Carbon Bike Flaws - Sand Through

[@Alejandro-vg7yt]

And to think that it's so easy/cheap to put a carbon or glass veil as the outermost layer so it serves as a sacrificial/tell tale layer for the sanding operators to avoid them going in too deep. Proper manufacturers do not shy away from even puting a superlight layer of woven glass (sub 20gsm) to help even more. Not to even mention that placing these sacrificial layers help with the surface finish out of the mold in a high volume operation (so less sanding is required), as it allows to vacate bubbles within the laminate by letting the matrix flow in a more free way during curing. Cheers for showing this and explaining that's its not a feature but a sign of bad QC and "less than ideal" manufacturing.

[@steveflor9942]

Point is well taken. I seen so many expensive bikes in showrooms W/ sand through swirl under clear coat. Astonishing..

[@miamatti]

Especially because the glass has better sanding and finishing properties with regards to fraying/fuzzing as well

[@polymerbikes]

Damage like this is prevented in part during layup. The EPS Inner moulding typically helps prevent wavy and bumpy surfaces still Sand-through happens. And on virtually every frame (to some degree). You’re most likely to see at the edges and major junctions. You may find that there wasn’t enough resin at the surface of the part in that local area. Another succinct and credible review, thank you.

[@Hambini]

Hambini's Top Advice,: Just by a Time skylon in bare carbon and you don't get this problem

[@vkzkv]

@@pauljennings3572 Right after some AbsoluteBlack advertisement on Hambini's channel :)

[@Hambini]

@Tadaias Cahill when i can get some gruppo

[@DavidJones-sc6jc]

@Hambuni Is 100% core correct. I’ve have several Time frames and they have been obviously of superior construction. All nude carbon who nearly zero paint. Their nude frames are no joke; it’s not a “cute” decorative 3k weave. It’s the real deal. They (Time) don’t have to hide by paint.

[@Hambini]

Less than ideal... I'll get my coat.

[@thomaslutro5560]

Or as Homer Simpson put it: "I believe I had a hat". :D

[@spdaltid]

Or T shirt.

[@zzzzz1102]

Hurry up with that Time build. Seems the only bike worth buying these days.

[@2mvX]

What does it mean Hambini?

[@rolandovera5935]

This makes me feel better about the material I’ve lost inside the chain stays on my cross bike due to mud and dirt. I figured the chain stay-bottom bracket junction must have tons of material. (Famous last words). Lol.

[@DilbertMuc]

You can buy special metal covers (3M) that can be glued on the chain stays with the adhesive side. They cost next to nothing but still, the companies hardly use them. I have severe chain suck on my chain stay and figured this out the hard way.

[@jaro6985]

Hopefully if its a cross frame, its a heavy frame. Put some clear protective tape on the chain stays if you can.

[@rolandovera5935]

@@DilbertMuc thanks for the recommendation. I’ve seen that product and I tried to fashion a diy version of it… gave up on the effort just did a couple of turns of gorilla tape. Lol. The bike has been relegated to fair-weather all road duties now so it won’t get any worse. I’m keeping the slight damage in my back pocket however as leverage to justify a new cross bike to wife some day. 😜

[@rolandovera5935]

@@jaro6985 that’s what I was thinking too. Cross bike must be a little chunkier in that area of the frame.

[@DilbertMuc]

@@rolandovera5935 Gorilla tape is not good. Too soft and get's destroyed easily.The 3M tape is very tough plastics and is smooth so that no dirt can collect.

[@steveflor9942]

What an eye opener! It would be funny if weren't so potentially catastrophic. Clear coated with intact, unsanded carbon...... for all to see. Close to ideal:) From what I've read: It is OK to clear coat carbon fiber. But, there must be UV filter in the clear coat. Otherwise, UV will breakdown composite resin. It is just amazing they would grind a steer tube like that. Frightening. Great video. Thanks Raoul

[@christianwparker]

BMC has a three year frame warranty while most companies have a lifetime warranty ( track/specialized). Sharp edges and corners have always been a poor design for carbon yet BMC has promoted its angular/square edges as a good design. Even their seatposts have sharp corners that fail as well.

