Another brazing thread

[krillin]

Hi Guys,

so after trolling a few forums, I have found some info here and there, but not all together.

So at the risk of being burnt, if anyone can assist with the below it would be great

If someone with the more knowledge, if you could answer a few simple questions would help

I would like to get into crawling, unfortunately my side of the world, we are very limited to what we have access to as the sport is not as big this side.

I am in the process of building a 3d printer for some parts that are unavailable, and keen to get into building tube chasis.

I've done the 3d printing thing before, and build many other devices, so not really my first rodeo in that sense.

Welding and brazing however, I have no clue whatsoever, so I need some assistance here.

So, from what I've gathered, you need a MAPP torch, some brazing rods, patience, and tubing.

A really noob question, why cant I use a butane torch, like a drememl versaflame/versatip? Does it not get hot enough? will the gass affect the solder? What temp do I need to braze at? is there a general guidline.

Tubing: I can get my hands on some brake line tubing, uncoated. Are there different types of tubing, or are they all the same metal? Apart from different sizes, is the actual metal the same?

Solder/brazing rods: Are there different types? so each melt at their own temps? ones that are stronger than others, ones that give a more rough finish etc? what would generally be the better one to use?

And then theres Flux, is flux flux, or are there differnt types of flux for different uses?

I have a general idea on the above, but I just want to get more peoples views on it if possible.

Cheers
K

 

[CREEPERBOB]

This place sells 3/16" OD DOM tubing, best stuff for your project "thumbsup"
https://stockcarsteel.com/checkout/cart/
And yes, Mapp or oxy acetylene.
And you can buy brass brazing rod with flux inside.

 

[UncleJohn]

I would go with oxy/acetylene. It is available everywhere and you can do much more with it than brazing. You'll need a mandrel-type bender so you don't kink the tubing when you make bends. Practice on cheap stuff, clothes hangers or whatever before you start brazing tubing. You need to develop a "touch". Go to the library and check out a welding/brazing book and study it. Go to the local welding supply store and ask questions. Oxy/acetylene rigs are available used. Look around at a flea market or swap meet or whatever you have in ZA.

Have Fun and Good Luck!

 

[krillin]

Noted, thanks

 

[BigSki]

MAPP gas doesn't get hot enough by itself to do brazing, what you'll get is a solder joint. You can use a silver solder and get a decent strength joint. Oxy/Mapp or Oxy/actylene combo will melt silicon bronze filler rod to get a stronger "braze" joint. The main differences between a solder joint and a braze joint is how hot the flame is, which dictates what sort of filler rod it can melt.

If you have a local welding supply company, they can be very helpful to getting you setup with the right kinds of equipment and supplies. Don't forget brazing goggles, the UV light given off is bright enough to damage unprotected eyes.

 

[hillbillyrc]

Here are some links I've bookmarked when I was researching about brazing.
http://www.rccrawler.com/forum/tools-procedures/548159-help-brazing.html

http://www.rccrawler.com/forum/tools-procedures/523524-brazing-torch-suggestions.html

http://www.rccrawler.com/forum/tools-procedures/440049-brazing-question.html

Hope these will answer some of your questions.

 

[krillin]

Here are some links I've bookmarked when I was researching about brazing.
http://www.rccrawler.com/forum/tools-procedures/548159-help-brazing.html

http://www.rccrawler.com/forum/tools-procedures/523524-brazing-torch-suggestions.html

http://www.rccrawler.com/forum/tools-procedures/440049-brazing-question.html

Hope these will answer some of your questions.

Thanks "thumbsup"

 

[Mike Flea]

MAPP gas doesn't get hot enough by itself to do brazing, what you'll get is a solder joint. You can use a silver solder and get a decent strength joint. Oxy/Mapp or Oxy/actylene combo will melt silicon bronze filler rod to get a stronger "braze" joint. The main differences between a solder joint and a braze joint is how hot the flame is, which dictates what sort of filler rod it can melt.

If you have a local welding supply company, they can be very helpful to getting you setup with the right kinds of equipment and supplies. Don't forget brazing goggles, the UV light given off is bright enough to damage unprotected eyes.

I disagree. MAPP gas does well with silver solder and flux with tubing. I made my 1/6 Jeep cage with MAPP gas, Silver rod, Safety-Silv Flux, and steel brake line.

I've used brass filler rod and a Propane torch to braze coat hanger together for craft projects for my wife.

As long as you fishmouth the joints, & apply flux to the mating surfaces, the silver, or brass will flow into the joint, and in my opinion, the rod works better than a coil.


I do agree that you should find a reputable welding supply to help you decide which to use. Airgas has stores all over: Airgas | Home Page, click on "Find a Branch" to find a store near you...and no, I don't work for them, but I do have one near me that answers my questions. "thumbsup"

 

[Raptorn]

I'm going to dig up this old thread to add my experience. Most of this is covered in threads linked before, but not as clearly.

Filler material: I must echo others and say Harris Safety-Silv rod with the accompanying flux. I found it at at Menards or Amazon. I paid $25 for 5 rods, but I bet you could build an entire chassis with one 18" rod. I found this chart helpful for understanding filler material types and uses. (https://www.harrisproductsgroup.com/~/media/Files/PDF/Requested%20Resources/FillerMetalSelectionChart.pdf) For steels you should use high silver content (40+%) brazing rods.

Heat source: To braze your parts need to exceed 1200 deg F (Safety-Silv 45 melting temp). What gas/torch should you use? Don't even try butane. Propane still won't cut it. I use MAPP gas because the torch is $40 at Menards. It works fine. Any oxygen burning torch is a step up, but just know the famed Smith Little Torch is not necessary and you can get away with less.

Excellent resource: RCCrawler.com- Your #1 source for Radio Controlled Rockcrawling!

The result using 3/16" solid rod:

For anyone curious, I brazed a few joints with generic 'brazing rods', but I would not recommend it. They have a higher melting temp than Safety-Silv and my MAPP torch really struggled to get hot enough. It took near a minute of heat on each joint to melt and flow.