DIY Soundproofing/ Vibration damping / Heat management for Mazda Miata

[Radiohead]

After reading a thread by Minuteman from the Gearheads website (http://gearheadsmiataclub.net/vB/showthread.php/421-Sound-Proofing-Interior-Tub/page2?highlight=Soundproofing), I have been inspired to begin soundproofing my interior. I am starting in the tub behind the seats. First step was to remove the carpeting by popping out all the clips that hold it in place. They all come off pretty easily although you may have to massage one or two to fully cooperate.
Once all the clips are out, CAREFULLY remove the carpet along with the rubber mat and rock wool insulation. Mazda used a very sticky glue to hold it all together and it's wet to the touch. You do not want this goo going everywhere! Since I will be reusing my carpet, I will be cleaning all that glue off the backside. Once you have this all removed you can begin to clean the tub area. Here are some pics of mine:

8465846484668467846884698470

[Radiohead]

There was one surprise that was unexpected, the mounting plate on the drivers side looks to be RUSTED OUT! There is also a rust spot on the vertical tubing as well. Take a look:

8473847284718474


So now I have to find out if this salvageable or do I have to purchase a replacement. Either way, I have hit my first setback.

[mini_fd]

I was very interested and now reading the second post i want to say ouch on that set.back. Its a good thing you were rummaging around on this project and found something potentially hazardous. Good find but bad.luck. Hope you can take it to.a shop and fix it.

[Agent☣Orange]

Aww noooo! You're going to have to pull out the bar and fix that rust, maybe even have a couple plates welded. That's an important structural point. Well, at least you caught it at this point instead of much worse.

[Radiohead]

I'm getting with a buddy of mine to see if it's salvageable. Worst case scenario is I have to replace it. Either way the project will continue. Next step will be posted once I get this sorted out.

[Agent☣Orange]

You might have a look at your rain rail while you're in there. It's probably leaking and caused this.

[Radiohead]

I had my top replaced a couple of years ago and it came with a new rain rail. They did say that the drains were completely blocked. Perhaps that was a contributing factor as well. The original install of the roll bar was over 10 years ago. It was at one of the first tech sessions that the club had.

[Phatmiata]

wow that is a lot of rust! how long has that bar been in there? im guessing that is caused by rain getting in there. Maybe take it to the shop Jeff is working with "Sinister Kustoms" and see if they can weld in some good metal?

[minuteman048]

Glad you caught that before it got even worse. Time to nip that in the bud, Budd. Im flattered that I inspired that project and the pay off is that you discovered the damage. I had one small rusted galvanized plate up on the deck I replaced. I will be doing a fuel pump swap out soon and see if things are still dry since I did that project. Never had any water in the trunk or interior but moisture did get to that panel which I replaced with a new one.

I currently have a style bar which does double duty as a rear shock tower brace. Plan on putting in a real roll bar next year and will be extra diligent on preventing rust. You guys that have older installs on roll bars should check your rides out also.

Do you park it in a garage or leave it outside?

Good luck and let me know if I can be of any assistance.

[Demon I Am]

So, setting the cancer aside, what are your plans for insulation?

Last year, I helped a friend line his wife's mx5 with "Reflectix" on the floor and transmission tunnel. The material is like a thick, metallic bubble wrap. It cut down on the internal cabin temps by quite a bit, but didn't do much for noise. My other concern with it is that if the cabin gets wet the plastic might not be breathable enough to dry properly.

[Radiohead]

wow that is a lot of rust! how long has that bar been in there?

See the post right above yours. lol

I already have a call into Jeff!

[Radiohead]

Glad you caught that before it got even worse. Time to nip that in the bud, Budd. Im flattered that I inspired that project and the pay off is that you discovered the damage. I had one small rusted galvanized plate up on the deck I replaced. I will be doing a fuel pump swap out soon and see if things are still dry since I did that project. Never had any water in the trunk or interior but moisture did get to that panel which I replaced with a new one.

I currently have a style bar which does double duty as a rear shock tower brace. Plan on putting in a real roll bar next year and will be extra diligent on preventing rust. You guys that have older installs on roll bars should check your rides out also.

Do you park it in a garage or leave it outside?

Good luck and let me know if I can be of any assistance.

