mrv 

howdy, frame builders
I've not built a frame, but I've enjoyed lurking this sight as I re-read again my Tablbot "Building Your Own Frameset" book, again.
I've got two junker '80s frames (Peugeot, Raleigh) I was planning on experimenting / learning / practicing with - brazing on rack attachments, second set of bottle cage attachments, and down tube shifter bosses. Then practice power coating the frames at my local Tech Shop.

I was all good to spend $40~$60 on a MAP gas torch handle and bottle. I was thinking flux and silver brazing rod would be in the $15 range.... (ok, quit laughing). Now I am aware that the cheap, genuine flux and Safety-Silv kit is nearly $70 (Home Depot online). I've already spent $35 on the braze on bits (half of that was shipping from NOVA!).

Now my question - for practicing / learning "how to braze" on junk frames I may only use for dirt road and coffee shop riding, is there any reason I can't use cheap, flux coated brazing rod from Lowes (Lincoln Electric 1/8-in Flux Coated Brazing Rod) ?
Can I assume the braze ons will pop off when I reach down to shift? I loose my rack on my commute to work?

Any words of advice, or links to posts that have already addressed this are appreciated. I was hoping to build a MTB or touring frame next year. I'm getting discouraged by the costs.
mrv

JohnDThompson 

It sounds like you've already invested a fair amount in this. My concern is your torch: MAPP/air is unlikely to be able to provide enough heat for anything beyond superficial braze-ons. You'll want a fuel/oxygen set-up for anything beyond that. I've not been impressed with flux-coated rods; instead use a good paste flux (e.g. GasFlux type-B paste for brass or type-U for silver) and plain rods. I'd recommend low-fuming bronze for brake bosses and Safety-Silv for braze-ons.

duanedr 

I have tried many of the commonly available fluxes at this point and really like Gasflux B for brazing with bronze/brass - I wish the texture was a bit sticky-er going on but once at temp, it's great as you can scoop it up and move it around quite well and it's pretty forgiving regarding temp control. I haven't tried their type-u. Cycle Design has several great fluxes. I really like cycle design stuff for silver and Wade is awesome to work with. He can provide feedback on what's going on if you send him pictures with stupid questions.

The coated bronze stuff will create a really hard glassy residue and it typically comes in thicker rods which require more heat which is bad for bike tubing - in general. I do use it infrequently when building fixtures with thicker stuff (eg 1/8 or 1/4 in. steel) but I also use additional powdered flux in those instances as well. You can't use too much flux - atmo.

MassiveD

You can build a bike with just an air mapp torch. Or even an air propane one, which is cleaner in my experience. But unless you enjoy the actual investigation in these techniques, you are better off getting a Tinman propane torch, and a propane cylinder, and an oxy cylinder.

best to get the SafetySilv off ebay if you can find it cheap. I got a 2 pound box at a rocking deal, but you can get an ounce also. Yeah, there are boutique offerings out there, but not for what you are proposing.

unterhausen

if you do it right, you can resell without losing much money. I'm not aware of any cheap ways of doing this. I think the way to go is the following: get a J28 clone torch on amazon, get a refurbished oxygen concentrator, and a gas grill propane bottle. I think this all will cost you around $500.

dsaul

This is exactly what I have and it works great. While you're at it, you might as well get the kevlar hoses too.

unterhausen

where did you get your oxygen concentrator?

dsaul

I found my O2 concentrator on Dotmed.com. Its sort of the Craigslist of medical supplies. You have to search for the low priced ones, but they can be had cheap if you're patient. When you contact the seller, make it clear that its not for medical use. They are not supposed to sell them for medical use without a prescription for O2. I got my Devilbiss 525 for $188 shipped. It was not rebuilt, but has pretty low hours on it, so it should last me forever.

dsaul

There is a listing on ebay right now for Devilbiss 515 oxygen contrators for $180. He has 10 units available.

Doug Fattic 

This is the model I have. One advantage of a Devilbiss over other manufacturers is that the plastic outlet barb (to attach the clear hose used to assist breathing) can unscrew from a brass size "B" fitting on the machine. This allows me to attach my brazing hose directly to the unit.

