The warming and machining characteristics of the material used for #4 lead me to believe that it's Polycarbonate and not Acrylic.
It took far longer to warm up than the same thickness Acrylic, the bubbles from overheating deformed the structure of the material far less than in the other tests. Other than two larger bubbles, the rest remain almost unnoticeable in size or distortion when held up against the LCD in front of me. [
] ]'>
This stuff seems to be a lot more brittle than Acrylic, drilling the mounting holes caused considerably more "chipout" and a sharper noise at breakthrough. When I was marking the holes while the the cooled material was still on the CRT, I was surprised by how quickly the first hole broke through. I was testing drill-through with the formed blank still on top of the mounting ears at the time, which was a bad idea. Chipout was markedly worse, which was expected, but he hairline beginnings of a crack in the formed piece resulted, which was semi-expected. However it grew to about 3/4" in length from the slight pressures I used in mounting it for the photos, which was not.
Acrylic shouldn't have done that, from what I've experienced in APlexi fabrication in the past. I'll test pieces of this against Acrylic with MEK when I get a chance. *****
I'll be thinking about ways to form and fuse together more complex parts for the MacQuarium project. In this round of experimentation I've demonstrated that there's not enough room within the ZipPlus bezel to achieve a flat surface to fuse to the rear portion of a vacuum formed CRT using the current process. I'll need to join more parts along compound curves if I can't noodle out a tweak for this process. I'll also post some piccies of the apparatus fabrication, process and results when I get a chance to prep them for upload. That way I don't have to worry about documentation or sticking to the use of K*I*S*S tools and methods of construction the next time around! [
] ]'>
It turns out that what I've been calling 1/8" is really 1/16" material. I finally put the digital calipers on it and immediately shook my head in dismay, that's one BIG oopsie that I never would have made back in the day, but everything about this exercise has been "hurry up and see what happens" methodology, right down to the photographic documentation. I may do a few more experimental runs using the ersatz 1/8" Acrylic just to see what happens.
I'll be re-thinking the process and going about it a lot more deliberately after properly designing and building a full size vacuum forming apparatus from new materials instead of wingin' it with the scrap I had on hand. Plaster casting experimentation in negative/positive/thicknessing iterations is next up on the list. As is the casting and finishing of "lost plaster" bucks for forming fairly complex parts with flat mating surfaces in hidden places.
Does anyone already know how to remove the CRT's metal mounting band using a non-destructive process? [}
] ]'>
*****WARNING: Methyl Ethyl Keytone is very nasty stuff, read the label several times if you consider buying a can. Stick with Acrylic cements if you're not experienced in handling HazMats. MEK is the active ingredient in cements for Acrylic, PVC, etc. which is the reason they all warn to use them only in well ventilated areas. The thickening agents in cements makes them less volatile, a bit slower working and a lot less dangerous. The thickening agent for Acrylic Cements is clear acrylic that is entirely dissolved in MEK.
Many years ago they began selling consumer rated Acrylic Cements and water based Contact Cements for doing laminate work. Use a respirator if you're smart/concerned, I use one using straight MEK even outdoors.
It took far longer to warm up than the same thickness Acrylic, the bubbles from overheating deformed the structure of the material far less than in the other tests. Other than two larger bubbles, the rest remain almost unnoticeable in size or distortion when held up against the LCD in front of me. [
] ]'>This stuff seems to be a lot more brittle than Acrylic, drilling the mounting holes caused considerably more "chipout" and a sharper noise at breakthrough. When I was marking the holes while the the cooled material was still on the CRT, I was surprised by how quickly the first hole broke through. I was testing drill-through with the formed blank still on top of the mounting ears at the time, which was a bad idea. Chipout was markedly worse, which was expected, but he hairline beginnings of a crack in the formed piece resulted, which was semi-expected. However it grew to about 3/4" in length from the slight pressures I used in mounting it for the photos, which was not.
Acrylic shouldn't have done that, from what I've experienced in APlexi fabrication in the past. I'll test pieces of this against Acrylic with MEK when I get a chance. *****
I'll be thinking about ways to form and fuse together more complex parts for the MacQuarium project. In this round of experimentation I've demonstrated that there's not enough room within the ZipPlus bezel to achieve a flat surface to fuse to the rear portion of a vacuum formed CRT using the current process. I'll need to join more parts along compound curves if I can't noodle out a tweak for this process. I'll also post some piccies of the apparatus fabrication, process and results when I get a chance to prep them for upload. That way I don't have to worry about documentation or sticking to the use of K*I*S*S tools and methods of construction the next time around! [
] ]'>It turns out that what I've been calling 1/8" is really 1/16" material. I finally put the digital calipers on it and immediately shook my head in dismay, that's one BIG oopsie that I never would have made back in the day, but everything about this exercise has been "hurry up and see what happens" methodology, right down to the photographic documentation. I may do a few more experimental runs using the ersatz 1/8" Acrylic just to see what happens.
I'll be re-thinking the process and going about it a lot more deliberately after properly designing and building a full size vacuum forming apparatus from new materials instead of wingin' it with the scrap I had on hand. Plaster casting experimentation in negative/positive/thicknessing iterations is next up on the list. As is the casting and finishing of "lost plaster" bucks for forming fairly complex parts with flat mating surfaces in hidden places.
Does anyone already know how to remove the CRT's metal mounting band using a non-destructive process? [}
] ]'>*****WARNING: Methyl Ethyl Keytone is very nasty stuff, read the label several times if you consider buying a can. Stick with Acrylic cements if you're not experienced in handling HazMats. MEK is the active ingredient in cements for Acrylic, PVC, etc. which is the reason they all warn to use them only in well ventilated areas. The thickening agents in cements makes them less volatile, a bit slower working and a lot less dangerous. The thickening agent for Acrylic Cements is clear acrylic that is entirely dissolved in MEK.
Many years ago they began selling consumer rated Acrylic Cements and water based Contact Cements for doing laminate work. Use a respirator if you're smart/concerned, I use one using straight MEK even outdoors.