Sheet metal covering holding tanks

[loberg]

Apparently the previous owner of my 2007 Safari 27FB SE needed accesss to the holding tanks. I've got some cut outs in the sheet metal that protects the tanks, that he tried covering up with good old duct tape. I would like to make the proper repair. I was told not to weld a patch because it would be too hot for the plastic tanks. This same person recommended that I rivet the patches on. This seems fine to me but as we all know rivets require predrilled holes. So my question is, how much clearance is there between the sheet metal and the tanks? I do not want to polk holes in the tanks. Thanks

[Aviator]

I would think a half inch or so. When you remove the tape, can you see the space to the tanks?

[cwf]

You can also get a 'drill depth' set.. a collar that clamps to the drill bit and gives the bit a 'stop point' so you don't over-achieve..

[Poolman]

I am in need of patching (or potentially replacing) my fresh water tank cover as well. Does anyone know what metal these are made of? I am concerned with using the wrong metal and starting some nice galvanic corrosion. Thanks in advance.

[Bill M.]

I use a wooden block on the drill to make a positive stop that cannot slip. Cutting holes to access the valves is a standard practice and is the way Airstream repair center gets in for that. I agree with checking carefully what is behind the openings before you proceed.

[dznf0g]

Originally Posted by Poolman

I am in need of patching (or potentially replacing) my fresh water tank cover as well. Does anyone know what metal these are made of? I am concerned with using the wrong metal and starting some nice galvanic corrosion. Thanks in advance.

Mine are galvanized steel.

I would probably pick up a small sheet of stainless at the big box store for the patch.

[perryg114]

Any HVAC supply place will have some galvanized steel. If the patch is small, you can use screws and be able to get back in there again. Find out what is under there. I used stainless steel pop rivets and the same thickness galvanized steel (.040") to patch mine. Inside of the patch was a proper sized opening that was screwed on with stainless steel screws. Unless the tank has been cut the entire width of the trailer there is no reason to worry from a structural standpoint.

Perry

[AWCHIEF]

Some time ago a I picked up an assortment of different metals and sizes from a welding shop. There were basically cut offs. I gave them $20 bucks for about 30lbs of metal. A number of them are big enough for patches and access plates.

[dbj216]

My 86 used galvanized steel for the tank cover. There was 1" styrofoam between the tank cover and the tanks. The tank cover is a bugger to get off due to the rusted sheet metal screws holding it up.

I wish Airstream would provide an easier way to perform maintenance on a problem dump valve. It is pretty common to have one get jammed or fail a rubber seal and start to leak. So I totally agree with creating an access cover under the dump valves that's easier to remove.

David

[loberg]

These replies have been very helpful, thank you. I too think that leaving these holes accessible is the way to go. I'll try sheet metal screws instead of rivets. Thanks again.

[Poolman]

Yes, thanks to all responses.

My pan has some issues in two spots, only on the bottom.
I've got a remnant from a sheet metal fabricator that should be big enough for my needs.

Planning on cleaning up the metal on the existing pan and overlaying the entire bottom and cutting some miters on the corners to overlap about an inch or so up all four sides for added support. Rivet back with steel rivets and paint her all up to seal. Back on with stainless steel bolts and washers.

So thats steel rivets on steel pan and steel bolts into steel frame. Seal to eliminate as much water as possible. No dissimilar metal corrosion.

You more experienced folks feel free to shoot holes in this plan

[dznf0g]

When I had my cover for the fresh drain area off, I applied some thin stick on weatherstrip between the cover and pan....just to reduce road spray from getting in and causing corrosion on the pan bottom. Don't know if it helps, but why not?

[dbj216]

Here is a photo of the valve cover I made for my Trade Wind. I have about 12 rivets to drill out if I need access to the dump valves. I made a mistake in that I did not allow enough clearance to slip the cover over the bayonet connector for the slinky. So I will have to saw the 3" ABS pipe and then replace the bayonet connector if I have to get at the valves. An extra $10 in parts. I maybe have made the valve cover in two pieces so it would come off easier.

David

[Poolman]

Now that is a sweet looking cover!

[Siegmann]

Poolman, you described making a tub of some sort under your pan and then sealing it. Be sure to allow some gaps so any future leak can drain out on to the ground.

[Poolman]

Siegmann-
Yeah, thanks for the reminder. Will do that. I believe that the pan bottom has a slope anyway, will leave some drain holes at the low point.

I get so focused on stopping leaks and rust, sometimes forget the obvious.