I used spray foam and it's better than Dynamat!

[leenjen]

-

ok, i see what you mean now.

 

[KEbert]

Well, I bought 3 cans of Great Stuff, because that was all my local harware store had, with intensions to do the back hatch. I got two minimal and one regular. The regular expanding Stuff had a broken can, so being the stupid person I am, I thought that there was a check-valve in the can so I stuck a seal pick in there and the foam proceded to spray out everywhere. I stuck my finger over it and ran over to my truck and let it stratigicly spray in the hatch. Which worked fine but it just went really fast. I still have a little touching-up to do so I will let you know what the difference in sound is.

I was also wondering what the name of the floor matting is because I would like to get some.

Also, I got a great deal on spray foam. Lumberjack sells foam that is made by MD, not Great Stuff, that comes in a much bigger can and is only $3.69 per can. I think it works better because it goes on a lot smoother. Happy Foaming!

 

[KaBoom]

Ok, stupid question here, but i read this post twice and am now confused exactly about the road noise people are complaining about. I get the impression that most of the noise is coming from the hatch. I don't really notice the road noise but maybe i'm looking for the wrong thing.

I would like to foam my hatch on possibly improving the sound quality in my X????quieter??. Where are you suppose to spray? DO you take any paneling off or just where the hatch closes on?

ANy help would be appreciated.

 

[ACBlessing]

Sorry about the delay guys, been out of town for a few days.

Kaboom, it's kinda hard to describe road noise if you're not aware of it. When you cruise down a wet road...you hear your tires splashing much louder. In general cruising around town and freeway, there is an ever present hum (depending what tires you have) and just general road noise. I guess the best way to tell is to listen to you X AFTER you soundproof it.

The difference is immediate and very noticeable. Sitting on the inside, a soundproofed X sounds and perceptively feels much more quiet, solid and luxurious. As for speakers, you're able to hear a difference in sound reproduction and accuracy because your speakers are not competing with the resonance of the body sheet metal.

Kebert, good job saving that one can, lol. Like I said, even after sealing off the rear quarters, I still had noise until I took the rear hatch panel off and looked at the cavernous space inside. No wonder. I shot spray foam up and down the C and D pillars and throughout the hatch door.

But remember, I said I used floor matting cut to fit between the hatch door sheet metal and the door lock mechanism (it's rods) and wiring etc. Oh, and I didn't spray anything on the handle area. Don't do what I did and get overzealous. I wanted even more spray in there so I unwittingly got it all over the door lock solenoid which caused it to stop working. Had to carved out the foam to get to it, remove and replace it.

As per someone who asked a couple questions...the floor matting I'm talking about is the stuff that sits between your old house floor and new laminate flooring. It is used to deaden sound when you walk across your new floor....turns out it works great in cars too because you can cut it to fit door panels and such. It's basically a very compressed fiber with plastic backing and comes in a roll of 3-feet by 33-feet. You can get it at Lowes (like I did) or Home Depot, etc.

I used it throughout my X as a barrier against spray foam touching stuff. For instance, in my front doors, I couldn't just spary foam in the whole door because obvisously, it would expand to where I couldn't roll the windows down. But, I cut the matting (in two strips) into the inside of the door and sprayed foam between the matting and the door sheet metal.

In the rear cargo area, I sprayed foam on top of the wheel wells (about an inch thick) and quickly covered the foam with the floor matting and then put the plastic panel back on. I put the panels back on right away so the foam doesn't over expand and prevents me from putting the panels back on at all.

Hope this helps...AC

 

[ACBlessing]

Did that answer anyone's questions?

-AC

 

[PsykoTone]

I'm planing in doing this to my X. I'm going to pull the carpet out (needs to be shampoo'd) and running all new speaker wire and electical. then i'm going to put the floor mat stuff under it and do my doors and rear with it then, i'll switch to doing my reson then foam experiment.

 

[ACBlessing]

Very kool Psyko...make sure to take picts along the way. I'm not one to talk as I've been taking picts but not posting because there's always ONE last thing I have to do....

AC

 

[Frshpwdr2k]

PICS would be great

Hey AC,
I have been reading this thread and liking what im hearing, so i have decided not to splurge and buy all that hella expensive dynomat. SO i am gonna do it the cheap mans way... hehe. Anwayz, if you posted the pictures of your installation it would help me out ALOT. Thanx man
Broderick

 

[ACBlessing]

Hey thanks Broderic! I know I need to get those picts in so I've cleared some time this weekend to finally get them up.

I was just thinking though...if you can afford to get the Dynamat done, you should have it done. Taking panels off and shooting foam could be tedious.

I did the foam because I didn't have the funds for Dynamat but I'm glad I went this route as you can't dynamat all those little caves and crevices or inside the pillars, etc. It just goes everywhere you can't see whereas Dynamat requires cutting to fit on flat surfaces.

