Expanded metal flooring?

[mosk22rte]

I have a new-to-me 12' Klamath aluminum V boat, and want to put in some floors. I know these are commonly done with something like carpet covered plywood and 2 X 4s, or with wooden slats, but I'm interested in trying something different. Instead of a material that's prone to rotting, I'd like to do my floors in expanded metal, with a welded metal sub-structure. Anyone ever do this?

McMaster-Carr (http://www.mcmaster.com) (search term: "expanded metal") has 4' X 8' sheets of expanded aluminum, steel, and stainless steel in various thicknesses. I think a single 4' X 8' sheet (or maybe a sheet and a half) should be enough.

I'm thinking of doing it in either aluminum or stainless steel.

Unfortunately, the aluminum they sell is a non-heat treatable 3000 series. Is this too malleable to use for a floor? If it isn't, any suggestion as to which thickness to use? Figure the material has to support the weight of a single 200 lb. person, and there would be a reasonable amount of support beneath the expanded metal surface to spread the load around.

Alternatively, if anyone has a source for-heat treated 5000-series or 6000-series expanded aluminum sheets, I'm all ears. :)

McMaster also sells stainless steel mesh, but this raises the problem of electrolysis, especially considering the wet operating environment, lol. My assumption is that electrolysis makes stainless steel an unsuitable choice for this, but I've never done this before, so maybe this is a wrong assumption?

Finally, before I settled on expanded metal, I also considered doing this in composite deck material, but I took a look at some of this material at Home Depot, and found it too dense and heavy. A little reading online also indicated that much of what's out there has at least some wood pulp as filler, and this makes it susceptible to rot as well. Or so the web told me...

Anyway, I'd appreciate hearing any suggestions or thoughts on the above. I'm new to boats but have a lot of experience with automotive mechanics and some experience with fabrication projects.

Thanks,

Jeff

[tazmann]

Personaly I would be a bit leary of exposed expanded metal anywhere on a boat, sharp stuff and geven the right cercumstances could rip fingers off?
Tom

[Lt. Holden]

Jeff,
I too have always thought there has to be something better than the typical ply/carpet (rot waiting to happen) formula. You could do the aluminum as you mentioned but should choose the type of opening and spacing carefully as Tom mentioned.
A similiar but perhaps better, cheaper, lighter and easier to work with alternative may be molded or pultruded fiberglass grating. I always thought that with this material you could install suitable snaps, cut your carpet into panels and simply remove them to air dry them with no possiblility of rot (especially with your aluminum hull). I want to try this in my fiberglass jet boat (I've had to replace the floor twice due to freshwater condensation rot).
I can't seem to imbed links so I will spell one out McNichols (dot) com.
They have a very comprehensive line of all types of metal and fiberglass gratings as well as structural pieces which you might need. Their free catalog also tells you how to select the material based on load, span spacing and environmental factors.
Could you post a picture of the hull interior? Do you currently stand on the keel/inside hull surface or is there a deck? If the floor is going to rest on the inside chines you would probably just need a longitudinal 'riser' on the keel to support the center length of the deck material.

Best of luck and let us know what you end up using.

Regards,
John Langevin

[jehardiman]

Conure with fiberglass gratings. Fire is the major reason metal decking is still used shipboard. Toxic gas should not really be a problem in an open boat fire, you will have bigger problems.

Expanded metal stiff enough to to support walking weight in most boat sized spans would be too heavy as well as requiring a boundary bracket for the cut edge. Additionally, all the sharp corners will wear any coating (even the SS passive) off quickly and you will get corrosion as well as cut into any support structure. Finally, you DO NOT want to fall onto expanded metal decking...period (can you say cheese grater?)

[robherc]

At the risk of sounding like the "Devil's Advocate" here I'll offer a dissenting opinion ;)

If you're planning on using your expanded metal UNDER CARPET, then I think you may like the results quite a bit...and I don't think the 30-50lbs of expanded metal will hurt you too badly for weight. That said, I would HIGHLY recommend painting WHATEVER metal you choose with a few coats of Rust-Oleum (at the least...preferably marine urethane paint) before you put the carpetting on top of it...to save yourself the oxidation hassles.

As far as metal selection, if your boat is already made of aluminum, I'd recommend using aluminum for the exp. metal deck, since using steel could produce some galvanic corrosion between the 2 different metals wherever they meet (I don't know for sure...haven't checked the values, but same-metal is always safer there). If the only avial. aluminum is 3000 series & you think it'll be too soft, you can always add another support beam underneath to fix that for a LOT less $$$ than replacing oxidised metal all over the boat!


....just my $0.02, take it or leave it.

[mosk22rte]

Thanks, these are great suggestions.

I'll look into the fiberglass flooring.

I think you guys raise some excellent points about the dangers of exposed, "raw" expanded metal flooring. If I do go that route, I'll either cover it with carpet or use a rubberized "dip" or spray-on coating.

Keep 'em coming :)

-Jeff

[drmiller100]

I too have thought about this.
Is the expanded metal lighter then suitable aluminum decking? I would think so.

There is also aluminum honeycomb, but it is pretty expensive.

I'm tired of wood also.

[tazmann]

One option I can think of is use 5052 grade 1/8" or 3/16" plate depending on the strength you need and the drill a series of lightning holes in it, size and pattern to your liking.
Tom

[robherc]

Tazmann, that sounds like about 15hrs of wasted effort to me...but if you have the time, power-drill, and drill bits to burn...more power to you!

[tazmann]

Tazmann, that sounds like about 15hrs of wasted effort to me...but if you have the time, power-drill, and drill bits to burn...more power to you!

It was only an option, If you dont want wood or expanded metal, never said it was cheap or easy. Aluminum diamond or tread bright plate would be another option but not cheap compared to plywood.
Tom

[drmiller100]

i drilled a bunch of holes in a race car once.

spent about 10 hours on one inner fender and saved about 5 pounds.

[Lt. Holden]

An alternative to carpeting could be interlocking foam flooring like they sell for workshop use, it offers a cushioned feel, is easily removed and it floats!

[robherc]

Good idea Lt....it's also pretty waterproof so it won't mold/rot like carpet either (though mold could still accumulate if you leave it damp for long enough).