Gluing 1/8" plywood to edge of 1/4" plywood

[mike sato]

Sounds like you've thought it through Mike. If your paint layer just hits fibers and doesn't span the open pore space (i.e. you can blow through the paint layer) you should be fine. If the paint coat is continuous, and you can't blow through it, I don't think it will work as effectively on frequencies above a few hundred hertz.

Please let us know how it works out, I haven't seen anyone try to paint rock wool in this context . There is the theory, and then there is the real world.

Sometimes you just need to try stuff. If the paint has too large an impact, you can always flip the panels so the paint is on the back side of the panels, against the plywood, then the paint won't have any significant impact.

I assume this will be outdoors.

Hi Mark,

Here's a follow up on painting the Rockboard in my generator's quiet box. The idea was to prevent loose fibers from being blown out of the box by the cooling air flow. I painted all of the exposed Rockboard inside of the quiet box and the paint is doing what I wanted. The paint formed a crust on the rock wool that prevents loose fibers from being blown out. The crust is stable as long as something doesn't hit it and break a piece off. In that case, just that small area will be damaged. Painting the Rockboard did not have any impact on the sound reduction.

Today, I published a youtube video about that sound reduction quiet box. When I shot the video, only the Rockboard in the intake end panel was painted (black) but the other panels were not painted yet. After shooting that video, I painted the rest of the panels since the paint on the test panel was holding up well.

The youtube video is titled "Generator or compressor sound reduction quiet box" and the thumbnail shows the compressor with the words "5X QUIETER" in red letters. It was published under the youtube name "Usefulgizmos".

Here's a link to make it more convenient for anyone who wants to view the video:
https://www.youtube.com/watch?v=_qPRIq-9U-4

View it in full screen to see the most detail,
Mike