The disadvantage of an oxygen concentrator is that you have to let it run for a few minutes to purge its tank and line before it has pure enough oxygen so it won't blow out the flame. This really doesn't matter if you can remember to turn it on when applying flux. And it makes enough background noise so I have to turn my stereo up a little more.

An oxygen concentrator at that price is cheaper than buying a tank and regulator. You use its flowmeter to regulate the oxygen. And of course you don't have to bother with the expense or transport of getting refills. And it is safer too since it isn't a pressurized potential missile/bomb.

JohnDThompson 

While it is possible to build a frame with a fuel/air setup, it paradoxically can result in much larger heat-affected areas on the tubes. With a good fuel/oxygen setup you can heat the work to the necessary temperature quickly, braze the joint, and get out much faster, so less of the tube is weakened by the heat.

mrv 

Thanks everyone for the input and advice. To braze a hand full of bits on to a couple of lead pipe frames, $500 seems a bit steep.
I'm leaning toward something more like:
Oxy/Map-Pro Torch Kit $60 at HomeDepot
Silver Flux $14 at Henry James
Harris SafetySilv 50N WIRE COIL 1 OUNCE $27 at Henry James

If I build a frame (next year) I'll probably add SafetySilv 56 for the lug joints. (Have I got that right, the higher temp, sluggish flow material for braze on bits, to fill in large gaps, and lower temp flow to fill in small gaps?)

I'm open to any guidance, correction, etc.
Thanks.

tuz

The oxy-map kits will work for a few braze-ons but you'll exhaust the oxygen quickly, meaning you'll have to buy more.

If you really want to build frames, it'll cost... Unfortunately framebuilding isn't really cheap. On top of the torch and filler/fluxes, you need a workshop, jigs, tube blocks, tools, etc... Think about a budget and we can advise?

JohnDThompson 

I'd do it the other way around. Brass for the lugs, unless you're sure of the precision of your mitering and tube fit in the lugs, since brass bridges gaps better than silver. Silver for the braze-ons, because less strength is needed and braze-ons often are placed on thinner sections of the tubes, beyond the butted areas. The lower temperature causes less heat damage under the braze-on.

MassiveD

I'm not advocating it, just saying it can be done, which was somewhat contradicted higher in the thread.

The fact one will be dealing with a larger heat affected zone means that while one is working with an already too cold torch, one is at the same time required to heat an even wider area, which is very inconvenient. But doesn't harm the metal or anything. You either have a problem or you don't. If you don't have a problem, small or large doesn't really mater. The average bike tube could care less, and will not be significantly weakened, or at all.

MassiveD

By definition brazing is north of 700 degrees, any damage to tempering in the tubes to the extent it is actually being relied on, is well cooked at those levels. Of course there is the back of the tube in some cases, but that is normally not an issue with standard thicknesses. Most people do not even back purge steel at 3K degrees.

I don't have much to offer about the rest of the advice, though I wouldn't use brass if I was messing around with sub standard torches.

MassiveD

I think you may be wasting your money on that torch. You don't have to spend 500 on a set-up, but those units are a waste of money. For small BOs, all you need is a hand held with a bottle Bernzomatic torch. For lugs, you can do them on the cheap with propane only, but it requires a really leaving the reservation, and it probably only pays if you already own the gear, or can make it nearly for free. Or possibly a party with a couple of other folks bringing hand held torches. But I think with lugs, or brazing frame sized pieces, while it can be done, you are better off doing it with a cheap real aircraft torch, either tinman (you can weld with it also), or an aircraft torch from ebay. Add a propane bottle, and get the cheapest source of Oxy, maybe you can use a stack of the bottles from the kit you were looking at. That is pro level, and you can resell most of that stuff for what you paid for it. The kits from HD are not worth it. You would be looking at 30 for an ebay torch lucky auction, or 75 new for a tinman. 25 for a cheap propane regulator, but they work, borrow a BBQ tank, + cheapest source of OXy, this is highly variable, can be some bottle source, the concentrator, etc... O2 is a difficult to compress gas, so you don't get much for your dollar in bottles.


