"How Do You Know If A Plastic Bottle/Container Is 'Styrene'?" Topic

In other words, how do you know if buying something from a store shelf, just for the cool container, is simply going to leave you with a piece of trash that will not take the same glues your Plastruct and Evergreen styrene strips and sheets take?

plastruct.com
evergreenscalemodels.com

Is there any way to tell beforehand?

EXAMPLE:

What about containers like these Yoplait Yogurt cups?

picture
picture

Thanks.

Dan

Recycling symbols molded on the bottom of the container.
See here:
link

Triangle with a "6" in the middle and "PS" underneath is for polystyrene, the friend of dumpster diving modelers.

I would think that Yoplait cups would be polystyrene. A matte white is USUALLY PS.

Darn!

It has a "5" within the triangle, with "PP" underneath.

Thanks for the info.

Dan

Then it's polypro. Good luck getting anything to stick to THAT! We used to make holding fixtures from PP because nothing stuck to it.

To the trash they go . . .

Dan
PS. I have a stack of hotel key cards ("3" with "RPVC" or "PVC" beneath the triangle). Do they stick well to styrene sheets?

You mean to the recycling they, I hope.

I just spent a little time (and I do mean litle) Googling polystyrene food containers. All of the links I found referenced foam containers.

Polystyrene has an extremely low melting point. I wonder if the reason that I can only find PS in the form of foam is that PS in solid form (sheet) would not hold up to the rigors and temperature variances during packing, shipping and storage.

Yes. That's right. That's exactly what I meant. To the recycling bin . . . :)

Dan

The "melting point" depends very much on the formulation. It is more accurately a "softening point". Vacuuform plastic sheets soften under the heat of a light bulb.
But, Yes, you would not want your soup container to ooze out from under the soup. Technically it is not melting, but practically speaking, there is little difference when your soup is all over the bottom of the microwave.

I have some Yoplait containers I am using as the basis for a project. Since I am casting the finished models I have filled the cups with plaster to add weight and stop them from flexing. Styrene pieces have been attached with Zap-a-gap medium CA+. I scour the cup with a bit of sandpaper or a file to help the glue take hold, but then I often do that with the styrene too. Procreate sculpting putty sticks to the cups better than Greenstuff (haven't tried brown stuff yet as I seldom use it). Going to try Aves products soon but I am guessing they will adhere well enough.

(I know some people have had issues using CA+ glues on styrene but this has never been an issue for me. No idea why, other than I never use zip kicker).

I have good success using Super Glue Brand fix all adhesive on Yoplait containers and the like, rather than super glue. It bends and flexes with the container, so pieces don't ofen pop off. But I also usually roughen the area to be glued with some sandpaper first.

PP is polypropelene.

Probably the only glue to use is superglue (cyanoacrylate) but even that will probabably not work too well.

Good luck though

AS

picture

It is not cheap but is made for PP, PS, etc. Really nice stuff.

link

Less expensive but takes steps, also good for PP, PS, etc.

If it's a larger piece…
I've stuck together odd bits of plastic using a series of drilled holes and plumber's epoxy (or JB Weld) pushed through the holes with a wad on either side… more like bolting than gluing… but it holds well.

Experts (maybe not as good as TMP experts, but experts all the same) recommend bonding polypropylene to other plastics with a mechanical bond with epoxy, as venusboys3 says, roughening the surfaces as Painbeast and Saxon Dog suggest.

It's not an "automatic recycle", it's a matter of finding the right tool for the job. Polypropylene is *meant* to be solvent-resistant, so don't bother using solvents!

Allen

"Experts (maybe not as good as TMP experts, but experts all the same)"

This one made me laugh. Is it live or is it…sarcasm?

Experts eh? Well I consulted with a real person, an industrial chemist friend of mine and he recommends picture I have used it on PP high density poly prop (starboard) and it works quite well..as nothing else will bond to starboard, nothing.

G/flex was made for polys. Polys are notorious for being difficult to bond and this is due to the consistent oil that flows through the material, creating a skin. What G/flex does is to leech out the oil and follows the molecular void with it's own body . This creates a matrix foothold. By preventing the oil from rebounding the curing epoxy is able to maintain its position.

