Casting - Help ?

[Gordon]

I've been PR casting Avery labels on brass tubes that have been powder coated gloss white without any problem. (30 psi - PR - 6 drops per oz -
cork sealed, for 5 hours).

However when I attempt to cast without the Avery labels directly to the powder coated tubes - the cured color of the tubes is only partially white and has a silver-like color at the tube ends.

Sorry I don't have the ability to provide a picture - but hoping someone
can advise.

Thanks as always.

Gordon

 

[td]

Because the powder coating process is based on heat to melt the particulates the problem is most likely the heat generated through the chemical reaction of the PR. Answer: Cast a regular blank then drill it and glue the PC tube in place.

Good Luck!

 

[its_virgil]

Hey Gordon, I don't understand what you are saying
...without the Avery labels...
...cured color of the tubes...
I can almost guarantee the silver-like color on the ends of the tubes is some how trapped air...
Air bubbles seem to stick to certain materials more than others. I have no problems with labels either and I paint the tubes with white primer, but other embedded material will cause problems much like you are seeing.

Do a good turn daily!
Don

However when I attempt to cast without the Avery labels directly to the powder coated tubes - the cured color of the tubes is only partially white and has a silver-like color at the tube ends.
Gordon

 

[Gordon]

Thanks guys

Gordon

 

[Blind_Squirrel]

The resin is separating from the tube. You are seeing the air gap.

Does it look similar to this, only on the ends?

 

[ldb2000]

I think allot of these problems are related to shrinkage. As the PR cures it shrinks and pulls away from the tubes . For clear casting Alumilite is better in some ways , it don't shrink .

 

[Blind_Squirrel]

I think allot of these problems are related to shrinkage. As the PR cures it shrinks and pulls away from the tubes . For clear casting Alumilite is better in some ways , it don't shrink .

The picture I posted IS Alumilite. I have never successfully cast a label or tube using Alumilite. They all separated like the one in the picture.

 

[Gordon]

Thanks - I'll try again.

Gordon

 

[its_virgil]

That is a problem with alumilite. That's why I continue to use PR for doing snake skins....it is much better for this application. Change to PR and your labels with come out really nice...and it's cheaper. Your turn Curtis.
Do a good turn daily!
Don

The picture I posted IS Alumilite. I have never successfully cast a label or tube using Alumilite. They all separated like the one in the picture.

 

[Blind_Squirrel]

That is a problem with alumilite. That's why I continue to use PR for doing snake skins....it is much better for this application. Change to PR and your labels with come out really nice...and it's cheaper. Your turn Curtis.
Do a good turn daily!
Don

I now only use PR. That picture is from when I was testing both products to make an informed decision.