Mortite, Rings and Gaskets

Toolfan66

Plumbers putty would be a mess, just use MD/Mortite..

hearingimpared

Yeah I remember using plumber's putty when I was a teen working with plumbers and contractors and that stuff left grey grease all over your fingers. Unless technology has produced a better putty as when I was a teen dinosaurs were still roaming the earth I wouldn't think of using it!:eek:

Just stick with Mortite as stated above or go with Parts Express speaker sealer putty, that what I use.

Isn't plumber's dope the same as the putty or was it used to place on the joint before welding/soldering it together. It was so long ago I just can't remember.

jimmydep

I don't think plumbers putty is good for this application, for one it's made with oil and has a tendency to "bleed" staining the wood or anything that is porous. Another problem is over a period of time, it tends to dry out and get hard when exposed to the air.

Joe, Plumbers dope is a thread sealant that is used primarily for threaded joints and compression fittings, where putty is used mostly to seal faucets and drains to sinks.
I stopped using putty years ago because it could stain natural stone surfaces, now I only use silicone to seal my sinks and faucets.

Jimmy

hearingimpared

hearingimpared wrote: »

Yeah I remember using plumber's putty when I was a teen working with plumbers and contractors and that stuff left grey grease all over your fingers. Unless technology has produced a better putty as when I was a teen dinosaurs were still roaming the earth I wouldn't think of using it!:eek:

Just stick with Mortite as stated above or go with Parts Express speaker sealer putty, that what I use.

Isn't plumber's dope the same as the putty or was it used to place on the joint before welding/soldering it together. It was so long ago I just can't remember.

jimmydep wrote: »

I don't think plumbers putty is good for this application, for one it's made with oil and has a tendency to "bleed" staining the wood or anything that is porous. Another problem is over a period of time, it tends to dry out and get hard when exposed to the air.

Joe, Plumbers dope is a thread sealant that is used primarily for threaded joints and compression fittings, where putty is used mostly to seal faucets and drains to sinks.
I stopped using putty years ago because it could stain natural stone surfaces, now I only use silicone to seal my sinks and faucets.

Jimmy

Thanks Jimmy. When I kept thinking about it trying to remember which was which, I stop because I realized that it was 40 years ago when I did that work!:eek::eek::( 40 YEARS!!! UGH!

inspiredsports

OK, now that TFL has handled the backside, someone needs to experiment and:

-- find the perfect material
-- create the sharp punch-out / cutting tool to precisely cut them
-- start producing and selling tweeter, mid-woofer and passive gaskets.

hearingimpared

inspiredsports wrote: »

OK, now that TFL has handled the backside, someone needs to experiment and:

-- find the perfect material
-- create the sharp punch-out / cutting tool to precisely cut them
-- start producing and selling tweeter, mid-woofer and passive gaskets.

I think the passive gaskets may be a little hard to handle and keep in place at least with the larger PRs but you are really onto something there Greg.

Knucklehead

I used Mortite when I rebuilt my Baby Advent's, I also used the criss cross pattern avoiding overtigtening, never had any problems and after the new foam surrounds were broken in they are some great sounding little speakers.

F1nut

inspiredsports wrote: »

OK, now that TFL has handled the backside, someone needs to experiment and:

-- find the perfect material

Polk already did.

inspiredsports

F1nut wrote: »

Polk already did.

Well, yes, but if I'm interpreting Raife's recap of Matt's comments correctly, that material was Mortite, so it seems to me a better cut gasket material might be out there.

hearingimpared

inspiredsports wrote: »

Well, yes, but if I'm interpreting Raife's recap of Matt's comments correctly, that material was Mortite, so it seems to me a better cut gasket material might be out there.

Greg, if I'm reading this correctly you are stating that the gasket are Mortite!?! I've found the original gaskets on my MWs to be cut perfectly and they are definitely not made of Mortite as they are a little on the foamy side.

inspiredsports

hearingimpared wrote: »

Greg, if I'm reading this correctly you are stating that the gasket are Mortite!?! I've found the original gaskets on my MWs to be cut perfectly and they are definitely not made of Mortite as they are a little on the foamy side.

No, I mean a sheet of something that would be precision cut to original size.

It might be felt, foam, rubber, cork, sorbothane or a laminate of more than one material (which would be a challenge considering the thinness desired).

My belief is is would be denser (like Mortite) than the the foam currently used, but obviously still very thin and compressible. Mortite is great, but a pain in the butt to work with.

I'd like to see a gasket that is clean to the touch that you simply put in place and tighten down, but has the benefit of the better coupling to the baffle that you get using Mortite.

hearingimpared

inspiredsports wrote: »

No, I mean a sheet of something that would be precision cut to original size.

It might be felt, foam, rubber, cork, sorbothane or a laminate of more than one material (which would be a challenge considering the thinness desired).

My belief is is would be denser (like Mortite) than the the foam currently used, but obviously still very thin and compressible. Mortite is great, but a pain in the butt to work with.

I'd like to see a gasket that is clean to the touch that you simply put in place and tighten down, but has the benefit of the better coupling to the baffle that you get using Mortite.

Ah, I see.:)

mmadden28

Hmm, That's a great idea. I might try rolling out some Mortite flat like dough, and then perhaps cut out the rings. Something like cured silicone would be cool like maybe getting some silicone caulk or something similar, spreading it out thin on a non-stick sheet, letting it cure and then cutting out the rings. Obviously not mass produced but a start for a DIY project.

fishbones

Seems to me that the main purpose is to create a better 'seal' to the speaker cabinet - this keeps air from leaking out when the drivers are in motion, and lets the passive radiator fully function the way it was designed to. I'm sure different speakers have different situations of original gasket conditions being that these are 20+ yrs old, and all treated by their original owners differently.