[@sandernightingale]

To be fair, lifetime warranty doesn't mean much either when they exclude almost everything in small print. It's mostly a marketing gimmick.

[@karlwalters3763]

@@sandernightingale Never ever had an issue with Giant. They've replaced lot's of frames for me even after knowing they get raced hard and crashed.

[@87togabito]

I think it depends on your LBS, and how far they are willing to go for you. I had a LBS which didn’t bother to lift a finger to help (basically told me to just buy a new frame), while another lbs which I was way closer with kept pushing till they got my triangle. I think that the manufacturers do really offer warranty which covers for such issue, but most of the time the dealers can’t be too arsed to help so they take the lazy way out

[@durianriders]

good luck getting warranty from many of the big brands. Most frames are so light now they will crash crack before anything else happens. Paint cracks are very common but to me not worth throwing the frame to landfill for it to break down over the next 4000 years.

[@kevinfrost1579]

Educational as ever Raoul just found this in the back catalogue, re-visit your vids so many times. A simple thank you for keeping us all aware and safer for it. Cheers 😁

[@DavidJones-sc6jc]

I’ve had/built several Time bikes and, I’ve have always been floored by their quality of construction. I hope to hell they survive as I’ve little confidence in any mainstream manufacturer of carbon frames.

[@galenkehler]

But is the frame lighter afterward 🤔

[@wasupwitdat1mofiki94]

What about Campagnolo? This marble appearance is a feature with Campy cranks and in some components.

[@thomasvmanning]

That's a different construction type. It is literally strands going in all directions and baked with resin. It's like the fiberglass mat of the carbon world.

[@RyonBeachner]

That may be from a Unidirectional process whereby they basically take a bunch of loose fiber, compact it and inject the resin. It looks like marble because there is no real layup and the light reflects randomly.

[@pmc881]

It's injection moulded fiber reinforced thermoplastic. Same with SRAM cranks. It's cheaper, labour free, and tolerances should be guaranteed. Not used in frames tho ... at least for now.

[@______________4296]

I've just finished hand sanding my Trek MADONE back to bare carbon. It took 30 hours in total, as I was super careful to not touch carbon (for >99 percent of the time anyway). The positive, is that there is almost zero sand-through across the entire frame, fork, seat posts and ISO Speed - just a couple of very small bits on some of the tighter radius corners - and a couple of 'very' small areas I unfortunately introduced.

[@costelloandsilke7321]

Shocking stuff Raoul - great job as always in exposing it - literally and metaphorically. If you look at the side of the BMC downtube at 11 mins - in between your two red lines, the marbling makes a distorted picture of Frankenstein - kind of appropriate I suppose!

[@thomaslutro5560]

Fun fact: Our main cycling publication here in Norway just ran a happy story about the Norwegian industry designer behind the BMC bikes. Wish there were engineers at the helm in the development of bloody any product that has a safety element to it....

[@EllisPedersen]

Industrial Designers are engineers

[@thomaslutro5560]

@@EllisPedersen I take it that engineer is rather widely defined term in english (specially in the US?) In Norwegian it is more narrowly defined, but still involves a good bit of advanced maths and physics. I google translated the industrial design BA program at Oslo Met (stp. is credits): 1st semester Project design office - the designer role BAPD1000 10 stp. Construction and shape BAPD1300 10 stp. Product development; aesthetics and market BAPD1500 10 stp. 2nd semester HSE, materials and working methods BAPD1020 10 stp. Design history and design theory BAPD1110 10 stp. Experimental use of materials and techniques BAPD1400 10 stp. 2nd year of study 3rd semester Project and branding BAPD2000 10 stp. Man and function - product and method BAPD2100 20 stp. 4th semester Cultural understanding and communication BAPD2210 20 stp. Cultural understanding and product aesthetics in a theoretical perspective BAPD2310 10 stp. 3rd year of study 5th semester Dynamic project management BAPD3000 10 stp. Critical reflection in design practice BAPD3100 20 stp. 6th semester Bachelor thesis BAPD3910 30 stp. This does not add up to engineering in the Norwegian meaning of the word.

