i have a bass reflex monitors built with birch ply and every time i pull out the woofer, i always get a strong whiff of a vinegar/glue like smell from the inside of the cabinet. i shellac-ed the inside and the out against moisture and it's a similar smell to that solvent which was just pure shellac flakes and alcohol. the box had plenty of time to air out and it's already almost an year since the assembly. but the smell... like i say it's very acidic/vinegar like smell, bit reminiscent of pvc glue and a bit of earthy wooden smell mixed into it. could this be natural smell of birch wood or something that i should be worried about?
Don't get sick from it, that's my advice.
There are some dangers from Formaldehyde in some instances. Just make sure is not the case.
YouTube - FEMA Trailers and Formaldehyde
There are some dangers from Formaldehyde in some instances. Just make sure is not the case.
YouTube - FEMA Trailers and Formaldehyde
I would be concerned
Hi Presapian,
Most plywoods designed for indoor use are made with something called urea-formaldehyde. Urea-formaldehyde can slowly break down into its components, urea, and formaldehyde. Formaldehyde is very toxic, causing skin, eye and nasal irritation/burning, nausea, headaches, and whole host of other symptoms. It's the active component of embalming fluid. It's also very reactive, and may be damaging your woofer. I've worked in a lab which uses both urea and various formaldehydes, though never urea-formaldehyde, and the smell you are describing may very well be formaldehyde. For the past 30-40 years, at least in the United States, urea formaldehyde for use in plywoods has been made in a modified form to reduce the release of formaldehyde, as required by the US government, which is why plywoods don't normally smell like your speaker. However, I don't know when or where your plywood was manufactured. And as you point out, the smell is probably building up inside your sealed cabinets. I wondered if the alcohol used for your shellac may have had an effect. I searched the web a bit, but couldn't find any info on the effect of alcohol on cured urea-formaldehyde. There are a lot of chemists where I work - I may ask one of them.
Unfortunately, if it is formaldehyde outgassing, I don't have a good solution to suggest other than occasionally airing out the inside of your cabinet - outdoors.
Wikipedia has a long article on urea-formaldehyde you may want to read.
-Byron
Hi Presapian,
Most plywoods designed for indoor use are made with something called urea-formaldehyde. Urea-formaldehyde can slowly break down into its components, urea, and formaldehyde. Formaldehyde is very toxic, causing skin, eye and nasal irritation/burning, nausea, headaches, and whole host of other symptoms. It's the active component of embalming fluid. It's also very reactive, and may be damaging your woofer. I've worked in a lab which uses both urea and various formaldehydes, though never urea-formaldehyde, and the smell you are describing may very well be formaldehyde. For the past 30-40 years, at least in the United States, urea formaldehyde for use in plywoods has been made in a modified form to reduce the release of formaldehyde, as required by the US government, which is why plywoods don't normally smell like your speaker. However, I don't know when or where your plywood was manufactured. And as you point out, the smell is probably building up inside your sealed cabinets. I wondered if the alcohol used for your shellac may have had an effect. I searched the web a bit, but couldn't find any info on the effect of alcohol on cured urea-formaldehyde. There are a lot of chemists where I work - I may ask one of them.
Unfortunately, if it is formaldehyde outgassing, I don't have a good solution to suggest other than occasionally airing out the inside of your cabinet - outdoors.
Wikipedia has a long article on urea-formaldehyde you may want to read.
-Byron
thank you byron, that was extremely through information. the plywood i bought was made in china but it was a surplus sheet from the ones they exported to germany, which made me think that they would've been made to the highest voc standards since germany's renowned for that. it's an ok quality birch 9ply, and was already several years in storage when i picked it up and the only odor i noticed from it was the natural wood smell when i cut it.
do you think there's still a good chance that it's offgassing formaldehyde? the only reason why i didn't go with mdf was this issue and now it looks as though i might have shot myself in the foot
thank you for your reply in advance, Byron.
do you think there's still a good chance that it's offgassing formaldehyde? the only reason why i didn't go with mdf was this issue and now it looks as though i might have shot myself in the foot
thank you for your reply in advance, Byron.
When I worked in the ornamental fish trade I used Powdered Activated Carbon
impregnated filter pads , it has a wide spectrum of chemicals that it adsorbs. It came in sheets about 12" by 15", you could try putting a piece of it in your boxes, wait a few days then open them up to see if the smell is still there.
