The pic below shows the hottest propane flame location, is this the correct distance(+-) from the lug/fillet the tip should be while brazing?

thanks , Brian

It's more complex than keeping the point of the flame at its hottest distance. It is one of the controlling factors including what size tip you choose as well as the speed you are moving the flame at what angle. When I am fillet brazing with brass I like to be a lot closer and use a smaller tip than when I am brazing a lug. When I am cleaning the shorelines I turn down the flame and move in closer. It is useful to know that the hottest part of a propane flame is not right at the tip like an acetylene flame but rather out in space a bit.

Here's another propane flame pic, from Paige Tools, to go with the above. I'm trying oxy/propane brazing(with oxy tank and bbq propane tank), how does one determine a reducing/neutral/oxidizing propane flame, easily determined with acet but not sure what to look for with propane.

This from: Welding Notes and Application in Cycle Frame Building Jim Cook, Nimbus Design in UK

Filler material is typically Nickel.Bronze type C5 or Silver Alloy type 1665 using a welding nozzle size of VICTOR 000 / 00TE Tip. Flame setting for Nickel bronze, very slightly oxidizing to eliminate the possibility of porosity in the braze deposit. Silver alloys should be applied with a slightly reducing flame by virtue of the rapid oxidation of silver. Actual joint temperature in fillet brazing is lower due to the process being in the solidous range of the filler material.

Does the fact this refers to C5 rather than C4 make a difference, or that this is in reference to OA? Should the propane flame be oxidizing?

thanks, Brian


Looks like the rose bud is slightly reducing but no idea on the others

By the color of the flame. When the ratio of propane to oxygen is greater, the color of the flame is kind of greenish. As more oxygen is added it goes from greenish to bluish (when it is a neutral flame) to purplish (when it is an oxidizing flame). A propane flame is not nearly as precise as the cones of an acetylene flame which allow you to clearly see the divisions. After awhile you get an instinct for setting the flame correctly.

Thanks Doug!

thanks for asking the question, I had no idea

Here is something I copied and pasted from somewhere to a section in my frame building class manual and I'm copying it here now. It tells the temperature in fahrenheit of the 3 different fuels usually used in bicycle frame brazing and also the ratio of fuel to oxygen. I didn't make a footnote of where I got this information. Looking at it fresh now I had forgotten how much more oxygen is used with propane than acetylene. I primarily use an oxygen generator so it doesn't matter to me what the ratio is as long as my concentrator can keep up. This is why those disposable oxygen canisters (with CGA600 fittings) wouldn't work well for making a frame because a person would use too many of them before they got done. There probably is enough propane or map gas in one of those canisters to make one frame. I experimented a couple of years ago with a 2 bottle (oxygen and map gas) Bernzomatic unit. The tip was actually about the right size for what we do but the oxygen bottle lasted just a bit more than 15minutes. A $10 each it would not be an economical solution.

NOTE: There will be a noticeable performance and temperature difference when using propylene (MAP//Pro) versus acetylene and an increase in oxygen consumption. Acetylene burns at 5589 deg F with an oxy/fuel ratio of 1-1 respectively. MAP//Pro burns at 5193 deg F with an oxy/fuel ratio of 3.5 - 1. Propane burns at 4579 deg F with an oxy/fuel ratio of 4 - 1.

Given this ratio is needed to reach that temp how does this relate to oxy/pro pressure? From searches I've done most recommended regulator pressures for brazing are roughly 5 psi propane/5 psi oxy( 1 - 1) when using an oxy cylinder(not an oxy generator) and # 2-3 torch tip(Victor), how does the 4 - 1 ratio fit in to these recommendations? Also wasn't sure if the Victor TEN tips had the same orifice size as acet tips, found this:



thanks, Brian

The Victor TEN tips have the same diameter orifice as other Victor tips with the same identifying #. The only difference is that the end is recessed a bit to help keep the flame attached to the tip. The depth of the recess is about the same as the orifice diameter. The illustration you provided shows that the orifices are all the same size but the doted line on the end of the TEN tip shows the recess diameter. I usually go up 2 Victor sizes when doing propane as compared to acetylene to get the same amount of BTUs. In other words a cooler frame but more volume gives the same heat output.

The Victor UN-J mixer elbow designed specially for propane has more and bigger oxygen supply holes than an acetylene mixer elbow. This is to up the ratio of oxygen to the flame. This means that the pressure in the line can be the same. In fact it is a problem to increase the oxygen pressure because it is more likely to blow out a propane flame.

