Gang,
I've been using closed cell foam in place of GM's original tarpaper in my big cars for years. I like quiet old cars and have spent a fair few days insulating the cabin from heat & noise.

I had the doors on my '66 Starfire apart over the weekend to install power window motors and decided up update/do a better job on water & sound insulation my doors. This a simple job but I thought I'd detail the process here for any of you who might like to do something similar.

Upfront it's important to mention that 1/4" thick material will make your door panel harder to re-fit. It's a lot thicker than tarpaper and wasn't meant to be there from the factory. If you're concerned about that, use 1/8" thick material. I've used this 1/4" stuff for years and it's been fine, but the door cards are a little tough to re-fit.

This time around I used 3M's strip caulk to be the adhesive holding the liner to the door:

Strip caulk is better than spray glue if you expect to be doing any door & window maintenance. Inset is what the stuff looks like in the box.

For a few decades I'd simply spray glued the liner to the inner door, but it always tore the liner to shreds the next time I removed it. I'm hoping the strip caulk will allow for cleaner liner remove down the road. Pretty much I used strip caulk around the edges and bit here & there in the center:

Strip caulk lines should liner removal more easily the next time I have to repair windows or vacuum lines, or door locks.

If you want to get fancy, the strip caulk lines work even better with a heat gun to soften them, but that larger surface area will be harder to remove.

There are tons of products out there which all claim to reduce noise, heat, cure the common cold and reduce global warming. My impression is so long as you have a 1/8 - 1/4" of closed cell foam that's about as well as you're going to do. I picked a roll of this stuff at a swap meet along the way:

Aluminum topped closed cell foam. Thickness at 1/4" makes re-fitting the door panel a little harder.


For my Starfire I cut 2 pieces of 21" by 42.5" of material from the roll. I wanted the water barrier to not be seen behind the door panel. The edges are rounded to follow the pattern on the door panel, but a little on the inside of the door panel edge.

I hung the new liner on the door with a bunch of pieces to blue tape to be sure it didn't move as I cut holes for the vent window handle, power window switch, door paddle and other door panel parts. Luckily I just picked up some cheap large hole punches so I just punched them where the needed to be with the door line loosely taped to the interior side of the door. Hole punches are way, way cleaner than my earlier efforts just hacking away with an Xacto. I used and Xacto knife (with fresh blade) to cut the square hols for the courtesy light and power door lock switch.

Square holes cut with #2 Xacto knife, round holes done with large diameter punch.

Since I had a roll of material and my doors have typical factory access voids, I doubled up on the material where the voids are. These were hand cut with the Xacto and I'm not a real good cutter:

Doubling up in door voids just _might_ make the cabin a bit quieter.

I cut the void shapes with the liner panel off the door freehand, then placed them loosely in their respective voids. Then I loosely replace the liner with blue tape on the top of the door so I could flip the panel up and down as I glued the void pieces to the main liner.

Here's the finished product:

1/4" thick closed cell foam is quieter than tarpaper as a door liner or water barrier as GM called it. But it makes the door panel a little harder to put back on...

I'm off to do the driver's side door now.

Cheers
Chris

 

Nice job.

 

Nice write up!!!
Was wondering, the instructions recommend shiny side out on door panels. Any reason you installed the way you did? Does the strip caulk stick better to the non shiny side?

 

I'm a guy. I read directions sporadically....

Shiny side out was the way the old ones were. Guess I didn't read _those_ directions either

Cheers
Chris

 

Looks very clean!!!
post some info on the hole punches?

 

I'm no hole punch expert, just a hobbyist who wanted tools to cut nice round holes right where I wanted 'em. I picked them up to remake rubber gaskets for power door locks, but found the larger sizes would be perfect for the door panel cuts for controls and bolts.

My criteria for success was simple: nice clean _round_ holes cut in foam material. And on an earlier project nice clean very carefully placed holes in rubber gaskets. Failure was having to tear the material or having to keep spinning the punch to find a sharp spot to finish an uncut part of a circle.

The blue box set is what I used in the water barrier foam project above. The defining attribute of this set was it cut nice round holes large enough to allow for margin of error around controls that were already in the doors: the latch paddle, the armrest holes and power door lock location. Cutting foam is kind of imprecise, so I wanted to leave myself enough room for error to be wrong and still have a useable piece.

I didn't use the punch tool on the right. I just sort of placed the punch and screwed it into the foam to get a nice round hole. Later I needed the punch as the cutting edges got dull.

Here's the best quality set I got, but it did not have really large diameter, plus if you're working on American cars whose holes are in inch-measurements, you'll have to translate hose sizes to metric. See my post on power door lock restoration for more on how I used this:

The good stuff: Owden. Probably still made offshore, but it did the job I needed it to do.

The less good stuff. As I recall these were really cheap on Amazon. The cheap part was great. Naturally they got dull after just a few holes which required me to get the Owden set above since the project was not finished. I have no idea what brand or thing I clicked to have these delivered to my door.

540,000th lesson in get good tools.

In the end, I wound up with water barriers that don't make me thing cr*ppy shade tree mechanic when I take the door panels off. I seem to do something with the doors every year or 3 - window motors, vacuum system repair, electrical something. So it's nice to have the underlay be well finished.

I'm sure there are very high quality punch sets. I don't think I bought any of them, but that's really because I don't expect to use them all that often. I'm sure your local upholstery shop could recommend better brands than what I found, but I'm just working on 2 cars.

Cheers
Chris

 

Thankyou for your write-up.

Don W