Brazing Questions

[shelljeep]

I am building first 1:10 tube chassis soon and have started practicing and gathering the right stuff. Got a few questions-
1. How important is it to take the surface to bare metal before applying flux? I am using 3/16 brake line and it appears to be galvanized(?). It's not the green brown painted stuff. I watched an excellent YouTube video on brazing brake line and it looked like he didn't scuff or take it down to bare metal. Wanting to skip the step if it isn't necessary.
2. I tried using 60/40 solder and the same waxy flux that I use to get great results with wiring. Even with bare metal, the solder would just roll off. Is the Harris 45 rod that much better? I will be ordering some today. Just wanted to see if this was a normal result from using 60/40.
3. I'm using oxy/acetylene with a micro brazing tip. Nice fine flame, can get the glow in about 5 seconds. I guess you guys suspend your work above the table? I tried it resting my fab table last night and it seemed to wick the heat away very fast.
4. Have any of you come up with an adjustable multi arm fixture to help hold things in place while you tack? Pics would be good.
5. How much draw occurs when brazing these little chassis? Should I skip around like I do for 1:1 stuff?
Thanks, Shell

[Duuuuuuuude]

The green coated brake line seems to have a coating under the paint as well. You can see it flow out when you get it hot enough. No matter what material I use I hit it with the wire wheel on the bench grinder first just for a piece of mind.

Real silver solder is pretty much a must.

Harbor Freight sells a cheap 3rd hand type thing that works pretty well. I've had some good success lately with the little neo magnets I picked up from Walmart. The heat kills them if they're too close, but a couple of them placed strategically will hold your work pretty damn well.

Definitely skip around. Otherwise things will skew out of shape.

[shelljeep]

Thanks. Was hoping you'd chime in.

Glad to hear the right solder will help.

I think burning the costing off will be more efficient. My bench wire wheel hardly seemed to touch it. I'll get tired of that real quick like.

I'm going to try to build a fixture from some 10ga solid wire I have left over. Something with 3-4 clips. Will post up after.

[SMR 510RR]

I would grind the coating off...Its not good to breath the galvanized fumes coming off of it when you heat it.

[C*H*U*D]

In my opinion, brake line isn't worth the hassle. Heating up galvanizing isn't good for you, and it's too much work to prep.

This stuff is more expensive, but it's also stronger. You don't have to mess with grinding, wire wheels or fumes which for me offsets the price difference. Once you try it, you'll never go back to brake line:

Metal Tube | MSCDirect.com

Here's a pic of the difference in wall thickness:



And Silver Solder flows extremely well:

[shelljeep]

Fawk yeah.
I am going to see if my metal supplier stocks that or something similar. This would just be called 1010 tubing?
I saw someone mention .25 DOM, is that something that is common?
Thanks Juan. BTW-My LCC Fastback is under 4 pounds now RTR, and I'm about to start a Fastback build for a good friend in a couple days. UGC!

[mjderstine]

Originally Posted by C*H*U*D

In my opinion, brake line isn't worth the hassle. Heating up galvanizing isn't good for you, and it's too much work to prep.

This stuff is more expensive, but it's also stronger. You don't have to mess with grinding, wire wheels or fumes which for me offsets the price difference. Once you try it, you'll never go back to brake line:

Metal Tube | MSCDirect.com

Here's a pic of the difference in wall thickness:


G]

not too much more really. 6 feet of 3/16 costs me about $8 at advanced auto parts. this stuff it about twn times better, and not having to spend 20 minutes sanding the paint off is awesome.

plus brake line is not just steel. its a couple different things all plated together, then its rolled together. when you sand it down it is very easy to find the seam.

thanks for the find man. love it.

[punkfan]

Someone else on here passed on a trick that I use to remove the coating on breakline. Just chuck it up in your hand drill then use some 80 grit followed by some 200 grit. problem solved. I generally cut to length then sand, but i guess you can do long sticks with a little help.

[Duuuuuuuude]

Originally Posted by punkfan

Someone else on here passed on a trick that I use to remove the coating on breakline. Just chuck it up in your hand drill then use some 80 grit followed by some 200 grit. problem solved. I generally cut to length then sand, but i guess you can do long sticks with a little help.

When I use it, I'll typically just clean the ends I'm going to braze together, then once I'm done brazing I'll scorch the paint from one end to the other. Takes a few seconds and makes it extremely easy to remove with a wire brush or even a file in those hard to reach places.

[BigSki]

I like the tubing that C.H.U.D. posted, I could definitely see an advantage for using the tubing in a lot of applications.

[brandonwalsh420]

Originally Posted by mjderstine

not too much more really. 6 feet of 3/16 costs me about $8 at advanced auto parts. this stuff it about twn times better, and not having to spend 20 minutes sanding the paint off is awesome.

plus brake line is not just steel. its a couple different things all plated together, then its rolled together. when you sand it down it is very easy to find the seam.

thanks for the find man. love it.

just got 2 tubes of 1/4 and 4 of 3/16... for 95 bucks with a new member discount of 25%