Silicone II

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Jump to Latest
kneadle

kneadle

Member
Joined 2002
diy.nachmu.com
Hello,

I have a tube of Silicone II caulking leftover from a non-DIYaudio loudspeaker project. Does anyone have an objection to its use, i.e., chemical reaction to drivers? I don't know what makes silicone II different from plain old silicone.

BTW, is there a formal "Frugal-phile" organization I can join?

Thanks,

Dave
 
Kravchenko_Audio

Kravchenko_Audio

Member
Joined 2002
kravchenko-audio.com
Paid Member
Caulker BEWARE

As for chemical reations I've never had a problem. I've used silicone to repair cones and surrounds when in trouble. Mounting a driver with it is prety much permanent. I did an isobaric sub with it about 12 years ago. When one driver developed a problem it was bloody murder to get them out. If you plan on using the silicone as a seal you might try spreading a thin layer of petroleum jelly on the basket and areas that will come into contact with the silicone. It should make getting them out allot easier.

Mark
 
J

johninCR

Member
Joined 2004
Don't use silicone as a driver gasket seal unless you let it cure fully first. On the interior of the cab the acetic acid vapor will settle on waterever metal it finds and start corroding whatever it is not resistant. That includes steel, rubber surrounds, etc. Small amounts might not be noticeable, but they will decrease the life of your drivers.
 
P

peace brainerd

Member
Joined 2004
I agree. I would be very careful of exposing expensive drivers to corrosive gasses from these glues. If you really are fond of the perfomance of silicone, you can hunt for the "non-acetic neutral cure" variety. Any brand that is specifically suitable for aquariums should do (but not always. sometimes they merely suggest a lengthy curing period to degass it before adding fish - read the label for neutral cure). There are other uses for neutral cure silicone in building materials since it is required for bonding certain reactive metals and some types of plastics. I haven't looked at lowes or home depot but you might find it there.
 
H

Hornlover

Member
Joined 2004
I read where people say 'dont use silicon' a lot these days on the net. I think this is mostly the typical 'rumor mill' that the net is so good at. One person says it, and now its true! Does anybody really have any evidence that the acetic acid harms loudspeakers, components, or anything else?
I ask, because I was using silicon RTV since the late 60's, used it for decades, and I have never had any problems from using it. No corroded metals, or anything else that I can blame on RTV. I still have, and have contact with, many of these loudspeakers from passed years, and they are working just fine. Yes, I have had foam loudspeaker surrounds rot, but not at a higher rate than commercial speakers that just used wood screws to mount drivers.
Just wondering where all this came from, and is it backed by any real data, or just an often repeated 'urban legend'!
 
J

johninCR

Member
Joined 2004
About a year and a half ago I built my first DIY speaker, a sealed sub for the car. I used silicone to seal all the corners of the cab. I waited just until the silicone firmed up somewhat. I put the driver in and started using it. About 2 months later, I took the driver out to try in my second project, a vented sub. When I opened it up, the silicone fumes were tremendous and driver basket and magnet assembly was wet with some fluid. Everything else was dry (stuffing etc.), so it wasn't condensation coming from the wood. The driver was one of those crome covered auto subs, so only the basket edges, pole vent screen, terminal posts, etc. were quite corroded. I wiped it down, let it dry for a day, wiped some WD40 on the corroded parts, and put it in the new cab. It works to this day.

I still use silicone, but I make sure it is fully cured before installing drivers and I don't use it as a gasket seal any more.
 
H

Hornlover

Member
Joined 2004
The stuff I used was the type with acetic acid. It always irritated my nose and eyes when I used it. Back then, it was the only type available, as far as I know. I used it for sealing in drivers, and sealing cabinet seams. 'No problem is too big it cant be fixed with RTV'. That was a typical motto back then. It was also easier to remove drivers when you needed too, compared to the newer RTVII stuff. It stayed more flexble (rubbery). I still prefer it to the new stuff.
 
M

markp

Member
Joined 2003
Hornlover said:
I read where people say 'dont use silicon' a lot these days on the net. I think this is mostly the typical 'rumor mill' that the net is so good at. One person says it, and now its true! Does anybody really have any evidence that the acetic acid harms loudspeakers, components, or anything else?
I ask, because I was using silicon RTV since the late 60's, used it for decades, and I have never had any problems from using it. No corroded metals, or anything else that I can blame on RTV. I still have, and have contact with, many of these loudspeakers from passed years, and they are working just fine. Yes, I have had foam loudspeaker surrounds rot, but not at a higher rate than commercial speakers that just used wood screws to mount drivers.
Just wondering where all this came from, and is it backed by any real data, or just an often repeated 'urban legend'!
Click to expand...
Here is your real life data: Many, many years ago while I was working at Speaker City we had a problem with one customer and all the Dynaudio 17W drivers he was getting. The surround on all of them would ripple and dimple all the way around a few days after the speaker was assembled. After lots of head scratching I suggested that he not silicon down the drivers as he had been to make it easier to remove them in order for us to examine the problem. Well, to make a long story short, he stopped having the problem when he stopped using the silicon! The volitile chemicals from the stuff hurt the surround rubber as the silicon dried.
 
H

Hornlover

Member
Joined 2004
Well, I'm still unconvinced. I used RTV on the 17W75's as well as 21W54's and a host of Dynaudio mids and tweeters, and I never had a problem. I still have a pair of old Dynaco A25 cabinets where I installed 21W75's in them, and because of the existing cutout, the only way I could get the drivers mounted was with a large amount of RTV. No screws, since there was no wood under the holes. This was about 15 or so years ago, and they still work fine. (I think they were called 21W75's. Maybe 22W75's?). Anyway, they are the oversized 8" units with the 3" VC.
 
M

markp

Member
Joined 2003
Hornlover said:
Well, I'm still unconvinced. I used RTV on the 17W75's as well as 21W54's and a host of Dynaudio mids and tweeters, and I never had a problem. I still have a pair of old Dynaco A25 cabinets where I installed 21W75's in them, and because of the existing cutout, the only way I could get the drivers mounted was with a large amount of RTV. No screws, since there was no wood under the holes. This was about 15 or so years ago, and they still work fine. (I think they were called 21W75's. Maybe 22W75's?). Anyway, they are the oversized 8" units with the 3" VC.
Click to expand...
Well, it DID happen. I don't know the brand of silicon used and that is a factor as they use different formulas. RTV is not clear silicon and does not have the same volitiles that the clear stuff has because it would be eaten up by petrolium products.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Top Bottom