Homemade, cheap and effective undercoating!!

[Gunfreak25]

The test was 2 pieces of sheet metal. We all know what sheet metal sounds like when you hit it. After applying 4 coats the undercoating the sheet metal went from sounding like.....sheetmetal.....to sounding like a dead, flat, vibration less piece of cardboard. Total night and day difference.

The recipe:

Behr exterior house paint (any brand will do)
Sand/gravel from the yard

Mix enough sand in to achieve a toothpaste like consistency (you know, the baking soda old school kind of toothpaste). Just thick enough to be brushed on and build up thickness quickly.

It didn't need as much texture as I put in there, that was all the gravel from the yard. When I make up a large batch for the cab I will be using playbox sand which is cheap and is rough enough for my liking.

This stuff works just as good if not BETTER than ANY off the shelf undercoating you can buy and is a fraction of the cost. The advantage of the behr being you can have it color matched to your desired shade.

I will be using black!

 

[Heath_h49008]

You can also use micro-balloons. Put the glass ones in BBQ or other high temp paint for thermal insulation.

 

[scoutmanadam]

Nice idea

 

[4x4 Forever]

You can also use micro-balloons. Put the glass ones in BBQ or other high temp paint for thermal insulation.

Good idea Heath, you can usually get micro-balloons at any fibreglass repair shop. I've seen then in automotive and boat repair shops or online. Make sure you use real good breathing protection as you are messing around with GLASS!

 

[Heath_h49008]

Micro-balloons and latex = sound deadener
Micro-balloons and high temp paint = thermal insulation.

I thought there was an acrylic balloon as well. They aren't all glass are they?

 

[donalloy1]

The test was 2 pieces of sheet metal. We all know what sheet metal sounds like when you hit it. After applying 4 coats the undercoating the sheet metal went from sounding like.....sheetmetal.....to sounding like a dead, flat, vibration less piece of cardboard. Total night and day difference.

The recipe:

Behr exterior house paint (any brand will do)
Sand/gravel from the yard

Mix enough sand in to achieve a toothpaste like consistency (you know, the baking soda old school kind of toothpaste). Just thick enough to be brushed on and build up thickness quickly.

It didn't need as much texture as I put in there, that was all the gravel from the yard. When I make up a large batch for the cab I will be using playbox sand which is cheap and is rough enough for my liking.

This stuff works just as good if not BETTER than ANY off the shelf undercoating you can buy and is a fraction of the cost. The advantage of the behr being you can have it color matched to your desired shade.

I will be using black!

How well does it hold to underside with sand added? How did you prepare underside before coating? Did you use Behr Ultra? Look forward to your response Gunfreak! DMLII sends...

 

[4x4 Forever]

Micro-balloons and latex = sound deadener
Micro-balloons and high temp paint = thermal insulation.

I thought there was an acrylic balloon as well. They aren't all glass are they?

I haven't seen an acrylic balloon, not saying that there is not one out there. I have used glass balloons to fair out the sides of fibreglass boats that I built, ALOT lighter than using talc as a filler. It will also not breakdown chemically like an acrylic product would, depending on the paint being used.

 

[Beerslayer]

Very cool!

 

[wsucougarx]

Outstanding idea!

 

[Gunfreak25]

Don Alloy1, I have not yet applied any to the cab. Just the sheet metal test piece. I used Behr plus ultra exterior 2 in 1. It is an excellent paint and by no means does it dry like "latex". It dries extremely hard but remains more flexible than enamels. It has always adhered very well to any surface I have applied it to, some require more prep than others. As for the bottom of the cab, this truck has been thoroughly scraped, cleaned and degreased in every corner thanks to hundreds of hours on my part ( and a little OCD ). Kind of funny that way.

If you are nervous about the undercoating falling off under the cab after a few years, do a prime job first with red oxide primer. But really, I do not see it being an issue.

I like the air beads idea heath! That deserves a push of the "thank" button. The GMC has been equipped with a 6.2 so it does not produce as much cab heat as the Multifuel. Still, I am cutting no corners with insulation. I have spent several dozen hours sealing up the cab's holes and calking every roof corner and seam, including better sealing of the windshields, doors, rear sliding window and all other things you can think of.

For thermal insulation, I am using 1/2" foil backed styrofoam sheeting from home depot on the entire interior of the cab including the floor. The foam is surprisingly resilient to squishing. Gray exterior carpeting is covering up everything, it is quite thin and is for cosmetics only.

As for sound deadening, that is what my homemade undercoating is for. I still can't believe how well it worked on the test panel. Night and day. I am going to apply a white undercoating mix to the top of the roof to cut noise, the white will help reflect a GREAT deal of summer heat next year.

Then a black mix will be applied to the outside firewall and under the cab. Lots of brushing!!

Lastly! The cab is being equipped with a 30,000 btu under dash AC evaporator. With all the work put into insulation/sealing this baby SHOULD stay in the 80 degree range during the hottest Yuma summer day's, which easily reach 117 during August.

Sorry for the long post, I spare no expense when it comes to details. Just store bought undercoating.

 

[FireFighterHill]

Gunfreak, have you taken a small piece of this foam insulation and seen how it reacts to fire? Styrofoam gives off deadly toxic gas when exposed to flames and can incapacitate a person in a very short ammount of time. It also spreads the fire very rapidly and is not easily extinguished with water alone. Just something to keep in mind for safety reasons.

 

[Gunfreak25]

FireFighterHill, I appreciate your concern and a fire hazard is the 1st thing that came to my mind when I thought "cheap insulation". I watched my brothers Honda go up in flames in his friends driveway, which in turn set the entire house on fire. Declared a total loss, the car and the house.
Both my uncles were firefighters so I am well aware of the dangers associated with styrofoam (we used to make "napalm" growing up and set our toy soldiers afire with the stuff).

I simply justified the use of the styrofoam with the high cost of modern insulation alternatives. There is a garden hose right next to the truck where it will be parked, that is the only "plan b" I have. Otherwise, if she goes out in flames of glory that is what is meant to be.

That being said, a great deal of precautionary measures are being taken on my end to assure nothing electrical related is in close proximity of the styrofoam. I also wanted to point out that few items on a 54 M211 are what I could consider up to "modern day standards" whatever that means. A great deal of risk goes into driving something nearly 60 years old. I have heard of handbrake drums exploding from microscopic hairline cracks/heat, steering gear shafts shearing off cleanly resulting in total steering loss, brake line failure on the single circuit hydraulic system, brake failure due to a ruptured electronic parking brake switch in the braking circuit, etc.

Point being, I understand the risks and am willing to take them. As for the cab roof and the market lights I installed, I will be installing a layer of rubber insulation between the marker light wires and the styrofoam to be installed to insure no wires are in contact with any foam sheeting.

This post was probably drawn out more than necessary, as I said I spare no expense when it comes to details.

Appreciate your concern though, I have a great deal of respect for firemen.