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I'm considering spending 60ish oxy/mapp torch to do braze on's at home since it's a slog to the Oxy/Acetylene torch I use for bigger stuff.
Will this be hot enough to sweat stainless dropouts? Seems like it should make short work of brazons (seen that around), but I know SS needs a bit of extra heat. Thoughts? I'm using Dazza's socketed drops with silver.
Thanks,
Jim
My understanding is that the brazing of SS is not any hotter a temp then with steel. But the SS does not conduct heat as quickly so a longer heat cycle might be needed. Andy.
I just missed out on the Uniweld 71 torch handle mentioned by Doug Fattic on eBay for 41$. See http://www.velocipedesalon.com/forum...ane-30480.html for discussion.
I think this should be a wiki/sticky/flicky!
cheers
andy walker
I struggled with stainless even using Cycledesigns Stainless Light so I emailed Wade Barosci and he was kind enough to reply, and I hope he won't mind my reposting here, dealing with stainless and my inability to get it to work. I share my quest with others so all may benefit, so I'm just a beginning tube-sticker-together-not-a-framebuilder-yet, and I couldn't get stainless brazeons to stick to steel tubes so I emailed Wade from Cycledesigns and he was kind enough to reply and help me so I hope he doesn't mind my sharing with others using his product:
Hi Andy,
The issue is likely to be both your cleaning procedure, and torch technique.
Stainless Steel develops a thin, high temperature chromium oxide layer
on its surface. This layer prevents the filler from flowing.
It needs to be removed by physical means. Usually it is sanded off.
after the surface is mechanically abraded, it needs to be re-cleaned.
An alcohol, or acetone wipe usually works well.
Brazing should take place within a short time of cleaning, less than
an hour would be preferable. Clean both the inside and outside of the
braze area as best as possible.
Flux should be allowed to stay on the surface for a few minutes, to
allow it to chemically remove any remaining oxides.
The next problem is the shape of the boss. It sticks out. Any time
you have a surface that sticks out, it catches the heat of the flame.
Keep the tip of your torch so the heat angles away from the boss, not
towards it as would seen sensible.
With a neutral flame (not oxidizing, it will ruin everything), heat
the area around the boss. Stainless dissipates heat faster than
steel, so it takes a bit more heat.
More heat requires a larger tip, or flame, and not moving the torch in closer.
The flux has 5 stages- paste, fluffy, fluffy with dark speckles,
globby liquid, thin liquid. You are up to temperature when the flux
changes from globby liquid to thin liquid.
At this point the stainless should just start to develop a red tint.
To dark a red tint, and everything will burn. Once the flux goes
thin, place your filler on the intersection between the tube and boss.
Flick the flame onto the silver, and it should melt and flow around
the joint. You may need to quickly move the flame around the boss to
get silver flow and penetration all of the way around.
So in general, you are overheating the boss, when the tube is not yet
recepitive to the silver. Clean everything well, check your flame,
and heat the area around the braze first.
Brazing stainless is difficult, but not impossible.
You can get some inexpensive practice materials at the hardware store.
A few nuts and bolts are great to practice with.
Let me know how everything goes, and don't hesitate to send more
photos, or call.
Thanks,
Wade
cheers
andy walker
Big Fan of Cycledesignusa.com obviously:)
Don't even need O2... here's my double-barrel, cat approved, Tidy Cat Bernzomatic MAPP-air setup. Built my latest with it:Attachment 49419Attachment 49420
I have one of those torches that I bought many years ago for a different purpose. MAPP/Oxy will get hot enough to braze anything you want for a bicycle. The problem is those small oxy cyclinders are good for maybe ten minutes. I went through a lot of them on my first frame, before I realized that my MAPP/Air torch was plenty hot for silver brazing and a single MAPP cyclinder lasts a long time.
On a different note: in response to afwalker, Amazon has the Uniweld 71 for $35. I just got one based on Doug Fattic's recomendation. The have it listed under Uniweld's Ameriflame line.
Anyone care to post links to product pages for the specific mapp/air setup you use?
I used 2 Bernzomatic JTH7 torches, clamped and duct taped together, which apparently they don't make anymore. One was just enough to do socket dropouts but not enough for the main tube joints. The cannisters are the yellow MAPP (actually, I think it's a propylene blend now?) ones ya get at Home Depot, along with the $3 casters that I attached to the bottom of the cat litter box. Cat ownership optional but recommended, of course...Quote:
Originally Posted by pruckelshaus
For instance, would this:
Shop BernzOmatic Soldering and Brazing Torch Head at Lowes.com
combined with this:
Shop BernzOmatic 14.1 oz Mapp/Map-Pro Gas Cylinder at Lowes.com
work?
Sure, but I'd get two torches and clamp them together, although these newer torches would be heavier and bulkier than the JTH7. At least the hose is a foot longer.Quote:
Originally Posted by pruckelshaus
I don't think one is enough with one gas cylinder working if you want to do large joints.
I have said this...oh at least 25 times...but nothing like a broken record?Quote:
Originally Posted by suhacycles
The whole discussion of fuel/air torches is bunk....Just because something kinda works is not an excuse to use it.
Let me count out the ways.. First this whole setup is false economy. The per unit costs of MAPP in these small containers cost a whole lot. It will cost as much as traditional fuel/oxy setups even in the short term.
In this example you need two torches. The results of brazing like this take a long time and are in most of the examples I have seen have terrible penetration and flow. There is not enough heat in a fuel/AIR setup to competently braze a joint.
I can find Oxy/acetylene kits used on Craigslist almost all the time for less than $200.00 that actually work. You are talking about spending nearly that much on bernzomatic torches with the subsequent extreme cost of fuel. Another issue for me? These cylinders end up in a land fill most of the time.
With a reasonable fuel/oxy torch you can do anything. You do not have to worry if you have enough heat capability to braze a fork crown or the like. To add some more harshness to this post because almost nothing irritates me more than this consistency of this particular piece of miss information spread across the internet. Think about it this way. If you cannot afford somewhere around $200 dollars to make a bike frame, you really shouldn't be making bike frames.
yup. every word. yes.Quote:
Originally Posted by dbohemian
Yup, I agree... and I'm cool with broken records so feel free. An O/A setup is definitely superior but the air-MAPP was a home garage experiment that ended up working better than I thought so why waste it was my thinking. It's an answer to the OP's original question, even if it's not the preferred answer...Quote:
Originally Posted by dbohemian
Hey, I use your tube blocks and they work great so I must be doing something right! :bigsmile:
a while back, I decided I wanted another torch and bought a j28 and an AW1A with a full assortment of tips. Cost me less than $300 on ebay. If you shop, you can definitely do the same thing I did (except for stopping at one torch) for ~$100 or so. The J28 tips are twice what the AW1A tips go for so that might change your buying decision. Buy a kevlar hose from Tinman for $50. Get an oxygen concentrator and a propane tank and you are ready to go for another $300. Top-notch setup for a very reasonable price.