Metallurgy For Cyclists – by Scot Nicol - article comments

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To prevent article pages from being miles long, but preserve all the useful questions and answers provided over time, I've decided to copy/paste the website comments to the forum - and "move" further discussions here.

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Metallurgy For Cyclists – by Scot Nicol

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If you can't find the answer to your question in this thread, please open a separate thread with your question/problem, in an appropriate forum section (this is the Frames, forks & seat-posts section).

Relja
 
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  1. Nando
    05/07/2021 at 10:42
    Interesting Article; it should be integrated by exploring the cost to manufacture a welded Steel or ALU frame vs Carbon Composite. By keeping apart the evident design freedom in favor of the 2nd one, and all the discussion about the materials Lightness, Stiffness, Elongation, Strenght it would be intersting to know each materials and manufacturing costs to see how much justifiable are the price of modern Carbon Bikes vs “vintage” Steel ones for whom bikers that aren’t so interested to extreme lightness. In other words, how much a “classic framed” but light steel race bike would cost compared to same made in different materials keeping into account their Manufacturing cost ? Which is the reason why steel isn’t so popular anymore ?
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      Relja
      05/07/2021 at 12:41
      Hi Nando,
      That’s an interesting line of thought, but I see a huge number of potential caveats.
      Without going into politics or ideology, one of the first things to start with is “The Capital” by Karl Marx (Amazon affiliate link… and a touch of irony 🙂 ).
      There, he does a thorough analysis of the market and capitalism, including the cost of making any products.
      Then, we can throw all that out of the window 🙂
      because, the way I see it, the modern market is primarily run by marketing (irrational, manipulating advertising, chasing after the people’s desires and fears).
      Price paid for any brand-name product, including the high-end hand-made steel frames
      is determined (limited) by how much a certain amount of people are willing to pay for it.
      Costs to produce, as defined by Marx, are only the lowest limit, below which a product won’t be produced at all (or all the manufacturers will quickly go bankrupt).
      Light sells well in the cycling world, so lighter materials are more sought after, most people believe a lighter bike is always better, and faster (in spite of the “engine’s” condition, as far as I can see 🙂 ).
      Buyers justify the prices. At least in capitalism. Everyone wants to have a bigger pay, a greater profit.
      If they can sell at a higher price (and no long-term goal is compromised by such a pricing policy) – they will.
      That’s without getting into the politics, the wastefulness and pollution caused by our current economic system, and the displacement of many jobs to the countries where people are very poor, hence willing to work for a lot less.
      It’s not black and white, no one is really evil there, they’re all just trying to stay afloat – if you aren’t growing, you’re getting taken by the competition.
      But the result of that is that we (the cyclists) are getting… brainwashed? into believing that all the modern gadgets are cool, better in every way, “a must-have” – and that we should be happy to pay more for that awesome stuff (it often is quite good, but not always, and not in every way – at least in my opinion).
      P.S. I grew up in great scarcity (no money, and no goods available to buy even if you had any) and have learned to value the amount of freedom and independence that simple, durable and robust things, that you can repair yourself, give. Learned that all one is used to can disappear overnight. That does still play a part in my buying choices, quite often. I’m not a good consumer – if all the people were like me, everyone would go bankrupt (except the bike shops, tools and book stores). 🙂
      Developed country cyclists and bike shops got a small taste of that over the past two years when the demand has far surpassed the supply and everything was difficult to come by. My friction shifting bikes could take practically any cassette and chain available – while many other cyclists have had a lot more trouble getting the right spare parts.
      Relja – the 5c-economist, and 10-pence philosopher 🙂