[@EllisPedersen]

@@thomaslutro5560 I’m actually an IDE student in the Netherlands and my curriculum is like slightly less intense ME with added sketching and project management.

[@thomaslutro5560]

@@EllisPedersen Quite different from the program at Oslo Met, then? The Oslo Met program reads like "how to put put something attractive on the shop floor".

[@ohshitnotanotherknob]

@@EllisPedersen no sorry they are not, their education focuses on design with enough engineering to be able to ask the right questions.

[@mareckik]

I've had few years old Cube Reaction frame painted with clear coat. Whole frame looked like in this video. I also have Scott CR1, from I think 2009/2010, and whole frame is in beautiful carbon fiber cross patern, without any of this crazy, post sending marbles. I also have BMC Team Elite... and I have to say, that i'm very happy because it's fully painted frame and I don't have chance to see this poor quality production method of modern bikes... 😉

[@zwamman]

If I may ask: how was the original paint removed before the clear coat was applied?

[@mareckik]

@@zwamman at Cube frame, there was only few graphics on it. It was black/natural carbon fiber frame. There is no colour added to the paint. Scott is also in natural finish.

[@Dolmar-Rick]

I remember back in 2012 when i had a test bike Giant tcr adv sl, one with bare raw carbon no paint just decals n clear coat. And I have have to say that looked amazing with non of this sand through or funny looking defects... obviously they don't do it as good now and mask with paint it would seem?🤔

[@northkyt]

Ugh. I like metal frames. But I still use a carbon fork. I wish all manufacturers had to run their carbon frames and forks through a scan analysis to discover any voids or flaws. Supposedly Canyon does this, but a lot probably depends on the quality of the scan and the analysis.

[@0mym]

I guess pretty much all carbon bikes have that to certain degree (except for Time), some underneath the paint, some exposed, do they? Should we really be worried?

[@utube7930]

WOW cool marble pattern 😮

[@ulrichr.487]

Very interesting! My BMC timemachine frame shows exactly the same looks at the same spots: top tube, chainstays, downtube. I am riding it since 2015, but i did not put very much kilometers in it, maybe 10k. Until today it works fine, no issues. Fingers crossed 🤞😌 !

[@jonathanbyrd12]

So I have a question. I have two bikes.(road and gravel.) My both bikes are carbon fiber. They're both Chinese knockoffs of specialized. It was a lot cheaper but it was a reputable brand. The one brand was a very good knockoff brand but in their country. I guess it's name brand. When I sanded the road bike it it down it was a perfect weave pattern through the whole bike with a little things that I saw like in your video in the bike. But then the gravel bike was from a different Chinese knock-off brand and almost got lost and took 7 months to get here and when I sanded it, I don't hardly see any weaving pattern at all. When I sand it off the paint. Sometimes I do but most of the time I see very long kind of like that fork you showed the specialized fork or it's a long strip at a 45 and then the darker image going. Another direction I guess is what you said. But the whole bike is like that. And I don't see any weaving the 3D or 4D weaving anywhere. Hardly anywhere on the bike. Is that normal or is that can the bike be not woven like that and just have these long strips of carbon fiber? Is that sound right? Because now it's ugly it doesn't look. My other bike came out great. I sanded it down, polished it put a poly epoxy resin paint job over it. Clear coat and it just pops is other one is just looks like almost looks like metal because it's just looks like different shades of gray going. Which way and what? And all kinds of damage marks like in your video but is that normal or should it have a 3D pattern and I haven't stand it enough? Or did I somehow sanded it off? I doubt I sanded it off cuz I'm very very careful when I do that but it's just weird it looks it has all that marbling in it like you had talked about lots of marbling a lot of those strips of black and white lighter shades of carbon fiber but not it doesn't look pretty at all. Sand it down compared to my other one. I'm excited because now I have a road and gravel bike but I wanted to show off the carbon fiber because I'm not very rich and so seeing a whole carbon fiber bike frame carbon fiber rims carbon fiber seat handlebars everything carbon fiber. It's you know I love showing it off and pulling up next to the someone with their for $5,000 bike in mines. All Chinese knockoff of their stuff and it's good. There's good and bad Chinese knockoff brands out there but this one was a very good Chinese knockoff brand. I've did a lot of research at least for the road bike. The gravel bike was just a no name. It was like 200 bucks for it and I got it but seems sturdy. It's very light but yeah what is up with the bike?

