Epoxy and Brass Tubes

[fitzman163]

Has anyone had trouble gluing brass tubes with 2 part epoxy? I have had 2 out of 10 fail, this is not acceptable. I have painted the outside of the tubes and tubes came out when I was using the barrel trimmer. I did notice that there was no paint on the tube that was exposed. I don’t know if it came off from the tube spinning in the blank or if there was a reaction with the glue. Any help would be appreciated.

 

[Chasper]

My first guess is that the ends of the tubes were not entirely clear. If even a small amount of epoxy gets into the tube and isn't entirely cleaned out, it will potentially heat up and bind the tube to the end mill shaft. The center shafts on the ends mills don't do much to dig out excess adhesive.

Plugging the end of the tube before interting it is the first defense against this, you might also try cleaning it out with a slightly smaller drill bit, I use a chain saw file to girnd out stubborn bits of epoxy or CA. Try sliding the tubed blank on the mandrel before end milling. If it will slide over the mandrel, then it is clean on the inside of the tube.

 

[turned_for_good]

I use nothing but epoxy and had one failure because of squeze out, meaning as the glue cured it pushed the tube out a little. I would try painting the inside of the blank more than the tube. Also try tinting the epoxy. It sounds like what you used to color the tubes would not bond to the tubes, espcially if there was no paint at all on the tubes when they came out.

 

[rherrell]

What kind of paint did you use? Did you wipe it down with lacquer thinner or acetone and rough it up with sandpaper?

 

[sailing_away]

I paint the insides of the blank with Testors model paint instead of the tubes. Also, try lightly sanding the tubes on the lathe with 120 grit paper to remove any oils / contaminates and give the epoxy a good surface to adhere to. Since I changed from painting the tubes, I have not had any failures.

 

[alamocdc]

Jim, I use nothing but epoxy and haven't had a problem. Make sure you scuff the tubes.

 

[Rifleman1776]

I don't know what you mean by "fail". All I use is two part epoxy. Never a problem. I'm kinda sloppy and have to clean drops from the ends sometimes. Also, I don't understand Chaspers "will potentially heat up and bind the tube to the end mill shaft". I think he is talking about problems that do not exist.
Here is how I do it: rough tube with coarse sandpaper, apply epoxy to tube, put tube into hole.
Nothing complicated. Works.

 

[turned_for_good]

To tell you honestly, I don't even rough up the tubes. Never had a problem yet.

 

[Blind_Squirrel]

Originally posted by fitzman163

Has anyone had trouble gluing brass tubes with 2 part epoxy? I have had 2 out of 10 fail, this is not acceptable. I have painted the outside of the tubes and tubes came out when I was using the barrel trimmer. I did notice that there was no paint on the tube that was exposed. I don’t know if it came off from the tube spinning in the blank or if there was a reaction with the glue. Any help would be appreciated.

From your description it sounds like your paint is failing. If the blank is opaque I would not use any paint. If the blank is transparent or translucent I would use a different paint (I use testers model paint) to paint the blank and tint the expoxy.

 

[fitzman163]

If I rough up the tube and then paint it so much for the roughness the paint just filled that in. If I paint it and then rough it up so much for the paint. What I ment by fail was it doesn't work.I have to paint the tubes because the tube shows through my blanks 90% of them. I think I will try the model paint and tinting to epoxy or maybe try thick CA glue. Thank you for all your input guys. If I have any more problems I will let you know.
Thanks,
Jim

 

[leehljp]

Originally posted by fitzman163

If I rough up the tube and then paint it so much for the roughness the paint just filled that in. If I paint it and then rough it up so much for the paint. What I ment by fail was it doesn't work.I have to paint the tubes because the tube shows through my blanks 90% of them. I think I will try the model paint and tinting to epoxy or maybe try thick CA glue. Thank you for all your input guys. If I have any more problems I will let you know.
Thanks,
Jim

The assumption here is that roughed brass will make paint stick, but that is not necessarily true. You can have rough teflon and paint still will not stick. The point is that it is not a matter of clean or rough, it is a matter that some kinds of paints will not stick well to certain material. Some plastic paints will stick to glass or metal until a little pressure is applied and then the paint will just chip off in large pieces. There is no bonding between the paint and metal. I think this is what RHerrel and Blind Squirrel are suggesting, and me too.

 

[JHFerrell]

I use a paint made specially for metals that I buy at a local art supply store. Rough the tubes, paint, let dry overnight, glue with epoxy. In three years, maybe 2 or 3 failures. Also, I use a small pen knife to remove any excess epoxy squeeze out from the ends of the tubes. Not a big deal. Certainly less aggravating than tubes coming out!

 

[Texatdurango]

Originally posted by fitzman163

...I have to paint the tubes because the tube shows through my blanks 90% of them. I think I will try the model paint and tinting to epoxy or maybe try thick CA glue. Thank you for all your input guys. If I have any more problems I will let you know.
Thanks,
Jim

There are other ways of getting around this problem. I posted a solution on another thread recently, you might find the information useful... http://162.42.234.18/forum/topic.asp?TOPIC_ID=36196&SearchTerms=pearl,ex

Don't fight the glue, let it work for you not against you! Save the model paint for models!

 

[BrentK]

I have had more trouble with CA glue than any so now I use gorilla glue with no problems at all.

 

[fitzman163]

Thanks again guys for all the great info. I should be able to get it now.As BrentK said I also use Gorilla Glue with no problems on all my other blanks but I read her somewhere that you can see the glue voids and air bubbles through the acrylic. I will try it and see what happens because I love that Gorilla Glue.

 

[Chasper]

tubes came out when I was using the barrel trimmer

As I read the original question, I think what fitzman is saying is that when he trims the ends of the blanks with a barrel trimmer the tube sticks to the shaft of the trimmer and comes out of the blank. I think this is caused by epoxy inside of the tube. I've the same thing a few times. The tube bonds to the trimmer shaft, breaking the bond between the paint and the blank and as it spins around. The paint from the tube sticks with the epoxy between the tube and inside of blank. When the trimmer is raised from the blank the tube comes with it and the paint is gone.