It is still best to prep with appropriate abrasive and clear/clean the surface.

As with any bonding process, the bond is act of creating a vacuum…this vacuum is what maintains the connection and the curing properties of the epoxy is what holds this vacuum. Some epoxies create a bond by melting surfaces together but with polys the melting requires the introduction of a third element…much like welding you use a poly rod and melt it into the void. This is all by passed by using a product like G/flex.

Anyway, take it for what it is worth. This G/flex is inexpensive and made for the product in question.

But you know what they say about opinions…everyone has one and they usually stink…

…TMP experts, classic…ah that circle of friends it must be tight, yes? il est difficile de venir des amis par particulièrement quand vous donnez un coup de pied le chien pour l'amusement…Je n'apprécie pas votre intention

*********************

Anyway Dan, check with your local West Marine if you have one…if not I have one right down the road, I could pick some up for you.

Thanks! I'll do that.

Dan

You mean to the recycling they, I hope.

If they bother to take it. I can only recycle "1" and "2" with my recycling center.

Have you guys seen this useful tool.

Stick this to that.Glue advice.

thistothat.com

It's strange whats out there.

This dude is my hero!

TMP link

Dan

Guys,

I've looked and looked and I still can't find a symbol for the Evergreen and Plastruct sheets, either on the wrapping or their website.

How do I know it's supposed to be the same plastic as the other ones with the "triangle with a '6' in the middle and 'PS' underneath is for polystyrene", as OFM says?

Thanks,

Dan
PS. Is there a list of which specific food containers bond well with cyanoacrylate? If so, I may have to change my diet to eat only those products with the right containers.

Cacique, plastic "For Sale", "garage Sale" and such signs (sold in Home depot, Wal Mart, etc) are styrene, and make a great and cheap way to get plenty of styrene sheet.

Also, plastic vanity license plates sold in dollar stores (mine had religious themes, felt guilty about cutting them up) are good for thick styrene sheet.

Dan,

I deal with plastics of all kinds in many different applications. Usually the only products that display the recyclable codes are those found within the food and food storage markets.

There are exceptions of course.

What exactly are you trying to do that is not succeeding? You know the basics of adhesives is two parts;

1) the creation and extension of a void/lack of air (make the gap go away)

2) create and maintain a molecular bond

"super glue" creates a melt point between surfaces so if you have a resistance surface then you get a band-aid of sorts or a chemical two sided "tape" section.

So what are you using that is resisting this wonder glue?

PVC takes solvent glues fairly well, but they may be different solvents than work on styrene.

Dan,
Evergreen sheets are polystyrene

and

Plastruct sheets are ABS plastic

Spartan 117

Spartan be careful there, Plastruct puts out sheets in at least 3 different plastics. If you use their solvent Plastiweld there generally isn't a problem at least with the plastics.

infojunky,
3 plastics now? Cool! Back when I used to do 1/35 models(long time ago) they only had ABS plastic sheets. I'll have to check them out again.

Spartan 117

Buy Plastruct's plastiweld glue. It uses a specific solvent that softens just about every kind of plastic.

I've even used it on (acrylic) aircraft windshields.

28mmMan: "What exactly are you trying to do that is not succeeding? … So what are you using that is resisting this wonder glue?"

I want to "dress up" these guys, with bits and pieces from from food containers and other plastic boxes:

link

Dan

And the super glue is not working I assume :(

If you have a weak surface like the plastic containers and the yo-yo's, have you tried a little roughing up of the surface (as noted by a couple of our fine TMPers)?

*****

What of these? link hmmmm

Example of something else I would like to glue Evergreen and Plastruct bits on:

picture

With very little modification, this packaging makes a really nice container home for 15mm SF scavengers.

And here are lots of other examples:

TMP link
TMP link
TMP link

Dan

The best thing to do is if you have a suspect bit of plastic. Dab a little Plastruct on a out of the way spot and see if it softens. If it does then got to town. If not a CA or epoxy is needed.

I prefer my epoxies in the tubes instead of the syringe. that way I have better control of how much I use.