[@17cream]

There are obviously no quality controls, who knows what is under those flashy paint jobs

[@nuttynut722]

this is why spesh pushing the hippy paint

[@pmcmpc]

There is infrastructure in place at most quality OEMs to do this, but the big brands just will not pay for it to be done, and they want to pay so little overall anyway, that quality is almost guaranteed to be poor. Best bet is house brands (I'd include Giant / Merida in this).

[@pmcmpc]

@Nate Dog Trek dealer by any chance? Trek aren't great, and they haven't made anything in the US for a long time. Waterloo is a paint shop for Project One and assembly. Zero production.

[@pmcmpc]

@Nate Dog No they do not. Trek haven't made any carbon bikes in the US for years. You're a shill. The Project One frames are sprayed there. Bikes are assembled and a small number of wheels are laced there. That's it. All production equipment was sold / transferred / mothballed years ago.

[@janeblogs324]

I watched a carbon frame factory tour today. All the workers were sanding the frames, paper face masks covered in carbon at the nose. They were definitely Sanding into the carbon and breathing it

[@antoniop1968]

I got tired of all the chips in my 2005 Roubaix paint so I decided to go clear. After too many hours of hand sanding, I grab my drill and disc and went to town. I have plenty of these aggressive sand areas all over the frame, some scary. My sandthrough looks less dangerous than some of the manufacturing bonding though. This was two years and some 6000+ miles ago and no problems.

[@______________4296]

Oh man, I can't believe you hit it with power tools! It took me 30 hours to hand sand my MADONE, and doing so gives me piece of mind I've not structurally affected the bike. But happy to hear for your sake that you haven't had any issues in spite of a lot of KM since.

[@pmcmpc]

So the 'marble' on naked Factor frames is sand through? Nice ...

[@nathanjimenez1562]

Found some sand through inside the frame of my brand new domane sl5 gen4 where the frame storage is, under the bottom of the down tube. Looks like they sanded through a few plys of carbon my question is why are they sanding inside the frame? and should I send a picture to trek and file a warranty claim. Funny thing is it has a green check mark next to it which I'm assuming means it passed qc even though there's an obvious deffect in manufacturing.

[@MS-bw7yt]

Why is silicone oil so bad? I tought silicone grease is pretty much compatible with everything? Of course ester or polyalkylene glycol based oils are incompatible with a lot of plastics and syntheic materials, but silicone?

[@shibaburn7725]

Yes, I'm wondering about the suitability of silicone grease also.

[@MS-bw7yt]

@Alfred Wedmore okay but how is silicone oil or grease causing delamination, when it normally should be completely fine with any typ of plastic or resin? 🤔

[@MS-bw7yt]

@Alfred Wedmore sorry but thats a description, not at all an explanation. Penetrating and causing delamination... okay sure. But a lot of oils are good at penetrating. So why should silicone oil be especially bad? And what is causing the delamination? Chemical reaction with the resin? Swelling of the fibre?

[@MS-bw7yt]

@Alfred Wedmore okay so basically you dont know an answer. Very helpful smart guy

[@MS-bw7yt]

@Alfred Wedmore sure that makes sense! Because it definitely can mess up the bonding and hardening. Especially when you use it as a spray oil, a thin film of it will be everywhere. But in this case we are talking about a finished product. So thats the reason, why I was wondering about silicone oil being not only bad but especially bad?!

[@event4216]

4:05 why do I see animal muzzle on a carbon steerer?

