Tubing surface rust - Help

Hey, guys. I have been getting my MPCNC up and running in the last couple of weeks and I have been noticing some oxidation of the tubing over time. It’s a very thin “coat” of rust.

I was wondering what the proper way was to protect the tubing over time.
Thanks in advance!

I used WD40 on mine periodically and it worked great.


The usual way is to clean the surface, and then apply several coats of wax. Apply the wax, let it harden and buff it down. Then do it a few more times.

I did that with my tubes and they’re fine after more than two years (in western Oregon: think frequent rain).



Hi Ratnik and welcome to the home of rust treatment! :smiley:

There’s no “one time” solution unfortunately, but this is how you can keep it all at bay and looking respectable:

The first step sounds like a bit of a hippy trick, but try it before you dismiss it. Clean the whole length of tubing because there are bound to be microscopic rust spots you can’t see using ALUMINIUM FOIL. (I’ve always got some left over from hat making sessions) .

You don’t need a lot, just scrunch it up into a ball and use a little water as a lubricant. You can use a little dishwashing liquid if you like to lubricate it a bit, but it works fine with plain water.

Next you can stabilise the rust (this is not entirely necessary, but it does lengthen the time between polishing) using a commercial rust converter, or a little phosphoric acid,( which is what most rust converters are made of)
DON’T use Cola. Not only will you end up with a sticky mess, the phosphoric acid content is around 0.05%

Clean off the acid and thoroughly dry.

Now give all of the tubing a couple of heavy coats of paste wax, buffing between coats. Carnauba wax in a cheap car polish is going to be a little more durable than bees wax based furniture wax, because it’s a little harder, but the difference will probably not be significant.

That’s it! If you keep an eye on what’s happening and depending on use apply the wax every so often you won’t have to go through the rust conversion process again. I tend to apply wax as soon as I notice a bit of rust “powder” starting to reappear.

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Thank you so much! I’ll give these a try!

Nice, thank you. I’ll see about getting some wax like Peter H recommended. Thank you!

I did do this before but I guess I didn’t do it frequently enough. I’ll try the wax method. Thanks for the help!

I’ve used Johnson paste wax. I live in Colorado though and we are a desert.

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Will work well (as you know) - I’ve found the harder waxes have a slightly longer time before reapplying but I usually use which ever is closer to the front of the shelf.

Yeah, but you live in a saltmarsh bog from what you tell us, and rust forms when you blink. I’m surprised you don’t pull a pig through your tubing to coat/paint/protect the inner surfaces…

A picture of the bog, the end of my street a couple of hundred metres from our front door. The sooner they drain that swamp the better - then I’ll be able to drive to California! :smiley:

I’m not sure how clear this pic is, but only the top surface is at risk. Waste of bacon aside, I don’t think there’s a problem internally.

Whether that’s because for some reason the salt settles out of the air, or the layer of dust holds the moisture I cannot say, but this is my sliding compound mitre saw - you can sort of make out the gloss from the waxed surface and that there’s no rust on the underside. This gets very regular wax treatment, lubed with ptfe spray and is covered when not in use. The rust pitting is not as bad as it looks, more of a discolouration on a ten year old machine.

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I was thinking along these lines…

But yeah, interesting that only the top surface seems impacted. Although that’s with a well-protected surface over years. That may require dust to trap moisture to speed the formation of rust. Is it still top-specific when the surface isn’t protected? Just curious, though. It’s all somewhat academic, since you have a functional solution, and I don’t suffer from the issue. :wink:

Now you’ve got me crawling under things to find out. It’s not top specific, but very exaggerated. Under my tablesaw wing for instance - twenty-five years or so and painted looks like this. The top has a ply sheet on it when not in use and is waxed yet after six months or so you can rub your hand over the cast iron and it will be covered in red dust (rust) - at that point I clean it all off with mineral spirits using scotchbrite and rewax.

More telling are the little details like this chromed spring retainer on my drill press - I probably haven’t given it a polish in ten years, so it’s overdue for some preventative. Will give it a dose of the aluminium foil and report back in a few minutes. Note all surfaces are slightly affected, but the top one is a lot worse.

I’ve had a chance to tear off a corner of my foil hat, go downstairs, give this part a quick rub. I don’t know what the science is or if it really is voodoo magic, but this is it - foil only and a smear of wax (hence the “scratch marks” which are actually just wax. If you view both images at full size you’ll see that the foil has somehow penetrated into the rust pores, or at least pulled it out from the hollows (it’s still there, waiting to come back! :wink: )

Hmmmm…pig launcher you say?..this gives me an idea…but the reply will most likely be in the “smoking meat” thread.