She has always been parked under the carport. Thanks! Im glad i decided to do this or i never would have known what going on back there with the roll bar. After reading thru your thread I had a pretty good idea on how to proceed. I will say this though, I hope my completed job looks half as good as yours! You were meticulous and it shows in all your pics!

[Radiohead]

So, setting the cancer aside, what are your plans for insulation?

Last year, I helped a friend line his wife's mx5 with "Reflectix" on the floor and transmission tunnel. The material is like a thick, metallic bubble wrap. It cut down on the internal cabin temps by quite a bit, but didn't do much for noise. My other concern with it is that if the cabin gets wet the plastic might not be breathable enough to dry properly.

Reflectix is good stuff! YellowYata endorses it! I'll be using it as well in my cabin.

[Phatmiata]

I'm no metallurgist but just wondering if maybe the two metals contacting each other combined with rain helped speed up the rust process?

Maybe put some thin rubber gasket between the plates when you go to re-install all of these parts?

[Demon I Am]

I sprayed the aluminum panels on both sides with ruberized undercoating/sound deadener from 3m, then used some thin stick-on foam to make a gasket, like Phat was suggesting

[Agent☣Orange]

I had my top replaced a couple of years ago and it came with a new rain rail. They did say that the drains were completely blocked. Perhaps that was a contributing factor as well. The original install of the roll bar was over 10 years ago. It was at one of the first tech sessions that the club had.

Plugged drains would most likely lead to a moist floor but a leaky rain rail will cause water in the trunk and parcel shelf rust as well as the main floor.


So, setting the cancer aside, what are your plans for insulation?

Last year, I helped a friend line his wife's mx5 with "Reflectix" on the floor and transmission tunnel. The material is like a thick, metallic bubble wrap. It cut down on the internal cabin temps by quite a bit, but didn't do much for noise. My other concern with it is that if the cabin gets wet the plastic might not be breathable enough to dry properly.Reflectix is a great heat barrier but a poor noise and moisture barrier. I lay sound damper to seal out moisture before any Reflectix.


Reflectix is good stuff! YellowYata endorses it! I'll be using it as well in my cabin.
Only in areas where it can be used as designed such as blocking heat from the tranny tunnel. It's worthless on the parcel shelf.

I use multiple layers of different materials for different functions. Here on the tranny tunnel, I used a base layer of Rattletrap (like Dynamat) to moisture proof the tunnel and stop resonation (sound damping) but then added two layers of duct insulation to address the primary problem, heat. Then one last layer of Reflectix for heat reduction and to stop the burning-calf syndrome. Now it gets barely warm to the touch, even on long drives plus the cabin stays cooler and the AC less overworked.
http://i1194.photobucket.com/albums/aa375/YellowYata/Stereo%20and%20sound%20damper%20and%20heat%20insul ation/IMG_6084.jpg


I'm no metallurgist but just wondering if maybe the two metals contacting each other combined with rain helped speed up the rust process? Maybe put some thin rubber gasket between the plates when you go to re-install all of these parts?. I think it's just a combination of time and iron content, maybe throw in a humid environment a little trapped moisture. Any time you drill holes for roll bars and frame rails, you're stripping away the rust-prevention. A rubber gasket would be cool but might trap moisture since the two surfaces aren't perfectly flat.

I'd just use a lot of spray-on with newly drilled areas along with silicone.. That roll bar and tunnel are going to need some thorough rust removal and hopefully the tunnel metal is okay. The roll bar can just be cleaned and powder coated. I'm wondering if that whole area coud benefit from some layers of spray-on PlastiDip. I've always wanted to experiment with that stuff for rust proofing.

[Radiohead]

I'm no metallurgist but just wondering if maybe the two metals contacting each other combined with rain helped speed up the rust process?

Maybe put some thin rubber gasket between the plates when you go to re-install all of these parts?

Very possible. Perhaps some type of galvanic reaction. I'll have the bar out shortly. Then it's off to the welder for the final diagnosis.
And oh yeah, it gets a gasket on both sides the second time around:D

[minuteman048]

She has always been parked under the carport. Thanks! Im glad i decided to do this or i never would have known what going on back there with the roll bar. After reading thru your thread I had a pretty good idea on how to proceed. I will say this though, I hope my completed job looks half as good as yours! You were meticulous and it shows in all your pics!

