Looking for tips for sweat fitting copper water lines.

I need to replace all the copper water lines in my basement ceiling. they were installed when the house was built in 1965 and are having pin-hole leaks.
I've been soldering electronic devices for 40 years and occasionally copper pipe, so I know the basics.
I plan to solder some of the pipe segments on the ground before I lift the pipes into place and then tie into the existing lines.
My questions are:
1. Is there any device or technique to check the integrity of a solder joint on a pipe? -I *really* don't want to have any leaks when I turn the water on.
2. No matter how I will run the pipes, there will be times when I'll have to solder a connection in a 'tight' location where I can't see all around the fitting. Any tips on how to make sure the solder is sufficiently wicked into the fitting? (the pipes run both parallel and perpendicular to the floor joists.)

3. How important is it that the pipes where the joint (with a sleeve coupling) be 'perfectly straight'? (Or as straight as possible?) I am thinking that if the joint is a little cocked that the solder won't wick into the joint.

4. I plan on using type M (thinner wall) pipe instead of L.....Any reason to consider using L? (this is a 'typica' suburban/residential house.

I have considered redoing with PEX but if my spouse detects a 'plastic taste' in the water from the PEX, I'll have to redo the piping.
Thanks for your thoughts/suggestions.
J

By the sounds of those questions on soldering, you have not done very much of it and likely not very proficient at it.
One reason to consider using Type L would be to avoid pin-hole leaks.

Thanks for your comments and pointers to the use of type L.
I have not done much soldering of copper pipc but I have done 4o years of soldering electrical/electronics things of all sorts, on radar sets, motors, tube radio and TVs to many SMT computer boards. I do understand the basic physics, and for electronics, I am very proficient. What I lack is a knowledge of 'tricks' (thinks to do/not do) when doing copper pipe - Things that come with experience in this particular setting.

The most important part is cleaning pipes and fittings, and a good flux.
A picture's worth a thousand words...
There are quite a few good videos on YouTube. Watch a few and practice on some pieces.
Don't overheat or solder will flow out of the joint

Excellent advice from House Doc!

You may want to do a couple of practice runs and observe how well the TIGHT fit between pipe and fitting lends itself to "capillary action drawing free-flowing molten solder into the narrow clearance between the fitting and the tube. Molten solder metal is drawn into the joint by capillary action regardless of whether the solder flow is upward, downward or horizontal."

Be sure neither the pipe nor the fitting is slightly out of round.

Review the following videos.
https://www.copper.org/applications/plumbing/cth/soldered-joints/cth_6soljts_solder.html

Just a thought..soldering does take some practicei would say if your experieced go ahead.....there is a less expensive method pexvery easy to use if you make a mistake you can cut the band off the fitting and start again.....i never used it before ,until i had a pipe burst and had to move all the copper in my basement it would have cost a fortune and there were some spots that would have been imposskble to solder in
i use copper rings and my crimper covers the ring and compresses the whole ring the is a gauge that yiu can use to check your crimps
this method is mucg faster than copper/soldering i supported my pex at every floor joist

The trick to sweating copper pipe is practice and more practice.

Overhead soldering like that, with framing and maybe drywall very close, is dangerous even for pros.
Burning down the house, or solder drips on your face or body.

Plus you can burn wiring or coax or internet network cables.
Or paper backing on insulation.

Sounds like the ideal time to watch videos on installing pex, with transitions to existing copper where needed.

You can rent a pex crimper, but you might consider Sharkbite fittings.
Or a mixture of crimping and Sharkbite.

Very diy friendly.

If you use this flux, The only way you will have a leak is if you forget to solder the damn thing, it pre cleans and tins . The Nick solder is fantastic. It is lead free but flows like it is lead solder
i love the stuff and these are what you find on my truck

https://www.ferguson.com/product/jw-harris-nick-nickel-solder-hnick61/_/A-ProdFamily-221103

use C-flux and Nick solder
The tricks to copper piping is CLEAN clean the pipe and inside of the fitting
do not touch the pipe ends after cleaning, the oil on your fingers will cause the flux to not take at that spot
after soldering you MUST wipe the joints wih a damp rag to remove unused flux

You question on soldering in tight spots. you actually answered you own question.
the solder wicks around the pipe.

the main trick is your torch. those big ass flame throwers they sell at the big box stores do not allow you control over your heat. it is off or on..