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    Nando
    14/07/2021 at 12:00
    Dear Relja
    I appreciated your comment that I fully agree.
    I have 2bikes (+1 of the 40s from conservative restoration ): a first love steel framed “Colnago” 30y old on which all my rides are written and from which I would never want to divorce and a Carbon MTB which was replaced the “ guaranteed for life” frame from the Producer (serious Manufacturer) because the original Carbon frame broke after 2y of soft usage (seatpost tube cracked !!).
    Based on that experience if have to look for a steel framed race bike and benefit of the undoubtful modern Bike technology advancing, which Premium manufacturer still propose it and @ which rational price ? Exactly your concept for “simple, durable and robust things….a lighter bike doesn’t overcome a good “engine’s” condition 🙂 ” .
    But OK, you perfectly summarized the Market push and Bikers desires (which “Chicken or Egg” comes first? However I think both are achieved, especially golden eggs !!! ) and also I very much appreciated the Market Independent Scot Nicol but Technical article.
    Bike it’s especially a philosophic matter where fatigue and its satisfaction meet
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    mike
    23/08/2021 at 10:27
    carbon fibre bikes are fine for race days and thats where they belong,its not really a good material for town bikes and city riding.
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    mike
    12/05/2023 at 10:06
    Hi Relja,I am painting a couple of chromemoly retro bicycles,here is what i intend on doing,strip frames back to bare metal then rough it up abit with 180 grit paper,then use an acid etch solvent based primer,then just do two final topcoats of industrial solvent based fast drying enamels,its the stuff they use for painting tractors and forklifts,heavy duty industrial stuff,one retro bike did have an epoxy primer on it followed by acrylic topcoat and then a clearcoat,the other old bike was previously painted with just solvent based enamel and i think it was baked in the oven after that as the enamel was quiet tough,i did paint one bike years ago with acrylics and clearcoat but that stuff was not very durable,just wondering if you have any tips cheers
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      BikeGremlin
      12/05/2023 at 10:46
      Hi Mike,
      I’m not an expert for painting, so take all I say with a grain of salt. Also, the quality of paints available in my country is… colourful. For example, practically every spray paint (one you buy in a pressurized can) is of poor quality.
      One option that worked well was to have a frame sanded, then powder-coated (plastic baked-on practically). That is quite good and durable. But I prefer the look and feel of real paint.
      For painting, preparation is 90% of the work. It makes sense to roughen the surface a bit with some sand paper, or scotch-brite (it may be an even better choice for just roughtening the surface for painting, if all the rust has been removed).
      I have no idea of a good primer to recommend. 🙁
      I can say that oil-based paints take ages to dry, but are tougher and more durable compared to any nitro or water-based paints. At least in my experience. The problem is you need a dust-free environment until they dry. At least for the finishing layer (for the first one-two layers, I suppose you could use some fine sand-paper to smooth it up before painting the next coat). Supermarket 95+ % alcohol works well for degreasing.
      Clearcoat on top sounds good.
      Relja
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    mike
    12/05/2023 at 13:41
    Hi Relja,thanks for that,I did think about powdercoat but the cost was an issue there and i do prefer paints,easy to re-do stuff down the track if you make a mistake,totally agree with you about those rattle can sprays not being the best quality but some are improving,its just hard to find the right ones,its been a try and see thing with me and i did throw away a few cans,they just were not up to the task,but i did finally manage to find some good products,i basically ended up getting all solvent based ones,they are not classed as being oil based nor acrylics they have other very strong solvents that dry enamel paints rock hard after drying and they dry fast,yes that dust is allways an issue so i just except that and give him a light sand after drying,i did see epoxy primers and epoxy enamels but there is no way to get that stuff off if you need to re-do anything,i was surprised these old retro bikes had no rust after 40 odd years,cheers
 
