Mortite Speaker Seals For SDA's

IrishNiner

Just finished the Moretite project on my RTA 15TL's and very much like the results. Subtle but noticable improvement to the sound stage. Only minor problem I had was the moretite not sticking to the driver baskets very well prior to installation.

Thanks for the tip,

Farrell

dbnh

Re: Mortitie not sticking - I've used this product at home and periodically noted that it may not stick at first application.

Also, Mortite makes a brown / wood colored caulking cord, for those who may not like the gray for their speakers or other home applications.

HB27

Just a couple of notes here:
1: It doesn't always come off cleanly or easily.
2: MOST important. This uses an oily base that WILL soak into veneers and leave stains in the black MDF motorboards. It's happened to me and keeping it away from the veneer and routed edges is a must. I haven't had any issues with the vinyl covering other than having to wipe off the "moisture" from the seal.
It's an excellent sealer for drivers and a little strip of this goes a long way.
Harry

awe-d-o-file

has a foam gasket too. You need to mortite that too!


ET

DarqueKnight

Mortite would not be a good choice for the crossover plate. You want to tightly couple the driver baskets to the baffle but you want to isolate the crossover plate from the baffle to minimize vibration transfer to the crossover components.

My SRS's and SRS 1.2TL's have a strip of soft 3/16" thick foam going around the crossover openning. This contrasts with the stiffer paper thin foam seals used on the drivers.

It would be a good idea to check your SRS crossover plate seals for cracks and replace with a similar weatherstripping tape if required.

skrol

I just did one of my RTA11TL's today with Moretite and I was surprised at the difference. Doing the leak check, pressing the PRs in and timing how long it takes the MWs to equalize pressure went from ~1.5 sec to ~3 sec. The bass is tight and defined.

+1 for Moretite. Thanks for tip.

Stan

zingo

Thanks for the great tip again Raife. I gave my drivers the Mortite (actually I used the Frost King basic brand :eek:) treatment as suggested and the results was as good as I had hoped. The seal is very good and the driver isolation is improved over stock. I also tried using some to dampen the baskets since it's removable, and it did a pretty good job. However, my next task will be removing the Mortite from its dampening duty, and I will be painting the baskets with liquid rubber dampening compound...

Face

Jake, I believe the purpose of the mortite is the couple the drivers with the cabinet, not isolate or dampen them.

zingo

Face wrote: »

Jake, I believe the purpose of the mortite is the couple the drivers with the cabinet, not isolate or dampen them.

Correct, and it works very well for that. I was also just mentioning that I tested it as a dampening agent and it worked decent for that too if you are in a pinch.

schwarcw

HB27 wrote: »

Just a couple of notes here:
1: It doesn't always come off cleanly or easily.
2: MOST important. This uses an oily base that WILL soak into veneers and leave stains in the black MDF motorboards. It's happened to me and keeping it away from the veneer and routed edges is a must. I haven't had any issues with the vinyl covering other than having to wipe off the "moisture" from the seal.
It's an excellent sealer for drivers and a little strip of this goes a long way.
Harry

Since the Mortite sticks, why not use plumber's putty?? It comes on a rope (or in a tube) and is very similar to the Mortite. Plumbers putty will seal natural gas in fittings. It stays pliable and is easily removed. I suspect it would work as a speaker gasket. Anyone have experience to the contrary?

F1nut

Jake, this is the comment Mike was referring to,

The seal is very good and the driver isolation is improved over stock.

I'm sure you meant couple.



Not that it matters, I'm sure, but I'll have to pass on this tweak.

hearingimpared

I'm going to use a speaker sealer in lieu of the Mortite. It just seems to me that Mortite wasn't made for this application and speaker sealer is. I've used Parts Express speaker sealer to seal a split in the joint of my right 1.2 TL as well as using it instead of the stock gaskets on the passive radiators with great success.

zingo

F1nut wrote: »

I'm sure you meant couple.

You're right Jesse.

DarqueKnight

HB27 wrote: »

Just a couple of notes here:

1: It doesn't always come off cleanly or easily.

2: MOST important. This uses an oily base that WILL soak into veneers and leave stains in the black MDF motorboards. It's happened to me and keeping it away from the veneer and routed edges is a must. I haven't had any issues with the vinyl covering other than having to wipe off the "moisture" from the seal.
It's an excellent sealer for drivers and a little strip of this goes a long way.
Harry

I decided to see how much oil, if any, leaks out of Mortite. I assumed that this version of Mortite must use some chemical formulation that keeps the oil base stabilized within the putty. Otherwise, it would leach out under pressure and loose its elastic properties. Their non-hardening claim would then be compromised.

