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Re: Chemical cleaning brass?

Posted: Mon Oct 03, 2016 7:55 am
by ovenpaa
I am a fan of stainless media regardless of the hassle of removing the pins, the LEM I use gives perfect results every time.

Re: Chemical cleaning brass?

Posted: Mon Oct 03, 2016 10:46 am
by WelshShooter
Birchwood Casey make a phosphoric acid based acid cleaner for case cleaning. However, this is a wet method (aren't all chemical methods wet?). I stopped using this mixture because it was difficult to control the time, temperature of solution and surface area to be coated. The cases would turn "rose gold" quite quickly.

The best results I have achieved is by ultrasonic washing with citric acid followed by a 20 minute tumble in treated corncob media to make 'em shine. The citric acid mix I've used is not as aggressive as the Birchwood casey cleaner but does a good job at softening up the baked on carbon. When the cases are put into the tumlber the corncob media does a good job at removing the remaining carbon and making the brass shine. The tumbling alone does not remove all the carbon.

The only difficulty is 100% removal of fouling on the inside of the case. The reason I clean is to remove exterior fouling so that my dies to not get damaged during sizing and also to make case inspection easier (e.g. looking for split necks). For this reason I find my cleaning regime to be acceptable.

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Re: Chemical cleaning brass?

Posted: Mon Oct 03, 2016 11:25 am
by Blackstuff
Is there a reason you don't want to tumble them in media? I do mine that way without de-priming the cases and then use a 'salad-spinner' style media separator, so there's no faffing around scraping the media out of the primer pocket/flash hole. After I deprime the cases I scrape out any carbon with a little tool which is a lot less hassle than picking the media out. I'm sure that's blasphemy to the uber-cleaners out there though lol

Re: Chemical cleaning brass?

Posted: Mon Oct 03, 2016 12:24 pm
by 1066

Re: Chemical cleaning brass?

Posted: Mon Oct 03, 2016 12:39 pm
by Gazza
Blackstuff wrote:Is there a reason you don't want to tumble them in media? I do mine that way without de-priming the cases and then use a 'salad-spinner' style media separator, so there's no faffing around scraping the media out of the primer pocket/flash hole. After I deprime the cases I scrape out any carbon with a little tool which is a lot less hassle than picking the media out. I'm sure that's blasphemy to the uber-cleaners out there though lol
No particular reason apart from.... I just thought in this day and age there could be some magical chemical that would sort it without the expense of buying tumbling gear and media and was also quicker.

When I was in the PCB making game we had an aqueous foam cleaner for removing photo resist film, flux and any other stuff that was contaminating the boards, this would be ideal but it was expensive and might have been a struggle to get right inside the cases.

Re: Chemical cleaning brass?

Posted: Mon Oct 03, 2016 12:39 pm
by ovenpaa
I always de-cap mine first using a home made universal de-capper then leave the machine to it.

Re: Chemical cleaning brass?

Posted: Mon Oct 03, 2016 1:13 pm
by WelshShooter
Gazza wrote:
Blackstuff wrote:Is there a reason you don't want to tumble them in media? I do mine that way without de-priming the cases and then use a 'salad-spinner' style media separator, so there's no faffing around scraping the media out of the primer pocket/flash hole. After I deprime the cases I scrape out any carbon with a little tool which is a lot less hassle than picking the media out. I'm sure that's blasphemy to the uber-cleaners out there though lol
No particular reason apart from.... I just thought in this day and age there could be some magical chemical that would sort it without the expense of buying tumbling gear and media and was also quicker.

When I was in the PCB making game we had an aqueous foam cleaner for removing photo resist film, flux and any other stuff that was contaminating the boards, this would be ideal but it was expensive and might have been a struggle to get right inside the cases.
I would imagine EKC-265 or ALEG-310 would be pretty expensive to buy for the individual consumer!

That being said, I did work on a process to soften resist polymers by using NF3/CF4 in a CVD process followed by a rinse with DI water. As it turns out, it was not as effective as the aforementioned "harsh" chemicals.

Re: Chemical cleaning brass?

Posted: Mon Oct 03, 2016 4:46 pm
by Robert303
I used Micro 90 Laboratory cleaner and tipped my deprimed cases into tubs of it, really blackened cases sometimes need to be twisted in a nylon pot scourer. Once finished you pour the Micro 90, which is diluted, back into a suitably marked container then leave the tubs of cases somewhere warm to dry out.