Recently set up O/P with oxygen concentrator. I ordered a A-set of Paige Tool tips which came with the M-3 as the smallest. I'm curious if the M-3 is the right size for fillet brazing or should i go smaller. I am trying to learn how to read the propane flame, as a learned with acetylene. I'm having a bit of a hard time establishing different greenishes, and blueishes, and purpleishes i've bee reading about.

To get a better idea of the subtle color changes, just turn one of the control knobs up and down a little bit when you are close to the right setting and watch closely as less oxygen is greenish and more oxygen is bluish and if you keep going there will be a hint of purple in the blue (which is way too much oxygen to propane ratio). Obviously you can turn either the propane or oxygen control knob up and down. It takes a very small amount of a turn to change the setting. Doing this a number of times will make it easier to understand the color differences unless you are color blind.

You may like a smaller Paige tip then their #3.What size tip is preferable for fillet brazing is a personal choice.My preference is for a very small tip.Beginners tend to do better with a smaller tip because it gives them a bit more time to react to the circumstances in the melting puddle.They have a harder time keeping the brass (really bronze) in between the liquid and solid state to control where it flows.They are most likely to leave the heat on a bit too long so the brass is runny and goes too far.

I know what you mean. I've been making sure it has no purple tones and going with what looks blue(neutral flame, as pictured in the above post showing Paige's tip size comparison) to me. I only see greenish color when the flame is really longer than I think is workable. Tip orifice size for the Paige tips is unknown to me, I'be searched around but no luck, other than their site saying the M3 is a medium. Victor #2 tip is .0464 and a Smith AW202 .0292 so if a M3 is in that range it should be ok, seems like that range is what Doug Fattic suggests, with the smaller probably easier to initially learn with. Did you use any other type of propane tip before the Paige tips? I'm using Victor type recessed tips, interested in how you like the Paige.

regards, Brian

It is difficult to compare orifice sizes as the side holes of Meco and Paige tips also put out heat. In fact it is difficult to compare the Paige and Meco tips because their side holes (or slots as is the case with Paige) are different from each other. The reason these multi-port tips work better when fillet brazing is because they are less likely to blow out from back pressure that might happen when the flame gets close to the puddle.

"The reason these multi-port tips work better when fillet brazing is because they are less likely to blow out from back pressure that might happen when the flame gets close to the puddle."

That's the only advantage? The Victor propane style recessed tips seem to solve that issue, any benefit of the Paige over the Victor?

thanks, Brian

I just got one of the 'Framebuilder Sets' from Paige and they are more stable and easier to light than the Victor TEN tips. I haven't tried fillet brazing with them yet.

Like Duane said the Paige tips offer some advantages over the Victor TEN tips. It’s like comparing an 8 speed shifting system with an electric 11. In testing the Paige vs TEN tips, it is more difficult to blow at a Paige. In addition the center flame on the Paige is narrower and sharper. I particularly like it for doing fillet brazing. My TEN tips vary in the flame quality they produce a bit. They have a more rounded flame tip. In addition some of my Gentec TEN tips have a better flame pattern than the Victor TENs and some Victor TENs are better than the Gentec. I wasn’t able to find some Victor TEN tips in the smaller sizes last time I checked. I had to buy Gentec tips which aren’t machined as well as the Victor tips but still work fine.

Since this subject thread will probably be read by someone wanting to buy new equipment, it makes the most sense for them to buy Paige tips.Each of their tips is less expensive and work better than Victor tips which also have spotty availability. If someone like Brian who already has a Victor TEN system that works well, it might or might not be worth it to upgrade.If one has a Smith AW1A torch handle then getting the Paige tips combined with the Smith AT-61 mixer/elbow is the way to go because Smith has discontinued the AW400 series of mixer/elbows that worked for propane.

Is the Gentec UN-J mixer available anywhere. Google really hates to answer any direct questions anymore

"....like Brian who already has a Victor TEN system that works well..." Doug

I only have #2 and #3 Gentec TEN tips(much cheaper than Victor), using only #2 and varying the torch pressure for practicing fillets(previously never did fillet brazing) and am slowly making progress. Since I've just started using propane I most likely will get the Paige tip package which seems like a good value, especially considering the number of tips you get(and my wife is interested in them for jewelry, so thats a plus/rationalization for getting the Paige). For those using the Paige tips for the first time please let me know what you think of them.

regards, Brian