Clear cast turned cloudy

[PTownSubbie]

I have been experimenting with casting and finally got around to turning one of the castings that my wife has done. It is a clear cast with some acrylic shavings in it from some other turnings.

We did the normal cast. Allowed it to dry for what seemed forever. It sat for well over a week. It didn't need that long, I just didn't have time to do anything with it. It didn't have any signs of air bubble in it. I squared it up and drilled the holes for the brass. Used Thick CA to glue the brass in the blank. Squared the faces of the blank with a pen mill and sander and then turned it.

After I finished I noticed that the blank was cloudy in a couple of areas. What do you think caused it?

BTW, it was with Casting Craft from Michaels. It was one of my first castings and have since turned a few from Silmar 40 and they turn much nicer.....

 

[sekach]

Fred, I have used the same PR materials from Michaels and have had some of the same issues. So far I can only narrow it down to excessive heat while sanding. I had a tendancy to get a little aggresive and did not wet sand. After going through a few of my clear blanks this way I switched over to wet sanding and the cloudy areas have been reduced, not totally eliminated though. So there is still something I am not doing quite right or am still coming across some heat maybe while turning (which is a possibility as well). Just my two cents worth....

Bob

 

[PTownSubbie]

Bob,

I always wetsand anything that is not wood. I try to keep the heat to a minimum but can't always do that of course.

I had something cross my mind last night after my post.....Could it be an area of the tube that does not have any CA glue on it and I am seeing the dust from drilling? I don't clean out the inside of the hole after it is drilled. Does anyone?

 

[gketell]

I think I can see the tube through the blank. Which means it could be the glue, not the PR, that has gone cloudy. Hard to tell from the picture. If you look through the blank across the top of the tube (not down at the tube, but across it at a tangent) is the PR clear or cloudy?

Heat can cause cloudiness; tool chatter (even at the microscopic level) can cause cloudiness. Make sure your tools are very very sharp and you aren't being too aggressive.

GK

 

[ed4copies]

Is the resin cloudy? Or did you not polish the INSIDE of the hole??

I suspect you are seeing the drill marks, that were not polished out on the inside of the hole. Glue will fill SOME and make them disappear, but this is NOT a reliable way to get a clear view.

 

[PTownSubbie]

Is the resin cloudy? Or did you not polish the INSIDE of the hole??

I suspect you are seeing the drill marks, that were not polished out on the inside of the hole. Glue will fill SOME and make them disappear, but this is NOT a reliable way to get a clear view.

Not knowing any better, do you have to polish the inside of the blank after you drill it? How do you polish it?

 

[ed4copies]

Here's a discussion:
http://www.penturners.org/forum/showthread.php?t=48070&highlight=demonstrator

There are probably others too, just search "demonstrator" (that's what "see through" pens are frequently called - they were used by salesmen to show the "innards")

 

[gketell]

Not knowing any better, do you have to polish the inside of the blank after you drill it? How do you polish it?

Only if you are trying for a clear blank. In this case the blank is clear so you can see the tube. But this also means that it is clear so you can see bad glue, bad drilling, scratches in the tube (you did rough it up so the glue sticks, right?), etc.

When I did my clear blank I sprayed the inside of the tube with pearlescent paint followed by gold paint. Now you have the clear blank showing off all the depth of what you cast but you can't see into the hole to see the tube, etc.

GK

 

[ed4copies]

That would also make it no longer a "demonstrator" pen.

Not bad or good, just changes the type.
I like your look, Greg!!

 

[DozerMite]

The best way to eliminate the problem is to cast the tube. No drilling to mark up the blank, no heat while drilling, and no glue to worry about.
The tube can be painted before casting it as well.
Just my $.02

 

[ed4copies]

The best way to eliminate the problem is to cast the tube. No drilling to mark up the blank, no heat while drilling, and no glue to worry about.
The tube can be painted before casting it as well.
Just my $.02

ABSOLUTELY correct, THAT problem goes away and about 20 new ones take its' place!!! (Depending on WHAT is on the tube).

 

[DozerMite]

Please elaborate Ed. I've never had any problems with that method.

 

[gketell]

Looking at THIS pen, it isn't a demonstrator. I agree that the thread you posted earlier would make zero sense to paint the hole. But for THIS pen....

 

[ed4copies]

Please elaborate Ed. I've never had any problems with that method.

The problems occur if you add something to the tube, like a snakeskin for example. I would also think if you paint the tubes, you want to wait quite a while for them to cure before casting. If you powder coat, a different set of issues could emerge.

Don't know everything, just know what problems WE have encountered. Some remain unsolved.

 

[ed4copies]

Looking at THIS pen, it isn't a demonstrator. I agree that the thread you posted earlier would make zero sense to paint the hole. But for THIS pen....

Greg, I was not trying to be argumentative, just warning that a search for "demonstrator" which I had suggested would not turn up YOUR solution, which is also a good solution.

 

[DozerMite]

Yes Ed, I know the problems that can arise with skins and that sort of addition to the tube. I didn't mention anything about that stuff because he isn't doing that kind of blank. Good point though.
I thought maybe you meant something like fingerprints or something.

With the paint, I've sprayed them and cast them later the same day. Probably a good idea to wait a day though. I've also cast over CA without any problems.

 

[PTownSubbie]

Thanks for all the input. This pen was really just a prototype to see what the casting looked like. I think in the future I will either paint the inner portion of the drilled hole or cast the tube in the acrylic.

I have a couple of fairly transparent blanks that we cast. How do you guys apply the paint to the inside of the tubes?

I was thinking Q-tips or something along those lines. Any better ideas?

 

[gketell]

I was thinking Q-tips or something along those lines. Any better ideas?

depends on whether you have spray paint or tube paint. For spray paint I just shoot through the hole and let the excess drip out. :biggrin: For tube/can paint, a couple of coats with a q-tip works fine but you need a couple of coats.

GK

 

[ed4copies]

Cigar pen?

If so, remember the paint will make your hole smaller. So, either overdrill or paint thin coats.

 

[PTownSubbie]

Cigar pen?

If so, remember the paint will make your hole smaller. So, either overdrill or paint thin coats.

Thanks for the tips!! I will give it a turn some time very soon.

 

[djpnevans]

Try and use some thing else as all the pens that I use CA with went cloudy.
David

 

[Smokey7385]

My first thought was that you used accelerant on the CA. This can sometimes cause some bubbling which comes out as a cloudy white mess.

 

[wolftat]

Try and use some thing else as all the pens that I use CA with went cloudy.
David

You have to let the CA gas out for 24 hrs before casting it or that happens.

 

[PTownSubbie]

I didn't use any CA accelerator and the brass was glued into the hole after the cast had hardened.

I really think, based on the feedback that I have read, that this was caused by not cleaning out the drilled hole in the blank before I glued the tube into the hole.

 

[elody21]

Try and use some thing else as all the pens that I use CA with went cloudy.
David

What should you use?
I have had clouding happen without using CA glue at all. I thought clouding was from the resin pulling away from the substance on the tube. I am not argueing I am just trying to understand.

 

[PTownSubbie]

Some guys use 5 min epoxy. Other than that, I am not sure what else to use....

 

[djpnevans]

I use epoxy or polyurethane glue, the only clear casting I do is for label casting so I dont need any glue.
David