Cardboard amp cabinet!

[Axtman]

I'm working on an old Harmoney H306 amplifier. I had to drill out the studs that hold the handle in place. To my horror I found out the amp cabinet is made of cardboard! Not particleboard or hardboard but cardboard (without the corrugations)!

I have heard that inexpensive suitcases used to be made of this stuff but never knew amps were made of cardboard.

[glebert]

I have an H305 and I'm sure the cabinet is the same. The sales guys at the guitar store where I do repairs LOVE this amp, and want me to clone it, but we joked it would need to have a cardboard cabinet to really capture the mojo:

[Axtman]

I am amazed this amp is not in worse shape and that the cardboard actually held up in rainy Seattle weather.

[galaxiex]

Might actually be "Bundy Board" not cardboard.
Bundy Board is a pressed paper kind of stuff.
Sorta like dense cardboard.

Lots of 60's 70's small low budget amps made with it.

Some of the small Silvertone amps come to mind...
I have a Silvertone 1481 made from that stuff.

[Chuck H]

As a house painter I come across this stuff from time to time as used for trim moulding profiles. It's awful. The moment it's exposed to moisture it "explodes" swelling and wicking . I do repairs by taking out all loose and unstable material and filling the void with a patching epoxy not dissimilar from Bondo. In fact Bondo makes a construction patching compound that is exactly like what I use (though it costs more because of the name brand). So that said anyone coming across this stuff in an undamaged state can at least assume the amp has been kept in a safe environment.. The cabinet material would tell all otherwise.

In the end it's just resin and paper fiber. Which is wood fiber. Not so different from the stuff they use to make peg board or even some composites like MDF. Really dead tonally. Or neutral if you look at it from the other direction. Just fine for making cabinets really. Just not the least bit water resistant.

[pdf64]

As MDF = medium density fibreboard, I think of that stuff as LDF low density fibreboard.

[Chuck H]

As MDF = medium density fibreboard, I think of that stuff as LDF low density fibreboard.

Actually there IS a low density fiber board. MDF has fine enough particulate that it no longer looks like wood chips very much. "OSB" (oriented strand board) on the other hand is made the same way from larger wood chips. Used mostly for temporary structureand cover and low weight bearing surfaces. No one with a soul would ever make an amp from this stuff .

[Axtman]

I should have taken pictures, but the "saw dust" was actually gray crumbs of cardboard. Imagine drilling through a gray cardboard.

The handle was held on by bent over rivets. I could not bend them back so I drilled them out. The washer spun and almost drilled through the top board. I was going to mount a "T" nut with screws for the new handle. Now I have to rethink that idea.