cleaning tubing for handling and welding

HomeBuiltAirplanes.com

Help Support HomeBuiltAirplanes.com:

mrmuzzy

New Member
Joined
Apr 12, 2003
Messages
2
Location
CoeurdAlene, Idaho
I'm just about ready to start cutting tubing for my first airplane which is a Cygnet . I would like know a cheap easy way to do it and leave it clean and possibly prevent rusting. I've read quite a lot about welding , cutting and fitting but no cleaning.
 

Craig

Well-Known Member
Joined
Jan 30, 2003
Messages
543
Location
Jupiter, Florida
Mel -
As for cutting, it's hard to beat a chop saw. I use either a die grinder or the bench grinder to form the cut end to the tube its being joined to.
Cleaning, I use the wire brush which is mounted on the other side of the bench grinder. If the tube is a long one, like a longeron or strut, I use emery cloth. Both ways I try to cledan back from the joint a few inches. Before welding, I use some MEK or acetone on a cotton rag.
After welding, use the wire brush or emery cloth to clean off any buildup.
As soon as you can, put some primer on the fresh weld, but don't do this before you finish the cluster, as the paint burning off leaves more carbon deposits. Obviously, I use oxyacetylene, not TIG, which is much cleaner!
Good luck with your project!
 

PTAirco

Well-Known Member
Joined
Sep 20, 2003
Messages
3,519
Location
Corona CA
Cleaning tubing

I have read in many places that cleaning a tube with wire brushes prior to welding is a no-no. The reason given is that the steel from t he bristles embeds itself in the metal of the tubes and contaminates the weld. I have built a fuselage using this method before reading this and was dismayed, but I used he same method on my CAA welding test pieces, which were tensile tested, cut apart,subjected to microscopic scrutiny and they passed. So, maybe a case of in theory; no, but in practice it makes no difference. I would have thought though that using aluminum oxide abrasive paper would contaminate the weld,. so make sure that the paper you use really is "emery" paper.
 

Jr.CubBuilder

Member
Joined
Oct 7, 2003
Messages
18
I use a little brush wheel chucked up in a drill for most of my cleaning, or sometimes a green pad. I think the wheel is a 3M product.
 

BMWSID

Active Member
Joined
Mar 6, 2004
Messages
39
Location
Western NY
As for shaping the ends, a tubing notcher that utilizes hole saws works great, if you are good at setting angles. I bought one from Harbor Freight. The actual bits are seperate, and can be changed, as the diameter tubing to be used.
As for cleaning for welding, make sure any residue from any chemicals is out of the atmosphere and off the parts. I personally know of several friends and my brother too, who have died from exposure to fumes from degreaser fluid, in this case, tri-chlor-ethelyne. Carbon tet works good too, but id also deadly in it is still present when you are welding. It turns into Phosgene (NERVE GAS!!) from the heat!!
Any airborne fumes can be lethal when welding, and often times the MSD sheets don't mention this. Better to be safe than sorry. Air the place out well. I don't remember the exact figures, but it is something like this; It takes 9 parts per million (PPM) to smell trichlor, but it only takes 3 PPM to be harmful. All this was found out by the welders where I was working for years, and managment knew it but wouldn't tell us!
I still enjoy welding aluminum, but am VERY careful about the atmosphere I do it in.
I hope this is not too late to help.
A stainless steel brush is better to brush aluminum with, dosn't leave as many deposits in the material to be welded.
With a steel welded joint, rust will start rapidly, as there is NO oil present after being over 2,000 degrees and does need to be protected with something soon as practically possible. Don't try to weld paint. Keep your head out of the cloud produced by welding, too.
 

Jr.CubBuilder

Member
Joined
Oct 7, 2003
Messages
18
What sort of tips are you using with the notcher? Standard hole saws grab to much on the thinwall tubing once they they get into the tube. I haven't been able to find something with smaller teeth or some type of abrasive edge that would work better.
 

BMWSID

Active Member
Joined
Mar 6, 2004
Messages
39
Location
Western NY
I have not used the notcher on thinwall tubing, but with the drill press, if you have the drill speed at max and feed the saw in slowly, it should be ok. I know I have seen bandsaw blades that have diamond dust embedded all the way around, on one edge, something like that on a hole saw cutter should solve the problem, if feeding it in slowly dosn't help. I will see if I can find something like that, and will post it here if I can.
 
Top