Platform undercoating - black tar vs. fiberglass

[DoctahDeane]

I have read a lot on this topic. I know that many go with the tar stuff but it also seemed that fiberglass could offer some benefits. I talked to reps at System Three who make a popular boat epoxy. Sounds like nasty stuff but also, the rep mentioned reapplication every 3-4 years ( I suppose that is for a boat?). Anyway, it seems that reapplying glass underneath a "done" trailer could be quite a hassle and although messy, the tar stuff could be easier to reapply (if anyone even does?).

Any thoughts on this? I am ready to attach the platform and move on top the profile and sides. Thanks!

[Kody]

Hi Doc.
There is no need to reapply glass cloth to the underside of the floor. In fact, there is absolutely no need to apply glass under the floor at all. I laid out the ply for the floor on top of the timber that it was to be screwed and glued to and lightly clamped it in position. I then ran a pencil around all the timbers and frame to mark out where the ply will be glued. The ply was then removed, turned over and the areas where the ply will be glued, I covered with masking tape. I then painted on two layers/coats of the tar stuff to protect and seal the ply. The masking tape was removed (must be removed before the tar stuff fully hardens/cures) and the ply set aside for the stuff to harden. The ply is then flipped over, aligned up in its precise position and glued and screwed in place. It's now an easy job to paint around the timber of the frame with two coats of tar stuff and of course, into the corner joints of the floor and bearers. You don't get the stuff dripping down all over yourself when you do it this way.
Glassing is only needed if you are working on a boat. There is a world of difference between what a boat operates in and what a TD operates in. The important part of the floor that must be fully sealed is around all the edges to keep out the water and the dry rot spores that fill the air.

Kody

[bobhenry]

I used this on 2 builds.



At less than $7.00 a gallon it goes a long ways.

I coated the barn trailer top and bottom. I cheated doing the bottom I chained it to the forklift at work and flipped it over and poured and mopped the stuff on wood and frame as well and it looked good when done and has been field tested for two years now and looks just as good now as then and yes it adhered well to the painted steel as well as the wood.

[DoctahDeane]

Great guys, thanks for the assist. One other related question. I read Ryan's postings with interest (Wyoming Woodie) and he used carriage bolts, countersunk, on the sleeping side of the platform. I have already drilled those eight holes and they line up perfectly etc. but wondering about once I countersink, are they supposed to be covered up in some way, perhaps by another 1/4" skin for a nice smooth sleeping surface? I don't think the sides will cover those bolts but I have not made it that far in planning yet.

[GuitarPhotog]

Generally the mattress covers the floor and you don't have to worry about it.

My 5" thick foam mattress covers a myriad of small bumps and defects in my floor, and since I'm no princess, I have no trouble sleeping on it.

<Chas>

[les45]

No need to cover the bolt heads or to countersink them. Your mattress will cover them.
Hint - when using carriage bolts, if they start turning on you as you tighten the bolt, cut a slot in the head with a hacksaw or Dremel tool so you can use a screwdriver to hold them.

[DoctahDeane]

Haha Chas, funny. Thanks guys, pretty stoked to be moving along to the sides. I know I will encounter a ton of other issues but the big one I just got over was that my platform was perfectly square but apparently the trailer itself was off by 1/4" on the front right corner (looking forward, from license plate end). Man, that was crazy. I got "close enough" by elongating the countersink holes around the bolts that the platform sides on, on top side of frame. I wanted at least 1/4" overhang so I could rout the sides that deep so that the sides would have some stability on the bottom sides, not just roof side. Anyway, onward. This is a great forum and I appreciate the advice. I got the Kuffel and Frederick's manuals but find that looking at photos does almost as much good. It will be great to have the platform fully attached.

[aggie79]

No need to cover the bolt heads or to countersink them. Your mattress will cover them.
Hint - when using carriage bolts, if they start turning on you as you tighten the bolt, cut a slot in the head with a hacksaw or Dremel tool so you can use a screwdriver to hold them.

Or you can use torque washers to help stop carriage bolts from spinning.

[Larry C]

Elevator bolts are completely flat on top.