Hairy Posted January 18, 2015 Posted January 18, 2015 Dammed GoLefty, I really love it when you get all technical
Ryanpmb Posted January 19, 2015 Posted January 19, 2015 Its not necessary to protect a steel frame unless you intend to immerse it in salt water for a year.Yes there will be corrosion from your sweat and sea air if at the coast but these steels are essentially stainless steels so the corrosion is not severe.If you want to add weight and attract dirt and other crap then coat the frame as suggested. your choice I never sealed one of my first steel frames that I got. I stripped it down after about 6 months and there was signs of rust inside the bb, head tube, seat tube - basically any contact point. Sure, as you say, they're not going to fall apart anytime soon but it the corrosion was still there. Weight - really - its a spray inside the frame. Wear short finger gloves if you're that concerned about weight... They do corrode. Use anticorrosion coating of sorts - why not?...
GoLefty!! Posted January 19, 2015 Posted January 19, 2015 If you had greased the components that fit inside the frame you would not have had the problem. I'll say it again because the "experts" can't read. Chro mo Steel will develop a surface layer of corrosion that prevents further corrosion. Anti corrosion coatings designed for the automotive and industrial industries are designed to be cleaned off and reapplied. Those that are not are heavy(bitumen based). Reapplication is necessary because the light coatings trap acids and other harmful compounds and therefore need to be removed according to a maintenance schedule and reapplied. You cannot clean these coatings out of your frame once it's there.... Maybe you get it now but do as you wish
rudi-h Posted January 19, 2015 Posted January 19, 2015 i'm not a corrosion expert, but the "surface layer" of rust that you all mention on a chromoly frame that prevents further rust... i don't know if my material science lecturers would agree with that. If you can essentially prevent the need for corrosion protection by using an low alloy steel such as 4130 chromoly, that would surely be used in structural and construction applications wouldn't it? the cheapest steel that I know of that does not require corrosion protection and only suffers of "surface rust" is 3CR12 which contains around 10% chrome if I am not mistaking. I would like if somebody could elaborate on the anti corrosion properties of 4130 chromoly and why it is virtually only used for bicycle frames if it has such great all-round properties.
guineapig Posted January 19, 2015 Author Posted January 19, 2015 If you had greased the components that fit inside the frame you would not have had the problem. I'll say it again because the "experts" can't read. Chro mo Steel will develop a surface layer of corrosion that prevents further corrosion. Anti corrosion coatings designed for the automotive and industrial industries are designed to be cleaned off and reapplied. Those that are not are heavy(bitumen based). Reapplication is necessary because the light coatings trap acids and other harmful compounds and therefore need to be removed according to a maintenance schedule and reapplied. You cannot clean these coatings out of your frame once it's there.... Maybe you get it now but do as you wishThe acids and harmful compounds - will they cause any corrosion? I was also under the impression that the frame would develop surface rust which prevents further corrosion. Thanks to everyone for adding to the confusion
Firozfx Posted January 19, 2015 Posted January 19, 2015 I concur with Golefty. Reignited my metallurgical brain cells. They dying here in government. You will only get a surface layer of minor rust. Unless you riding in the beach water, there is no point in doing any rust protection.
JXV Posted January 19, 2015 Posted January 19, 2015 Living durban everyrhing gets coated in salt spray which is flushed down into the frame via breather/drain holes and seatpost when you wash it. The worst corrosion occurs around the bb where that water settles....btdt. It may not be enough to shorten the bike's life but purely for peace of mind I would treat it. I go with Rudi's comments about 3CR12 and have used it very successfully for walkway gratings in a coastal facility. It develops an unsightly rough layer of surface rust and then stops....Ignore that BS about acids and stuff....what is the source of these mysterious 'acids' and how would they get through the waxy tectyl layer to the steel and how would NOT treating the steel impart greater resistance to them..... And btw tectyl is designed for permanent application...... Anyway do whatever you like. I have a 20 year old Giant cromoly frame that is still ok without treatment but it was a mission to get the BB out of the rusty threads when it needed changing.
