Texture on inner quarters. What is it?

[bull]

Just wondering what that texture is made of that's on the inner part of the quarter panels? Why is it there and how did they apply it at the factory?

[terrible one]

I think it's some kind of corrosion preventer.

[Dennis K]

I'm pretty sure it's the same stuff they used for undercoating, except in the quarters and doors it is for sound deadening. They sprayed it on with a special type of sprayer. Year One sells the stuff and the sprayer.

[69 OUR/TEA]

Bingo !!,like Dennis K said,is for sound deadening.On my car,I still have all original panels,1/4's ,trunk floor,floor pans ,etc.,and all of that undercoating/sound deadener is still there and in great shape,so after the car is painted I am going to repaint the underside to make it look new again.Alot of people strip the underneath,and paint body color,that does look awesome,but if I am chosing to leave it ,as it was how this car was built,and you can't get anymore original than that.Here is a pic of the inside trunk wall so you can see how  to duplicate.

[B5 Charger]

Wow, that is a nice looking trunk!   

[mikepmcs]

    I was thinking the same thing when I saw that.  The paint in the trunk is better than the paint on my exterior.

[bill440rt]

I used 3M's Rocker Shutz in my trunk for the sound deadener. Similar stuff. I also used a special spray gun to apply it. I probably used one can per 1/4 to get the right thickness & texture.
Tip: I used a small piece of cardboard around my marker lamp opening & up the back corner instead of masking tape to get a "factory" looking edge. Masking tape will give you too sharp of a line, but there needs to be a break-off point or you'll have a messy edge. The cardboard trick worked great.
Good Luck!