[@hq355]

Hey Raoul, bring back the yellow marker..😁

[@thomaslutro5560]

A question. I've always assumed the outer mould would be close to perfect, and that the pressure would be close to perfectly pressing the material against it. If anything, I'd expect any deviation from perfect outside shape to be depressions rather than protrusions, and to require filling rather than sanding?

[@davidburgess741]

Your videos make me glad I chose aluminum. However the fork is carbon with aluminum steer tube and dropouts. The fork seems as stiff as the rest of this track bike, so maybe it's over built. I do look at the junction areas for cracks periodically. As a road bike, this one feels amazing on short sharp pitches!

[@SethJayson]

Aluminum is not inherently superior, and depending on design and fab, it's often much worse. It's very tricky to make a strong, light aluminum frame -- though much easier to make a strong, dependable, but heavier one. (welding thin wall materials is really hard) I have aluminum frames I trust, but they're thicker wall, or they've got extra lugs and gussets where the welds are. Fat tube, thinner wall aluminum frames, such as those for racey bikes, do stuff like this: kzbin.info/www/bejne/hpy1qqWLbK11jrM

[@SethJayson]

2:27 for a major crack down the middle of the downtube that was completely hidden by paint. FWIW, KHS stopped making this model of road bike from aluminum after a couple years and went back to steel, so they were clearly aware of the problems and didn't want to deal with Aluminum.

[@davidburgess741]

@@SethJayson I believe that my track bike is of the heavier dependable variety. The welds are much cleaner than that example and there are no bottle bosses Without accessories and with heavy wheels it weighs about 20lbs.

[@shibaburn7725]

Hi. You mentioned that silicon oil is particularly damaging to carbon fiber laminates. I assume that would apply to silicon grease also. Is there any grease or paste that is suitable?. I want to seal up the gap between plastic plugs that I 3D printed and the frame to prevent water ingress. Thanks!

[@blooptastic]

I would seriously hope the sanding is factored into the design, with the top N layers deemed dispensable?! Of course, there's no guarantee that the chaps in the factory won't sand away more... power sanders on a carbon frame FTW 😨

[@DilbertMuc]

No, you can't hope on that. In FEM modelling you calculate the frame strength (amount of different layers needed) to take the predefined loads. You would need to know how much material the factory workers would remove during the process and then add those dispensable layers in advance... and only on those places where the tool can reach. Impossible. So, first you don't know that and second you want to create the lightest stiffest and best super-duper frame that is available on the market without excessive material. That's according to Specialized marketing brochures. I've been to an Asian carbon factory and was sobered up about the work load that the ladies had every day (yep, mostly women were working the carbon mats into the molds). 100% concentration all the time, no mistakes, no material wasted, no time wasted and frame after frame after frame the whole day. But that goes only so far, because they are only human.

[@SethJayson]

I laid up certain portions of my home-build CF bikes that way, but there I'm joining and/or reinforcing CF tubes of known layup schedule, and building from those diameters outward with epoxy-soaked cloth which is compressed for cure -- so there were spots where I'd put on extra layers and sand back -- for instance to reach a perfect OD for nesting into a specific ID, or to give myself several extra layers so I could fair back to a nice smooth transition. With prepreg layups bladder molded outward into aluminum mandrels (is that the standard for most of these?) I'm wondering how they get such a janky outer finish to begin with, and certainly sanding through means losing structure. Even an idiot DIYer like me can understand that. As for the look, well Calfee's enormous doped-tow joins sanded back to smooth curves played on that cool, bowling-ball-finish type look, and "forged carbon" is another phenomenon playing on it. But Calfee's giant, oversized lugs could handle the sand, and "forged carbon" is a style, not a structure.

[@markhutson3265]

There will be a safety factor applied. I don't know what the industry standard would be, but safety factors are standard practice. If we assume a safety factor of 2, the component would have a design strength of double the forces that it's expected to encounter. This gives a decent safety margin and provides some buffer for minor accidents and mishandling. I would expect that the sanding doesn't remove so much material as to negate the safety factor, but this and other manufacturing issue will eat away at the surplus and reduce the overall durability of the frame. In practice you may end up with a safety factor of 1.2 rather than a safety factor of 2 (made up numbers). All reputable brands will also be doing physical testing on frames pulled off the production line to ensure they they meet the requirements set out. So, to surmise; I would expect that the sanding isn't directly accounted for in the FEA, but that it and all other manufacturing issues are indirectly factored into the overall process.

