Cleaning Oatey No. 95 from inside of pipes?

Blend9684 · February 5

Soldering newbie… I've been using Oatey No. 95 (lead-free) for soldering hydronic heating pipes and am starting to get the hang of it. I've likely been using too much as it I see it run down the inside of ball valves. Been doing my best to clean the outside and some of the inside.

I still feel film on the outside and the inside isn't particularly easy to clean, though the instructions just say to flush with water (though it's petroleum-based). I didn't want to use a water-based flux because I read that it might get fried at lower temps.

I'm assuming the outside will clean well once there's hot water running through the pipes, but should I be concerned about a stainless steel fire tube heat exchanger and this flux running through the system?

I've seen recommendations for flushing soon after initial fill, so maybe that will help. I can also try flushing individual pipe sections where I can.

Even in the worst-case, 1.7 oz of flux in a system (with buffer tank) that has ~41 gallons (5248 oz) of water makes me think I'm being overly cautious and I should just do my best.

Intplm. · February 5

Overly cautious? It depends on your soldering skills and how much solder is left behind on the inside diameter. Practicing soldering, if you are so inclined to be so concerned, should be done before any permanent soldering. Practicing should be done on copper tubing you don't necessary want to install.

mattmia2 · February 5

i don't think their issue is excess solder, it is the flux running around out of the joint, which is completely normal, just wipe it up on the outside with a wet rag and i'd probably just fill it, run it a couple days, drain and if i can flush then refill. there are system cleaners intoned for new systems you can run to clean it out if you want but unless you dumped the whole tub of flux in the system i'd doubt you'll have a problem.

Big Ed_4 · February 5

95/5 is a tough solder to work with. Try a roll of Sterling , it is worth the price .. It flows nicely with less heat .. A wet rag with detergent works well for cleaning off the excess flux .

Blend9684 · February 5

https://forum.heatinghelp.com/discussion/comment/1886428#Comment_1886428

The lead-free brass makes this harder (should have chosen something else for hydronics). But it hasn't been all that bad. When the joint is "ready," the solder just flows, similar to my experience with electronics soldering.

I need to do some potable water joints as well, so I need 95/5 there. I did order water-soluable though.

mattmia2 · February 5

lead free solder melts at a higher temp than tin-lead solder so there is a smaller window between where the joint is hot enough to melt the solder and where the flux burns away. different lead free alloys flow differently

ChrisJ · February 5

My favorite solder for plumbing has been Bridgit.

I also have a spool of Sterling but I like the Bridgit more.

https://www.supplyhouse.com/Harris-BRGT61-Bridgit-1-8-x-1lb-Spool-of-Solder

My preferred flux

https://www.supplyhouse.com/Oatey-30374-No-95-Tinning-Flux-1-7-oz

For cleaning outside you need to wipe it with a wet rag while it's still fairly hot. Not super hot because that's bad for the solder but still pretty hot.

I've never heard of cleaning the inside and can't imagine how you'd do that.

For valves I like wrap a wet rag around them to keep them cool obviously not on the side you're soldering. Most do not do this but I'm not as fast as them.

mattmia2 · February 5

i like using npt valves and adapters so if i burn something up it is a $1 adapter and not a $30 valve.

the idea of the tinning flux is that it tins the surfaces before the flux burns out even if you overheat the joint. i'v used both tinning and non-tinning flux with lead free solder and have no strong preference either way but have found that sometimes the solder particles in the tinning flux seem to sort of corrode and it gets kind of funky. much more important is clean both surfaces and flux both surfaces, heat the more massive part, move the torch around or away if you are applying solder for a while.

i see people doing electronic soldering on videos where they are doing mechanical stuff and they are doing everything wrong, it is painful to watch. dipping the iron in the flux, putting solder on the iron and trying to melt it in to the joint…

what do you mean about a wet rag being bad for the solder? most use a rag to smooth out the molten solder and sometimes to quench the joint

ChrisJ · February 5

https://forum.heatinghelp.com/discussion/comment/1886453#Comment_1886453

There's been threads on here as well as articles written on it. They say the thermal shock causes cracking.

That's all I've got.

I solder valves because I like less leak points but I can see benefits to both.

With an iron I be add solder to the iron usually to transfer heat. Sometimes I'll cheat and use it to hold solder but I try to avoid it. It'll only work if the joint or wire is already tinned.

mattmia2 · 12:00AM

there needs to be a little solder on the iron to transfer the heat but the adding solder to heat the joint usually is more getting flux from the core of the solder on the joint while wasting some solder. putting some flux on the joint helps a lot. small joints can be made with solder on the iron if you put flux on the joint but they weren't doing that. using liquid or paste electronic flux saves a lot of solder.

ChrisJ · 12:12AM

https://forum.heatinghelp.com/discussion/comment/1886471#Comment_1886471

I do it more when I'm soldering two wires together or doing point to point and I don't have a third hand. It's lazy but often will work.

EBEBRATT-Ed · 12:29AM

Stay away from 95/5 it is difficult to work with because if you look it up the temp it becomes solid is the same as the temp it becomes liquid…no in between. I like Silvabright but any of the newer solders are better than 95/5

hot_rod · 1:08AM

it is a good idea to run a hydronic cleaner through a system after soldering.

They are basically a strong detergent, that will clean flux, oils, pipe dope from all the components. Flush and fill with good water and add a conditioner

Fernox, Axiom are good brands. Use the screw on aerosol cans

Cleaning Oatey No. 95 from inside of pipes?

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