how to clean the inside of tubes?

raticus · Sat Jun 27, 2015 9:20 pm

I learned the hard way building my roll cage in my race car this past winter, that all the cleaning on the outside of the tubes when TIG welding means nothing if you forget to clean the inside of the tubes as well (though I'm sure that as a beginner just learning how to TIG I was probably running a bit too hot exacerbating the issue), as 2 of my 10 joints turned into a contamination nightmare that had me stumped at the time trying to figure out why. About to build some custom exhaust tubes for my daily driver (an old unrestored 67 Dodge Coronet), and got some decent mandrel bent exhaust tubes to cut up and weld together and I remember my issue with my roll cage, and as I was cleaning them I was having a hard time trying to clean the grease out of the inside of the tubes. My stuffing of an old sock soaked in acetone attached to an 1/8" filler rod isn't exactly the best method, and thinking about smaller tubes it wouldn't work at all... So how exactly do you clean the inside of tubing you're about to weld? thanks!

Braehill · Sat Jun 27, 2015 9:51 pm

I use a flapper wheel on a die grinder if it's big enough and on smaller tube you can use a s/s plumbers brush made for copper tubing. Then you can use the acetone soaked rag to remove the residual crap. Just remember that any oil in the pipe will turn to vapors and find it's way to your weld, it's drawn by the temperature rise.

Plug the end and fill the pipe up with acetone, MEK, toluene, thinner, anything that will breakdown the oil and dump it into a bucket where it can be re-used for the next one. You'll get more miles out of your chemicals that way. Brake cleaners work well also, just remember to use the non-chlorinated ones to eliminate the chance to produce Phosgene gas when it heats up, bad stuff.

There's also a cleaner that's used to make things Oxygen clean that's available at most Dive shops called Blue Gold. I did a review on it in the "Product Review" thread.

Len

raticus · Mon Jun 29, 2015 11:33 pm

Braehill wrote:I use a flapper wheel on a die grinder if it's big enough and on smaller tube you can use a s/s plumbers brush made for copper tubing. Then you can use the acetone soaked rag to remove the residual crap. Just remember that any oil in the pipe will turn to vapors and find it's way to your weld, it's drawn by the temperature rise.

Plug the end and fill the pipe up with acetone, MEK, toluene, thinner, anything that will breakdown the oil and dump it into a bucket where it can be re-used for the next one. You'll get more miles out of your chemicals that way. Brake cleaners work well also, just remember to use the non-chlorinated ones to eliminate the chance to produce Phosgene gas when it heats up, bad stuff.

There's also a cleaner that's used to make things Oxygen clean that's available at most Dive shops called Blue Gold. I did a review on it in the "Product Review" thread.

Len

the largest tubes I'll weld with are exhaust tubing (around 3") and roll cage tubing (1.5"-1.75"), and the lengths can be pretty long so stuffing a brush into the them doesn't seem too feasible, especially the bent tubes. As far as pouring cleaners in them, would any of those work well on thick grease? I've received tubes with a very thick white grease inside some of them, I'm guessing they're used in the cutting and/or bending processes after being formed (though I can't seem to find out exactly what kind of grease it is). For the smaller tubing I guess it wouldn't take too much acetone (or whatever) to fill it up, but for the exhaust tubing that would take a lot of liquid. I'm surprised I have never seen much talked about when it comes to cleaning the inside of tubing for welding. I wonder if there's a quicker easier method, possible even using a power washer or something in that thought. Or better yet, a steel supplier that offers cleaned tubing, or at least heavy grease free. Wish there was a dry cleaners I could take my tubing to, and get my shirts done at the same time!

thanks for the info Len!

kiwi2wheels · Tue Jun 30, 2015 4:39 am

Try something like these, weld an extension on for the longer lengths.

http://www.torringtonbrushes.com/nylon- ... ushes.html

Soak the bends in a bucket of solvent, or whatever you have, overnight. After, a hot water wash (with dish washing
solution ) and hot rinse helps.

castweldsolutions · Tue Jun 30, 2015 12:25 pm

Braehill wrote: . . . Brake cleaners work well also, just remember to use the non-chlorinated ones to eliminate the chance to produce Phosgene gas when it heats up, bad stuff. . . Len

Just did a google search on this. Holy crap I'm lucky to be alive and I feel like a retard now. I've been using brake cleaner for prepping transmission welds for months. I've been using a 75% helium mix so I hope I'm not as bad off as what I'm reading, and I atleast had the common sense to blow dry the parts afterwards so the liquid never flamed up, but there are several times I can recall where the aluminum exploded into thimble size craters with a whole bunch of junk in it. Apparently symptoms can show up a long time after use too.