  1. mike
    14/05/2023 at 06:40
    the easy way i found to remove enamel paint from the chromemoly bikes was to simply scrape it all off using the side part of a nice sharp paint scraper,if i came across a tough bit i then hit it with a heat gun but the side edge of the scraper did most of the work,the harder bits like around lugs and welds i just used the point on old scizzors to dig that out,using acid etch primers you cant leave any paint on bike at all,acid etch primers are quiet good,they give a nice bond for the topcoats,some etch primers you can directly paint your topcoat on top,normal metal primers just dont stick well enough,so after the acid etch primer i will just topcoat that with tractor and forklift enamel,they have some nice colours,john deer green,catapillar yellow,saphire blue,if its good enough for tractors it will be more than good enough for bikes
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    mike
    17/07/2023 at 08:50
    Hi Relja,I did heaps of researching and talking to auto body painting professionals and they are using the good high end paints,2 pack system and some bicycle frame builders are also using the 2 pack system,its basically an epoxy based paint,this is the best paint on the market however this paint is not for the home diy fixes as it is extremly toxic and you need a full body suit and a oxygen fed mask and proper spray booth,i did come across another paint range that does a reasonable home job,1k acid etch primer and surfacer,than topcoat that with acrylic lacquer paint then put a 1k clear over the top,it gives a very nice looking finish,they painted cars with this gear years ago,one other option is to use a clear over base auto paint system,for $250 australian i bought enough custom made up rattle cans from a local auto paint supplier and i have enough to paint 3 bikes,the acrylic lacquers give a very respectable home finish cheers
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    mike
    18/07/2023 at 05:46
    Hi Relja,the 2 pack system is highly resistant to fuel and other solvents and is very durable and it is also made in rattle cans,the 1k acrylic systems are not resistant to fuel and solvents but they are much easier to work with and cheaper,the 2 pack system has an activator/hardener at the base of the can and you have a limited time frame to use it once activated,the 1k acrylics are very to work with and fast drying,it would be almost impossible for the home diy to use anything other than 1k acrylics due to 2 pack system being very toxic and the longer drying times,auto paint stores carry a whole range of paints,they even can mix up custom colours to match anything but these paint are mostly acrylics,either 1k acrylic lacquer or acrylic clear over a base colour,cheers
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      mike
      31/07/2023 at 08:44
      Hi Relja,just been to a powder coating place to get a retro bike coated,the price for basic solid colours is $150 Australian,if you want other powder coating effects its around $400 ,for this price they do sandblasting as well,so if you just want a white coloured bike or similar its much cheaper than any painting,the same place i went to also does the auto 2 pack paint system but he has powder coated alot of bikes and he said powder coating is much more durable so its no more messing about with spray cans,sometimes we just need to let the professionals do their job,i thought powder coating would be expensive but it is the best option for retro steel bikes cheers,ps you were right about the spray cans as they are not durable enough
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    mike
    21/07/2023 at 12:00
    Hi Relja,I have been trying out quiet a few bicycle shops lately and what I am finding they seem to be only interested in selling you big stuff to make money,one thing alot of bicycle stores lack is experience and good quality service,they just dont have that passion for bicycles and I think what lets them down is they only have very limited suppliers they can call on,dont get me wrong there are some very professional shops out there,I just went to one awesome simply awesome shop that not only sells new bikes there are two yes only two guys working at this shop but nothing is too big or small for them,one guy custom makes any type of wheels,the other guy the boss handmakes lugged columbus frames any size,I just had one retro steel bike that had damaged rear brake bridge,not a problem for them,they brazed in a new brake bridge at a very reasonable cost,when i picked the bike up i had another small problem with a thread on the bike,not a problem he re-threaded that while i waited,these guys and their fathers before them have been building columbus tubing frames for a very long time,50 plus years or so,pretty much they will do anything bicycle related,they are a wealth of knowledge,nothing is too hard for them without all the bulldust that you find in some shops,it was very refreshing to find folks so passionate about bikes,,just like you are Relja very passionate about what you do,you are a rare breed as well,when this carbon fibre fad is finished i would love to see the old bike building come back,i talked to a few bike riders and other shops around the bike shop,all plus A1 reports about this bicycle shop,they are keeping the craft alive,columbus tubing is still going strong but i do not know what other tube makers are now doing,I will go back to this bike store to get a custom made columbus tubing bike,their work is very high class,no mistakes here cheers
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      mike
      10/08/2023 at 14:33
      columbus tubing is still a family run setup in Italy as far as i know,they are now making high end modern tubing,most of the older tubing is finished,reynolds tubing is in england and still operating,they too are now making modern high end tubing,i think tange tubing is no longer about,but i do see alot of american frame builders are making their own type of tubing,they are making some nice frames but i see alot of small medium and large ones,still nothing like the old retro bikes,to get a decent taller bike you still need to go get one custom made and thats quiet expensive,cheers
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    mike
    10/08/2023 at 14:17
    Hi Relja,just got a bike back from the powder coating guys and I must say its the best finish i have ever seen on any bicycle,awesome finish,simply awesome,the only thing that you need to do after powder coating is you need to clean out a few threads as the powder coating is thick,the guy said he would mask up the threads but that did not happen,they have a big turn over so i guess they just dont have the time to mask stuff up,anyway i can highly recommend powder coating for the older retro bikes,very pleased with the end result,far better than any paint job cheers
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      mike
      12/08/2023 at 07:27
      Hi Relja,if powder coating older steel bikes you do need to chase out all threads with a tap,the ones that work the best for removing thick powder coating from threads is called an intermediate tap,this tap tool has a taper on the end and it cleans up threads nicely,you simply cannot do this with anything else,the tap tool for the derailer hanger is size M 10 with a 1mm thread pitch,the one for the bottle cage bolts is M 5 with a 0.8 thread pitch,for the crank area i did mange to clean that out using an old bottom bracket cup,they do sell a thread tool for that as well but it costs way too much,i just used oil there and threaded the part very slowly bit by bit,it took alot of work but eventually i got there,i will go chase up the special threading tool for the bottom bracket,alot of bicycle places do have that one,if i go get any more bikes powder coated i think the best thing to do would be to leave the bolts in the bike as its being powder coated,like anything we do Relja its all apart of learning and jumping in and trying new things cheers
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      BikeGremlin
      12/08/2023 at 07:48
      Hi Mike,
      For powder coating, I screwed in old cup-and-cone BB cups to keep the BB threads clean. The other threads are relatively easily cleaned with taps, I just wanted to avoid having to start taps on the very fine BB threads covered in plastic.
      An old BB cup with cut slots in the threads (with a “dremel” disc) works OK as an improvised thread cleaner.
      Relja
 
