Prowler 

Clearly everyone is concerned about removing rust from steel but I've been working on growing rust cuz, eh, it's winter and cuz I can. I've been intrigued, lately, with the use of tung oil for treating rust spots on my bikes. I've sealed two frames with multiple coats of boiled linseed oil which seems to work but each coat takes too long to "dry". I've also tried tung oil on a few things (like axe heads and hammers) and that seems to work nicely and does not take very long to dry between coats. So, being winter I decided to be more "scientific" about it and evaluate how tung oil performs in "the wild" vs unprotected iron.

Instead of recycling a cast iron brake rotor I used a wire brush to scrub the braking surface of all rust, nothing but bare cast iron. I coated 1/3 of that surface with tung oil, two coats, and left the rest. Once dry I took a photo. On February 1st, I flopped it down in the weeds next to the shop door, unprotected from the elements. Truth be told it is on a north facing slope so does not get much direct sun but does get all the rain, dew and winter mix. That position probably extends the times the rotor is wet as the sun does not help much. I took another photo on March 1st. See for yourself.




Don't get too geeky about the relative shine as I didn't get too geeky about the sun angle. I've no reason to think the tung oil "yellowed" the iron. It did change the reflectivity so sun angle and camera angle highlighted the coated sector.



One month out in the elements. I'll take additional photos each month for a few, until it gets boring. No question the tung oil helps a lot, even with full time exposure. Far more exposure than my bike frames get.. Now to see how it holds up with extend exposure.

ehcoplex 

Interesting! Was it a 'pure' tung oil, or the stuff from HD/Lowe's etc that has 'driers' in it? IIRC, tung oil is a 'polymerizing' oil, so should become more or less a very thin plastic-y film.

79pmooney

Is tung oil the next framesaver?

I should run a test like that with the AMSOil HD Metal Protector I've been using to framesave.

zandoval 

Coming from Central Texas and then living a few years in Galveston taught me allot about Rust. I resurrected a UO-8 that had been stored outside less than a quarter mile from the waves. The inside of the frame had been treated with 50/50 Denatured Alcohol and Linseed oil and it worked.

I also saw Penitrol being used on metal equipment that was going to be stored before a final paint scheme was decided. People who live close to salt water are well educated in rust and its prevention and treatment. Here is a link...

Prowler 

I think tung oil and BLO were, maybe, the first framesavers. None of this hoy ploy fancy modern chemistry for this ole man 😵‍💫. Time will tell but that rotor has already seen far worse treatment than my bikes will ever get.

Yes, the stuff I used had driers in it. If the mixture dries in a day then it’s easy to apply multiple coats. IIRC when I treated my Voyageur with BLO, laced with a bit of OMS, I applied 10 or 12 very thin coats. I had a couple of winter months to do it. My “office” smelled great for that time.

AngryScientist 

I use marine grade corrosion inhibitor from the local boat shop. Protects engine components in salt water environment, so definitely good enough for the inside of my bike tubes and readily available.

Cool experiment though! Coincidentally, I need to do a brake job on the family van in the next few months, maybe i'll follow your lead and see how my choice holds up!

Prowler 

update: 2 months out in the winter weather. Total neglect but the tung oil seems to be holding up well. This is already FAR beyond any level of neglect any of my bikes will ever experience. I'm quite happy but I'll let the abuse continue. Spring has sprung here so less cold and frost but more rain and dew. We'll see next month.

ehcoplex 

Thanks for the update! Inspired in part by this I just gave a stripped and bare-steel Holdsworth the tung oil treatment. I diluted it a little bit with citrus solvent so it would apply on a little easier, brushed it on, wiped down lightly with a rag. Repeated three times with about a day between each coat, then waxed (I'm not sure the wax is necessary/does anything, but I had it, so....). My intention in doing this was to give the frame some protection so I can ride it this season while I decide on paint for next winter, but I'm actually really starting to like the raw steel look- it's a kind of elegant 'rat-rod'/steam-punk look- so it's possible I may just keep it like this. If the weather cooperates, I'm going to take some photos of the bike later today.

georges1

I have used rustoil and kf ,which gave me good results for protecting chromed surfaces. When I buy a frame,I always inspect the condition of the bottom bracket,seat tube and steerer tube.

