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-   -   Dicro (http://talk.craftweb.com/showthread.php?t=12658)

Chris Lowry 08-26-2020 05:33 AM

Dicro
 
Iíve seen a lot of Dicro being used these days, is there a new supplier? Where do people get comparable dicro sheets?

Rosanna Gusler 08-26-2020 09:37 AM

https://cbs-dichroic.com

Pete VanderLaan 08-26-2020 10:13 AM

Sandburg is the glass of choice. Howard bought a phenomenal amount of glass stock back when Eric was going out of business at Uroboros so all that stock is still available. The pedestal machines they have are the best and they have their process well worked out. Other sources have been kind of anemic in the coating in my opinion. I no longer work with the stuff except in MB's jewelry and we have lots of it.

Shawn Everette 08-26-2020 10:31 AM

They're doing it on wissmach now, which is bottom barrel price wise. You get what you pay for.

Greg Vriethoff 08-26-2020 01:08 PM

God, I remember how long it took me to get the noodles just right. They kept kicking 'em back to us due to the surfaces not being smooth. Black was the hardest. Getting the 90s right was even harder.

Pete VanderLaan 08-26-2020 09:30 PM

Quote:

Originally Posted by Shawn Everette (Post 148581)
They're doing it on wissmach now, which is bottom barrel price wise. You get what you pay for.

***
"They" being who exactly?

Shawn Everette 08-26-2020 11:18 PM

The proverbial they. Apparently atf, cbs, and dichromagic. Never paid that much attention to manufacturer since it looked to be repackaged and I was buying for tests. Never got it to perform as well as the old pricey cbs.

Eben Horton 08-27-2020 07:31 AM

I am often asked how dicro is made. Can anyone explain it?

Shawn Everette 08-27-2020 08:25 AM

A piece is placed in a chamber under vacuum, precious metal is then vaporized and attaches to the surface. Not sure what kind of heats are involved, but it's at anneal or less since only the surface is effected, and no change in form occurs. Supposedly originally developed for nasa to coat the windows, but don't quote me on that.

Eben Horton 08-27-2020 08:29 AM

Thanks Shawn. Thatís actually verbatim of what I tell people. But Iím curious what metals and how does the metals attach? An electrical charge ?

Pete VanderLaan 08-27-2020 08:51 AM

Quote:

Originally Posted by Shawn Everette (Post 148588)
A piece is placed in a chamber under vacuum, precious metal is then vaporized and attaches to the surface. Not sure what kind of heats are involved, but it's at anneal or less since only the surface is effected, and no change in form occurs. Supposedly originally developed for nasa to coat the windows, but don't quote me on that.

****
Boeing. It's a sputtering process and yes the glass is charged electrically to receive the sputter. Howard always referred to the "Cryo" chamber when we talked about it.

Larry Bell was really the first artist to apply it to glass and that was back in the '80's. Coatings by Sandburg really became the big kid on the block having set up five slot pedestal machines. It's a slow process, taking about three hours to coat a sheet so five pedestal machines were critical but they cost 10K each. and then it depended on whether you wanted an outer coating of quartz which did a great job of keeping the coating from burning off.

Shawn Everette 08-27-2020 04:33 PM

I believe silver, gold, and titanium are the usual culprits. Possibly palladium. It similar to an electrostaic deposition, think really expensive powder coating. You often see an anode mark of bare glass on larger sheets. I'm thinking that not much heat is involved because there's not a ton of adhesion and can be somewhat easy to flake off until it's fired. At least with some anyway.

Art Freas 08-27-2020 07:04 PM

Any of them use iridium?

Larry Cazes 08-27-2020 07:08 PM

Quote:

Originally Posted by Shawn Everette (Post 148597)
I believe silver, gold, and titanium are the usual culprits. Possibly palladium. It similar to an electrostaic deposition, think really expensive powder coating. You often see an anode mark of bare glass on larger sheets. I'm thinking that not much heat is involved because there's not a ton of adhesion and can be somewhat easy to flake off until it's fired. At least with some anyway.

what temp do you fire at? 1400ish? I use the boro based versions

Shawn Everette 08-27-2020 08:27 PM

I'm afraid a question like that is above my pay grade. With the architectural glass that isn't meant to be fired again there's probably significantly more leeway in terms of what could be deposited since it is more of a surface treatment and compatibility with other glass isn't a concern.

