Can someone talk about brazing/soldering rods?

I'm speaking specifically about the ones you see on FB or at trade shows where they repair a hole in a soda can with a propane torch, but also other "real" brazing rods.

I can solder things pretty well, and by that I mean electronics and copper plumbing.  I can weld stick and MIG with pretty good skill as well.  I have never brazed.  So when I see those "but wait, there's more" infomercials for the ones you use with a propane torch it makes me wonder.

At the theater it would be nice to fabricate some things with aluminum.  They wouldn't be structural things, more like decorative things like wall flats, etc.

My arsenal includes:  MAPP and propane torches (the little ones that just screw on the cans), Oxy/Acetylene kit with assorted torches, welder capable of stick, tig, mig, and spool.  So far my attempts at aluminum mig have been catastrophic, and all of my tig experience can be summed up in three minutes.  (and this machine is scratch tig).

So I have the equipment to do nearly everything, but I've never delved into the middle ground... that stuff between soldering and welding.  Are those fancy infomercial brazing rods worth anything?

They work.  I have used one to repair a hole in an aluminum radiator.  The real trick for me was to scrape the surface you are working with.  I was using a dental pick type tool.  I used them for something else, but I don't remember what.  The reality is, there really aren't a lot of things to use them on (unless you have a great need to repair aluminum cans).  Certainly something good to have around, just in case (they are pretty cheap).

I wouldn't use them to repair anything structural of course, but they do work.  I got mine at HF (they still have them)

Here is one of the customer reviews from the HF site that might be useful:
 

...for me, in working with aluminum. Read through other reviews, good and bad, and figured it was worth a shot. I have a lot of experience in soldering, not so much in welding. I cleaned everything with scotch brite right before beginning, and used a propane torch (working with THIN (.063 and .050) aluminum). Keep the torch moving, and the hot part of the flame is NOT the bright blue cone- it's beyond that. Run a practice pool on a scrap beforehand- get a feel for how it wets out on the sheet- it'll go pretty flat- that's a good bond. If it's a chunk of rod, it is NOT working/bonding/hot enough. If the aluminum suddenly vanishes, that was too hot, and you didn't keep the torch moving. I was able to form a 2" tube out of sheet, and seal it with a thin bead on the inside seam. Neat stuff!

I used them to build the holding bracket for my ignition pickup on my 924.

You need stainless tools dedicated to the job to clean the corrosion off the aluminum and larger items need to be preheated in an oven or similar.

I’m not sure about older cast aluminum, it’s likely to be really dirty and hard to work with, but I’ve not tried yet either.

Actual real Lotus 7 frames were brazed.  Done properly, it's stronger than welding, they say.

I have used them to make fairing stays multiple times for my race bikes.  Worked well enough. I would not use them for a structural build. 

I tried to use them on radiator tubes, not successful. Tubes were to thin, they melted before the rod. 

Sounds like it's worth a shot.  What all do the HF/soda can rods bond to?  Anything non-ferrous?

I'm thinking about using it for repairing props, making props, cosmetic repairs to things, etc.

I've never had luck with the infomercial rods but I'm sure they will work if things are kept clean. 

For what you are doing, I'd be tempted to use something like JB Weld. It works on just about anything, no fire required. 

Toyman01 said:

no fire required. 

I've used the ones from HF for a number of things and they've worked out well.  The most stress I've put them under is in the charge pipes on the Neon.  I got a bunch of aluminum elbows and straights but I'm not set up to weld aluminum so I got those rods and whatever they sell instead of MAPP gas today.  I didn't really do a lot of cleaning beyond wiping it down with a dry rag but I clamped the two sections to each other and went around to join it together.  Still holding up fine 7 or 8 years later.

Dr. Hess said:

Actual real Lotus 7 frames were brazed.  Done properly, it's stronger than welding, they say.

Joints are/were less brittle than welded ones, IIRC.

A lot of the custom motorcycle frame builders in the UK - the likes of Rickman - brazed their frames, too.

Then why do restoration people curse brazing?