brewerkz 

I use Eastwood Heavy Duty Anti Rustor rust encapsulator or amber anti rust, applying it with there 24" extension hose nozzle, the nozzle has 4 openings that create a 360 degree spray pattern. Basically feed the hose in the frame and spray as your pulling the hose out.

https://www.eastwood.com/eastwood-he...ce=google&wv=4

https://www.eastwood.com/aerosol-noz...ce=google&wv=4

fliplap

Few years back someone over at MTBR did a controlled comparison between Corrosion X HD, Frame Saver, WD-40 Corrosion Inhibitor, Boeshield, Amsoil Heavy duty metal protector and Fluid Film

Most were totally effective under normal conditions, but really, chromoly steel is pretty rust resistant. The author eventually graduated to applying salt, and then battery acid.

it’s a long thread, but here are the results. Scroll up for photos. https://www.mtbr.com/threads/anti-co...#post-13693944

Prowler 

Following along, the rotor has now been out in the weather, full time for 3 months. The lilac bush this sits under is full of leaves and flowers so it does not see any sun. But sees plenty of weeds and damp and rain and dew, and a spot of bird doo. For iron or steel, pretty miserable condition. Seems to be doing well though, doncha think? Back again early June.

Piff 

I see no reason why I wouldn't also apply rust inhibitors like this to other steel components on my bike....right? I don't see how they could harm aluminum if they got caught in the spray.

Great thread, btw

I wonder about which framesaver is most earth-friendly? I would be willing to bet some of the most effective ones are also ones that introduce PTFE-like compounds into the environment.

Don't mean to derail the thread, and I'm not passing judgement on anyone who uses the stuff. I have used stuff that contains PTFE, and will certainly will in the future. Just a thought.

unworthy1

AFAIK there's no PTFEs in either Tung oil (pure is certainly devoid of them) or a blend with BLO and solvents...or with just BLO ("Boiled" Linseed Oil which contains both solvent and chemical "drying agents").
But if you are concerned with using any "industrial products" such as petroleum-distilled solvents or resins then a pure vegetable-derived oil like Tung or Linseed (if you can find it) would be the closest thing to "vegan".
Oils without additives will take a looooong time to fully cure, but that would not be much of a concern inside a steel bicycle tube. It might be if applied to exterior surfaces.

ehcoplex 

I’ve sourced pure/organic linseed oil from solventfreepaint.com and pure tung oil from realmilkpaint.com
Neither cheap, but good stuff. The tung dries much, much, much faster…

ehcoplex 

I put a few coats of pure tung oil on my stripped-to-raw-steel Holdsworth Pro a couple months ago. I don't ride this one in the wet/rain, but it does live in a kinda damp basement. I've been keeping my eye on it to see if flash/surface rusting starts to happen. There was one part of the top tube that started getting some rust spotting- I must missed it with some of the oiling. Scotch-brite'd it and gave the area a couple coats. Obviously it hasn't been very long, but so far holding up really well I think...

Prowler 

Its been 7 months for this cast iron rotor out in the weather, weeds and dead leaves. I think I'll call it quits. The treated section is starting to rust a bit. I'll never have a bike that will suffer such treatment. I'm impressed with the results.

SJX426 

I am wondering about treating a bare frame with Tung oil I tryied WD-40 but it needed refresh every year or so.
1983 Trek 610 60 cm (24") on Flickr

ehcoplex 

I'd only rate the tung-oil treatment I did on my Holdsworth (see above in thread) as 'so-so'- it's rusting now in several spots. A fair amount on the top tube where I think I must rub the frame when standing over the bike, etc. And also in places where any debris, etc has kicked up on the frame (behind the seat-tube, underside of the down-tube, etc.). So, not particularly 'durable'- I assumed if I decided to keep the frame 'raw' I'd have to reapply at least every season, but now I think I'll strip it again and paint.

merziac

Following around on this and Thin man's current thread.

And as we haven't seen it yet that I see, we need to emphasize the need to very thoroughly strip anything that has been treated for rust, ideally it should be "hot tanked" but I don't think its easy to find anymore and they cannot be too hot for this lest it compromises the brazing, temper, etc.

Lacquer thinner, acetone, etc and the like should be employed with some heat at least.

The same thing that makes these products work is the same thing that will prevent proper paint adhesion, it needs to be completely leached out of the metal before any paint is applied.

Complete stripping, cleaning and drying are all critical for the paint to be done right.