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ET2SN · 04-27-22, 07:07 AM

You could start here:

https://bsi-inc.com/

I'm not a big fan of CA/superglue. Too tricky to apply in tight quarters, you always have to guess how long its going to take for the glue to "flash" and harden, not such a good track record over time (the glue joint tends to get weaker), fogs clear plastic like you wouldn't believe.

CA glue works by forming crystals as it cures. At a microscopic level, the liquid glue sinks into cracks and pits in the surfaces you are trying to bond. CA also reacts to air, where part of the liquid evaporates leaving the crystals behind. The crystals tend to "lock" themselves into deformations on the two surfaces while also locking into the other crystals that are produced.

The problem is that CA never really stops curing until those crystals turn into a powder.

It might take a couple of years, but eventually the glue joint is going to fail.

On the other hand, there is Plastic Cement (not the same as plastic glue). Cement is always some form of liquid, from a slimy gel to a liquid thinner than water. Cement works by chemically dissolving a thin layer of the surfaces that are to be joined together. This "mush" of plastic and cement then dries and cures to produce the joint. The perfect form of cement for styrene plastic (the stuff we work with) would be pure Acetone. The problem is that Acetone doesn't stop dissolving plastic until it fully evaporates, so you would wind up with an entire model made out of mush. Old school model glue is basically a gel form of Toluene, it has the same characteristics of Acetone but in a more buffered form. The one big hassle with styrene cements is that they will only bond styrene. Try using them on some other type of plastic (ie, ABS) and all you will get is a mess.

Meanwhile, anyone who has ever used Tamiya Acrylic paint (or any of the Japanese acrylics) knows why you have to have that plastic wrench and rubber cup. Acrylics dry a LOT like glue. Maybe not as strong, but close enough when you're trying to get that cap off.

I noticed that the Tamiya clear colors were harder to open than the regular pigment acrylic paints..

And, we're talking about a joint between plastic and glass.

What I did was buy another pot/jar of Tamiya clear but I didn't dilute it with Tamiya thinner (the big secret to working with Tamiya acrylics is that you're supposed to fill a new jar up to the bend in the glass with thinner, this makes the paint ready for brush painting, they just never told us). It..works.

Again, not as strong as CA but much easier to apply. Once the acrylic cures, it stays cured for the long haul.

One other benefit to acrylic is that it shrinks quite a bit as it dries and cures, leaving a minimal spot as a glue joint. Since its undiluted paint, it takes longer to dry.

Another option might be "clear parts glue". This stuff is somewhere in between regular white glue and acrylic paint. I had to try this out once on a nice die-cast Mercedes CL600 that used photo etched CL600 letters on the trunk. While doing a cleaning and a quick spray of high gloss detailing auto wax* I noticed the L on the trunk fell off.

The gods were smiling and I found the tiny L on my work bench (this was back when my eyes were sharper) so it meant that I had to fix it. I carefully glued the L back in place with some clear parts glue and a toothpick then added a clear top coat to all the letters to keep them uniform, then crossed my fingers and let it dry for a couple of days.

*- Not related to this topic but something I will be adding to the Modeling Resources thread is High Gloss (detailing) Car Wax. It goes by many names, but its the fast liquid clean and shine spray stuff you can find in most stores.

It does a terrific job on die cast models, but also works well as a cleaner and protectant layer on clear plastic parts.

04-27-22, 07:07 AM	#3
ET2SN ET2/SS Join Date: Oct 2017 Posts: 2,513 Downloads: 58 Uploads: 0	You could start here: https://bsi-inc.com/ I'm not a big fan of CA/superglue. Too tricky to apply in tight quarters, you always have to guess how long its going to take for the glue to "flash" and harden, not such a good track record over time (the glue joint tends to get weaker), fogs clear plastic like you wouldn't believe. CA glue works by forming crystals as it cures. At a microscopic level, the liquid glue sinks into cracks and pits in the surfaces you are trying to bond. CA also reacts to air, where part of the liquid evaporates leaving the crystals behind. The crystals tend to "lock" themselves into deformations on the two surfaces while also locking into the other crystals that are produced. The problem is that CA never really stops curing until those crystals turn into a powder. It might take a couple of years, but eventually the glue joint is going to fail. On the other hand, there is Plastic Cement (not the same as plastic glue). Cement is always some form of liquid, from a slimy gel to a liquid thinner than water. Cement works by chemically dissolving a thin layer of the surfaces that are to be joined together. This "mush" of plastic and cement then dries and cures to produce the joint. The perfect form of cement for styrene plastic (the stuff we work with) would be pure Acetone. The problem is that Acetone doesn't stop dissolving plastic until it fully evaporates, so you would wind up with an entire model made out of mush. Old school model glue is basically a gel form of Toluene, it has the same characteristics of Acetone but in a more buffered form. The one big hassle with styrene cements is that they will only bond styrene. Try using them on some other type of plastic (ie, ABS) and all you will get is a mess. Meanwhile, anyone who has ever used Tamiya Acrylic paint (or any of the Japanese acrylics) knows why you have to have that plastic wrench and rubber cup. Acrylics dry a LOT like glue. Maybe not as strong, but close enough when you're trying to get that cap off. I noticed that the Tamiya clear colors were harder to open than the regular pigment acrylic paints.. And, we're talking about a joint between plastic and glass. What I did was buy another pot/jar of Tamiya clear but I didn't dilute it with Tamiya thinner (the big secret to working with Tamiya acrylics is that you're supposed to fill a new jar up to the bend in the glass with thinner, this makes the paint ready for brush painting, they just never told us). It..works. Again, not as strong as CA but much easier to apply. Once the acrylic cures, it stays cured for the long haul. One other benefit to acrylic is that it shrinks quite a bit as it dries and cures, leaving a minimal spot as a glue joint. Since its undiluted paint, it takes longer to dry. Another option might be "clear parts glue". This stuff is somewhere in between regular white glue and acrylic paint. I had to try this out once on a nice die-cast Mercedes CL600 that used photo etched CL600 letters on the trunk. While doing a cleaning and a quick spray of high gloss detailing auto wax* I noticed the L on the trunk fell off. The gods were smiling and I found the tiny L on my work bench (this was back when my eyes were sharper) so it meant that I had to fix it. I carefully glued the L back in place with some clear parts glue and a toothpick then added a clear top coat to all the letters to keep them uniform, then crossed my fingers and let it dry for a couple of days. *- Not related to this topic but something I will be adding to the Modeling Resources thread is High Gloss (detailing) Car Wax. It goes by many names, but its the fast liquid clean and shine spray stuff you can find in most stores. It does a terrific job on die cast models, but also works well as a cleaner and protectant layer on clear plastic parts.