Snow Trac WOOD FLOOR discussion

UPDATE: 1-31-2006

I just came in from the garage after inspecting the ST4. I put it up on the lift because I wanted to inspect the underside. I had 2 reasons.

First, I wanted to weld up a couple brackets for an exhaust line to match the one Villi has on his where it runs under the cab and then out the right side ahead of the large rear wheel. The two muffler brackets are now welded in place, and painted with grey primer. It looks just like the underside of Villi's Snow Trac (except mine doesn't have an exhaust pipe!)

Second, I had it out in the corn field 2 weeks ago and ran it through a couple rough fields that had small shrubs, etc. So I figured I'd do some damage inspection.

Let me strongly recommend that if you have access to an air compressor, you should use 2-part epoxy and "Rhino-Line" the underside of your Snow Tracs! The floor of the Snow Tracs are plywood. Mine was in excellent condition so I did not have to replace it. But I also wanted to protect it. The chassis on my unit was also completely rebuilt with new steel about 3 years ago and I wanted to protect that as much as possible. Given the amount of mud on my unit from the corn field the epoxy did an excellent job of preventing the mud from sticking to the under side of the chassis. I was simply amazed at how clean it was.

The epoxy coating is fairly slippery and very abrasion resistant and I'm sure that is the reason it stayed so clean when everything around it was caked with mud. The epoxy is also waterproof so it protects the wood from rotting, while it protects it from abrasion, scratches, etc.

Re: 1972 Aktiv Fischer ST4 "Snow Trac"

B_Skurka said:

The floor of the Snow Tracs are plywood.

Click to expand...

Bob,

Is that plywood floor the only thing under the machine and is exposed to whatever you may run over (small trees or whatever)? If so, wouldn't some sort of steel skid plate be in order?

Re: 1972 Aktiv Fischer ST4 "Snow Trac"

There is a steel frame chassis under the plywood floor, but it is a simple square steel tube frame. The plywood simply sits on top of the frame.

At the front of the Snow Trac, the body panel extends down under the engine to not only protect the engine, but to act as a skid plate to smooth the snow and both deflect snow under the ST and to act to raise the ST up onto the snow. Behind that panel is where the square tube chassis is exposed with the plywood sitting up above that.


I put my Snow Trac on my 4 post lift and this photo below shows the underside. It is taken from the rear looking toward the front. You can see the black steel chassis. Looking forward you can see the very bottom part the orange skid plate that curves upward toward the front bumper. (this is an old photo, before I sprayed the 2-part epoxy to protect the underside)

Re: 1972 Aktiv Fischer ST4 "Snow Trac"

Thanks for the pic Bob.

For snow (the primary intent of the vehicle), that seems quite adequate.

If I was to have one of these machines, it would be used all seasons, in all terrain/conditions. With the potential of branches kicking up when driving over them or the possibility of running over saplings and such, I would probably put polyisocyanurate insulation between the steel framework (for insulation as well as noise reduction), then cover the entire belly with a sheet of steel.

Re: 1972 Aktiv Fischer ST4 "Snow Trac"

Brian, I think a better solution is to use a different material for the floor. If you put a steel pan under the wood floor, it would hold in dirt and moisture that would somehow find its way into the area between the wood floor and the steel plate.

I looked at many ways to protect the wood floor and the only 2 that made sense to me were either to replace the wood with some sort of reinforced fiberglass floor, or to somehow bond a durable & waterproof material to the wood floor.

WEST SYSTEM epoxy, used by boaters, could have been used to protect the floor, but I was unsure if it was flexible enough and if it would simply crack at each of the stress points. But removing the wood floor and using the WEST SYSTEM may well be a very viable option. I used a 2-part spray epoxy, which I think is also a pretty good solution. It is waterproof, helps deaden sound and vibration, and it is mildly flexible, while also being very resistant to abrasion. It has the added benefit of also protecting the steel frame chassis.

Replacing the plywood with a sheet of aluminum or steel is not viable because it would have to be thick enough so that it does not deform, and thickness equals weight, which is not ideal when you are trying to float your machine across snow. It would also be loud & cold.

