What is the strongest possible glue for styrene-styrene bonding?

General Discussion General Modeling Discussion
1

Hello

I need to bone styrene to styrene. It needs to resist some very strong springs. What is the strongest type of glue that will set:
a) within 2 hours
b) within 24 hours

Cement glues bone quickly but never seem to regain the full strength of the original virgin styrene material.

I am guessing some sort of epoxy glue but which one?

With thanks

J

P.S. Later I will need to bond styrene to ABS plastic as strongly as possible too.

2

I used to use epoxy if I needed a really strong bond, but lately I find the epoxy not sticking to the styrene. I still find CA works best. For a real close fitting seam, regular thin CA is fine, if the fit is not the best, then Gel CA works great, and better than the regular thin stuff.

I don’t know if the mfgs are using a new formula for styrene or not, or if the epoxies are changing, but sure have had bad luck with epoxy/styrene in last couple of years.

3

Definately a solvent type glue, such as Tamiya thin or Tenax or MEK. Just let it dry 2 days or so. Make sure you use a good amount of pressure while the glue joint sets up, using clamps or whatever you have.

4

Solvent. Use staight MEK. Just give it time to fully cure. Solvent creates a chemical bond. Something none of the other glues do. It’s the absolute strongest, but it will take a few days to fully harden.

5

Interesting - I recently bought some Plastic Fusion epoxy (I think - 2 part anyhow!) glue made by Super Glue corp, off a merchand on eBay. http://www.ebay.co.uk/itm/261508621516

I have tried 3 times now and each time it is not setting properly. It’s not going as yellow as I’ve seen it go in videos. On the last attempt attempt I measured v carefully and mixed for a full minute and 24 hours later I could scrape it off with a fingernail.

So I am now thinking that the epoxy itself has gone off for some reason. Confusingly there is no sell-by date on the packaging, and having never used it before I have not way of knowing if this is the case.

I wonder if your epoxy has gone off too? :^/

6

Thanks. I don’t know if there is much difference between cements but I have been using EMA Plastic Weld (and have recently bought though have not properly experimented with Mr Cement S and Tamiya Extra Thin too).

I am finding that even when I use quite a lot of solvent the bond I get is never quite as strong as the original styrene (plasticard/HIPS). You may have a slight point that I have not been allowing my bonds to dry out for quite long enough. Hmm… but time is money and I cant really afford to wait 2 full days.

I am slightly hazy as to what solvents these cements actually contain - is it Methyl Ethyl Ketone (MEK) or Methylene Chloride (or are they proprietary blends)?

For a really strong blond would there ever be a case for using acetone?

I am now thinking about using a different plastic too (e.g. ABS?) because I need to create a stronger housing for then stiff torsion spring that I am using in my model (of a novel product) and I am slightly constrained on space.

I’m not completely sure where to go next in terms of a stronger plastic AND a stronger glue!

7

Thanks - this sounds promising. Btw, can you recommend a cheap retailer and fast here in the UK?

Cheers

8

I agree. I would not use MEK. It’s fumes are nasty, canrcinogenic, and the stuff is pretty flamable. While that is also true of the other solvents, there’s a big difference between a 1.5 oz. bottle and a 32 oz. can on the bench.

9

Wait, “MEK” as in Methyl Ethyl Ketone? Wow, be careful with that stuff. That isn’t what’s in Tamiya Extra Thin and Mr. Super Thin, is it?

10

I don’t know what the active ingredient is, but I use Testor’s “Cement for Plastic Models” (3501x), which is intended for use with polystyrene and ABS plastics. I also use Plastruct’s Bondene and Weldene, on styrene-to-styrene bonds. The both set within your required times. As far as holding a join is concerned, I haven’t had any joins break, and the welds seem to be pretty consistent. But you also note that your joins need to resist “strong springs”. I don’t subject my models to any kind of regular, planned shocks (I have dropped things, on occasion), so I can’t say how well the joins might hold up to the stress.

11

It was hard for a time to get MEK in hardware stores- all I could find were cans of “MEK substitute.” However, I am now seeing regular MEK on shelves again. I keep an old bottle (and brush) from a commercial solvent glue, and pour the MEK into bottle when I need a refill. The big can stays closed except when filling the little bottle.

12

Don, that’s exactly what I do. The bottle is open for only a very brief time while using the MEK.

Gary

13

Just a thought, but if you are having trouble finding a glue that will work, is it possible to use a mechanical fastener like a screw or nut/bolt combo? Is the seam in a hidden area and could a fastener be hidden as well?

14

Tenax or Plast i Weld will actually melt and fuse the plastic together making a solid bond. It sets up within one our and is fully cured overnight.