I'm glad you decided to go the foam route and you won't be disappointed...just make sure to follow my advice in this forum like having tape squares ready, using low-epansion foam, not overspraying (have patience)...because I made a lot of mistakes that I wouldn't have made if I knew what I know now.

Happy sprayin...

AC

P.s. Thick foam areas can take several days to cure, even though the bottle says 8 hours. I oversprayed an area by the wheel well and foam kept creeping out for days. I should've been more patient or used less foam...remember, it expands, lol.

 

[ACBlessing]

Oh and I was just thinkin Broderic....use the Dynamat where it's practical like on the ceiling and floors...can't really foam there anyway.

 

[ACBlessing]

Just a quick update....with our warmer weather, I'm getting a little foam plume (like a 4-inch mushroom cloud) seeping out of my fender well. It's kinda funny to see but just goes to show how easy it is to overspray...and that this stuff is still wet after 3 weeks.

This was from my covering the wheel wells with an inch-thick layer of foam when I should have made it thinner.

Drove in the rain today.......no wet road noise whatsoever...my X is quiet!

 

[KEbert]

Well, I am still stuck on the matting. The only stuff I have found similar to what you have described as is made by Pergo (the imitation wood-floor company) called "Silent Step". I was wondering, AC, if you could tell me the name and/or brand of the matting. It would help a lot. I am getting a lot of foaming done and I need it! A new product I found to deaden sound is that spray-on bedliner. It works great!

 

[DocVijay]

Sounds good.... but

This is really a great idea. Except for one thing. I'm a medical student, and I live near the border to Mexico. I go across the border frequently to work in some of the hospitals there. When I come back across to the US, the customs agents like to knock on the side of your car to see if theres anything "bad" hidden under there. I can just imagine the trouble it would cause if I did this. They would knock on the panel, hear the sound, and immediately pull me over and strip the car to it's bare chassis. Good idea, but not for me.

 

[ACBlessing]

I remember when we lived in San Antonio and went to Mexico a lot...we'd always drive the beater car there (75 Cordoba) instead of a tempting X. But you're right, I remember our car being searched too...all the way. I just wouldn't stop fixing up my X for the possibility of being looked into. Up here, we go to Canada a lot but they're nowhere near as intrusive as Mexican border guards.

-AC

 

[KEbert]

Fine. Don't answer my question.

 

[ACBlessing]

Ooops, didn't see your qiestion from before...yes, Silent Step is the stuff I used. Used it in the door too as a barrier between the spray foam and window mechanics.

AC

 

[KEbert]

Cool. Thank you for all the help. I am going now to get some of it!

 

[russelb]

Food for thought.

I discussed using spray foam with my brother who is building V8 240Z. He had considered using the spray foam inside the frame to reduce noise and vibration and to improve stiffness, but decided against it because it requires air to dry. AC, this may be why even after 3 weeks you are getting foam mushrooms still dripping out.

It seems like the spray foam is a good solution if you are spraying it in an area that will get sufficient air to allow it to dry, but it might remain wet if you spray it into area with no air flow. Wet spray foam inside of your frame could lead to rust. I have not tried any of this myself, so I do not mean to disparage anyone who has already done it. I would just be concerned about the possibility of creating a really big mess that would be nearly impossible to clean up.

There is supposed to be some type of spray foam epoxy that they use for boats that does not require exposure to air to dry. Apparently it is two compounds and the mixing of the compounds creates the foam and no air is required. This might be a better solution. Apparently you can pick it up at boat shops. I don't know how much this stuff costs or much about it. Anyone ever heard of this boat foam?

 

[exploreraudio]

Hey, guys

Ya, I have seen the boat foam before. It is MUCH different to work with than the canned stuff that has been discussed here. You mix two parts together like epoxy (it actually looks just like it), and an hour or so later, you have this very solid foam. It expands like crazy, and I guess there's quite a bit of force involved, so I'm not sure it's well suited to this application (but hey...if someone wants to try, let me know how it works out!)

Another tip for those wanting to find a cheap dynamat replacement is roofing shingles! No, not the whole shingle, but if you look at them, 50% has the little rocks embedded in it, and the rest doesn't! I tried this on an older Honda Civic, and it worked really well. It was applied with spray glue, and then applied with a heat gun. The heat helps make the asphalt bendable, and it helps the glue stick better.

Hope that helps

 

[DocVijay]

2-part epoxy foam.

I've seen one application of a 2-part exapnding epoxy foam. It was used in the frame rails of a 300ZX. This was some pretty fierce foam, though. It dries hard as steel, and the whole frame becaomes 30% (or so) stiffer by filling the frame with this foam. One problemis that this foam PERMANENTLY sticks to anything it touches. Really nasty stuff.