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Framebuilders Thinking about a custom frame? Lugged vs Fillet Brazed. Different Frame materials? Newvex or Pacenti Lugs? why get a custom Road, Mountain, or Track Frame? Got a question about framebuilding? Lets discuss framebuilding at it's finest.

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Old 12-07-08, 01:11 AM   #1
lemondzurich
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My first lugged steel bike - quick question

I probably should have posted here, but I started it here already:

New project

I'm getting pretty close to done actually but was wondering if people drill small drain holes in any of their tubes.
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Old 12-07-08, 01:41 AM   #2
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a drain in the bb seems to be pretty important. Otherwise, did you drill vent holes?
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Old 12-07-08, 08:30 AM   #3
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I agree with unterhausen. drill the bottom of the bb. other than that make sure you have vent holes in all of your joints. spray wd 40 inside the frame whenever its apart.

Last edited by nicolacycles; 12-07-08 at 09:03 AM. Reason: added info
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Old 12-07-08, 08:47 AM   #4
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Looks like you're having fun.
A bit early to be offering frames to others though, you haven't broken the first one yet !

Is the video you posted the dt/ht braze for this frame? FWIW, there are a few gaps in that joint.
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Old 12-07-08, 09:55 AM   #5
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Thanks for posting the links. Hope you are having fun with your project.

Sorry if this sounds critical but the video of the braze joint scares me; you don't have anywhere near enough braze filler going into your joint. The video says something about attempt #2 so did you already braze the joint before and now you are going back to fill voids? I'm a bit of an overfiller myself since I want to make sure the joint is 100% full.

What I recommend is that you get the entire joint up to temperature before attempting to touch the brazing material to the joint - that means all sides of the joint, not just one side. In the video you focused your heat on one side of the joint which will create warpage. Also, use more flux - much more - 3 times are much as you show on the video. This will keep the metal from turning black as quickly as shown in the video.

When you feed the filler into the joint use gravity more to help out. For example, when filling the down tube portion of the joint turn the frame so the down tube is facing up. I recommend you get the entire joint up to temp and then feed a small amount of filler into the joint on all sides, on both tubes, to tack it together so to speak before you go back to the beginning and feed more filler in. The amount of filler you feed into the joint was only sufficient to tack it together - you have major gaps in your brazing and that joint is sure to fail.

The key to getting complete fill on your joints is to feed the filler into the joint on one end and pull it through the joint with the heat until it comes out the other side. For example, feed the filler into one side of a lug and make sure you feed enough until it comes out the bottom. On the bottom bracket for example, feed into the joint on the tube side and watch until it comes out on the inside of the bottom bracket threads. For a joint like you made it's harder to see the filler come out on the inside which is why it's important to feed in filler and pull it through the joint.

Honestly, sorry is this sounds critical but the joint in your video is going to fail unless you did more than what the video represents. Please be safe. If you don't believe me, take a look inside the down tube with a flashlight and look to see if there is filler on the inside of the tube on all sides - there needs to be. I usually have a small puddle on the inside because I'm paranoid about not having enough filler so I overfill so to speak and extra winds up inside.

Good luck and keep going with it.
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Old 12-07-08, 10:44 AM   #6
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A couple of photos illustrating how to judge how much filler to add to a joint.

Take note of the small puddle of filler on the inside of the bottom bracket shell - this filler was fed in from the outside of the joint and pulled down with gravity and heat. Also note the small puddle of filler on the edge of the lug - this is not ideal and will require some scraping to remove. Again, it's fine with me since since I'd rather scrape a little rather than not have the joint 100% filled.


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Old 12-07-08, 11:54 AM   #7
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Nessism - Thanks for the tips. Now that I've gotten the rest of the frame together, my brazing has gotten better and to your point, I now know that joint was underfilled. I've gotten much better at pulling silver from one side to the other as well. (Still have a lot to learn though.)

I'm going to go back and re-braze my early attempts (like the one in the video) and try to get the puddling like you show above.

Thanks again for the tips... let me know if you have any more!
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Old 12-07-08, 12:09 PM   #8
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Quote:
Originally Posted by lemondzurich View Post
Nessism - Thanks for the tips. Now that I've gotten the rest of the frame together, my brazing has gotten better and to your point, I now know that joint was underfilled. I've gotten much better at pulling silver from one side to the other as well. (Still have a lot to learn though.)

I'm going to go back and re-braze my early attempts (like the one in the video) and try to get the puddling like you show above.

Thanks again for the tips... let me know if you have any more!

Good deal on going back and redoing those joints. You need about 3 or 4 times as much filler as you used...no kidding.

