Cleaning INSIDE 2" copper pipe

[900footjesus]

Howdy,

I have spent lots of time reading the mountain of information posted here by you kind souls. All I can say is thank you! I have decided to take the plunge, after several years of dallying about.

I have secured 6 feet of 2" copper type L from a local salvage yard. The outside looks great, but the inside is pretty much covered in a yellow/red layer of some sort. I would assume that this probably needs to come out before I get started soldering. I have made some tentative attempts to remove it with vinegar, 3M scrubbies and coarse steel wool. Seems like I am pissing in the wind, regardless of how much junk comes out at the end of the exercise. I even rigged up a wooden dowel with steel wool stapled to it and ran it through the pipe with my drill. I got quite a bit of stuff out, but the layer of junk is still there. I have also considered using high-strength Starsan, which cleans my copper immersion chiller wonderfully.

According to the scrap guy, this pipe was water line, so I'm not worried about nasty chemical residue. I'm assuming that this stuff is oxidation until proven otherwise. And, yes, I have read the posts about different acids, just haven't seen anything dealing with this specific problem.

Questions:

1. Should I be worried about this layer of stuff?
2. Does anyone have a better way than what I have already described for cleaning INSIDE a pipe?
3. Should I just solder up and clean in place after everything is together?

I am planning on a 48" Bokabob on a 15.5 gallon beer keg fired with a propane burner.

Please discuss.

[LWTCS]

I would do some layout, cut and mock up your head. Then clean your pipe as smaller peices.

I have used a 4 to 1 muriatic acid solution and find that it does a very good job. Then a thurogh rinse.

I also employ a cylinder hone and drill motor for the smaller peices as the stem on the hone is only 12" long.

Good luck.

[ozone39]

Hate to be a sour apple. But a water line on a domestic water system is one thing, a water pipe that's been installed on a heating system is a completely different problem. Heating systems run ethylene glycol as well as rust inhibitors. I'm not sure if I would trust it, not sure what it would take to clean that stuff out of there 100%.

[900footjesus]

I just got some muriatic acid, so we will see. I'll report back this afternoon with the results.

[900footjesus]

I just did a little test run, I think we have a winner in the 1:4 acid/water solution. The only thing I have to solve now is how to submerge the pipe in the solution. Does anyone know if schedule 40 PVC is acid proof? I'm thinking a stick of 3" PVC and an end cap might do it for a vessel if it is.

Stuff came out without too much trouble after dunking one end in a glass jar of it, sat for about a minute, rinsed and scrubbed. I bet a longer soak, or multiple soaks would probably do the trick before running my steel wool gadget through it. I am sooo glad I have a pair of acid proof gauntlet gloves.

[myerfire]

Go to a plumbing supply house and get a rubber plug for one end and just fill the pipe with your solution.
myerfire

[900footjesus]

Hadn't thought of that. Thanks. I have to go back and buy a couple more fittings, so I'll pick up one of those while I am there.

[LWTCS]

Acid won't touch your plastic bucket (or the like).

[rubber duck]

I like to use a 2" flue brush on a 3' extension attached to a drill to clean my column.