Soundproofing a bump/dent

[averagef250]

I have been researching soundproofing this week as I want to step up my game so to speak with the diesel conversions I do. My dad's 77 F-350 2wd super camper is getting an interior update next week with new weatherstripping, new carpet and I want to attempt a go at making the interior really, truely as quiet as it can be. Use this truck as a "test case" for how quiet I can make an old truck inside.

Has anyone here done this to a bump or dent?

My loosely formed plan at this point is using soundedenershowdown.com CLD tiles at thier recommended 25% coverage on all flat panels followed with full coverage of 1/4" armaflex closed cell foam with a final full coverage of 1/8" 1lb/ square foot mas loaded vinyl. I'm going to cover from the top of the firewall to the rear cab wall and remove the firewall pad (it does not fit anymore anyway, I moved the center of the firewall to the rear 1.5" when I installed a 5.9 Cummins).

I will be doing the insides of the doors and the roof above the headliner as time permits as well.

[speed bump]

Heres the minimal stuff that I have done that has worked well.

Cleaned out and then partially filled the cab corners with spray foam, this actually reduced quite a bit of the road noise.
From the hardware store bought a bunch of that closed cell, aluminum faced insulation (I think grainger sells it with an adhesive backing) and used 3m spray goop to put that up on the top of the cab and in the doors. If I took my interior apart again though I would definitely put it on the floor, the firewall, and the back wall as well. You can really tell a difference not only in noise level but comfort level during the winter and summer.

I haven't gotten around to doing the head liner yet but I am going to take mine, use some heavier material, put foam on it, and then cover it with leftover vinyl from my dashpad.

[71cc]

Heres the minimal stuff that I have done that has worked well.

Cleaned out and then partially filled the cab corners with spray foam, this actually reduced quite a bit of the road noise.
From the hardware store bought a bunch of that closed cell, aluminum faced insulation (I think grainger sells it with an adhesive backing) and used 3m spray goop to put that up on the top of the cab and in the doors. If I took my interior apart again though I would definitely put it on the floor, the firewall, and the back wall as well. You can really tell a difference not only in noise level but comfort level during the winter and summer.

I haven't gotten around to doing the head liner yet but I am going to take mine, use some heavier material, put foam on it, and then cover it with leftover vinyl from my dashpad.

OK, I will warn against this again... DO NOT use the spray foam. It caused my cab to collect condensation and rust a perfect cab from the INSIDE out.. I now have another cab to swap. And I already had painted the interior of mine. It took about 8 years to show up, but now in the last two years I am beginning to worry that my glass might fall out.. I need to take some pics...

[fireguywtc]

I would like to know of a good option to seal up the cab corners. It seems like a lot of the noise does come from there, but I would be afriad of rust as well. Everything else seem fairly straight forward to me.

[averagef250]

I'm working on a dent so cab corners are a non-issue (totally different rear cab floor design). If this was a bump I would clean and paint the cab corners with good aliphatic urathane before installing the same soundproofing materials used elsewhere. I would not glue anything in, instead just using velcro to hold the mats in so they could be easily removed for cleaning. Well the CLD tiles, closed cell foam and mass loaded vinyl to do the firewall and the floor ran me about $203. I will eventually do the insides of the doors and above the headliner, but for now this will due fine. I will post pictures and a followup to how it works out soon.