Tig Steel from zero

[schollen]

Well, i gave it my best shot and after another 3 hours of trying to weld it without burning a hole i gave up and just brazed it. I think the seat stays were too large of diameter (16mm) for the 28.6 mm seat tube. they were almost butted up against each other compared to my last bike where i used 14mm seat stays and could more easily weld the two stays. i think this welding job was a little bit above my skillset. as i started coming into the narrow section between the stays my bead kept pulling away from the junction of the stay and seat tube. Anyway i ended up tossing a bunch of flux in between the stays and brazing the final gap. this was my first attempt at a fillet stylebraze and its pretty ugly but i think after some (a lot) of cleanup it will look ok.

IMG_20131108_223220.jpgIMG_20131108_195025.jpgIMG_20131020_231619.jpg

[schollen]

Last picture above was the wrong one, heres the right one:

IMG_20131108_194959.jpg

[GEBLA]

Hi Scott,

it seems you do not backpurge? If not, consider it. It makes welding tiny spots much easier. It is not needed for not too thin tubing, but since it makes a better weld and is easier too, I do it on all of my frames.

Greetings,
Georg

[Amaro Bikes]

Scott.

The ss situation you mention is pretty common and sometimes you might even have to deal with slightly compound miters, it will depend on tube diameters/position. And yes, it's a challenging time!

My advise would be that before frustrating yourself too much with this kind of situations with a complete frame, make a lot of practicing hours with "normal" straight gauge thick tubes on tight and difficult angles/positions, an once you feel more comfortable with the torch you can step forward into getting hands into the complete frame and then concentrate in the specific questions of it without having to keep your mind busy with other things they should be just "natural".

Cheers

[schollen]

Update.....I just got the frame back from the sand blaster. During sand blasting two tiny holes opened up. One right below the ss st junction and one right below the st tt junction. The cause of this is due to excess sanding/filing in those areas because of the original hole in the st and the braze job i did at the ss st junction. When i got the frame back, it was mentioned to me that the st seems extra thin compared to a normal st. i thought that is weird because i bought butted tubing and i was sure i oriented it correctly (thick side up). it then occured to me that i trimmed the st from the top after welding the st bb junction. Looking back at the specs of the tube, there was only 10 cm of butted length....so i am assuming that i cut that off....which is likely why i burnt a hole in the st in the first place. At this point there is not much i can do. I added some braze to fill the small holes and i am having it powder coated. I am however worried for my safety on this bike...is having that thin wall tubing (.6 mm) where the ss and st join likely going to catastrophically fail? obviously there is no way to predict this, so i guess my questions is. when poor decisions are made and there is poor welding done such as in my case, do frames usually fail slowly is do they just crack in half. I have never seen a broken steel frame before so i am not sure what to expect. I am hoping that because it is steel and not aluminum i will be able to detect a crack slowly happening. Any thoughts on this? Experience this similar situations?

[RCP FAB]

*EDIT: Assuming this is a .6/.9 tube for a 27.2mm post*

You installed the tube upside down from the get go. The .9mm section goes at bb shell, and the .6mm end gets sleeved or put in a lug in most cases. For tigged frames use a 1.2/.6./9 externally butted seat tube.

[schollen]

welllllllllll.......sh*t

[afwalker]

28.6 EXTERNAL BUTT SEAT TUBE 1.2/0.6/0.9 x 520 :: EXTERNAL BUTT SEAT TUBES :: ROUND TUBES :: MAIN TUBES :: TUBES STEEL :: Nova Cycles Supply Inc.
no help now, but I recently found I reamed too much inside my first Knard bike seat tube which wasn't an ex butted seat tube and it recently cracked. I've brazed a bunch of brass and it's riding again.
Now I'm tig welding I'm using the ex butt to keep from burning through the thin sections. Lots of ex butt options out there, most tubing companies have them.
fatbike | Walker Bicycle Company
cheers
andy walker

[RCP FAB]

I really have a hard time recommending Nova's tubes for any reason. They are 2x the cost they should be for chinese tubes. Bringheli has Columbus and Deda externally butted seat tubes for about $25, and HJ has the True Temper versions.

[Jonathan]

I really have a hard time recommending Nova's tubes for any reason. They are 2x the cost they should be for chinese tubes. Bringheli has Columbus and Deda externally butted seat tubes for about $25, and HJ has the True Temper versions.

Is it the quality you find lacking or the label. The few nova tubes I've used were straight, had a nice finish and did the job well. Nova seems to have a selection of tubes with thicker butts than what I normally use so its nice to have more options in the market.

[schollen]

Thanks for the replys. good for future reference. I bought true temper tubing from henry james. i just bought one of their kits. i am now realizing that the kit i bought was for lugs due to the small diameter st that put the ss's super close together, the larger tt diameter than st diameter which made mitering difficult, and now the st which did not have the correct butting. oh well....i suppose i can always rebraze if a crack forms as Andy did. Onto planning the next frame. Ill be sure to check with you all after i make my tubing selection this time.

[RCP FAB]

My biggest issue is the fact that its made in china. I try to use as many US made products as possible, in my frames, in my shop, and in my life.

My second issue is, if you are going to use it, why pay nearly the same as the US and Italian made tubes?

[Jonathan]

My biggest issue is the fact that its made in china. I try to use as many US made products as possible, in my frames, in my shop, and in my life.

My second issue is, if you are going to use it, why pay nearly the same as the US and Italian made tubes?

I try to buy USA too. Ill pay more to do so when I can and I was also so completely satisfied with the quality of the Nova tubes I used they were worth every dollar I spent. It never occurred to me they should be cheaper just because of the country of origin since the quality seemed high. The specs were as advertised.

