Brazing brass: Another child's rock box

[Cliff Rohrabacher]

In Brass:
What braizing rod and flux might work best for an edge joint that's about 6" - 7" long and a skosh thinner on the edge than an eighth of an inch?

The project is a 7.5" diameter solid Elm sphere with a deep pocket cut in it to accommodate the magic rock It sits on a little elm pedestal that captures and cups it just enough.

The big flat ovoid beastly ugly (magic) rock is a snug fit in the pocket.

Making the door has been an issue.

I sliced a pile of apple wood strips that will bend to conform to the spherical shape and looked to laminate them under pressure with epoxy.
Haven't taken it past the slices.

I have got a strip of brass and pounded it to the curvature of the sphere in one dimension but it's still flat across the face. This is the most hopeful so far. It may work but, to assure that the metal doesn't bend from use I gotta weld/braze some brass strips cut along an edge to the sphere geometry and braze them to the under side of the door piece.

What brazing rod and flux might work best?

I don't know if I can trust plumbing silver solder to be striong in this edge joint application that's a scosh thinner than an eighth of an inch

[ian maybury]

The problem with brazing brass is that it's really welding - the parent material and the filler metal will melt around the same temperature.

Brazing steel on the other hand is more like soldering because the brass in the filler rod melts well below the temperature of the steel.

Silver solder (the proper variety that is much stronger and harder than lead and tin based plumbing solders) might be your best bet - as far as i can recall this gets you back into having a decent temperature differential, and is still a pretty strong material. The only problem is that it won't match the colour of the brass.

When gas welding aluminium it's normal to use a rod of an alloy composition (my memory is fuzzy, but possibly with 5% silicon?) that melts not much but enough below the temperature of the parent alloy to prevent problems with melting of it provided your torch control is good. There are other rods that melt a lot lower, but at some expense in respect of strength.

I can't be sure, but a call to a welding consumables outfit might just establish that there's a low melting point brass filler rod available - i may just have heard of that years ago.

Hope it helps...

[Jerry Bruette]

Cliff

You could try some high strength solder from a gunsmithing source. I've used a product from midwayusa.com to solder front sights onto rifle barrels and the stuff works great. It has a low melting point but is stronger than lead solder. I think the product I have is #813132 on their website.

Jerry

[Robert Eiffert]

Silver solder is used on hi-quality steel bikes. The tubes crack before the joint comes loose.

[Cliff Rohrabacher]

I think the product I have is #813132 on their website. Jerry

So I went there and plugged that number into their search and it returned nothing

So I trued key words and got this page:
http://www.midwayusa.com/viewproduct/?productnumber=813132
which has that exact same product number.

It flows at 430-F whcih id definitely in the Solder range.
Brass starts to melt as 1652-F I'd definitely want my braise or solder to flow before that to avoid slumping the metal base.

I found "I Shore" whom I've purchased files from in the past. The guy seems to run a one man show and lists lots and lots of things which he simply has dropp shipped from the manufactuyrer. They are cheaper than a lot of other places for a lot of things - just don't call the guy and ask him any technical questions. When I spoke to him I came away with the impression that he doesn't really handle or know very much about the things he sells.
This is their silver solders page http://www.shorinternational.com/Solders.htm
I may try one of the higher temp solders Solders

[Cliff Rohrabacher]

This video is "exactly" the sort of joint I gotta do
http://www.weldingsupplyco.com/ssq1clip.html
The only difference is my piece is not bent at an angle to make it stand up independently
But that's easy enough to rig.

The claim there is that the solder is 18 Times more strong than "regular solders." Whatever "regular solders" means.
I have no clue whether they mean old school lead, or the silver alloyed stuff plumbers have to use now, or if they mean a silver solder.
and melts at 1050 F with is about right for me

[Tom Walz]

A very popular braze alloy for this sort of work is A56T (56% Silver with Copper, Zinc, Nickel and tin) which the American Welding Society designates as Bag-7. It melts over a range of 1145 – 1205F. It flows well, is easy to use and has good strength. It should also provide a pretty good color match.

For information on brazing go to our web site at
http://www.carbideprocessors.com/brazing.htm (http://www.carbideprocessors.com/brazing.htm)

We sell a brazing kit online at
http://www.carbideprocessors.com/store/brazingkit.html
(The eyedropper is for cleanliness testing.)

Cliff, if you want one send me a private message and I’ll sneak you one out free.

Tom

[harry strasil]

Brass is a copper/zinc alloy and Bronze is a copper/tin alloy mostly. I used to braze (bronze) the thin tubes in the center of the old maytag washers years ago. Brass is ready to take bronze rod when you see little sweat beads on the brass.