Here is the article I found in the search - http://www.chopcult.com/news/articles/t ... oning.html

Thanks a lot for the heads up fellas. I'm definitely changing how I prep my metals now.

Geeze, do I need to go see a doctor? I'm kinda freaked out now.

What about acetone? Is there chlorides in that? Is it safe to prep with?

hey_allen · Tue Jun 30, 2015 12:45 pm

If you haven't died yet, you're probably good. Phosgene is fairly fast acting, as in, within minutes you'd have felt it, and shortly after been in medical care or dead.

A number of cleaners work, as Braehill said above. Even some forms of brake cleaner that are CFC free, but still not a comfortable feeling when you are thinking about it.
Watch for the ingredient list to have something like the red can in the article you linked. In that one, Tetrachloroethylene is the chlorinated solvent that is the risk when exposed to heat and UV when welding.

Braehill · Tue Jun 30, 2015 2:09 pm

This has been out there for quite awhile now about brake/contact cleaners and I have to say I'm surprised that there's not a bigger warning on the label of this stuff. We tell people to wash their hands after they use the restroom, but we can't warn people of real dangers?

@raticus,
There's lots of different size bottle brushes out there that should take some of the heavy stuff out. I would think on the larger ones if you clean a fair distance away from the weld joint that you should be good. The heat will be limited to a short distance from the weld while you weld it. After that just let the fumes vent for awhile.

I'm not sure why they would need heavy grease on the inside of a pipe while they mandrel bend it, but if it's there it's there and you have to deal with it.

Len

Oscar · Tue Jun 30, 2015 3:25 pm

Thanks for the brush link, I needed some of those.

raticus · Tue Jun 30, 2015 10:51 pm

castweldsolutions wrote:
Braehill wrote: . . . Brake cleaners work well also, just remember to use the non-chlorinated ones to eliminate the chance to produce Phosgene gas when it heats up, bad stuff. . . Len
Just did a google search on this. Holy crap I'm lucky to be alive and I feel like a retard now. I've been using brake cleaner for prepping transmission welds for months. I've been using a 75% helium mix so I hope I'm not as bad off as what I'm reading, and I atleast had the common sense to blow dry the parts afterwards so the liquid never flamed up, but there are several times I can recall where the aluminum exploded into thimble size craters with a whole bunch of junk in it. Apparently symptoms can show up a long time after use too.

Here is the article I found in the search - http://www.chopcult.com/news/articles/t ... oning.html

Thanks a lot for the heads up fellas. I'm definitely changing how I prep my metals now.

Geeze, do I need to go see a doctor? I'm kinda freaked out now.

What about acetone? Is there chlorides in that? Is it safe to prep with?

the first (and last) time I tried using Brakleen to clean some steel to weld, I only welded for about a minute and the fumes were so overpowering I had to run out of my basement and open up all the doors and windows of my house. It was noticeably dangerously toxic, not like other chemical fumes that may give you notice in one way or another, but more like a natural flight response to impending death... I'm surprised you didn't notice it yourself!

castweldsolutions · Mon Jul 27, 2015 10:10 am

Well, when I used brake cleaner, I always took an air nozzle and blew the part completely dry to avoid a fire hazard. Maybe this was some saving grace for me. I'm thinking about getting some "blue gold cleaner", I've read some good reviews about it and I think it might be worth the investment. Either way, I'm done with brake cleaner and I'm already teaching about its effects to the my students in the safety briefing.

Mon Jul 27, 2015 8:50 pm

"Chlorides" are the risk.

Anything containing Methylene Chloride is right out. TCE (Tetrachloroethylene) is also a no-no. and any old-school cans of anything using Freon as the propellant is downright deadly.

Use ONLY non-chlorinated solvents when prepping metal for hot work. (Note I didn't say "weld"... NO hot work, cutting grinding, buffing, etc. should be done on anything cleaned in a chlorinated solvent unless it's been BAKED dry.)

Steve S