[RCP FAB]

To each his own.

[Todd Mosley]

Thanks for the replys. good for future reference. I bought true temper tubing from henry james. i just bought one of their kits. i am now realizing that the kit i bought was for lugs due to the small diameter st that put the ss's super close together, the larger tt diameter than st diameter which made mitering difficult, and now the st which did not have the correct butting. oh well....i suppose i can always rebraze if a crack forms as Andy did. Onto planning the next frame. Ill be sure to check with you all after i make my tubing selection this time.

What diameter seat tube? You can always braze on a sleeve to add extra material. Squish your seat stay tips, and top tube so it will fit the seat tube.

[and this should be my 100th post, putting my in the 100 club!]

[afwalker]

^woohoo Todd!

Lots of ex butt options out there, most tubing companies have them.

TT, Deda, Reynolds just picked nova since it's the only one you can click to order:)
I use all tubes, all styles, all the techniques from those who go before me.
Just a midget standing on the shoulders of giants:)
So much yet to learn, I'm not gonna throw stones.
I was just trying to cheer the op up and say I've made a similar mistake, and learned from it. That's what matters.
That nova tube is great, and besides, Carl Snarl recommended it in my welding class
Walker Bicycle welds. « Metal Guru
cheers
andy walker

[Amaro Bikes]

Thanks for the replys. good for future reference. I bought true temper tubing from henry james. i just bought one of their kits. i am now realizing that the kit i bought was for lugs due to the small diameter st that put the ss's super close together, the larger tt diameter than st diameter which made mitering difficult, and now the st which did not have the correct butting. oh well....i suppose i can always rebraze if a crack forms as Andy did. Onto planning the next frame. Ill be sure to check with you all after i make my tubing selection this time.

Hi Scott.

First of all, do not punish yourself too hard about that because not only you've not been the first one to go through it, but also because is for sure best lesson to get on all that, the most mistakes you make in your training frames, the best learning you'll get. Now you've already learnt about thickness, buttings, lugs vs tig, etc. And all that just with one frame.

Unless you want to make mixed techniques (brazing a st sleeve) or going for adding a top seat tube sleeve big tig fusion (paragon has some of those), your best call is externally butted seat tubes. You have a big enough choice out there so to fit any of your needs both in tube diameters (28,6-31,7-etc) and lengths (you have to keep in mind the external butted section is limited and you'll have to make sure the butted sections top-bottom will fit in your frame geomtries (it's not the same a 56cm squared geometry road frame or a mtb frame with and agressive sloping tt). One you got clear the type of frame you want, then you only need to look for the right st. About st-tt junction problems, of course it's always easier if tt is same diameter or smaller than st, but even if you're using 31,7 tt and 28,6 st, you can make them fit simply "showing the tt who is boss" (atmo royalties) putting one end in the vise and helping it to get to a nice oval shape. Remember you should be the one choosing the frame you want to build, and not being the tubes telling you what is going to be like.

The main problem with the thin walled seat tubes on tig, is that you could actually build a frame with the 0,6mm wall thickness seat tube and feel that your job is properly done, but as probably the seat tube reamer would have take small amount of wall away (due to the tube ovalization, even if it's small), at certain places this tube will have <0,6mm thickness and this might mean too weak point were future fatigue create a breaking point. Specially if it's a 28,6 tube with 27,2mm seatpost where not even place for internal shim (which can help to reinforce the "weak" st). Using those externally butted seat tubes, you're not only adding some meat to the st for strength, but you're also minimizing the st round shape deformation due to weld heat, this meaning and almost perfect round shape so when you're reaming the st there's almost no need if it and wal thickness is almost as originally (1,2mm) which in addition is double the thickness of the "thin" 0,6mm you've used.

Anyway, take this first frame as the best way to learn things and put all those learned lessons into your #2 so to find some new mistakes to learn from and get into #3, period. Probably, by #100 you'll still be getting nuts about how many things you can learn and how infinitely deep is the learning layered sea, but as soon as each new frame is getting you into a new level and you can better understand all what's happening so to apply it in the next ones, you'll be doing the right steps. No matter what you read, what you see, to properly know and understand how something goes, you have to experience it by yourself, and with this repetition you'll end up getting your own lessons and way of doing things, then probably you'll see this "tig steel from zero" post and will decide it does nothing to do with your own stuff and you're much more confortable doing things in a whole different way. No worries, there's not just one way to reach rome.

Cheers

[afwalker]

Apologies to Aimar,
I was trying to cheer shollen up, not the original poster:P
I've enjoyed this thread about tig welding, well done. Very thoughtful descriptions, you put a lot of time into this.
cheers
andy walker

[Amaro Bikes]

Apologies to Aimar,
I was trying to cheer shollen up, not the original poster:P
I've enjoyed this thread about tig welding, well done. Very thoughtful descriptions, you put a lot of time into this.
cheers
andy walker

I might be missing something, but I can't see why you should apologize at all, this post was started fully open to anyone to post any replies related with the conversation, and that's just what you did, so all good to me.

Cheers

[bedovelo]

Hi all

Thanks for this wonderful thread, I'm new in the form and this is my first post. Aimar, one question abut the seat tube sleeve from paragon, have you ever used them? do you braze them inside oder weld it? I have used sleeves from silva and always not sure what brazing rod to take. would prefer to use silver but if you weld on the sleeve you might burn the silver? and if you use braze I want be sure if its really brazed through. how are you doing this?

hope you do understand my english ;)

thanks
beat