What sort of brush to clean capsules?

[cyrano]

Demi water should also do the trick. All mineral content is gone. What remains is substances that are dissolved in the water. They are always volatile enough not to leave remains on the capsule.

 

[kingkorg]

Here's how Dan Alexander does it:

Dear lord! M7 has a venting hole drilled through the backplate, please don't try anything like this. Old ones might have microscopic holes where diaphragm glue came loose. This is a really bad idea.

 

[kingkorg]

I had discussed this with Neumann and they provided me with a description on how to clean them. Of course that email is long gone, but basically, carefully drip feed distilled water across the membrane surface, its good to have say a white saucer/dinner plate underneath collecting the water so you can see if any particles come off, hopefully no gold plating. If there appears to be foreign particles still on the surface that are not washing off, use something like a lens brush, the finest hair brush you can source and gently brush while running the distilled water across it. If you see any gold particles, stop brushing immediately. Cleaning with a brush should only be done if there is a performance issue with the microphone and not something you should do periodically. If you have a condensor that shuts down for a number of seconds, could be 10 -15 seconds at high sound pressure levels, then it most likely needs cleaning. After cleaning, with an open mouth, softly "huff' on the microphone surface, it should no longer shut down.

Hard to go against instruction from Neumann, but sometimes i wonder if they are aware of all the quirks. In the end, if things go south, they can replace the whole thing.

Here's the original capsule with cut in the spacer. One should at least be aware of it if liquid is used.

 

[soapy_goat]

Here is Neumann's capsule cleaning tech paper from a few moons ago

 

[terry setter]

OK, I'm fessin'-up....

This is what happens when an M7 meets Dust Off during .001 second of inattention. I happened to give it a squirt at a 90 degree angle. $900 lesson learned - FOREVER!

For the sharp eyed among you, yes, this is an M7 out of a Gefell UM70.

Don't bother to taunt me about this. I ain't proud. Hopefully, other people will be able to learn from my mistake.

By the way, I still use Dust Off to get lose debris off of capsules, but only at VERY STEEP ANGLES and NEVER at full thrust.

 

[k brown]

"Kids, see what happened to Uncle Terry? - just say NO to Dust Off."

Brush is all that's needed. If it won't come off with that - leave it; your mic aint gonna sound no differn't.

 

[Junction]

Hard to go against instruction from Neumann, but sometimes i wonder if they are aware of all the quirks. In the end, if things go south, they can replace the whole thing.

Here's the original capsule with cut in the spacer. One should at least be aware of it if liquid is used.

I will clarify, the instruction I received from Neumann was specific to a vintage U67, it may not apply to other mics and capsules. It is always worth contacting the manufacturer, they should know best. And the surgery was very successful, I had a problem with the mic muting of sorts for more than 5 seconds with slow recovery over a longer period on high sound pressure levels (vocals)

 

[k brown]

If someone tries to pour water over your capsule - give them the brush . . .

 

[soliloqueen]

i wonder if one could use an engineering fluid like a novec

 

[MicMaven]

i wonder if one could use an engineering fluid like a novec

Serving Suggestion No. 2983

I successfully cleaned a very dirty old capsule with a specialized digital camera sensor cleaner, which dissolved nearly all built-up gunk and crud. It was easy to control because I applied the cleaner to the brush, and not directly to the capsule. I think I prefer a specialized bristle type sensor brush over the foam type. The trick is to apply a minimal amount of cleaner directly to the brush, not the capsule, which provides more precise dosage and placement on the capsule, minimizing the chances liquid will seep inside the capsule. I "rinsed" it with a small quantity of purified water acquired from a pharmacy. I used a separate brush for each phase of the two step process.

I would certainly not dunk a capsule into any liquid, and I would not use harsh cleansers or solvents of any kind. I would never use canned air at any angle.

Of course, I am no expert, but I once stayed in a Holiday Inn Express ... and it was a very old, expendable capsule. Your mileage may vary. James - K8JHR

 

[tomas.borgstrom]

Distilled water and a squirrel hair brush

I've cleaned hundreds of capsules

This is how I do it to. No damaged capsules yet. I once tried my best to remove the gold from a capsule from the 50's with a squirrel hair brush but I cound't get it off.

 

[MicMaven]

Tom says -- "This is how I do it to. No damaged capsules yet."
___________________________________________________________

Ah ... the old "So-Far-So-Good" logical fallacy.