Not sure if you have seen Richard Sach's photos but they are very informative as far as photos go. Maybe we need to prod him to make a video or two brazing a joint...you out there Richard? His photos show how much flux to use for example. One caution though, Mr. Sachs is a master and his joints don't show hardly any filler on the lug edge - this is because he knows what he is doing and 1) only adds as much as necessary and 2) he pulls any extra inside the joint. Don't be fooled into thinking you need your joints to look like his; you would be much better off to add too much filler and then have to scrap it off the outside vs. not adding enough and underfilling the joint.

Keep going...

http://www.flickr.com/photos/9866331@N08/sets/
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Last edited by Nessism; 12-10-08 at 08:50 AM.
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Old 12-07-08, 03:08 PM   #9
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Nessism - Just redid both head tube lugs and got the silver to go from top to bottom. It's not pretty, but to your point, I'd rather have to scrape some off than to have a weak joint.

Question for you... I'm still getting some black oxidation. Not a ton, but it's there. Either I can't seem to get enough flux on there or my flame is too hot. Too hot doesn't make sense though since I'm using MAPP and it's not as hot as oxy-ace. Maybe I'm not being fluid enough with my movement and focusing the heat in one place too much? Let me know if you have any tips. Thanks!
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Old 12-07-08, 03:37 PM   #10
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Is there much of a difference between brazing chromalloy and regular steel?
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Old 12-07-08, 04:23 PM   #11
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Is there much of a difference between brazing chromalloy and regular steel?
same
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Old 12-07-08, 05:05 PM   #12
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Thank you, mapp or propane, proper flux and solder? I've done copper home plumbing so I got a handle on the basics, plus been a manual mill machinist for 12 or so yrs so making a frame jig should be easy.
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Old 12-07-08, 10:11 PM   #13
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Paradoxically colder seems to be tougher on the flux. Rather than flicking it with 7000 degrees one is using a lot less heat and cooking, and cooking it. It is harder to bring a large part up to heat because the heat transfer isn't fast enough. This is why it works reasonably well with racks or water bottle BOs, because these parts are often small enough that the heat transfer is pretty much instant. A part that is a little big for propane will flash off quickly with mapp.
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Old 12-08-08, 12:48 AM   #14
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Did you slather on a ton of flux like those eRitchey photos show? You really need to pile it on. I've never used MAPP gas so can't comment. If the problem is related to the flame used you could try black flux, it has more staying power.

To clean up the lug edges get some needle files and go to work. Take a couple of them and dress the tip with a grinder to square them off. Instead of filing with them you can use them as a pushing-type scraper. Works great if you used 56% silver but doesn't work for crap on brass and lower silver content rods. Also make sure you soak the entire joint in water, don't just scrape off the flux on the outside - you used flux inside the joint right? Getting the flux off will protect the joint since flux is acid.

Good luck.
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Old 12-08-08, 09:45 AM   #15
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Nice work.

Those stay braces are going to break really quickly... just a heads up before you paint...

I would remove the cs brace, and not have one there, then redesign the seat stay brace ... needs to be one piece unless you beef up your joining methods.
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Old 12-08-08, 10:12 AM   #16
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Do those braces really take that much stress? What other joining methods are there that would be stronger? My thought was that the angled pieces provided more surface area for the joint and that would be a good thing. Granted, the angle itself creates a concentrated stress point at the inside angle which I was worried about, but I figured it was just scrap anyway and I could always re do it.

I'm actually thinking about just riding the bike bare for a couple weeks to see if everything stays together. Then, if everything looks good, I'll sand it down and then clear coat it.
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Old 12-08-08, 11:22 AM   #17
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Quote:
Originally Posted by lemondzurich View Post
Do those braces really take that much stress? What other joining methods are there that would be stronger? My thought was that the angled pieces provided more surface area for the joint and that would be a good thing. Granted, the angle itself creates a concentrated stress point at the inside angle which I was worried about, but I figured it was just scrap anyway and I could always re do it.

I'm actually thinking about just riding the bike bare for a couple weeks to see if everything stays together. Then, if everything looks good, I'll sand it down and then clear coat it.
I have a bit of a different opinion:
The seatstay bridge will be fine as the bike doesn't have a rear brake, it will see very little stress.
The cs bridge will stress the stays a bit and might cause a break over a long time, but if your stays are thick enough, it should be fine. I don't think the brigdes will break at the points of your brazing was good.

I do like that chevron shape for the ss bridge- Don Walker used to do this a lot in the 90's and you still see them pop up on customs from time to time.
Now, go ride that thing!
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Old 12-08-08, 05:48 PM   #18
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http://www.muggyweld.com/index2.html Check out the powdered siver solder videos, any opinions, experiences with this co.?
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Old 12-08-08, 08:05 PM   #19
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Live Wire - thanks for the perspective. Those stay braces are probably the best brazing I did on the whole bike. First, because they were the last ones I did. Second, because they were relatively easy brazes since there's not a lot of metal there. Also, I fed the silver from the point and drew it down into the V and left a small pool of silver there to try to create a small fillet to reduce the stress concentration there. I guess we'll see... LBS wasn't open today so I'm going to go tomorrow and have them do the reaming I need.

