protecting braided stainless line

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jacksoni
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protecting braided stainless line

Post by jacksoni » Mon Oct 02, 2017 4:12 pm

I have a Bonneville car with fuel pump and tank in the rear. I am replacing the current hard line which has corroded and sprung some leaks after a number of years of corrosion despite post racing washing and paint (which may not have gotten in every nook and cranny. I am thinking the salt may corrode the stainless braid (not bother the rubber) and be difficult to remove and am wondering about ideas to protect it some. Could I paint it, cover with silicone totally, ignore the issue and just wash best I can or what? Ideas, thoughts? The lines cannot run inside the car at all.

Thanks.

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Re: protecting braided stainless line

Post by emsvitil » Mon Oct 02, 2017 8:28 pm

The one I got for my motorcycle's front wheel was a braided line with a vinyl covering.
Ed

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Re: protecting braided stainless line

Post by ijames » Mon Oct 02, 2017 9:35 pm

Chloride ions attack 300 series stainless steels. 316 is more resistant than 304, but of course it's much more $$$. Passivation helps a lot but even passivated 304 will slowly rust soaking in salt water. Commercial passivation is done with concentrated nitric and sulfuric acids, and I don't know if you could get anyone to try passivating the outer braid on fuel line. You can use citric acid which is much friendlier and easy to do at home. It doesn't do quite as good a job but it's cheap and safe to do at home and really helps. Buy 5 lbs of citric acid on ebay for about $15, doesn't have to be "non gmo" or food grade, just get the cheapest you can find. Use a stainless steel stock pot or a plastic 5 gal bucket (no mild steel or aluminum), heat 1 gallon tap water to 160-170 deg F, put in the pot, add 1.5 cups of citric acid powder to make roughly a 10% solution, and stir until dissolved. Seal the ends of your braided line, coil up the line, and submerge it in the solution. Let the ends stick up so you can't get water inside, you just won't passivate the last few inches of each end. Stir and swirl and let it soak for 15 minutes, then take it out and rinse in the sink. The 10% citric acid is basically concentrated orange juice so it's drain friendly. You can save the 10% solution and reuse it for a few months but eventually stuff will start growing in it. If the steel braid is oily or dirty clean with soap and water and rinse well before passivating it. Sounds weird, I know, but we had a problem with small 304 SS tanks rusting in some equipment we manufactured at my last job, and doing this kept the rust from starting for 1.5-2 years on average, instead of a week to a month, which made the tanks last about as long as it seemed to take our users to blow up the piezoelectric nebulizer crystals in the humidfier. Oh, make sure you let the stainless steel age for at least a month before you get it salty, just to finish the job. I would bake our tanks for an hour at 400 F, but I doubt your tubing could take that :-). Even if you splurge and find 316 SS braid you can do this for even more protection.

If you have a stainless steel sink or pots that have rust pits, clean them with a scotch brite pad (citric acid won't remove rust by itself) then do this procedure. In a sink just fold up a paper towel, lay it on the area to be passivated, and keep it wet with hot solution for 15-20 minutes. Chloride attack is why you never, ever put bleach in your wife's stainless steel sink, and this is how to fix it if you do :-). I've never passivated braided tubing, but I have done this many, many times on various items like those tanks, baffles, nuts and bolts, etc.

jacksoni
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Re: protecting braided stainless line

Post by jacksoni » Tue Oct 03, 2017 8:24 am

Thanks ijames. That looks like a good idea. Have ordered some citric acid. Have some stainless fasteners that may benefit as well.

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Re: protecting braided stainless line

Post by ijames » Tue Oct 03, 2017 10:01 am

Forgot to mention that if you do nuts and bolts make sure to put some kind of lube on the threads before using them since you need to wash them clean before passivation. A drop of oil, grease, antiseize, something. Nothing else that I've had the, um, pleasure :-), of working with galls faster than clean, dry stainless steel on clean dry stainless steel, and once you feel it start to grab while tightening you only get maybe another 1/4 turn in either direction before it's fully welded and time to break or cut or drill (or drink :-)).

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Re: protecting braided stainless line

Post by bill jones » Tue Oct 03, 2017 5:22 pm

Jack---what about using shrink sleeve over the stainless steel hose?

-maybe lightly grease the braided stainless steel---and then run the shrink sleeve long enough to cover each end out over the part of the fittings that contain the braided hose ends.

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Re: protecting braided stainless line

Post by Kenova » Tue Oct 03, 2017 10:37 pm

Fragola has a line of braided stainless with a vinyl covering. It's a little stiff but looks durable.
You could also try the shrink tube on your hard lines. Use the high quality stuff with heat activated adhesive on the inside.

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Re: protecting braided stainless line

Post by jacksoni » Wed Oct 04, 2017 7:26 am

Thanks all. The hard lines already out and the new already purchased. The shrink tube is a good idea Bill as it basically does what I am thinking without some chemical ( paint or other) that might somehow damage the line. Will see what can source. Am prepping the bed and some rusty spots now.

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