Speaking of concentrators generally, there are referbed concentrators from jewellery supply houses, that are hot rodded to push more gas, and these have shown up on local auction sites, and "new" they aren't that expensive in the US.

Rio Grande 2014 Tools and Equipment Catalog

If you google around, there is a lot of interesting concentrator info and you can find hours of use guidelines for buying second hand. You want low hours, and the machines record that info. Sadly for the primary users, many will be low hours.

Doug Fattic 

Mrv, what I think I hear you saying is that you want to start learning how to braze by putting braze-ons on some old frames so eventually you can make a frame using Talbot’s book. I’ve been teaching framebuilding classes longer than many posters here have been alive so I hope those experiences gives me some authority to make some alternate suggestions. But first I want to tell you an unrelated story to illustrate the point I want to make.

My wife went to get some running shoes at a shoe store so she could start running. She found them surprisingly knowledgeable about how to guide her to make the right choice. Much more so than another mall store she went to first. As she was expressing her appreciation to them they said they can always tell how long term successful someone will be running by their choice of shoes. Those that get the ones for only $29.95 don't last. She has been really happy with the results of her more expensive guided choice.

My illustration would be about someone wanting to get into bicycling by buying a $150 bike at Wal-mart. It makes the odds they will enjoy cycling pretty low.

So my point is that if you eventually want to learn how to braze so you can build a frame for yourself, then get the right equipment. If costs are an issue than keep your eyes open for deals on eBay, craigslist or local classifieds. $29.95 running shoes, bikes from Wal-mart and a map gas torch and bottle from Home Depot aren’t tools that lead to a high probability of success.

unterhausen

After monitoring framebuilding sites and email lists for quite a while now, there have been a few people over the years that insist on buying the bernzomatic setup and then find themselves blowing $$$ on the oxygen cylinders. I have never seen any of those people that have come back and said that it worked fine. Mostly they come back and admit they wasted a lot of money. I guess it depends on if you are sincerely going to give this a try -- if not, don't buy anything. I have always figured it costs at least $1k before you know if you really want to work on frames or not. I got my torch from someone who couldn't afford to go to his class and knew he was never going to build a frame otherwise. In my book, there is no shame in giving up before you start if your heart isn't in it.

MassiveD

That is good advice, but as regards the OP:

1) you can get lifetime bonds to your BOs with safety silv and using only a propane torch. Everyone needs a propane torch sooner or later, money well spent.

2) You can't really use the coated rods, and getting a real PO torch can be done at a cost that is pretty low, and it is the only tool that really makes sense. You will recover most of your expenditure if you flog it at the end of the project.

What is missing from framebuilding is a pure hobby path. There are people interested in doing it, but most of the activity is based around a pro approach. As a result it has been tough to get any info out. People who bring it out, give up talking about it or face a sandstorm of sometimes ill informed comment.

I remember reading an article about the scientists who are trying to break through to eternal life. One project consisted of identifying the barriers, which amount to something like 8 things that need to be overcome. There isn't any real reason to believe the 8 things are impossible to overcome, there are other organisms that have individual capabilites that show the way. In the same way, to make steel bike building possible for the masses only requires overcoming a few barriers. Most of these barriers do not exist to the construction of composite bikes/wood. I think they can be overcome for home builders but there is so much hostility to the idea, that we won't soon get a common direction that will bring acceptance to the necessary products or techniques.

dsaul

Back to the OP's original question. You can use a straight MAPP gas torch and Safety Silv 56 to attach braze ons to your frame. I built my first frame(lugged) with one of those Bernzomatic MAPP/Oxy setups and and Safety Silv 56. I went through a lot of Oxy cylinders before I realized that the MAPP alone would work for most of the joints(not enough heat for the bottom bracket or fork crown). Those Oxy cylinders run out very quickly and it really sucks to run out in the middle of a joint and cover the whole thing with soot. At that point, you have to let it cool down and clean the joint again before making another attempt.

