Diesel fuel question

super99 · Aug 30, 2023

Im replacing the shut off valve on the fender tank on my Oliver 1850 and the pipe nipple twisted off. Got the broken piece out, its 1/4 inch pipe. Can I use galvanized pipe nipple that I have or do I need black pipe that I need to go to town and buy? I always see black pipe fittings used instead of galvanized, not sure why other than cheaper.

Jim.ME · Aug 30, 2023

while there can be a reaction between the diesel and galvanizing. I doubt that one fitting would amount to much of a problem. That said, I would get a schedule 80 nipple or a hydraulic system steel nipple which are heavier, especially if the shut off valve mounts on the nipple.

LPgas only · Aug 30, 2023

What Jim said

tomturkey · Aug 30, 2023

If you are in no hurry do as Jim says, but if you need to get up and running, yesterday, use what you have. The old one was working fine until you wrenched it off. just sayin gobble

MarkB_MI · Aug 30, 2023

The risk is that the galvanizing may flake off, which could cause a problem downstream. I read somewhere that this really isn't a problem with newer pipe; natural gas utilities have been using galvanized fittings for years.

Personally, I'd go into town and get a black pipe nipple, just so I wouldn't have to listen to the know-it-alls say 'You can't use galvanized pipe for that!'.

Texasmark · Aug 30, 2023

My recollection of galvanized fittings is that the threads are cut after the galvanizing process....so you are looking at raw steel where you make the interface. Haven 't looked at black lately, nor have a recollection.

john in la · Aug 30, 2023

Go to town and get the black iron pipe.
Diesel will have a chemical reaction with galvanized.
They do not play well together.

Geo-TH,In · Aug 30, 2023

What about using brass?

Dave G9N · Aug 30, 2023

(quoted from post at 07:41:28 08/30/23) What about using brass?

hadn't heard about diesel and zinc, so I looked it up. Diesel reacts with both copper and zinc. Brass is a copper alloy containing zinc and was on the list of metals to avoid.

The small fitting is not going to do anything in a hurry. The problem is more with storage. A small galvanized fitting as a temporary repair should be OK for a while.

Immersion in a hot caustic solution or room temperature hydrochloric acid will remove the zinc from galvanized steel. The acid does not need to be very strong, so diluting it with water will work well, but a bit slower without the fumes. Zn is generally not resistant to any acid, so citric acid or vinegar will work. Adding some salt to vinegar or citric acid will effectively make a dilute hydrochloric acid, which will strip the Zn faster.

https://www.practical-sailor.com/boat-maintenance/are-copper-zinc-and-brass-mucking-up-our-fuel

This post was edited by Dave G9N on 08/30/2023 at 11:59 am.

caterpillar guy · Aug 31, 2023

Use it and don't worry about it. If you had not asked nobody would have said boo about it. For a 1/4 inch nipple less than an inch long go fo it the flakes could not be that big from it and I have never seen a problem with fuel that has been spilled on it steel we had galvanized or not. Filters would catch anything that would be a peoblem before it got to the pump or injectors. OR get a stainless nipple and for get the rust later too.

Diesel fuel question

super99

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Jim.ME

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LPgas only

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tomturkey

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MarkB_MI

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Texasmark

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john in la

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Geo-TH,In

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Dave G9N

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caterpillar guy

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