# Best vs. acceptable adhesives for expanded poystyrene?



## Molinero (Sep 20, 2012)

Hi, gang,

I've been searching for threads on the best ways to adhere sheets of expanded polystyrene to one another, and it seems the consensus is 3M 78 or their specialty adhesive for that purpose. 

I have several cans of 77, however, so I'm wondering if anyone's had any good experiences using that on polystyrene -- or will it just eat the foam?

Thanks!


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## Jackalope (Sep 20, 2012)

I've used the 78 and it does work. I've tried 77 with mixed results, the results usually being not very good. Another product that was mentioned here was 3M 30nf "green glue". I haven't tried it yet, but whoever suggested it sang its praises.

hope that helps


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## Molinero (Sep 21, 2012)

Appreciate the response. Ordering the 78 now. Thanks!


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## erichart (Sep 23, 2012)

I second the use of 3M Fastbond 30NF "Green Glue". It's strong, water-based, and emits far less toxic vapors than most cements.


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## Van (Sep 24, 2012)

30 NF is , by far , the best adhesive for both Expanded Polstyrene and Extruded Polystyrene. IMHO.


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## mikebowen (Sep 25, 2012)

Hi
we use a product called PL 300, which is an actual foam board adhesive.


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## BioHazardCustoms (Sep 26, 2012)

Something else you might want to try is Glidden Gripper primer. We use it a lot in the haunted attraction industry, and once glued together, the foam boards can't be pulled apart. Hope this helps!


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## Jackalope (Sep 28, 2012)

Van said:


> 30 NF is , by far , the best adhesive for both Expanded Polstyrene and Extruded Polystyrene. IMHO.



Does the 30 NF "cut" well or does the glue leave a ridge after carving? . I.e I bond two pieces together before shaping, hotknife etc.?


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## TEarlywine (Sep 28, 2012)

We use spray expansion foam from the Hardware Store as if it was Gorilla Glue. Both are just polyurethane.
-Spray (and spread if you need to)
-press together to pop bubbles and get on both pieces
-let sit apart 8 minutes-or-so
-press and hold together and it will never come apart.

once dry, it carves just like HD-EPS (although there may be occasional bubble void if you use it to fill also)

Just be aware nothing really removes it from anything except a knife/sanding/pumice stone (and don't bother with those until it is dry)... so tarp, wear gloves, eye protection, read the MSDS, etc.


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## TEarlywine (Sep 28, 2012)

ps/fyi: although there are plenty other chemicals that will also eat the foam, generally it is the propellant in aerosol cans that eats the foam... YMMV, read your MSDS


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