Frames can and have been built that way, but I would not recommend it to anyone who doesn't have a feel for knowing when they have pulled silver though the entire joint. It worked for me to get that first frame built, but I would never do it again.

unterhausen

I don't see that $1000 is a particularly high cost of entry for a hobby, particularly one where you build things that could severely injure someone if you do it wrong. Of course, with an expenditure of $1000 you would be ridiculously under-equipped to build frames, even if you were using files, straight edges and a vise as your main tools. Life is too short for the MAPP/Air approach. Although it has been done, there is even a book about it.

mrv 

I am greatly appreciating all the feedback on this forum. There's been a great deal of helpful and useful information, and some opinions I agree with and some I disagree with.
- Yes, $1000 is a particularly high cost to enter a hobby. Particularly if you don't know if it's something you want to do or not. (I'm not even checking with my wife on this one!)
- I completely understand and agree: "The bitterness of poor quality remains long after the sweetness of low price is forgotten." (I'm a runner and biker, so I know shoes and tires, and the better quality and higher cost ones are BETTER.)
- I understand that heating up a lugged joint properly is going to take more than propane/air or MAPP/air.
- There are a few of you who seem to understand there needs to be a more affordable way to try out and experiment with the materials (steel braze ons, steel frames, silbraze, flux, torches, clamps, files, vices, jigs, and on....). Some of this I have (piles of files, a vice, a cheap propane torch), some I'm ready to buy (MAPP/air torch, flux, silbraze, Swiss die maker files), and some I'm not ready to buy (O2 generator, regulators, frame jig, a nice MECO torch head, hoses, and MORE!).

If I look at the physics of it (see temps at the end of the post), I don't think I'll have a complete disaster on my hands if I use propane/air to attach water bottle cage braze-ons, rack braze-ons, and down tube shifter braze ons. And considering if they fall off, nothing is going to fall into the front wheel: I'll be completely fine (I've actually have been fine when stuff got in the front wheel, but I'm not willing to try it again.....). AND if I make the attachments, enjoy the process, and the powder coating and re-assembling my "re-cycles", I can make the next $750 ~ $1000 step of building a lugged frame - with confidence it's something I'll want to do many times. It may turn out I have the same attitude toward bikes as I do to photography - I love being out (hiking, biking) taking pictures, I hate sitting at a PC editing, cropping, posting). Possibly I'll work on these junk frames, get them coated, and realize, "I really do prefer riding them as opposed to building them - then I can drive over to Doug Fattic's and have him build me a super-awesome touring frame! (money better spent)

I'll keep watching this spot for more comments. I definitely want to hang on to the advice and views here. Thanks again.

Propane / air 1,995 °C (3,623 °F)
MAPP / air 2,020 °C (3,670 °F)
Propane / oxygen 2,820 °C (5,110 °F)
MAPP / oxygen 2925 °C (5300 °F)

50% Ag 1305° F / 707° C (liquidus)
56% Ag 1205° F / 652° C (liquidus)

Mark V.

tuz

I got started on a mapp torch. I made a bunch of racks and it works well for that. It'll work for braze-ons. And people make it work for frames too. I'm tempted to build a lugged brass frame using a small torch and firebricks just to see if it can be done. But building frames will certainly involve some spending. Just the raw materials for a single frame will cost $200 if you are lucky.

Btw the flame temperature is not that relevant compared to the amount of heat (BTU). With oxy, you're burning fuel much more rapidly.

waterlaz

I'm only building my first frame(almost done) but maybe you will find my experience usefull.
You can mitter tubes with a hand saw, a couple of files and a printed template. You can get away without a jig or an alignment table.
But you really need that oxy/fuel torch, especially if you are not very good at brazing. It can be quite frustrating to not be able to apply heat as fast as you want to.

PS. I don't think this is such a big problem to buy some used oxy/propane setup.
Though, I don't have a wife so I guess it is much easier for me to spend money.