CA vs plastic cement: wonder if I'm missing something

riplikash · Post by **riplikash** » Thu Feb 23, 2012 12:56 pm

So I just posted a lengthy reply on another topic about the benefits of CA glue, but I wonder if there are additional properties and benefits to plastic cement I am unaware of. Now I have about 10 years modelling/miniature painting experience (ignoring everything I did as a child/teenager, as I was crappy at it and not actively improving), and from my experience CA glue seems to have so many benefits over plastic cement I now use it exclusively, and typically recommend it to those new to the hobby.

However, I know plastic cement is the default for many modelers with a lot more experience than I (especially on this forum many seem to have 30+ years in), so I figure there must be benefits to it I'm not seeing.

Here is my experience on the topic. Corrections and criticisms would be welcome and appreciated.

Plastic Cements main benefit seems to be its strong hold (as it is melting together the pieces). However, it is VERY unforgiving. A loose string of glue or a bit on the finger can ruin a finish, and heaven help you if you, for whatever reason, realize you need to take something apart after you glue it. In short, one mistake and you may ruin your model.

CA glue doesn't bond as strongly, but but seems more than strong enough for 99% of models out there. It works well on almost all materials (plastic, metal, resin), so it makes a good one product solution. It has numerous modelling applications, from gap filling to texturing. It additive rather than deformative, so if you need to you can always sand back down to the original model. You have more control over the drying time either via pressure (flat surfaces can be slid around and then fix when pressed together) or chemical (There are spray products to instantly set CA glue, or you can use baking soda).

But best of all (to me), when you make a mistake (which I always seem to) you can pry the parts apart, sand them down, and do it again. If they have been set for awhile you can do this either by freezing them, which makes the paint brittle, or using one of the CA glue dissolvants on the market.

So what am I missing here? Plastic cement still seems to dominate the hobby, at least for larger scale models (CA glue seems more popular in the miniature market). What else does plastic cement bring to the table?

Rogviler · Post by **Rogviler** » Thu Feb 23, 2012 3:08 pm

Probably strength is what most will say. But there are other things, like the fact that you can clamp parts together and then wick the plastic cement into the joint. There are certainly water-thin superglues out there that can do the same, but you have to be REALLY careful because it gets everywhere and doesn't evaporate like plastic cement.

Really I think it's just personal preference. I use both. Usually plastic cement for tiny pieces that I don't want to have to glue 20 times throughout the course of the build, and CA for gap filling and extra reinforcement. I also like the thin CA linked above for building up a hole or gap with baking soda and then dripping the water thin CA on. Much better than glue first and hoping enough baking soda soaks in before it sets.

Plastic cement also melts plastic (obviously), so that can be used in multiple advantageous ways.

-Rog

Scott Hasty · Post by **Scott Hasty** » Thu Feb 23, 2012 3:58 pm

If it works successfully for you, then keep with it! The drawback, in my mind, is CA bonds the pieces and could become more brittle over time (temperature variations, handling, etc.). Whereas liquid cement creates a single, solid piece and is dirt cheap if you use something like MEK. The 'string' created from tube glues can be reduced by using an applicator (like a toothpick). Personally, I havent used tube cement in years and only use CA for things like fiber optics or using something other than plastic.

Richard Baker · Post by **Richard Baker** » Thu Feb 23, 2012 7:40 pm

I hate CA due to it's lack of tensile strength- it does hold pieces firmly and does a good job- then it can suddenly shear loose into powder.
I am old fashioned I suppose, but I have used tube (gel) glue since the early sizties and I know how make it dance. I like the secure fusion and it provides and the gel thickness actually helps with some types of detail.
If I do need to glue things tube glue will not work with like a resin kit I use two-part epoxy instead.

southwestforests · Post by **southwestforests** » Thu Feb 23, 2012 9:12 pm

As has been said, the liquid plastic glues weld the material.
Tube glues - a little bit but no so much as the liquids.
Each has things it is better for.

Also, when sanding, CA is immensely harder than styrene or ABS; that's something to keep in mind.

Ah, that brings up that styrene and ABS require different glues.

Tankmodeler · Post by **Tankmodeler** » Mon Feb 27, 2012 5:18 pm

Richard Baker wrote:I hate CA due to it's lack of tensile strength- it does hold pieces firmly and does a good job- then it can suddenly shear loose into powder.

Just to be a nit picker, as you say it is the shear strength (and its cousin, peel strength) of CAs that is low. The tensile strength is quite good.

I also like the strength of liquid cement when joining thermoplastic to thermoplastic. CA is good for most resin & PE assembly tasks, although I also use epoxy for resin & PE bits that will see a lot of load.

The CA is harder and sets up much faster than I usually want. I use it if I have to, but not because I want to.

I also don't generally need to disassemble anything. I'm much more likely to knock off a CA glued part & curse having to clean it up & stick it back on again.

kryptosdaddy · Post by **kryptosdaddy** » Thu Mar 01, 2012 10:15 am

I use CA sparingly- I don't trust it, the dollar store super glues are fine sometimes- but i like something thicker, so i still find myself using old Testors tube!

Blob a bit on a piece of card and dab it on with a toothpick or a piece of wire- I do the same with the CA's but I still find myself going back to the orange tubes-

One tool you need to learn to use for scratching is a hot glue gun- takes some practice but I love it. Guess I'm old fashioned? CR

Saturn · Post by **Saturn** » Thu Mar 01, 2012 3:36 pm

Scott Hasty wrote: Personally, I havent used tube cement in years and only use CA for things like fiber optics or using something other than plastic.

Ditto on this. I especially like that I'm faster with liquid cement than I ever was on tube-based cements. Once you get the hang of it, it is infinitely cleaner and less messy than the stringy tube stuff. But working with liquid cement takes longer to learn. There are tools that can make it easier, but most just use a #0 paint brush.

And I can only use CA for photoetch. (usually the super thin CA and accelerator) I don't trust it anywhere else.

Kylwell · Post by **Kylwell** » Thu Mar 01, 2012 4:06 pm

CAs vary from manufacturer to manufacturer. Some are made for a longer shelf life (like the Mercury Adhesives) others are low expansion (yes, Ca can and does expand). My current love affair is with Gorilla rubber strengthen CA. I'll empty a bottle before it dries out thanks to the nicely design cap that never seems to clog. The addition of a rubber massively increases it's shear strength and softens the glue after curing. You can still sand it a week later. It's also thick enough that it won't run out of a seem and onto your hand causing all sorts of issues.

My preferred styrene cement is Tenax 7R. I use an old able brush as an applicator (it doesn't gunk up like synthetic brushes might). A little in the seam and you can get a seamless joint. You can also use it to soften the surface of the plastic to apply textured effects.