Keep your Whisky away from your Flame Polished Acrylic

[griffindodd]

I didn't know this before watching this video, but it's made me reconsider using acrylic on my CP baring in mind how much we love Glenlivet in this house

[Seith]

Duly noted... I am going to have to check my bottles of cleaner to make sure they are alcohol-free before they get anywhere near my CP when it's done.

[DaOld Man]

Also, dont use crazy glue to glue pieces of acrylic together, it burns it bad.

[selfie]

As stated its the Alcohol that's the killer but it only reacts to acrylic that has been heated to near boiling the water that is still present in the material.

[griffindodd]

As stated its the Alcohol that's the killer but it only reacts to acrylic that has been heated to near boiling the water that is still present in the material.

Yup, I guess hand polishing is still ok right?

[pinballjim]

Yikes, wonder if this explains some of the issues people have with the cornchip plastics from CPR.

[Xiaou2]

Interesting.

  Makes me wonder whats happening.  Maybe the extreme heat causes micro fractures... and the alcohol is then able to penetrate into them, due to the strong penetrating vapor,  ...which then clouds the edges of the fractures.

 As a kid, I once got ticked off at a cd that didnt play.  After just about every trick was tried... I went to nail polish remover.   Instant cd eraser!   lol    Turned out that my brand new Pioneer Laser Disc player was defective.   Ooops.

 This vid makes me a bit annoyed, because one of the ramp vendors at a Pinball show, flame polished a ramp I bought.  >.<


 

[ChadTower]

If you can manage to get whiskey onto a ramp that's installed in a game then you deserve to have that happen.

[Le Chuck]

As stated its the Alcohol that's the killer but it only reacts to acrylic that has been heated to near boiling the water that is still present in the material.

Is there a good method for home kiln drying acrylic?  Remove the water and remove the problem right?

[ChadTower]

Only if the vapor can escape and only if the material can change shape to compensate.

[griffindodd]

You can anneal acrylic by heating it to 180f and then letting it slow cool

[lilshawn]

I think the issue is that the flame messes with the internal structure of the plastic, setting up an uneven pressure zone on the edge of the plastic (A mechanical stress). the alcohol induces a CHEMICAL stress...since the edge of the plastic now has an uneven MECHANICAL stress area, the alcohol is just compounding an already stressed area.

Once a craze is formed this creates a path so that the attack can continue internally and the crazing process  accelerates.

How chemicals induce a stress in plastics is still not fully understood, and it has been studied for decades!

[griffindodd]

My sexiness induces stress in all kinds of materials.

[Mental]

I never would have imagined that would happen. Thanks for the great lesson! I'll consider myself warned.

[Mysterioii]

I think the issue is that the flame messes with the internal structure of the plastic, setting up an uneven pressure zone on the edge of the plastic (A mechanical stress). the alcohol induces a CHEMICAL stress...since the edge of the plastic now has an uneven MECHANICAL stress area, the alcohol is just compounding an already stressed area.

Once a craze is formed this creates a path so that the attack can continue internally and the crazing process  accelerates.

How chemicals induce a stress in plastics is still not fully understood, and it has been studied for decades!

My guess too, pretty much.  Wiki "season cracking" and "residual stress". 

[RandyT]

Looks to me like the stress is created by the heating process, and the alcohol, being a pretty strong solvent, eats into the surface of the stressed area, creating a microscopic path of stress release.  The moment such a path is created, all of the surrounding stresses are channeled to that small area, and it tries to normalize, thus creating the fractures.

RandyT

[pinballjim]

Well, off to refill all my empty Jack Daniel's bottles with denatured alcohol.

[xefned]

Cool! Now I know how to reproduce an authentic vintage look to my acrylic.   

[griffindodd]

Well, off to refill all my empty Jack Daniel's bottles with denatured alcohol.

Yep it's the weekend, party at Jim's house

[SavannahLion]

First off, denatured is fairly high proof. Not sure if whiskey will trigger it, I know beer won't.

Second, before everyone goes off half cocked, do the research. I came across this for a related issue and found posts like this from 2007. Pay attention to the annealing link. In a nutshell, it's fixable.... Not after the fact of course.

Heat treating your pinball parts isn't worrisome unless you intend to fill your table with moonshine or some such.

note: fixed URL. Sorry about that, I didn't notice it when I posted the first time.....

[PL1]

My sexiness induces stress in all kinds of materials.

Is that the explaination for Rodney's reaction (multiple times) in your build thread?   

TROUSERS MESSED!!!!!!!

Scott

[selfie]

I think the issue is that the flame messes with the internal structure of the plastic, setting up an uneven pressure zone on the edge of the plastic (A mechanical stress). the alcohol induces a CHEMICAL stress...since the edge of the plastic now has an uneven MECHANICAL stress area, the alcohol is just compounding an already stressed area.

Once a craze is formed this creates a path so that the attack can continue internally and the crazing process  accelerates.

How chemicals induce a stress in plastics is still not fully understood, and it has been studied for decades!

That is what I understand to be happening too.

You can anneal acrylic by heating it to 180f and then letting it slow cool

Spot on. Polycarbonate (lexan) needs to be "annealed" before thermoforming. The process is more accurately Drying than annealing.

Crazing is more an issue with flame polished edges than LASER cut edges. A higher powered LASER cutter can cut the acrylic at a higher speed which transfers less heat into the material than flame polishing. I regularly solvent bold LASER cut edges and VERY, VERY rarely have issues.

[RandyT]

Crazing is more an issue with flame polished edges than LASER cut edges. A higher powered LASER cutter can cut the acrylic at a higher speed which transfers less heat into the material than flame polishing. I regularly solvent bold LASER cut edges and VERY, VERY rarely have issues.

It depends on the type of material you laser cut.  Extruded acrylic will do the same thing when alcohol hits the edges.  Perhaps you are cutting the cast variety?  They use different base materials, and the cast variety is less susceptible to this phenomenon.