painted tube failures

[healeydays]

Folks,

I've been doing a lot of searches and reading and can't find what I am looking for so I thought I would ask.

I have been doing alot with Carbon Fiber and other tube coverings with no issues, but what I would like to do is paint a tube and then attach items such as watch parts etc to the painted tubes.

I have used acrylic paints, nail polish and enamel paint and the CA I use is low bloom due to allergies.

I usually let the tubes cure at every stage for at least a week to let everything to cure completely before the next step.

I have had different types of failures such as:

1) CA causing paint to soften/dissolve
2) when doing casting with PR, and turn the blank, the PR separates from the painted surface on the top and bottom of the blanks.


Does anyone have a suggestion on what will work everytime so I don't have blank failures? I'm looking for a foolproof method so I can get these blanks done with custom colors being the covering on the tubes.

Mike B

 

[Ed McDonnell]

Hi Mike - Is the PR separated from the painted tube at the ends after you start turning (and not before) or do you just notice it once you start turning, but the separation happened during the cure?

Is the separation only at the ends and nowhere else?

How are you casting the PR on the painted tube? Vertical molds? Horizontal silicone resin saver molds? Rotocasting?

I've cast a lot of painted tubes (using horizontal silicone molds and rotocasting) and I've not had the type of failure you are describing.

Any pictures (of the failed PR blanks, not the CA ones)?

Ed

 

[Turned Around]

I recently painted 20 tubes with a metalic spray from Testors. Then glued fly fishing lures them and casted all that. When I finally got to assembling them all, the acrylic seperated from the tube, leaving bubbles on every single blank. BIG bubbles.

 

[healeydays]

Hi Mike - Is the PR separated from the painted tube at the ends after you start turning (and not before) or do you just notice it once you start turning, but the separation happened during the cure?

Is the separation only at the ends and nowhere else?

How are you casting the PR on the painted tube? Vertical molds? Horizontal silicone resin saver molds? Rotocasting?

I've cast a lot of painted tubes (using horizontal silicone molds and rotocasting) and I've not had the type of failure you are describing.

Any pictures (of the failed PR blanks, not the CA ones)?

Ed

The separation is at the end of the tubes. I only notice it when I have turned the blank. These are made in horizontal molds or both resin saver and other horizontal in tube type molds.

 

[Ed McDonnell]

The separation is at the end of the tubes. I only notice it when I have turned the blank. These are made in horizontal molds or both resin saver and other horizontal in tube type molds.

I've had resin separate from the tube in three different situations:

1) I cast tube in in rigid (acetal) molds. The resin did not pull away from the rigid tube mold as it shrank during curing. Instead it pulled away from the brass tube as it shrank. This was not limited to just the ends though. Although using a release agent mostly solved this problem, I don't do tube in casting in rigid molds anymore. This doesn't sound like your problem.

2) using silicone molds with the black rubber plugs (like Fred Wissen sells) I've had the resin pull away from the ends of the tubes when removing the black plugs the wrong way. I wiggled the black rubber plugs laterally to try and break them free. This is a bad thing to do when the resin is still soft (from heat curing in a toaster oven). It left the resin unattached to the tubes at the ends. This sounds more like what you are experiencing, but without pictures and with the tiny bit of information you are sharing I'm just wagging it. Making sure the resin is at room temp and / or not exerting any lateral force on the resin when removing the black plugs solved the issue for me with these molds. I use these molds to do all my tube in casting now.

3) using the silicone resin saver molds, where the plugs are an integral part of the mold. Trying to remove the tubes from the mold before the resin was fully hard would sometimes pull the resin away from the tubes at one or both ends.

In addition to those problems, if the ends of your tubes are not perfectly flat and trimmed back fully to the brass (and / or your bushings are not clean) it is possible to crack the resin off the brass tubes at the ends as you apply pressure with your tail stock. I would expect you to also see cracks in the resin in this case, so I kind of doubt this is your problem.

None of this may be your problem, but it's what I can think of.

Ed

 

[healeydays]

It could be taking the blanks out of the molds early. Some I take out before totally hard, others I have left for a week. I'm going to have to do a test cast to test it out.

Mike B

 

[ALexG]

you can paint the tubes with a couple of coats of permanent marker, use epoxy with one drop of acrylic paint for gluing.
CA with acrylic paint in the tubes didn't work for me

 

[healeydays]

you can paint the tubes with a couple of coats of permanent marker, use epoxy with one drop of acrylic paint for gluing.
CA with acrylic paint in the tubes didn't work for me

Thanks for the idea, but wouldn't work for what I am doing as I am doing custom colored tubes and markers don't come in the colors I need.

 

[alparent]

My father-in-law works with stained glass. He gave me a bottle of stuff they spread on metal parts to blacken them. I just put the liquid in a jar, put the blanks in and instant black tubes.

 

[raar25]

What is the chemical you are using to blacken the tubes? I have tried a couple things and have had not sucess?

 

[alparent]

I think it's called Novacan

 

[healeydays]

Doesn't really belong in this forum, as this was about painted tube failures, but here you guys go...

Patina Formulas for Brass, Bronze and Copper

 

[NittanyLion]

Mike,

I haven't tried this in the application you mention, but I would suggest powder coating your tubes. If you wan to try it, I can powdercoat a set for you, no charge, just mail me the tubes. My colors are limited, but I think this might solve your problem. PM me if interested.