porosity in silver

[creighton]

What is the cause of this? The fillet material is 50% Ag.. I used plenty of flux and did not cook it at all... the flux did turn a bit green though..here and there..

I used the wire to catch and re-apply the drippy molten flux to the area I was working. Is this a weak joint because of the bubbles?

Thank you for your time, CW

P.S. the TT is not file undercut.. its an illusion made by a shorter wash line...working on even fillet flow and line.. had to mention for those keeping score.....and that I am my own worst critic.

[Curt Goodrich]

Can be lots of things. Too hot. Not hot enough. Garbage in the flux. Be careful doing silver fillets. There's no real good reason to do it and plenty of reasons not to. Nice work on the seat stays plugs.

[Dazza]

using Astro 165 rod.
55% ag
and with this rod I really had to try hard to get a pin hole
I know this is contrary to the US builders thoughts
but Casarti and many others in Europe have used silver for many years this way.
I loved silver for fillet brazing, I hated brass
especially on funky shaped tubes {which I do not use now}
alignments stayed sweeter {all those in built stresses from the shaping, yuk, so it's only lugs for Dazza}
and never a failure and never micro cracking that Hank Folson speaks of, and I did ask him and the Harris people to show evidence of this etc etc.
All came up with nil!
Silver feathers out so easy to the edge.
But an expensive way to go!

[Dazza]

I never use a brush for flux, always a hair would burn up in the joint, I used a stainless rod dipped and wiped the flux to the joints, in fact that is all I do.
and I brushed a thin layer of flux onto each rod before use when I filleted

[Dave Kirk]

I've got a buck that says the rod was dirty or tarnished.

Dave

[Jason Musgrave]

Yup--acetone is your friend

[Dazza]

and I used harris black flux for filleting

[creighton]

Thanks all... yeah, tarnished.. I have the 'sometimes' habit of wiping the wire with scotch-brite then acetone/tee shirt rag. I need to make it my 'everytime' habit from now on.. or is this just anouther way to introduce garbage into the joint? I use(d) the same method for the tubes as well???

No one has commented on joint strength or lack there of because of the porosity.. So I am guessing that its good..just ugly? I feel that its good...

I will do much better the next time!

CW

[Dazza]

Thanks all... yeah, tarnished.. I have the 'sometimes' habit of wiping the wire with scotch-brite then acetone/tee shirt rag. I need to make it my 'everytime' habit from now on.. or is this just anouther way to introduce garbage into the joint? I use(d) the same method for the tubes as well???

No one has commented on joint strength or lack there of because of the porosity.. So I am guessing that its good..just ugly? I feel that its good...

I will do much better the next time!

CW

The joint will not fail
I am not a fan of acetone in the workshop, I have it, but only use it for a few jobs and never daily. It can be nasty stuff for one's health.
Rods, if gruby, I rub down with 240 grit and then wipe with a clean rag. Not sure if that is the way of the wise, but I rather that than acetone fumes, skin contact etc.
Just my way.

[EnginCycles]

Available everywhere

[creighton]

howa bout this for a less toxic/acetone free method for cleaning tubes...

Simple green+ 2.5 gallon bucket+ sealed lid + various brass barrel bore brushes for small and weird shaped stay ends/ drum mandrel for 240g for coped big round tube ends and lugs... all spun with a drill motor. Use a standard issue green scrubby/sponge thingy for the outsides. rinse.. Then.. anouther 2.5 gal sealable bucket of isopropyl alcohol to soak for removal of the simple green and to absorb remaining water..? All flamables then stored next to the water heater and radiator furnace for maximum safety...


Sound okay?

C

[crumpton]

acetone isn't so bad as most think. and it lives in your acetylene tank!

Toxicology

Acetone is believed to exhibit only slight toxicity in normal use, and there is no strong evidence of chronic health effects if basic precautions are followed.

http://en.wikipedia.org/wiki/Acetone

it is basically ketones which is present in the body.

simple green on the other hand leaves a nasty residue/dirt magnet requiring more effort to remove than is worth. i banned it from the shop years ago.

[e-RICHIE]

no chemicals atmo.

[K Bedford]

When doing silver clean is the name of the game. When you think everything's clean, clean it again. This includes degreasing to remove even sweat and oils from your hands.
When you buy your rod if it's in a good container keep in there except for what you're using and if you have a piece you used even yesterday, clean it by sanding with fine emory or scotch brite.
Once exposed the brazing material will begin to oxidize immediately.
Also, if your flux is in a larger container, even a pint or so I would recommend using a smaller container with only enough for a couple days use so you have to refill it with clean stuff out of the larger container regularly.
I've found that every time you open the container and dip a brush or whatever in and brush it on the work piece you picking up junk that makes it back into the clean flux when you dip again which inevitably keeps building up until the remaining flux in the main container is dirty.
Keep it clean.
Be happy.
Kelly