Above is a pos flame thrower, Below This is the second choice
https://www.plumbingsupplynow.com/stk-9-torch-swirl-for-use-with-map-pro-or-lp-gas-0386-0403?msclkid=055a0d9636741781af6053a852ef7faa&utm_source=bing&utm_medium=cpc&utm_campaign=**LP Bing Shopping All Products&utm_term=4574861726366157&utm_content=Catch All

First choice, The one that will do every thing you want will run you about 200 bucks
https://www.plumbersstock.com/uniweld-k37-acetylene-b-tank-brazing-kit-wth3-sc.html?
utm_source=bing&utm_medium=cpc&scid=scbplp6665&sc_intid=6665

that is the torch, then you need a ''B" tank
https://www.riogrande.com/product/BAcetyleneTank/500060?msclkid=31583b3143c51f1d8b3d650f25cd4ca8&utm_source=bing&utm_medium=cpc&utm_campaign=Shopping_Tools & Equipment&utm_term=4584963490469890&utm_content=Tools & Equipment

I have a tank I will sell for 50 bucks. but shipping would kill that deal

the better the torch the better the solder job.


heat the back side bottom of fitting and solder the opposite side top
the solder will run to the heat.
I tippy tap. While i am heating i am tapping the pipe with my solder. when it starts to run I pull the heat away

when soldering a vertical joint, solder the top first then the bottom

TIP
if you have to solder in a tight spot up against something
heat the pipe 2 or 3 inches back. it will heat the joint. takes a minute longer . no biggie

Jeff Handy said:

The trick to sweating copper pipe is practice and more practice.

Overhead soldering like that, with framing and maybe drywall very close, is dangerous even for pros.
Burning down the house, or solder drips on your face or body.

Plus you can burn wiring or coax or internet network cables.
Or paper backing on insulation.

Sounds like the ideal time to watch videos on installing pex, with transitions to existing copper where needed.

You can rent a pex crimper, but you might consider Sharkbite fittings.
Or a mixture of crimping and Sharkbite.

Very diy friendly.

Click to expand...

No disrespect to you

FUK PEX !!!!!!!!!!!!!!!!!!!!!!!!

One way you could practice at the same time as installing you could run your mains 1st if its a straight run its just soldering couplingsthen come back and solder your tees and ballvalves fot your branches

Frodo, what is wrong with pex?

There's nothing wrong with PEX.

I think it may have something to do with teaching old dogs new tricks.

Jeff Handy said:

Frodo, what is wrong with pex?

Click to expand...

mice like to chew holes in it to get water
also squirrels

voletl said:

There's nothing wrong with PEX.

Click to expand...

They said the same thing about polybutaliene
mice like to eat it also.
then the pipe started cracking where it had been stretched over barb fittings
then a huge lawsuit

pex is not time tested, i can not in good conscience recommend a product for a owner to install that is not proven to withstand 20 years of use

Diehard said:

I think it may have something to do with teaching old dogs new tricks.

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new does not equate to better. it only equates to being new and shiny

I found the following comment interesting.

"Years ago when all this fun PEX became the "greatest thing since beer goggles" for the masses, it was debunked or unheard of that this piping was oblivious to these problems.

Well, truth be told, this product does have issues with this sort of rodent issue along with guys who pull this stuff through holes or graze upon nails or HVAC sharp ductwork edges and cold air return panning.

That causes the outside of the piping to get skinned or gouged during installation that can possibly lead to other issues over time.

And on top of that, having to hide this piping from the sun, covering up the piping in basements where indirect UV rays can slowly break the piping down.

Sure is a lot of conditioning for something that proves to be new age process....doncha think?"

EDIT: BTW...I'm an old dog myself.

“mice like to chew holes in it to get water
also squirrels”

I didn’t know that mice like to eat squirrels!
Thanks for the info.

Jeff Handy said:

“mice like to chew holes in it to get water
also squirrels”

I didn’t know that mice like to eat squirrels!
Thanks for the info.

Click to expand...

every watch the movie Ben ?

frodo said:

every watch the movie Ben ?

Click to expand...

I loved that movie!!!