[@DilbertMuc]

@@SethJayson Cold forged carbon... :D))) Love that.

[@a.sarmiento5116]

So the ideal here is uniformed carbon pattern. What if the sander is the one doing it wrong causing uneven looks hence looks delaminated.is that possible? But then I guess ideal here is adding more ply so even in areas of delamination, underneath is more support. If that is for repair you'll trim that then add another ply or total remove it?

[@josephalbanese1393]

Thank you for bringing that to our attention. So what carbon bike can we truly trust anymore?

[@edmundscycles1]

I had a raw tifosi frame . That had zero of this marbled look . I could see the weave was uniformal, I could see on the fork the different directions of the weave but there was no sanding marks but I could see the joins in the carbon . It wasn't an expensive frame and obviously not to a high standard like time but it seems like they at least took some care in manufacturing.

[@luukrutten1295]

So many bikes have varying degrees of sand through. Like nearly all of them. My ROSE bike looked mostly like the BMCs in many places.

[@maddoc68]

Another example for a non-existing qc at the bling bike brands. 😂. Happy with my flawless noname bike with perfect layers under a thin clear coat.

[@jc3496]

Well pointed out. Thank you

[@durianriders]

When the bankers got involved with cycling everything went to shite.

[@eoinfitzgibbon8729]

What’s your opinion on the finish of your SLC

[@andywalford7544]

Surely there is a single non structural lightweight lamination on the outside to allow for just this kind of thing and general wear and tear in general usage? Plus a factor of safety in the design assumptions?

[@andywalford7544]

Accepting that sanding through multiple laminations is “less than ideal”

[@markblanch2905]

You're suggesting manufactures add 2 or 3 plies for that?

[@rolandovera5935]

I was once told by a specialized sales rep that was indeed the case. I was worried about some deep cable rub and he told me no to worry because apparently the top layers were “sacrificial”. He wasn’t an engineer but I did think he was trustworthy. This was years ago however.

[@Factoryseconds123]

Losing 1 ply or a few isn't going to result in instant failure but it does set the stage for future failures, both slow and quick (slow being fatigue failures and quick being an overload event like hitting a pothole at high speed by accident and the frame cracking)

[@felixjackson2670]

Simply not acceptable...especially considering the price tag.

[@luisgarcia22]

I just don’t get it. How is carbon supposed to be so strong when used properly, yet so fragile when these things happen.

[@LuescherTeknik]

It's the same with any material, design and manufacturing is the issue.

[@FiveMinuteVelo]

Different materials have different properties and there are many different properties for each material. In this particular case the properties you're referring to are strength and toughness. From a lay pective they might soundl the same but we engineers treat them as different properties. In simple terms strength is about the internal loads that the material can with stand where is toughness is about how much energy the material can absorb before failure. It is perfectly possible to have a high strength low toughness material and vice versa. In addition the design, manufacture and loading will influence the component strength and toughness. Yes it's complicated.

[@shannondeckard8587]

@@LuescherTeknik But it appears that CFRP bikes need more proper design and manufacturing processes to make them safer. It has been more than a 100 years of Steel bike manufacturing and we can find steel bikes that are still from the 30s/40s that are still safe to ride even after decades of abuse. But have a minor crash even on a properly design and built CFRP bike and the owner needs a specialist expert like you to have it checked out. What if the owner doesn't have someone like you close by? There aren't many experts in this field that can perform such tests. Even if they do have someone local, they may not know that they have to get it tested after a minor crash or is unwilling to spend the money to do so. So please tell me again, why is CFRP still a good material to make bikes out of that the average joe uses?