Anyone have any recos for tools for reaming? Might be worth getting some if I make a number of bikes in the future.
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Old 12-08-08, 09:40 PM   #20
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What did you do about checking alignment of the frame? Do you have a surface plate? If not, find a local framebuilder and pay him to check alignment...and coldset as needed. If the frame survives the coldset ordeal, it should be fine on the road...for a while at least.

Oh, and don't even consider letting anyone else ride your frame(s) until you have at least 10k miles on one. Not trying to sound harsh but until you have built at least 10 frames, and have suitable alignment equipment, I strongly suggest you forgo any professional aspirations.
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Old 12-08-08, 10:06 PM   #21
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Wow... 10K miles?! My car hasn't had 10K miles in the last 2 years. Is it the miles that really matters? Would I be better off doing some miles on bumpy pavement, off small jumps (at low speed) or even light off road stuff to test out the strength of the bike? Or is it the slow build of vibrations and low level stress over time that's the bigger indicator?

Also, I haven't aligned it precisely. I've just used my little homemade jig to get everything as square as possible. It seems pretty close given the tools I have at the ready. I think one of my track ends is a degree or two off, but it doesn't seem worth the trouble to cold set that. Is alignment primarily a safety issue or just a handling issue (granted, their somewhat related.)
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Old 12-09-08, 09:25 AM   #22
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Your comment about being willing to build a frame for someone else as long as they foot the costs concerns me. In my opinion, you are jumping the gun big time by throwing out an offer like that before your first frame has even seen a pedal stroke.

Two factors to consider before providing frames to other people: safety of the frame and protection for you from legal action in case a rider is injured. The part about providing safe frames goes without saying and unfortunate reality in our litigious society is that if you are serious about providing frames for other people you “should” protect yourself by having insurance.

My comment about 10k miles is just something arbitrary I threw out. The point is to test the frame under real world conditions for an extended period of time before you put someone’s safety under your responsibility.
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Old 12-09-08, 12:27 PM   #23
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"Wow... 10K miles?! My car hasn't had 10K miles in the last 2 years. Is it the miles that really matters? Would I be better off doing some miles on bumpy pavement, off small jumps (at low speed) or even light off road stuff to test out the strength of the bike? Or is it the slow build of vibrations and low level stress over time that's the bigger indicator?"

It depends what you are testing it for. There are all kinds of failure modes. Is the bike doing long mileages or lots of drops or crashes. Personally, 10K is a lot of use for me, but if one passes a steel frame on to the general marketplace, it could still be in use 50 years from now, one never knows how much or what kind of use it will see. I think it is all so complicated to organize from first principles that a QC approach is more reasonable. One thing about bikes is that unlike building a wooden glider, one is not responsible for the composition of the parts, and there are conventional design details that can be followed. Not to say there is nothing that can go wrong, or experience doesn't play a part, but it is also perfectly possible to get parts in a form that amounts to a kit and a design rolled into one.

"Also, I haven't aligned it precisely. I've just used my little homemade jig to get everything as square as possible. It seems pretty close given the tools I have at the ready. I think one of my track ends is a degree or two off, but it doesn't seem worth the trouble to cold set that."

A degree or two is a big error, not saying anything about your case, but just that degrees are gross errors in the bike world. A degree error in the head tube angle would be a significant change in the design. A degree error in a picture frame joint would be cause to toss it. For a woodworker, minutes will cause signifcant eror over the run of a mdeium sized frame. You have to think in much smaller increments that that. Now whether anything bad comes of it; in a given situation will it just draw in under skewer pressure, hard to say. If it is over a short distance in the drop area it could be pretty resistant to correction.

"Is alignment primarily a safety issue or just a handling issue (granted, their somewhat related.)"

Depends. For an experienced hand it is a final refining step, though it is also a little controversial. For the beginner, it helps to verify quality control and get feedback about how well one is doing with the joints. It could indicate bigger potential problems in the process, and it should be a constant series of checks as the bike goes together.
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Old 12-09-08, 02:30 PM   #24
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Silver isn't very strong in that application (the welded/angles braces). Just my 2 cents.. your idea to ride it a while unpainted is a good one.

Good luck, and report back!
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Old 12-09-08, 04:29 PM   #25
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Thanks for everyone's input. The frame is at the LBS getting the headset put in and getting the seat tube reamed. Hopefully, I'll have it together by the end of the week and can ride it a little bit! I'll send some pictures and an update shortly. (I do know the frame itself was 4.76 lbs though.)
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