Wouldn't you be able to test it, by moving a feather around all the outer edges of the drivers (and radiator) while playing music at a certain SPL to determine if you have any leaks? If you do have leaks with the original gaskets, then it sounds like mortite would be your only option (for the driver that leaked). This test would also be just as important after you do the mortite - to make sure you put it on as evenly as you thought.

I have never done it, so I'm certianly no expert, just seems to make sense to me? But, I'm just a noob....:D

Regards,
Troy

heiney9

The "air" seal is part of it but coupling to the baffle is just as important and it helps with that as well. It's not just about sealing the air in.

http://en.wikipedia.org/wiki/Loudspeaker_enclosure

http://www.polkaudio.com/forums/showthread.php?p=1359788

H9

P.s. I should be clear, when I'm saying proper coupling, I mean de-coupling from the baffle.

fishbones

I hesitated posting that because of the knowledgeable people already on this thread, but I'm glad I did....I (once again) have learned more, and that's what makes this hobby fun!


Thanks H9

F1nut

Seeing that the original gaskets are 1/64" thick and work perfectly, the seal part matters a whole lot less than coupling the drivers to the baffle. The rings are the real solution. I'd be willing to bet that when using the rings, a gasket of any sort isn't needed.

I should be clear, when I'm saying proper coupling, I mean de-coupling from the baffle.

Huh?

Face

F1nut wrote: »

Seeing that the original gaskets are 1/64" thick and work perfectly, the seal part matters a whole lot less than coupling the drivers to the baffle. The rings are the real solution. I'd be willing to bet that when using the rings, a gasket of any sort isn't needed.

Polk didn't use a gasket on the LSi's mid woofers or tweeters.

heiney9

F1nut wrote: »

Huh?

Perhaps I'm a little confused. I thought the purpose of the gaskets or mortite was to keep the driver baskets from making direct contact with the baffle and keeping vibration, ringing and other things to a minimum. If not, what's the purpose of the gasket? That's why i used the word de-couple. Maybe it means something else in this context.

H9

FTGV

Face wrote: »

Polk didn't use a gasket on the LSi's mid woofers or tweeters.

I'm guessing that would require tight tolerances on the driver cut outs in the baffle to prevent air leaks.

Face

FTGV wrote: »

I'm guessing that would require tight tolerances on the driver cut outs in the baffle to prevent air leaks.

Yep, sometimes making them difficult to remove.

F1nut

heiney9 wrote: »

Perhaps I'm a little confused. I thought the purpose of the gaskets or mortite was to keep the driver baskets from making direct contact with the baffle and keeping vibration, ringing and other things to a minimum. If not, what's the purpose of the gasket? That's why i used the word de-couple. Maybe it means something else in this context.

H9

The purpose of the original gaskets was to provide a better air seal due to the relatively poor method Polk used to attach the baskets to the baffle.

The bottom line is you want the baskets coupled to the baffle as tightly as possible, which is why the rings are so great.

Face

anonymouse wrote: »

The LSi line is ported. Nowhere near the internal air pressure and need for sealing as the SDA's, which are a sealed PR design. I thought the LSi drivers had a gasket affixed though?

The air pressure is less, but a leak would still affect their low end.

heiney9

F1nut wrote: »

The purpose of the original gaskets was to provide a better air seal due to the relatively poor method Polk used to attach the baskets to the baffle.

The bottom line is you want the baskets coupled to the baffle as tightly as possible, which is why the rings are so great.

Well, I'll be doing some more experimenting when I get the rings installed in both the 1C's and 5B's this Winter . In the end I may change my mind. For now, I'm happy with the improvement on the 5B's.

H9

hearingimpared

heiney9 wrote: »

The "air" seal is part of it but coupling to the baffle is just as important and it helps with that as well. It's not just about sealing the air in.

http://en.wikipedia.org/wiki/Loudspeaker_enclosure

http://www.polkaudio.com/forums/showthread.php?p=1359788

H9

P.s. I should be clear, when I'm saying proper coupling, I mean de-coupling from the baffle.

Brock, IMHO coupling the drivers to the cabinet is what gives you the proper means of draining the vibration, resonance and extraneous frequencies caused by the driver which renders them harmless as the cabinet is huge and dissipates the nasties. De-coupling from cabinet let's all those nasties be directed back to the driver.

FTGV

F1nut wrote: »

The bottom line is you want the baskets coupled to the baffle as tightly as possible, which is why the rings are so great.

Exactly ,as this rigid mounting should improve bass and midband definition.As for the mortite acting as a decoupler,I would think once the screws were tightened the driver would no longer be 'decoupled'.The srews would effectively short circuit the compliant mounting.

F1nut

FTGV wrote: »

Exactly ,as this rigid mounting should improve bass and midband definition.As for the mortite acting as a decoupler,I would think once the screws were tightened the driver would no longer be 'decoupled'.The srews would effectively short circuit the compliant mounting.

Interesting notion. I'll have to give that some thought.

FTGV

F1nut wrote: »

Interesting notion. I'll have to give that some thought.

Wouldn't vibration in the driver frame be transmitted to the front baffle through the screws?For the driver to be truly 'decoupled' would require the mounting hardware to be isolated from the baffle as well.A number of years ago I believe both KEF and PSB had such a driver mounting system in some of their higher end models.

HollowState

Oooohhh . . . OK, now that's an original idea! Seal the porosity of the MDF and create a flat surface. Use the original gasket. Then apply the rings. Should create a strong mechanical bond and give the coupling effect we're all looking for. I'm thinking Larry the machinist is a genius!!