I get 2 weeks off between Christmas and New Years so I was able to take my time and work in comfortable temperatures. It's easier to do a big job when you are not rushed and working in comfortable conditions (not summer heat). Yata did his before I did mine and he was my inspiration. I used a small wooden roller you would use for doing wall paper to get the material to match the contures of the floor pan. It came with the Fatmat roll which I used for the job. Good luck.

[Agent☣Orange]

I admired MM's work too. Looks like it came from the factory that way. If you don't do it for a living, it's a major pain to cut rolls of damper and fit custom shaped pieces so they all look seamless.

You can't use your good scissors because you'll get sticky tar all over them and crawling in and out of the Miata with the top up so you can reach the parcel shelf is an unenviable chore not to mention having to press every square inch. It's one thing to look at pictures but anyone who has done this sure has my respect.

That's why I prefer the "since you're already in there" approach to this project. If you're replacing your top, lay down some stuff since you're already in there. If you're replacing your floor carpet, lay down some stuff since you're already in there.

[Radiohead]

I have removed all the nuts and bolts that anchor the roll bar. Since I'm by myself, I was unable to lift it out. Hopefully, I may have someone tonight to help me. I'll post up pics showing the water damage to the bar and base when it's out.

[Radiohead]

Roll bar is out and the sheet metal under the mounting tab looks good! Just need to do some light sanding and apply some rust inhibitor. The roll bar mounting plate has plenty of metal left so its salvageable. Lots of sanding and more rust inhibitor should take care of it.

[Agent☣Orange]

That's great! Now get that rust out. BTW, when was the last time you pulled up the main carpet and checked for moisture?

[Radiohead]

That's great! Now get that rust out. BTW, when was the last time you pulled up the main carpet and checked for moisture?

That would be NEVER lol. That's next. BTW, the drain holes on both sides of the tub are jammed full of leaves and the like. Guess what I will no longer be neglecting! Any suggestions on how to clear the drains? I have one of those clothes dryer pipe brush looking things. I'm going to give that a whirl.

[Agent☣Orange]

You HAVE to check your floorboards once in a while for moisture/rust. The carpet is waterproof but water gets in beneath it because of clogged drains. It gets soaked up by the batting and since the carpet is non-porous, water gets trapped beneath it forever. It can't evaporate; just sits there like a wet towel creating a perfect condition for rust. Worst case scenario.

This is not a major operation. Just pull up the plastic door sills, lift up the edge of the carpet and stick your hand in and feel around for moisture. If you feel anything wet, yank out the front kick panels and seats and really lift the carpet for a thorough look/dry out.

You can clean your drains with any long object but do it somewhat gently so you don't disconnect the tube. If you've never done it, you might see all sorts of crud dump out in front of the rear tires.

[Pfunk]

Soundproofing and reducing cabin heat are going to happen with a seam-weld and repaint sooner than later for my car but I need to take a small break after what I had done with the motor and transmission... *sigh* the list is never-ending.

[Radiohead]

You HAVE to check your floorboards once in a while for moisture/rust. The carpet is waterproof but water gets in beneath it because of clogged drains. It gets soaked up by the batting and since the carpet is non-porous, water gets trapped beneath it forever. It can't evaporate; just sits there like a wet towel creating a perfect condition for rust. Worst case scenario.

You can clean your drains with any long object but do it somewhat gently so you don't disconnect the tube. If you've never done it, you might see all sorts of crud dump out in front of the rear tires.

Since I'm pulling the seats and carpeting out to do this little project, I'll be able to inspect the entire cabin. I'm hoping to not see anything (best case scenario) and preparing for the worst! Hopefully what I find will be somewhere between the two.

I'll be extra careful with the drains. Judging by what I felt at the top, they may be considerably clogged. I'll start out with the shop vac and an attachment I made from an old radiator hose for reaching into tight spaces. After that, I'll work a flexible piece of cable in there until its cleared. I just have to incorporate drain inspection into my normal maintenance routine going forward.

[Johnnie]

Since I'm pulling the seats and carpeting out to do this little project, I'll be able to inspect the entire cabin. I'm hoping to not see anything (best case scenario) and preparing for the worst! Hopefully what I find will be somewhere between the two.