Shawn Everette 08-27-2020 08:46 PM

Depends on the application.

For a fused piece, temperatures much past 1400 will start to see a degradation fairly quickly. I'm primarily using the cheap scrap, so the heavier cbs may fair better. It will retain something no matter what, but the difference between peaks and valleys on variegated glass is significant. A lot of jewelry people will only fire to 1350. Nearly all of the surface variation is retained under a sheet of clear, and there's almost no loss of sparkle.

I'll do hot plate pick ups where a pattern was originally fired to 1450, whatever is left from that is good up to gather temp. The film does seem to add a significant level of stiffness. I'd say not as much as silver foil, but it's noticeable.

On boro I just dive right in from room temp. The key there is trying to get it covered as quickly as you can. The temperature of the glass is less of a consideration than hitting the film directly with the flame. There's a fairly significant sparkle loss early on, but I'm really only using minimal quantities for marbles. I have no idea what make I've got, been working off a damn near full sheet that someone gave me because they couldn't figure out how to use it. Once that's gone I may investigate further.

Pete VanderLaan 08-28-2020 08:32 AM

the extra quartz coat makes all the difference in the world on burn out.

Shawn Everette 08-28-2020 09:01 AM

I'm imagining that's what the cheap ones are skipping. Makes me lean towards the burn out being a reaction with atmosphere when heat is applied, since only some of it goes away and it tends to follow the patterns of the glass.

Honestly I don't use it for much. Think it looks nice used sparingly in marbles, but most other applications get tacky quickly. I chose glass because of the qualities of glass, not glitter.

Pete VanderLaan 08-28-2020 09:22 AM

When I was still working, I had an entire line of vases using pre imaged along with our own patterns and it was all furnace worked. It had to be premium colors and it had to be worked in with a cold furnace. It grayed up instantly in the gloryhole. Done slowly, it worked very well, always cased in clear. I made zanfirico cane and murrinis in them as well. Sort of like Hay extender for horses. We used hundreds of sheets a year.

Mary beth uses it still in her jewelry and fires to about 1365F for her basic fuse. Once the clear is on, and we make our own clear, she does what she likes. Too many clears devitrify.

Greg Vriethoff 08-28-2020 11:22 AM

I know only very little about the process, and I know the science is above everyone's pay grade here. I know the process is performed in a vacuum chamber, but I didn't know heat is involved. I've been told that it employs what are commonly referred to as "reactive metals" (titanium, niobium, etc.). Gold (I believe) is the least reactive of metals. Lastly, how do you get an electrostatic charge on glass? Is there a conductive coating applied to the surface first?

Shawn Everette 08-28-2020 12:13 PM

I'm not saying heat is involved, beyond what is going on with the laser anyway, only that it would be at anneal or lower should it occur at all. It's way more of a surface treatment than being fused to the glass. The quartz coating process may be a bit different, but none of the sheets have any indication of slumping, softening of edges, or picking up the backing surface, that would indicate temperatures past anneal.

I too have be curious about how the charge actually works, glass being a pretty good electric insulator and all.

Tom Fuhrman 08-28-2020 12:16 PM

Check the CBS-Dichroic glass website and most of these questions will be answered. they have a lot of replies to FAQs.

Shawn Everette 08-28-2020 12:25 PM

When I would pick up I always fused it with a sheet of clear over top first. That negated any effect of the glory or degradation from gather temp. Again, really only for marbles, and that interest was never particularly high.

Most of the programs from jewelry makers I've seen are pretty fly by wire. Jump to somewhere in the mid 1300's, stay for a minute, barely anneal. The process temp is right in the devit zone, but the program speed and lack of thermal mass from tiny kilns usually lets people get away with it. Unless you're using wissmach clear, that's the devil incarnate for devit in any situation.

Greg Vriethoff 08-28-2020 12:49 PM

Quote:

Originally Posted by Tom Fuhrman (Post 148616)
Check the CBS-Dichroic glass website and most of these questions will be answered. they have a lot of replies to FAQs.

Thanks, Tom. That makes sense. Should have looked there first.

Ted Trower 09-06-2020 08:28 PM

Search the term sputtering on YouTube. It has a lot of applications other than dichroic glass but the process is very similar.


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