Test 1: I placed a small lump of Mortite on a sheet of highly absorbent Strathmore Bond 100% cotton writing paper and rolled the lump flat with a spray paint can. I will leave it there for a week to see how much oil leaches out.

Test 2: I placed a short cord of Mortite between two strips of Strathmore Bond writing paper and placed the "Mortite sandwich" in a vice and tightened down as far as I could. This will be left for a week and then examined.

I saved the front and rear panels from my Mortite box. There was no oily residue on either panel. Mortite is packaged with no wrapping between it and the box. The box says "Made in China", therefore I assume the Mortite had been its box for at least a couple of months between the time it was packaged in China and arrived at my local Home Depot.

Results next week.

DarqueKnight

Test 1: I placed a small lump of Mortite on a sheet of highly absorbent Strathmore Bond 100% cotton writing paper and rolled the lump flat with a spray paint can. I left it there for a week.

Results: No oil leached out of the Mortite (1st picture below). The dark spots in the watermark area are small pieces of Mortite that stuck to the paper.

Test 2: I placed a short cord of Mortite between two strips of Strathmore Bond writing paper and placed the "Mortite sandwich" in a vice and tightened down as far as I could. I left it there for a week.

Results: The Mortite was compressed down to paper sheet thinness between two slips of paper. Oil leached out and left a spot that was the same size as the flattened Mortite cord. The paper slips cracked open due to the pressure and an oil pattern the same width and length as the cracks was observed on the rubber vise pads. Oil did not seep through the paper.

I took out one tweeter and one driver and examined the baffle board for oil stains. None were found. This was after being in compression for three weeks.

thsmith

Excellent testing and results !

Thanks DarqueKnight

schwarcw

The question for me is how will the Mortite release after being compressed by an SDA driver for a couple of years or more?

Let me say it again why not plumber's putty? It comes in a rope or a can. It may leach some oil, or it may not. I think this depends more on the quality of the product. I do know that plumber's putty will release after being torqued with a pipe wrench, sitting in the sun, with hot water running through it. I also know it will seal brass fittings with a few psi of natural gas running through them. ****, I have some of this stuff (1/4" rope) that is still soft after about 20 years just sitting in a can (no oil). Just another suggestion,

I'd worry about my drivers drying to the baffle. If you never blow one, no big deal. If the Mortite hardens like epoxy, the repair becomes a little more complex.:mad: Not overwhelming, just something I'd rather not deal with.

Teflon tape is also a very good sealer. Get it before the EPA Militia take it away.

6'&glassy

Plumbers putty is composed of linseed oil and clay and will dry out and crack, especially when applied between driver and untreated particle board which wiill suck out the linseed oil like a sponge...vibration doesnt help either. Cord weatherstripping is a nice tweak. I have some residual cord that has been sitting in its box for over a couple of years and the paper box is not compromised or stained, and the cord is still usable.

DarqueKnight

schwarcw wrote: »

The question for me is how will the Mortite release after being compressed by an SDA driver for a couple of years or more?

I'll let you know in a couple of years. If I forget, remind me.:)

Since this Mortite formulation seems to be very stable with regard to oil leaching, I expect that it will still be soft two years from now and beyond. The vice was an extreme test that flattened the Mortite cord to literal paper thinness, and yet only enough oil leached out to wet the surface of the paper. The flattened Mortite strip was still soft and flexible and the paper strips were easily pealed away from it.

schwarcw wrote: »

Let me say it again why not plumber's putty? It comes in a rope or a can. It may leach some oil, or it may not. I think this depends more on the quality of the product. I do know that plumber's putty will release after being torqued with a pipe wrench, sitting in the sun, with hot water running through it. I also know it will seal brass fittings with a few psi of natural gas running through them. ****, I have some of this stuff (1/4" rope) that is still soft after about 20 years just sitting in a can (no oil). Just another suggestion,

Try some and let us know. Don't forget to take pictures.

schwarcw wrote: »

I'd worry about my drivers drying to the baffle.

C'mon Carl...I know you have a crowbar around the house. Don't be afraid to use it. Those SDA baffle boards are tougher than you can imagine.

schwarcw wrote: »

If the Mortite hardens like epoxy, the repair becomes a little more complex.:mad:

The Mortite box says "non hardening" and it seems that it has been in use for decades by speaker companies and DIY'ers as a dampening and gasketing material. If you google "mortite speaker", you will find many references to its use.