Another option would be to use a thin sheet of aluminum or steel, but reinforce the chassis frame under it. Again not ideal. It would still be loud and very cold.

Another option, and possibly a very good one, would be a foam & metal sandwich, that type of structure would give allow for thin sheets of steel, would give both sound & climate insulation to the floor (which the wood provides) but it would likely be a much thicker floor than a wood floor to equal its regidity?

I'm certainly open to other suggestions, but this was/is my solution for now and I expect it will last for many years.

Re: 1972 Aktiv Fischer ST4 "Snow Trac"

Hmmm. Bob your plywood floor is different from mine. I cant figure it out yet but I know mine is different. I believe mine has cut out for the emergency brake cables? I'm not sure. I will take a look.

Re: 1972 Aktiv Fischer ST4 "Snow Trac"

I do know a way we could insulate and protect the main floor. I would cut some 1/2" ACX marine grade ply wood to fit in the spaces between the frame. Epoxy paint the main floor first then epxoy paint the 1/2" plywood. Get some 1" thick foam panels and cut to fit. place those on the main floor then simply screw the 1/2" plywood to the main floor. That would sandwich the foam and provide insulation from cold and noise. Maybe even place some sound panels on before the insulation?

Re: 1972 Aktiv Fischer ST4 "Snow Trac"

Nice Snow Trac lift bob!

Re: 1972 Aktiv Fischer ST4 "Snow Trac"

Snowcat Operations said:

Hmmm. Bob your plywood floor is different from mine. I cant figure it out yet but I know mine is different. I believe mine has cut out for the emergency brake cables? I'm not sure. I will take a look.

Click to expand...

The red box in the floor with the two black cables coming out of it is where the emergency brake is located. That box covers the underside of the mechanism.

The 4 post lift is a "Direct Lift" brand car lift. I know a guy who had an extra one (he races cars) and couldn't use this one so he came over and set it up in my garage/shop area for me. It has a hydraulic pump that is driven with standard 110/120volt motor and will easily lift and hold a large SUV.

Re: 1972 Aktiv Fischer ST4 "Snow Trac"

Consider a layer of a composite sandwich panel under the chassis. I'd suggest it as a replacement for the plywood, but I think you're too far along with your coatings, etc. Here's a link to one type of composite panel; I'm sure there are many more alternatives. I didn't Google this; I recalled it from an episode of "Shipshape TV" where they used the panels as a deck material when rebuilding a boat. I've seen similar material used as a replacement for plywood in pontoon boat renovation. I didn't look into the costs; regardless of how expensive, they have to be relatively minor in the overall scheme of a restoration, especially when compared to the core problems they solve.

Don, that is exactly what I would have used if I knew about it. Regardless of cost! Even if that is the world's most expensive plywood composite material, it looks like it would be a nearly permanent solution to the problem.

Do you know if it offers any significant advantage in insulation properties (sound and or climate insulation)?


EDIT : Because this thread changed directions, I split the thread from the main thread so we could explore this topic in much greater detail.

Bob,
My floor is stock and looks brand new.. Wasnt you snow trac open with the top off when they found it? That would have destroyed the plywood for sure. The original plywood is fantastic stuff. Multi multi layer (20 or more) and is of a marine grade. Insulating would be easy but not really needed.

My wood is was only used in snow 2 or 3 times before I got it (the guy who owned it only used it a couple times before I bought it), but it is a sheet of regular plywood. Based on the smooth finish on both sides, it was a very good grade of plywood, but it was not a marine grade plywood. There was a water mark in one corner of the top surface of the plywood but no water marks on the underside. The water marked area showed no signs of damage or delamination. The wood was replaced by the Salvage Squad TV show a few years ago.

When I sprayed in the 2-part epoxy liner I made sure that extra material went around the perimeter to fill in all the edges around the cabin so it is sealed very well from the top. On the underside, I sprayed it while on the 4 post lift so I was able to get the spray nozzle into all the nooks and crannies between the wood and the chassis. I don't think I will have any problems with mine, but if I had to replace it, I would use one of the boat deck type panels like OkeeDon provided in the link above.