For those that had the pleasure of watching my demo crash around me at Reef Ed 2016, I thought I would share some research that identified the culprit.
The backstory is this: I was trying to assemble a frag tank as a demo for an Acrylics 101 bonding. Typically, you place a number of "pins" under the edge of the piece to be bonded, apply Weld-on 4 solvent from a thing gauge needle and wait about 90 secs. By then, the solvent has begun the chemical bonding and is "melting" the two pieces. The pins are removed and the pieces are allowed to continue to bond. Within a few minutes, the pieces are quite firm and within 10 mins they are not separating without serious force. However, when I removed the pins, the pieces moved around like they were at a Wet n' Wild water park. 5 mins later they were barely gooey.
This had never happened to me before in the 10 years I have been messing with acrylic on a hobby level. My suspect was the unusually rough edge left by the CNC which is normally mirror smooth or perhaps the acrylic itself.
Desperate to find an answer I took the pieces of the project into Plasticare where I purchased the material and had it cut on the CNC router. The owner came out within a few minutes as the employees had no suggestions. He immediately pulled out some weld-on and tried to bond a couple of pieces that I had brought in that we cut into thirds for testing. Within 2 mins it was solid as a rock. Then we tried my solvent (same product). The bond never took.
Bottom line - bad solvent. He had never heard of this before. The date on the can was Jan 2015. As far as we knew, weld-on does not expire. It just evaporates over time.
Plasticare has offered to re-cut and replace the pieces for me (free of charge). Excellent group! I am tempted to contact the manufacturer to see what they say, but for now, I am just happy I have some answers. Lesson learned - test bond a scrap piece before trying it on that $1000 project!
Shawn
The backstory is this: I was trying to assemble a frag tank as a demo for an Acrylics 101 bonding. Typically, you place a number of "pins" under the edge of the piece to be bonded, apply Weld-on 4 solvent from a thing gauge needle and wait about 90 secs. By then, the solvent has begun the chemical bonding and is "melting" the two pieces. The pins are removed and the pieces are allowed to continue to bond. Within a few minutes, the pieces are quite firm and within 10 mins they are not separating without serious force. However, when I removed the pins, the pieces moved around like they were at a Wet n' Wild water park. 5 mins later they were barely gooey.
This had never happened to me before in the 10 years I have been messing with acrylic on a hobby level. My suspect was the unusually rough edge left by the CNC which is normally mirror smooth or perhaps the acrylic itself.
Desperate to find an answer I took the pieces of the project into Plasticare where I purchased the material and had it cut on the CNC router. The owner came out within a few minutes as the employees had no suggestions. He immediately pulled out some weld-on and tried to bond a couple of pieces that I had brought in that we cut into thirds for testing. Within 2 mins it was solid as a rock. Then we tried my solvent (same product). The bond never took.
Bottom line - bad solvent. He had never heard of this before. The date on the can was Jan 2015. As far as we knew, weld-on does not expire. It just evaporates over time.
Plasticare has offered to re-cut and replace the pieces for me (free of charge). Excellent group! I am tempted to contact the manufacturer to see what they say, but for now, I am just happy I have some answers. Lesson learned - test bond a scrap piece before trying it on that $1000 project!
Shawn