Here is another example: A guy claiming he can disprove the Theory of Gravity, assembles a crowd of witnesses and a Notary Public to certify the feat, and leaps off (what else?) the Empire State Building. Half way down he triumphantly shouts - "See ... so far, so good!"

(OK, just poking fun - nothing serious in this one.) James

 

[GeorgeToledo]

Most of the gunk I've seen on vintage Neumanns wouldn't be touched by water.

Skin oils and tobacco tar are not water soluble.

It seems it is usually the dust getting moisture that makes it short out though, so whether or not cleaning needs to remove more than dust is probably debatable.

On more than one occasion I have found that just cleaning the perimeter of a dirty center terminated capsule is often enough to get one to stop shorting under breath moisture. Like, the outside tension ring and a little bit in, on the area with no gold.

Not too long ago a long time forum acquaintance had a k67 that had a fair amount of the gold already rubbed off, and with breath moisture issues. They also found this approach of just cleaning the perimeter worked for the issue they had.

 

[GeorgeToledo]

I remember reading at various times - in different sources - that AKG, Neumann, and others have tested their products against ammonia. Probably a better idea than alcohol.

 

[soliloqueen]

I remember reading at various times - in different sources - that AKG, Neumann, and others have tested their products against ammonia. Probably a better idea than alcohol.

Ammonia and pet are not chemically compatible according to the data sheets

 

[Electrobumps]

I remember reading at various times - in different sources - that AKG, Neumann, and others have tested their products against ammonia. Probably a better idea than alcohol.

Testing and cleaning are different things. I wouldn't put ammonia anywhere near a capsule no idea what it would do to mylar but it corrode's brass and other metals.

Dry brush first as has been suggested is sensible. If this doesn't work and the mic still has issues try Neumann instructions as posted above.

My issue was the degraded foam on the 87 capsule mount had shed all over the capsule. Dry brush did not remove. I did not have blotting paper but used the lint free sponge type q tips to dab up any small amount of water left on the capsule.

At the end of the day you take the risk to clean yourself or send it away to be cleaned/reskinned by someone who is an "expert".

Personally it worked for me and I thought it was a pretty easy. Also much less downtime on the mic as I did not have to send it away.

You do have the potential to destroy your capsule and this kinda of job is not for everyone.

 

[papadajoke]

Chemist here. Ammonia will dissolve a fair share of metals, so keep it away from your capsules unless that's your intent. On the subject of "canned air" or Dusters, that chemical is usually Difluoroethane, which is a refrigerant. Works great for removing debris at steep angles as I've seen mentioned earlier in this post. Do not turn the can upside down and spray as this will dispense the liquid, which extremely cold!

 

[GeorgeToledo]

I’m looking at a spec sheet now and seeing that.

It reminds me of a couple other things I’ve heard of people using…benzene, and the freon coolant that used to go into cars. I’d think the benzene would leave a residue though.

 

[Tim Campbell]

Ammonia should only be used to clean acrylic. Ammonia will oxidize brass but I would be surprised if it would actually dissolve it. I have had brass in ammonia baths and sealed chambers with ammonia gas and all that achieved was darkening it's color. Ammonia however is very good at dissolving gold.

For cleaning membranes I would only recommend distilled water or distilled water with a little alcohol added .

Neumann/Gefell M7 capsules have a tiny hole at their perimeter.

Dry cleaning fluid has been mentioned at various times but then I would say that you are more concerned with looks than performance. A slightly dirty capsule will usually perform excellently.

 

[Icantthinkofaname]

Ammonia should only be used to clean acrylic. Ammonia will oxidize brass but I would be surprised if it would actually dissolve it. I have had brass in ammonia baths and sealed chambers with ammonia gas and all that achieved was darkening it's color. Ammonia however is very good at dissolving gold.

For cleaning membranes I would only recommend distilled water or distilled water with a little alcohol added .

Neumann/Gefell M7 capsules have a tiny hole at their perimeter.

Dry cleaning fluid has been mentioned at various times but then I would say that you are more concerned with looks than performance. A slightly dirty capsule will usually perform excellently.

I just know a mic I don't mind risking is noisy and I've cleaned the PCB already. I wouldn't clean something like my C414 B-ULS cause that works fine.