Tinning Flux

[MarkB_MI]

I had some plumbing to do over the weekend, so I dug out my supplies, including a tin of Oatey "Tinning Flux". When I started to sweat my connections, I remembered why I quit using the tinning flux: Instead of cleaning the copper, this flux quickly turned black, leaving me with a very suspect-looking joint. I switched to a tin of regular Harvey flux, and my problems went away.

Has anyone else tried using the Oatey Tinning Flux? Is it just lousy flux or am I doing something wrong?

 

[Anonymous-0]

I have gotten a bad can of flux before, have not used this product.

 

[caterpillar guy]

If your having trouble with it turning black you are heating the place to hot. Try not heating so hot and if the solder is flowing til the joint is full with no holes then your good to go. wiring needs rosin for the flux and items like copper pipe and the like use acid or zinc chloride the mixture of acid and zinc. Just can't remember the acid used to make it wether it is hydrochloric or sulfuric. you disolve the zinc in the acid to a certain level of zinc.

 

[Anonymous-0]

That tinning flux contains powdered silver solder. You must use lead free solid core solder with the tinning flux. Use of lead and acid core solder will make a real mess.

 

[Anonymous-0]

The flux you are refering to is cut acid flux. It is made by dissolving zinc in hydrocloric acid. Zinc is added until no more will dissolve into solution. It does a good job of dissolving oxides and prevents oxides from forming when the metal is heated. It helps lower the surface tension of the molten solder so it flows better Since it is corrosive is must be washed off after soldering is complete or it will corrode the metal. It might be too strong for use on copper where milder solder paste will do the job. It works well on galvanized sheet metal.

 

[Stan in Oly, WA]

Hi Mark,

I use Oatey Tinning Flux for sweat fitting copper plumbing. I'm not convinced that it's the best product available for the job, but I've got a large tub of it and it has always seemed to work well enough.

You might try wiping off all excess flux from the exterior of the joint(s) before you apply the heat. Once the fittings have been cleaned, fluxed, and assembled, wiping the exterior will not contaminate the joint and will produce a cleaner result. You should also wipe all excess flux from the joint after it is soldered.

All the best, Stan

 

[T_Bone]

Hi Mark,

If you preclean the joint, 80grit emery paper the pipe and wire brush the fitting, a flux will not be required for any of the common metals.

I use the above method even to make a 100% silver solder brazed joint on high pressure (500psi) refrigeration piping with excellent results.

It's that pesky oxidized surface layer that requires the flux, like a hidden large area flat surface or multiple bundle of wires. Here a flux used for precleaning is just faster and more simpler to use.

The cheapest and best flux can be made from borax and alcohol.

T_Bone

 

[Anonymous-0]

Borax and alcohol. Interesting. Do you make a paste or solution? Does it need washing afterward?

 

[T_Bone]

Hi mj,

You can pretty well use it how you want. That's what's so easy about it as it's one shoe fits all type flux.

Depending on the type of metal, but generally it leaves a soft like glass covering. Used for gold, leaves behind a hard glass that can be chipped.

They way I wrote my post would leave someone too think I use this flux for everything. There's a place for cut acid flux in sheetmetal work that would out preform the borax hands down.

T_Bone

 

[MarkB_MI]

Hi Stan,

Thanks for your response and thanks to everyone else as well. I think you're right, the trick must be to wipe off any excess before soldering. Even though I try to not apply any more heat than necessary, this flux starts to blacken before the joint gets hot enough to melt solder. I now recall that I've had similar problems with other Oatey products as well.

At any rate, I solved this particular problem by pitching my Oatey Tinning Flux in the garbage.

 

[Anonymous-0]

Ive used a paste flux called Nokorode for over 50 years.Acid flux is good on radiator work.Getting a clean surface is the answer to solder.I dont use a flame ,big solder irons work better.Open flame burns the flux.A Bernzomatic torch with a solder iron tip works best.