Non-porous gasket and/or sealant?

Jan 30, 2008 16 Replies

Hello all,



I am building a frame/box onto a metal cart - long story. The chase is that it needs to be water resistant, and there will be a couple of butt joints that would benefit from a gasket of some type. Whatever I use needs to be non-porous.



RTV sealant strikes me as a reasonable choice (perhaps I'm having too much fun tinkering my truck). Any concerns about using it on Enco's extruded Al tubing? Some quick searches suggest avoiding acetic acid. Any other concerns?



Any better ideas? Again, porous materials will be a problem.



Thanks,



Bill



If you want to use RTV, but don't want acetic acid, find some electronic assembly grade RTV.

Paul

3M 5200 marine polyurethane. Stands up to constant immersion. Very strongly adhesive.

On Wed, 30 Jan 2008 15:08:22 -0500, with neither quill nor qualm, Bill Schwab quickly quoth:

Why can't you weld, braze, or solder them, Bill?

I don't think Plumber's GOOP exuded acetic acid. Smells more like toluene IIRC.

Yes, next time: state the materials you're planning on using, the size, the actual usage, the weight it will support, etc.

-- My future starts when I wake up every morning... Every day I find something creative to do with my life. -- Miles Davis

MIG welding is not something I do. Even if it were, any such method seems (no offense intended) very clumsy for something that needs to be adjusted to fit the existing cart.

2" square tubing; weight is not really a consideration, as the intent is to make a "radar bubble" to accommodate some items that do not quite fit on a shelf on a mobile cart.

Bill

Interesting. It might be too much of a good thing, but I will consider it.

Thanks!

Bill

ProSeal. Used to seal rivetted gas tanks on aircraft. Probably overkill, but it will work!!!!

On Wed, 30 Jan 2008 19:05:17 -0500, with neither quill nor qualm, Bill Schwab quickly quoth:

I feel the same way about adhesives, so we're even there. Besides, I'd TIG or solder it if it were sheetmetal.

Also, if you're building it to fit one existing cart, why should it have to be adjustable? Just measure it and build it, eh?

Ah, "mobile cart" size based on a 2" square tube frame. Gotcha. Little red wagon size, ATV size, car size, truck size, semi size, or NASA size mobile cart?

Never mind. I'll just jump off here.

-- My future starts when I wake up every morning... Every day I find something creative to do with my life. -- Miles Davis

*dont* consider it for any joint you might want to dissasemble non-destructively. If you get any on your skin, you'll have its stains with you far about a month. You can also forget about getting it off any soft or poreous surface that its got onto. Its also got a *very* short shelf life once opened. 3M 4200 is somewhat less drastic and Sikaflex do a range of marine sealants, one or more of which should suit your purpose.

IIRC your cart is all or part Alumuinium and you are concerned about corrosion. You may wish to google "poultice corrosion". In any wet (non-potable water) application if I have Aluminium faying surfaces without a specific gasket, I use Duralac (an inhibiting Barium Bichromate goop), ESPECIALLY IF DISSIMILAR METALS ARE INVOLVED.

Huh. I never have any trouble cleaning up with naphtha.

Try working with it in a boatyard with a 1/3 mile walk to the washroom. The job was a real ***tard one rebedding something or other that was awkward to reassemble upsidedown, deep in a locker. By the time I got it done the stray 5200 was allready starting to set. I got as much off as I could before ging to wash up but was scarcely presentable for our fitting out supper the next week.

Hard to understand that, given it takes 5 to 7 DAYS to cure.

To cure through yes, but it seemed to skin enough to be annoying and as I said, what was on my hands didn't clean up very well. I should probably explain that although I'd started this vile job in the afternoon, it was well into the evening by the time I cleaned myself up. I didn't have any cleanup problems with where I'd gotten it on the hull which would probably be about 2 to 3 hours after I started applying it and all the tools cleaned up reasonably well, and I remember we'd had to schedule this at least a week before we launched which was almost certainly due to the setting time you quote. Its also possible that there were traces of something else on my hands accelerating the 5200's cure as I'd been working with a variety of nasty substances. My skin were almost certainly dry and very rough inspite of the barrier cream from all the work I'd been doing.

I doubt I'm confusing it with another product because where we were, The skipper had had to import the 3M product specially. Neither it nor any of the Sikaflex range could be found locally, (I suspect due to overwhelming faith on silicone sealant usually applied as a poltice round a failing joint and faith in Allah) and what with the language problem we couldn't find anyone who'd get some in for us.

Next time get a bottle of Mineral Spirits. Cheap and dissolve 5200 (as long as it is not set) and doesn't evaporate quickly. Keep a wiping rag wetted with the stuff to wipe your hands, ears, etc., while working. Also works well to clean up extra sealant that squirts out of the joint when tightening fasteners.

If you don;t get your hands clean before the sealant sets up, well, sandpaper will easily remove it :-(

Bruce-in-Bangkok (Note:remove underscores from address for reply)

I do agree, it is a wonderfully messy item to keep where it belongs, requiring meticuluous technique. My rule is 1 roll of paper towels per hour of working with it. Lots of popsicle sticks from the craft store. You touch it once with a spreader or a wiper, and then you toss that spreader or wiper. But what performance, bedding stainless fittings onto a boat hull!

About as good as you can get.

Bruce-in-Bangkok (Note:remove underscores from address for reply)

Keeping water out or some other liquid in?

The correct type of sealant will depend on what you want to contain.

DO NOT use RTV for fuel.

Mark ( i dont have to tell you how I know, do i?)

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