[@LuescherTeknik]

@@shannondeckard8587 That is the exact point, it is not the material, rather the design and manufacturing. Bad metal frames also fail, good bikes of any material can last a long time.

[@danielmoorhouse6506]

Any news yet on getting some road ridden SL7 forks from viewers in? Surely a quick video asking for them would get you plenty of offers. Seems it's all getting more about t-shirts. Less than ideal.

[@DanTuber]

Would you advise against sanding off a pre painted frame to get it repainted?

[@wasupwitdat1mofiki94]

If you want to repaint anything you should only sand the surface to eliminate the glaze and leave as much of the original coats because they already have good adhesion to the substrate. I know this builds more coats of paint and weight but it will insure your paint sticks better. Even if you have chips that are deep into the primer or substrate don't try to sand them down to even the surface, you fill those spots with a glazing putty first and then sand for an even surface. Ultimately the ideal perfectly even surface will be achieved with the clearcoat applied over the paint by sanding and buffing which will hide a lot.

[@jc3496]

Could it be that the sanding through happened when they removed the paint? Fork specialized

[@LuescherTeknik]

No this is how they supply forks to be painted in a clear sealed condition.

[@cycling8189]

But the frame is molded in that shape, they are not sanding the carbon down to achieve that shape. Don’t they typically do a light surface sanding to smoothen it out on all carbon frames? Most frames that are bare carbon come with a finish like that. But frames like Time with the 3k weave just have a “beauty” top layer of carbon to give it that look. I’m from the aerospace industry and have worked with carbon and for us to achieve that beautiful top layer like Time or Pagani Zonda it’s just a extra top layer of carbon. I could be wrong but that’s what I’m thinking.

[@LuescherTeknik]

That's the point, the light sanding to prep for paint, remove flash etc, is a bit too heavy.

[@zwamman]

Hey Raoul, considering all these sanding issues, what is your opinion on sand-blasting frames for paint removal? (in order to re-paint or in order to save weight) Any risk of removing structural material in that process?

[@borano2031]

You should not use sand as a medium. Nutshell or similar which is less abrasive. ETOE has a video on this topic. Rgr

[@pinny492]

It seems most big name bikes have these flaws, and in practical terms they probably cant be altogether avoided. I wander if there are actually any well known brands that do produce frames largely devoid of such defects?

[@Jon1Surf1Lim]

Perhaps show some examples where a sand through has resulted in a frame failure, as it stands this video doesn’t prove anything has been done poorly that could result in a flawed dangerous product 🤔

[@rolandovera5935]

I agree. I’ve learned a ton from this channel and this guy is clearly very knowledgeable. But it is a reoccurring theme, point out all the flaws but never commit to saying something being dangerous or unsafe to ride. That said, I know there are horror stories out there about spontaneous failures for apparently no reason. I’ve witnessed one myself on a brand new bike. And look at Canyon and Specialized who just recently issued recalls. Maybe he doesn’t go there for legal reasons. I take his videos as informational but not prescriptive I guess. But you make a good point.

[@robertp7209]

@@rolandovera5935 there is no way he can make such a prediction, there are too many factors involved, just like how heavy a rider is, the terrain, if one hits a hole or road crack. And just how many times. If the manufacturer’s design compensates for it with added structure, fine, but we don’t know that. Most certainly, one can readily get out of hand doing the sanding with those tools, so much like why auto lug nuts seem always over tightened, thanks to hammer wrenches. Even at dealerships. Which should never to used for such work of torquing bolts. I would think the injury lawsuit settlements are kept confidential for several years.

[@christoingram]

So what you're saying is we should only buy frames that are painted in opaque colours? Ignorance is bliss right?

[@FiveMinuteVelo]

In my experience they use a belt sander not a disc sander. Is that what you meant? Sorry about being so picky about the details. Nevertheless it doesn't really change the impact of your examples.

[@LuescherTeknik]

I have seen both used, however the majority were 3" disc sanders, it might have changed now.

[@crumptoncycles]

@@LuescherTeknik Almost always a 3" DA sander. Belt sanders dig and score. Contrary to what you want in paint prep.