GoLefty!! Posted January 19, 2015 Posted January 19, 2015 i'm not a corrosion expert, but the "surface layer" of rust that you all mention on a chromoly frame that prevents further rust... i don't know if my material science lecturers would agree with that. If you can essentially prevent the need for corrosion protection by using an low alloy steel such as 4130 chromoly, that would surely be used in structural and construction applications wouldn't it? the cheapest steel that I know of that does not require corrosion protection and only suffers of "surface rust" is 3CR12 which contains around 10% chrome if I am not mistaking. I would like if somebody could elaborate on the anti corrosion properties of 4130 chromoly and why it is virtually only used for bicycle frames if it has such great all-round properties. 4130 is used in many structural applications.Airframes, motorcycle space frames. race car space frames (Rally cars etc).Especially in airframes, good fatigue and corrosion resistance is important
GoLefty!! Posted January 19, 2015 Posted January 19, 2015 Living durban everyrhing gets coated in salt spray which is flushed down into the frame via breather/drain holes and seatpost when you wash it. The worst corrosion occurs around the bb where that water settles....btdt. It may not be enough to shorten the bike's life but purely for peace of mind I would treat it. I go with Rudi's comments about 3CR12 and have used it very successfully for walkway gratings in a coastal facility. It develops an unsightly rough layer of surface rust and then stops....Ignore that BS about acids and stuff....what is the source of these mysterious 'acids' and how would they get through the waxy tectyl layer to the steel and how would NOT treating the steel impart greater resistance to them..... And btw tectyl is designed for permanent application...... Anyway do whatever you like. I have a 20 year old Giant cromoly frame that is still ok without treatment but it was a mission to get the BB out of the rusty threads when it needed changing. Which tectyl do you refer to Mr. tectyl Expert? source of acids? Sweat, rain water, I assume you are talking about aerosol applied Tectyl. Its paraffin wax based with a healthy dose of tackifier, and anti corrosion additive.Anything non aerosol and that needs to be applied with a brush is likely bitumen based or based on a high ISO base oil. you seem hung up on Tectyl. You running a special this week?
Loose cog Posted January 19, 2015 Posted January 19, 2015 I restore old steel bikes and have bought a couple from the coast. Never seen any major rust in tubes even for 1950's frames. Personally, I wouldn't recommend any interior treatment but would recommend that you take the stem and seat post out of the frame every 2-3 years or so and apply thin film of grease to stem and seat post before putting them back. Remove the BB and do the same every 5-8 years. Make sure when cleaning the frame you don't let excess water into mountings for bottle cages and don't power wash the BB, crank. These are only areas where water gets into frame. Some steel frames from days gone by had cutouts in their BB. This was meant to drain water out of the frame. Take care of these frame as they could rust the BB lugs.
quintonb Posted January 19, 2015 Posted January 19, 2015 I'm with Loose Cog here. Coat the frame or don't, personal choice, but do lubricate seat posts, BB's and stems. Down here in Durban I have always used copper slip. I find grease tends to go waxy after a while. Copper slip doesn't. I have a few old steel frames and I don't coat them inside the tubes, but I copper slip every single screw on each of my bikes.
JXV Posted January 19, 2015 Posted January 19, 2015 Which tectyl do you refer to Mr. tectyl Expert? source of acids? Sweat, rain water, I assume you are talking about aerosol applied Tectyl. Its paraffin wax based with a healthy dose of tackifier, and anti corrosion additive.Anything non aerosol and that needs to be applied with a brush is likely bitumen based or based on a high ISO base oil. you seem hung up on Tectyl. You running a special this week?Sarcasm unnecessary ...I'm just trying to help the OP here with real info based on decades of engineering experience in Durban climate. I mention tectyl because it is locally available but other brands also OK. My choice - Tectyl 506 spray because I have a can of it in my garage. Used successfully on several home-built windsurfing trailers to protect the inside of the steel tubing....and a few classic Landrover chassis among other projects. Avail at many hardware and car spares places in Dbn It is a thin liquid spray but sets to a tacky waxy finish. Useless for external but great for internal coating of steel frames and tubing Apply thinly if you gonna use it and clear out the drain holes after it sets cos it will block them before it dries and sets. If the bike will be used for beach and coastal rides I would protect it, otherwise maybe overkill. I would rather have zero rust in my frame than have to explain the internal surface rust away when I try to sell the bike in future. Happy for anyone to disagree ...personal preference prevails.
RogM Posted March 14, 2019 Posted March 14, 2019 Doing a bit of research, as I am respraying a steel frame.. Came across this: https://surlybikes.com/info_hole/spew/spew_care_and_feeding_of_your_steel_frame
Recommended Posts
Archived
This topic is now archived and is closed to further replies.