deveng

Foam off gassing and mic capsules
« on: April 29, 2020, 10:54:21 PM »
Has anyone considered or seen information related to the off gassing of foams used for storing microphones?   Could the long term storage of a LDC vintage mic in a mic box with foam cause damage or early failure to the diaphram?   In the studio I used to tech at they stored a crap load of expensive vintage mics on wood shelves with plastic bags to keep the dust off.   So many mics have built in pop filters made of foam.  What about storing in a wood box with closed cell or open cell foam, or Kaizen foam?  All these foams off gas.    Just curious!
« Last Edit: April 30, 2020, 12:43:16 AM by deveng »


Re: Foam off gassing and mic capsules
« Reply #1 on: April 30, 2020, 04:41:38 AM »
I've heard of foams sticking to the microphone in really hot, humid environments. Can't remember if it also affects the capsule.

I've never seen a large diaphragm condenser with a built in foam windscreen. I've only seen that on dynamics and cheap OEM crap like the BM-700 and BM-800 depending on which company is selling it.

TLRT

Re: Foam off gassing and mic capsules
« Reply #2 on: April 30, 2020, 08:18:51 AM »
AKG Solidtube had foam inside the headbasket if I remember right...?

rogs

Re: Foam off gassing and mic capsules
« Reply #3 on: April 30, 2020, 09:06:55 AM »
Some external windshields come with  toxicity warnings on the labelling..
 I have a Samson WS03 here that warns:
 'This product contains chemicals including DEHP known to the State of California to cause birth defects and other reproductive harm'
I'm  not pregnant - nor do I live in California - so I should be OK  :)    .. but these windshields do give off a bit of a smell when you first open the packaging....
Now whether it's similar to internal mic foam - which may cause problems???...
www.amx.jp137.com - A DIY RF condenser mic project

Re: Foam off gassing and mic capsules
« Reply #4 on: April 30, 2020, 09:57:06 AM »
For all my DIY mics I store them  in an unused flight sock - collected a few over the  years - and also a bubble plastic bag I made to suit. Then they are housed in an ABS case of suitable dimensions. I avoid using any foam, because I  have seen what can happen to it over the years. Best kept away from mics, in my opinion!
Kindest regards,
zephyrmic

Khron

Re: Foam off gassing and mic capsules
« Reply #5 on: April 30, 2020, 10:27:25 AM »
Virtually EVERYTHING is "known by the state of California to cause <any number of health issues>" ;D ... Because reasons(?).

Some external windshields come with  toxicity warnings on the labelling..
 I have a Samson WS03 here that warns:
 'This product contains chemicals including DEHP known to the State of California to cause birth defects and other reproductive harm'
I'm  not pregnant - nor do I live in California - so I should be OK  :)    .. but these windshields do give off a bit of a smell when you first open the packaging....
Now whether it's similar to internal mic foam - which may cause problems???...
Khron's Cave - Electronics - Audio - Teardowns - Mods - Repairs - Projects - Music - Rants - Shenanigans

Re: Foam off gassing and mic capsules
« Reply #6 on: April 30, 2020, 03:32:47 PM »
Virtually EVERYTHING is "known by the state of California to cause <any number of health issues>" ;D ... Because reasons(?).
Hey, at least they stopped putting cancer warning labels on coffee. That's progress, right?

deveng

Re: Foam off gassing and mic capsules
« Reply #7 on: April 30, 2020, 07:53:58 PM »
One reason I asked this question is I recently purchased a custom cherry wood case for my vintage Neumann U87.   I just happened to have some Kaizen foam that was used in a shipment I received.  Kaizen foam is very cool.  Its easy to cut and pull the layers to fit anything.   I decided to use this foam for the U87 case.   It hit me when preparing the foam that all foams off gas.   The chemicals in the air eventually break down and destroy the surrounds in my JBL speakers.    So not only does the microphone capsule get exposed to the chemicals in the air, now its in close contact with a foam that is off gassing.    I've repaired EV RE20's with baby rattle, I'm working on replacing foam in some old Shure SM59's and the foam in some of my old mic boxes, all of it totally disintigrated into a gooey mess.  Could this "polution" shorten the life of capsules?    I sure don't know!

Re: Foam off gassing and mic capsules
« Reply #8 on: May 01, 2020, 01:35:56 AM »
U87 also used to have foam at the base of the head basket for awhile, presumably to help with internal reflections in the headbasket, but it can wind up a little bit of a disaster as it decomposes.

I think that many mic manufacturers have adapted as they have figured out the way foam degrades. I wonder if back in the 60s and on, the expectation was that much of it would last longer, or if it was that the mics wouldn’t be used for as long as they have been.

It’s not all made the same either, so maybe over generalizations aren’t always so constructive.

 

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