  1. mike
    12/08/2023 at 11:00
    Hi Relja,thats a real good tip to dremel out the bottom bracket cup,R J the bike guy on youtube did that with a thread but i have never tried it and i was not sure it would work,will try your tip on the next one cheers
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    mike
    09/09/2023 at 16:32
    Hi Relja,hows the weather over there,its just coming into spring down under,very nice bike riding weather now,just made myself a chain stay protector,got small diameter tubing from plumbing section at hardware store,cut that down the whole length with hacksaw blade,then fitted it over drive side chain stay,hit it with the heat gun just enough so it followed the exact shape of the chainstay,i also made a gap so i can remove it,the heat gun trick worked very well,i did not not have any paint laying around so i just got a texta colour on it,looks good,i think i also solved my chain drop issue on my 1×8 system,bought a chain guide from amazon called MUQZI,this one will fit most bikes with any size front cog and where it clamps around bike tubing it covers a few different size tubing,most other chain guides i had a look at were limited by the front cog sizes and they only covered one size tubing,this one is good quality cheers
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    mike
    12/09/2023 at 08:58
    Hi Relja just wondering if you have ever tried a home made rim tape like gaffa tape gorilla tape etc,I have a skinny rim where the rim holes go up the rim wall abit and my usual rim tape being zefal cloth tape and nylon reusable ones slide around and expose the rim holes and i get flats,some of these new double walled alloy rim have angle drilling so the holes go up the rim wall a fair bit,i have seen some youtube clips of guys cutting gaffa tape to size from a wide roll and just wondering does it last cheers
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      BikeGremlin
      13/09/2023 at 08:25
      Hi Mike,
      I’ve often resorted to the cloth sticky tape (keper in Serbian). It has worked well.
      Anything that doesn’t stretch (like electric insulation tape) and is sticky should work OK.
      Haven’t tried gorilla tape though. If it stretches before breaking, it won’t protect the tube from getting cut on the valve holes of double walled rims. Especially on narrow high pressure tyres.
      Relja
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    mike
    13/09/2023 at 11:50
    Hi Relja thanks,I have some T-rex gaffer tape,gorilla tape and another one called bear gaffa tape,will give these ago and see what happens,i did try insulation tape before but that was not sticky enough or strong enough,these gaffa tapes should do the trick,i am not wasting any more money on shop rim tapes as they are only good for flat bed rims,if this gorilla tape works its only $12 per roll for about 10 rim tapes,i got it in a wide roll and just watched a youtube clip on how to trim it exacty to the right size while its still on the roll,cheers
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    mike
    14/09/2023 at 06:03
    to trim the tape you just get a small length of 16mm thick piece of wood,then clamp a stanley knife blade to that,then lay the roll of tape flat and spin it around and at the same time feed it onto the blade,it cuts perfectly,alot of youtube clips about it,just search for diy rim tapes
 
mike
18/09/2023 at 07:36
Hi Relja,after extensive research on using home made rim tapes its the gorilla black tape that folk have been using for years without any problems,even some wheel builders are now using it,both on tube tires and tubless setups,shop rim tapes are just too thin or they lack enough stickyness,gorilla tape wrapped twice around the rim does the trick,gorilla tape is a top of the line gaffa tape,very good adhesion and it says its weather proof,it layed down quiet smooth on my skinny rims with zero wrinkles or bubbles,it layed down alot better than the other duct tape that i used cheers
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    mike
    25/09/2023 at 12:17
    Hi Relja,i have put my front chainguide to the test over very rough bumpy ground,my chain does not drop anymore,what i think was happening on my 1×8 system before the chainguide went on,was the weight of the chain was enough to pull the rear mech foward over rough ground and at the same time it would bounce off the chainring top,i do read that some folks run a clutched rear mech and a narrow wide chainring,but even with that setup they still get a chain drop,i am just using a front chainguide with nothing else,zero issues so far,cheers
 
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