50k and min qty of 1000 to get a shop to talk to you that is your best bet.Luckily audio stuff is such low frequency you have lots of options.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 19, 2013, 10:21:10 pm
content: For this sort of thing you probably want to make it first then get it plated. The basic shape can be lasercut or photochemical etched with minimal tooling cost - bends can be more tricky, but if qty is low you could probably do it manually.Should be possible to find someone to plate it - I think there are some DIY plating methods but no idea how effective.Parts would probably need to be done in a sheet or web, plated then seperated out afterwards.

author: IanB
author_rank: Super Contributor
timestamp: January 19, 2013, 10:37:42 pm
content: As far as I know DIY plating is difficult--you have to control every aspect of the process (surface prep, cleaning, plating solution, plating conditions) very precisely to get a satisfactory result. But are there any electro-plating shops nearby in your local area? You could possibly take them a sheet of brass, have them plate it to your requirements, and then cut and form pieces out of it afterwards? The cut edges won't be plated, but perhaps that's OK.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 19, 2013, 10:49:33 pm
content: You can buy brass sheet with photoresist for processing with DIY PCB chemistry - you could use this to make the shapes tabbed in a sheet and get the sheet platedhttp://www.megauk.com/brass_sheet.php

author: G7PSK
author_rank: Super Contributor
timestamp: January 19, 2013, 11:05:01 pm
content: Gold plating is one of the easier ones to do, there are lots of kits available both brush on and electro plating.http://www.goldn.co.uk/manual2/http://puregoldplating.co.uk/gold-plating-kitshttp://www.goldsolutionsonline.co.uk/

author: Glug
author_rank: Contributor
timestamp: January 19, 2013, 11:18:34 pm
content: Good suggestions! Please keep them coming.The idea of using photoresist with brass sheets is interesting, and could save a lot of work. I do wonder about possible residual chemical contamination issues when doing the subsequent plating. An acid etch would probably solve that.I did some searches on gold plating and apparently there are many variations in terms of the final hardness. Some of my contacts will be static, others will see sliding motion from another gold contact that is very expensive. I need to be wary of any possible abrassion issues. And corroding the part I am interfacing with must also be avoided. So more research will be needed on that.Cutting or forming a piece of metal with another piece of metal can introduce microscopic contamination that causes subsequent corrosion. Like cutting brass with an x-acto blade. I'm not sure if that will be a problem but it is a concern.

author: nanofrog
author_rank: Super Contributor
timestamp: January 20, 2013, 01:13:54 am
content: If you plate it yourself, you'd want to use electroplating (autocatylitic) rather than an immersion method. The reason for this, is that immersion results in a thin plating (few atoms thick), vs. elecroplating will continue to plate until you remove it, or the solution is exhausted of it's gold content. And you'll want a nickel plate under the gold.Another thing to keep in mind, is part preparation before plating. It has to be absolutely clean for proper adhesion (no oxides, ..., or it will wear off very easily).Example of a low cost electroplate kit:http://www.ebay.com/itm/Plug-It-Plate-It-24kt-Gold-Plating-Machine-kit-/160907101128?pt=LH_DefaultDomain_0&hash=item2576cf83c8Hope this helps.

author: G7PSK
author_rank: Super Contributor
timestamp: January 20, 2013, 12:14:13 pm
content: To get really good gold plating requires the use of cyanide compounds so be careful if doing it yourself with this process, get yourself some good rubber gloves and a gas mask.

author: hlavac
author_rank: Frequent Contributor
timestamp: January 20, 2013, 12:58:30 pm
content: Pluck a pin from a gold plated pin header, bend it

author: nctnico
author_rank: Super Contributor
timestamp: January 20, 2013, 04:43:02 pm
content: Quote from: marshallh on January 19, 2013, 10:11:46 pmI agree. Making a good contact takes more than putting two pieces of metal together. I'd order some catalogs from Farnell, Digikey, etc and brands like Samtec, Tyco, etc and browse through them. There are thousands of connectors on the market.

author: robrenz
author_rank: Super Contributor
timestamp: January 20, 2013, 07:48:34 pm
content: Brass is not a good material for a spring contact. That is why good contacts use beryllium copper for its higher yield point and fatigue life. designing a contact is not a trivial thing as the maximum stress levels need to be considered. Electroplating is an art. getting good adhesion and controlling the quality of the deposited material is not easy. I would suggest finding a existing pin and socket and work with them as is or use the functional parts of them in your design.