I will caution you to be mindful that it seems that all rope caulks have come to be called "Mortite" just as all clear adhesive tapes in a roll dispenser have come to be called "Scotch tape". Some rope caulks are excessively oily and do harden over time. True Mortite, from what I have read, does not.

schwarcw

6'&glassy wrote: »

Plumbers putty is composed of linseed oil and clay and will dry out and crack, especially when applied between driver and untreated particle board which wiill suck out the linseed oil like a sponge...vibration doesnt help either. Cord weatherstripping is a nice tweak. I have some residual cord that has been sitting in its box for over a couple of years and the paper box is not compromised or stained, and the cord is still usable.

You're not using the same putty I am.

schwarcw

DarqueKnight wrote: »

C'mon Carl...I know you have a crowbar around the house. Don't be afraid to use it. Those SDA baffle boards are tougher than you can imagine.

:):D:):D:):D:):D:):D:)


Good fun Raife! I love your audio experiments and I always look forward to learning something. It's fun to play the Devil's advocate too!;)

I'm off to find my router! LOL!

Carl

6'&glassy

schwarcw wrote: »

You're not using the same putty I am.

You're right. After googling plumbers putty, it seems the next century has provided us with a plastic, non-hardening variety which is inexpensive and definitely worth a try.

6'&glassy

Bought some Mortite weatherstripping cord and found it to be much to non-pliable to my liking, too stiff and without much tackiness. I wouldnt use Mortite brand as I believe its relatively unpliable nature and its inability to flatten out easily would cause too much strain on existing screwholes. A superior weatherstrip cord made by M-D building products has worked well for me. Maybe I had a bad batch of Mortite but I think I prefer M-D cord for its workability.

skrol

I found it to be rather stiff too. I rolled it between my fingers to make it thinner. When I applied it, I flattened it down to reduce stress on the speaker baskets. I also only snugged the screws and would tighten them a little each day in a cross pattern to avoid warping the baskets. As far as tackiness, I hope I never have to remove the drivers. They are STUCK. It is tedious and a more pliable putty/cord may work better.

inspiredsports

Mortite can tend be a bit stiff; I keep an old hair dryer handy to warm it up a bit before working with it.

It's a tried and true product with which many in the group have reported great success; just study this post to learn the nuances and have at it. Matt Polk personally mentioned using Mortite during testing in the early days when there was no gasket material left on the shelf.

The pressure needed to draw a driver securely down into the seal is the biggest problem. Many older speakers have screwholes that are worn to the point that the chance of stripping the threads becomes a problem.

It would be great if somone could conduct the same type of testing that DK has performed on Mortite with some of the newer, more pliable plumber's putties.

dbnh

inspiredsports wrote: »

The pressure needed to draw a driver securely down into the seal is the biggest problem. Many older speakers have screwholes that are worn to the point that the chance of stripping the threads becomes a problem.

Re: pressure / screwholes - when reinstalling drivers / tweeters / passive radiators, I have used the same type gradual tightening technique one uses when reinstalling an auto's wheel. Haven't yet had any problem with my 1988-ish SDA-1Cs when applying the Mortite - like many things in life, easy does it.

Then, there's always flat toothpicks to help fill wood holes the may have seen a lot of use; they make for a relatively easy fix.

Happy holidays to all, and happy listening!

Lightstar1

Hey DK.....
Once again, you have given us another great amount of info!! I just completed resealing my SDA-SRS monsters with MD from Homedepot (they didn't have the Mortite brand). The bass was much improved in clarity....thanks for posting this!! I would have never suspected a problem with the old seals...now for the crossover rebuild that Ben will be doing for me and I will have practically new speakers!!

Lightstar1

Stew

inspiredsports wrote: »

It would be great if somone could conduct the same type of testing that DK has performed on Mortite with some of the newer, more pliable plumber's putties.

Has anyone tried Staput Ultra? (Info sheet is attached.) I've never seen this stuff in a store but it sounds like good stuff!

Stew

Has anyone who has used Mortite (or similar) sealed the binding post plates to the cabinets? These plates screw to the cabinet and have the same type gaskets used for the drivers.

ben62670

I think the positive results I had were more from coupling, and killing resonance than air sealing. I would only use it on the drivers.