What goes between the floor and the chassis? Anything?

[VermonTear]

Neighbor just asked me if I was going to put something between my plywood floor sandwich and the trailer chassis, or was I just going to bolt the wood right to the steel? His implication was that I should consider some kind of padding, or something in between. I have a good solid plywood sandwich floor, several coats of epoxy, Rustoleom on the bottom, Poly on top. I'd planned to bolt it right to my painted chassis. What's your experience?

Ken

[absolutsnwbrdr]

I ran a bead of black asphalt based caulk between my frame and wood. Probably didn't need to, but at least it should prevent any water and road grit from working its way between the metal and wood.

[KCStudly]

Is your neighbor in to old cars? Or is he just a cagey old timer?

Chassis welting was very common in the old days of automobiles before rubber body mounts and was used to help spread the body load on to the chassis (taking up minor irregularities) and preventing chaffing of the thin body sheet metal. A quick web search for "chassis welting" found it described as treated or oil impregnated canvas, although I suspect that there are also modern versions available in the hot rod car restoration industry.

Here's a link to a Model A Ford restoration parts specialist that sells chassis welting.
http://www.mikes-afordable.com/page/MFP/CTGY/1042
Not much of a technical description, but then I did not spend much time looking.

I have considered using a thin (1/16) layer of rolled rubber strip. If not, then I will do like Zach and use a soft caulking of some sort (something that can be cut thru with a thin wire if the cabin needs to be removed for major repair, heaven forbid ).

The tar coat that many people here use is probably adequate, by itself. The applied sealer method that Zach used might actually add some extra structural rigidity to the trailer frame by tying the cabin in to the frame better (essentially a glue bond to the torsion box).

[Martiangod]

This trailer I'm building on was built, I would say 10 to 15 years ago, everywhere in it that wood touched metal there is what appears to be resin impregnated fiberglass tape and its still somewhat sticky. The metal is in great shaper and the wood is still intack where the two meet

[VermonTear]

Thanks, Zack. That seems reasonable.

KC: My Neighbor was suggesting something I think he called Trailer Pad, that goes between a pickup truck bed liner and the pickup. His concern was the road grime getting up between the chassis and the floor and ultimatly doing harm. Both the rolled rubber strip or the Zach's sealer seem like a solution to that potential problem.

ken

[VermonTear]

Chris: You're saying there was a fiberglass tape (?) installed between the chassis and the wood?

[Martiangod]

Thats what it looks like, its woven, about 1/16th thick compressed, could be cotton resin impregnated tape, stuffed into angle iron side rails, on top of frame, wrapping the edges of the plywood, has kinda a yellow colour and still tacky after many years.
Trailer came from the west coast, guy was probably an old time boat builder.
On iron framed wooden planked ships they used some form of a gasket between the wood and the ironI think to protect the iron from moister conducted through the wood, just cant find out in researching if it was impregnated with resin
The steel on the outside has some surface rust, but on the inside where the plywood was bolted to it it should be rusty as heck, but its not, whatever this tape is it protected both the wood and the steel

[KCStudly]

Does it look like this stuff (from the link I posted above)?

[Martiangod]

Really hard to say, more translucent. After doing some more searching, I'm starting to wonder if its not Linsead oil based and cotton welting
Mixing tar with linseed oil varnish produces tar paint. Tar paint has a translucent brownish hue, and can be used to saturate and tone wood and protect it from weather
Now if cotton welting was soaked in Linsead tar, it may be the yellowish hew I'm seeing. Or it may be welting like your showing thats beet soaked in Linsead oil, realy hard to say without a labrat to test it

[Sonoma ZR2]

When I was building RV's for a living they now just apply a bead of caulk and screw down the floor. The only bolts used was attaching the chassis to welded frame. Everything else is screwed on with self tapping screws. The main flooring surface is 1/4 plywood with foam sandwich and 1/4 ply with a aluminum skin. They did have some wood in the sandwich but not near as much as most home built floors. I built Winnebago's for six years and saw many C body's roll out the door.

[synaps3]

The nasty black goop / tar paint is so tacky that it basically adhered the plywood to my frame. I had to reposition one of the floor boards, and it left a whole bunch of rubber paint residue behind. As long as your boards are properly coated on the bottom, I don't think you have anything to worry about.

As for attaching, I didn't want to mess with bolts, so I used wood-to-metal screws they had at Home Depot. They were self-tapping, took a standard phillips bit, sat flush in the wood when secured, and were fully weatherproofed with the same coating Deckmates have. I couldn't find a picture online of them, but the brand was TEK, and they were in the hardware aisle.

[48Rob]

I used strips of a rubber sound deadening material the kids use in their cars to keep their sound systems from vibrating the car too much, dynamat I think it is called?
I actually used ice dam material, pretty similar I believe.
I screwed the plywood to the frame. Only 6 years, and several thousand miles, but still looks good...

Rob

[bobhenry]

LEXAN

[aggie79]

I wrapped the painted frame with window flashing.



Then I attached the insulated floor floor to the frame with stainless steel self-drilling, self-tapping trailer deck screws. (I did pre-drill holes to prevent the stainless steel screws from shearing off.)

[VermonTear]

Wow! You guys are full of great suggestions! I'm going to use them ALL! Caulk, Dyanmat, Ice Dam, Window Flashing, Screws, Bolts. That sucker will never move (or come off!) Maybe I should research all of these.... Do 2 feet of each method, then report back in 15 years. Y'all up for that?

Just kidding, of course. I appreciate the responses. I already have 6 angle plates welded flush and drilled on my chassis that match up with spots on my floor where I added blocking. So, I will be using six 5/16th inch stainless bolts with ny-lock nuts at a minimum. The ice dam and window flashing both sound good for keeping crud out of any cracks, and a bead of caulk in addition along the edge might not be bad. Probably decide on the spot as I get chassis and floor together when Vermont gets a little warmer. Then if I need to add more screws for extra security, I can.