I'll be extra careful with the drains. Judging by what I felt at the top, they may be considerably clogged. I'll start out with the shop vac and an attachment I made from an old radiator hose for reaching into tight spaces. After that, I'll work a flexible piece of cable in there until its cleared. I just have to incorporate drain inspection into my normal maintenance routine going forward.
I bought a trombone brush just for cleaning the top drains-- long plastic coated cable with a little brush at each end. Snake it down the drain until you see it pop out underneath the car and then pull it through. Repeat until no more crud comes out with it.

[Radiohead]

Now that sounds neat. Where can I pick one up? There's a Paragon Music up the street.

[Johnnie]

I got mine at Sam Ash on McMullen Booth.

[Radiohead]

Cool,
Thnx

[Pfunk]

Reflectix is a great heat barrier but a poor noise and moisture barrier. I lay sound damper to seal out moisture before any Reflectix

How many square feet of Rattle Trap and how many of Reflectix would you recommend for an NB, full tub job? If I could cut down on cabin heat and noise I would be pretty stoked, and get major points from the wife, which would lead to more... stokage.

[BoBo]

That would be NEVER lol. That's next. BTW, the drain holes on both sides of the tub are jammed full of leaves and the like. Guess what I will no longer be neglecting! Any suggestions on how to clear the drains? I have one of those clothes dryer pipe brush looking things. I'm going to give that a whirl.

Use a coat hanger to make the drain holes bigger near the jack point if it's plugged. In addition, a coat hanger can also be use to grab those annoying leave at the top drain hole next to the soft top. Unless you have a vacuum w/ a tube or one of those instrument brush. A hardtop would help prevent leaves jamming up the drains.

I think who ever installed the roll bar didn't rust proof the hole the bolt went into. Plus the old rain rail might have gone bad a while back. I have seen worst, sand paper, steel brush, and some oem touchup paint will take care of business. I usually don't see that kind of rust happening on the NB. I'm forgetting the NB's are getting up there.

[Radiohead]

8507850985108511Carpet is out! Took awhile but, got r' done! Here are some pics of the passenger side prior to cleaning. Luckily, there was only a wee bit of surface rust in the right rear corner as you can see in the pic. Driver's side pics to follow tomorrow.

[Radiohead]

Another 8 hours in today! I was able to get the following done:
Cleaned both drains
Cleaned drivers side of the tub
Lightly sanded and cleaned oxidized areas (just a couple)
Used an etching primer to cover affected areas
Started application of foil/ asphalt butyl sound and heat barrier

I started on the passenger side and the pics will show far I got today. As mentioned by MM and YelloYata, this is not for the faint of heart. It's hard, sweaty and very tedious. Did I mention my back is killing me? Any way, good progress today. Hoping to have all the area behind the seats, package tray, and tunnels done tomorrow !

[Radiohead]

More pics!

[Radiohead]

Hi all,
Been awhile since my last post.
The project has continued to move forward, the interior is now completely lined(minus the doors) with the sound damper (doubled up in the appropriate places). The material was fairly easy to work with but, installing it in 90+ degree weather and equally repressive humidity was not.
I started cutting and test fitting the next layer, closed cell foam. I am using 3/8 thick neoprene. This will provide additional insulation and act as my decoupler layer. After that comes the reflectix layer applied to the hot spots (tunnel, floorboards).
Last but not least will be MLV (mass loaded vinyl) this stuff is not cheap or light! Everything I've read suggests that it is the most effective material for sound deadening. I'll be making some calls this coming week to try and get some reasonable prices!

[Radiohead]

YellowYata,
Do you have any additional pics you can post up? I am using yours and Joe's threads as my instruction manual for my install. And Lordy, this has been one labor intensive mod!

[Agent☣Orange]

I have some I can post up here soon. On a pad right now. I can't believe after all this time, I haven't done my own write up but your thread is inspiring me to get it done.

Wow! You have done a fantastic job there and seems like you've been studying up on damping and barriers are all about. Where are you so far? Testing? What do you think?

[Phatmiata]

Looking good Pete!! If you need any seam sealer or gap filler for the miata let me know! I have a lot of Vulkem Seam Sealant like they use on the AirStream Trailers, as well as the new Chemlink M1 polyether seam sealant. That way you can keep moisture out, as most all rust problems on a car will start in the seams.

Here is a related photo of what most of the auto body shops will do, later after repainting it will look 100% better
http://farm8.staticflickr.com/7324/12934008094_5b8f0cc577_c.jpg