[@AandA697]

Nice, but what's up with the clapping at the end? 😅

[@markblanch2905]

What was the clap Raoul?

[@RyonBeachner]

probably where he meant to edit something out and just accidentally missed it.

[@treyquattro]

getting camera to focus

[@RollingnBodfish93518]

This is dangerous ladies snd gents. Whatever happened to nice soft wet sanding by hand ✋ with 3k, 6k or 10k paper?

[@markblanch2905]

Skills. Sheer ripoff profit over integrity

[@shannondeckard8587]

Tell me again why CFRP is a good material to make bikes out of? Isn't CFRP supposed to be stronger and never fatigue?

[@LuescherTeknik]

Any material with flaws can fail, it is a design and manufacturing issue not a material issue.

[@HolmsOnBikes]

That's like a baker burning a cake and you blaming the ingredients. It isn't the carbon fiber's fault, it's the manufacturer's fault.

[@wasupwitdat1mofiki94]

@@LuescherTeknik My titanium frame is never going to fail. USA made titanium and a US custom welder built it. 😁

[@robertp7209]

@@wasupwitdat1mofiki94 welds can fail, were the welds xrayed? No they were not, you know why? Not for bikes. $$$.

[@RyonBeachner]

@@wasupwitdat1mofiki94 Titanium bikes are prone to cracking, and it’s not always at the welds. Feel free to google around. They’ll typically last quite a long time until it happens, but it’s something to be aware of. My buddy just had his custom Ti bike fail fairly spectacularly in the down tube/BB junction after 6 years.

[@danbanham728]

"what is the result and the effect on the structural properties?" I can answer that... it's less than ideal.

[@paulhyland4653]

Good informative video thanks 😊

[@phoebetan7519]

Sharp edges is the entire BMC design ethos. Alrighty then, no BMC carbon bikes for me!

[@nationsnumber1chump]

Watches video. Checks 2017 Specialized Crux fork. Cries. 😭

[@nationsnumber1chump]

I wonder if they'll give me a refund

[@borano2031]

@@nationsnumber1chump Most probably, they´ll send you the "Crux Fork Fixing Kit". Not the same as "SL7 Fork Fixing Kit". Rgr

[@Jojoairbus]

Oh shit, my whole bike looks like that... Now I´m a little bit worried, using it since 2016.

[@WowRixter]

I'm surprised this passes QA😱. It's so obvious, not even hidden within the tubes

[@wasupwitdat1mofiki94]

@13:35 My man has a brain cramp. Sorry, it happens to me too all the time.😉

[@shekofriends]

Makes one to seriously consider going back to alu frame or even Ti. This I know can't ever happen. Like they said can't turn back the clock.

[@xxcusme]

that particular marble-pattern salesman dislike this video

[@ebigarella]

Bike industry solution to this problem "let's paint the corners"

[@davemellor4697]

Raul...you are as dry as a desert,but i like your style!

[@ulaev]

This bmc is one of best looking bike ever. No problems at all.

[@DilbertMuc]

Specialized recently had a series of bikes with just clear coat and decals only. You could see all the layers ... and nice marble art. (Just kidding ;)

[@msagoo29]

I still don't trust carbon mtb handlebars. I trust the material, but not the quality control in mass manufacturing

[@SethJayson]

Wow that's bad. It's not cool marble material, it's badly-varied layers which you've then futzed back to smooth! I had no idea this was available on commercial bikes. You can do a better job at home wrapping tubes with doped cloth and compressing with cling wrap!

[@SethJayson]

And that specialized fork is worse than cheapos I've purchased straight from China.

[@lucblain7957]

I don't like sand, it's coarse, rough and irritating...

[@waynosfotos]

Star wars

[@ybratley]

and it get in everywhere😂

[@FaiscaaaH]

BMC most expensive bike always has the worst crap carbon frames...

[@chrisko6439]

This is too fast for playing it at 1.25x speed 😁

[@larrbrown7277]

Steel is real carbon💩💩💩

[@foundfoundfound1]

carbon, as a material, is less than ideal.