You might want to give the cut piece a gentle vacuuming before you put it in there though as P.A.C inherently gives off dust from the manufacturing process. I would have suggested you pour some Granulated activated carbon onto the floor of your speaker boxes but the free pellets could rub each other through vibration and create more carbon dust. (BAD)! As it could be blown out the ports.
impregnated filter pads , it has a wide spectrum of chemicals that it adsorbs. It came in sheets about 12" by 15", you could try putting a piece of it in your boxes, wait a few days then open them up to see if the smell is still there.
You might want to give the cut piece a gentle vacuuming before you put it in there though as P.A.C inherently gives off dust from the manufacturing process. I would have suggested you pour some Granulated activated carbon onto the floor of your speaker boxes but the free pellets could rub each other through vibration and create more carbon dust. (BAD)! As it could be blown out the ports.
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Hi PreSapian,
I'm a cabinet maker (20 years). This is a perplexing problem. I literally have used tons of cabinet plywood of all kinds over the years and haven't run into this problem, nor have any customers ever complained about something like this. My shop is full of this stuff. Since this material has been in storage for a long while, any out gassing should have ceased by now. Also, shellac is a very effective sealer. Shellac based primers are used in restoring buildings that have experienced smoke damage (seals up the smell) from a fire. I suppose it is possible that this material was put on the surplus market because it was defective or contaminated in some way. However you stated there was no smell when you cut the material. In my experience that's when any odor from material is the strongest. All this leads me to believe that the plywood is not the source of what you are smelling.
~Mike
I'm a cabinet maker (20 years). This is a perplexing problem. I literally have used tons of cabinet plywood of all kinds over the years and haven't run into this problem, nor have any customers ever complained about something like this. My shop is full of this stuff. Since this material has been in storage for a long while, any out gassing should have ceased by now. Also, shellac is a very effective sealer. Shellac based primers are used in restoring buildings that have experienced smoke damage (seals up the smell) from a fire. I suppose it is possible that this material was put on the surplus market because it was defective or contaminated in some way. However you stated there was no smell when you cut the material. In my experience that's when any odor from material is the strongest. All this leads me to believe that the plywood is not the source of what you are smelling.
~Mike
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thank you byron, that was extremely through information. the plywood i bought was made in china but it was a surplus sheet from the ones they exported to germany, which made me think that they would've been made to the highest voc standards since germany's renowned for that. it's an ok quality birch 9ply, and was already several years in storage when i picked it up and the only odor i noticed from it was the natural wood smell when i cut it.
do you think there's still a good chance that it's offgassing formaldehyde? the only reason why i didn't go with mdf was this issue and now it looks as though i might have shot myself in the foot
thank you for your reply in advance, Byron.
It's difficult to say for sure but Chinese made manufactured building materials have been implicated in the past with toxic ingredients and sold in world markets (drywall in particular). I haven't heard anything regarding plywood but it might be worth exploring further.
The vinegar smell is a strange clue ... could it be that the Room Temperature Vulcanizing Silicon sealant (RTV Silicon) has not cured completely due to product breakdown or defect of some kind?
Alternately, is this a fully sealed enclosure? Although I find it a bit unlikely considering the time elapsed and the fact that you've opened it a few times, I suppose it's possible that there is not enough circulation inside to allow full curing. Maybe popping the back or woofer for two days might clear that up if it's the case.
Do you think you might just be very sensitive to the smell? It's hard to get a good sense in a forum of what is really a sensory experience. Have you asked a friend what he thinks?
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thank you byron, that was extremely through information. the plywood i bought was made in china but it was a surplus sheet from the ones they exported to germany, which made me think that they would've been made to the highest voc standards since germany's renowned for that. it's an ok quality birch 9ply, and was already several years in storage when i picked it up and the only odor i noticed from it was the natural wood smell when i cut it.
do you think there's still a good chance that it's offgassing formaldehyde? the only reason why i didn't go with mdf was this issue and now it looks as though i might have shot myself in the foot
thank you for your reply in advance, Byron.
It's difficult to say for sure but Chinese made manufactured building materials have been implicated in the past with toxic ingredients and sold in world markets (drywall in particular). I haven't heard anything regarding plywood but it might be worth exploring further.
info on chinese plywood
I found this forum where people talked about bad experiences with Chinese made plywood.
Problems with Chinese Plywood
Also, I can't find any records of ethanol dissolving urea-formaldehyde one it is cured. However, formaldehyde is soluble in ethanol.
I found this forum where people talked about bad experiences with Chinese made plywood.
Problems with Chinese Plywood
Also, I can't find any records of ethanol dissolving urea-formaldehyde one it is cured. However, formaldehyde is soluble in ethanol.
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