Glueing polyethylene - polypropylene / coroplast
 

I was surfing around trying to find a glue for coroplast as PP is notoriously difficult to glue.

These guys claim to have a glue (primer/activator + glue) for PE and PP (coroplast / corplast) :
PASCO - SHOP - Prime & Pepp
Hit the "More" link (next to "add to cart") for more info on both products.
I haven't used it, and I don't know wether anyone on here has.


I've also found someone reporting that SIKAFLEX-11FC from Sika.com works.

Someone told me that nothing sticks to PP, no glue, no paint. I went ahead and glued a reinforcement to the underside of my Kammback with some universal shoe glue (Pattex) and it's held up for over 15 months, including temperatures from -31°C to +34°C.
There is some discusion here, too:
Coroplast Kammback: joining or bending?

hot glue works for me, no issues yet

Pop rivets perhaps?
I would get some wide washers to spread out the load (aluminum preferably since the body of most pop rivets is aluminum, but stainless steel would also provide corrosion resistance), with the center hole matched to the rivet. Then just go washer, CP panel A, CP panel B, washer, with a rivet through all of them. Putting a little RTV sealant (just purpose-specific silicone caulk) on the face of the washer that meets the panel, and even between the panels could help minimize the possibility of tear-out due to vibration or other strain. It won't bond to the CP panels, but would provide some traction so the components don't slide past each other so easily.
If you want to do a butt joint, pick up a small roll of aluminum flashing (check the siding/roofing area of your local home improvement megamart), cut a strip a couple inches wide to span the joint and provide some grip area (overlap between the panels and strip) for the rivets. Cut a similar panel for the back side of the joint so you get the same metal-panel-metal sandwich the washers provided. Ever so slightly rolling the edge of the metal strips so they press against the CP panels when installed should keep things smooth airflow-wise, though the rivet heads would still stick out a little.

I've never glued coroplast, but I have glued polyethylene. I find that heating the surface with a heat gun just to the point where the surface starts to become glossy helps the glue to adhere better. I read in an engineering textbook that this polarizes the surface in the proper way to improve adhesion. It can be kind of tricky, though, making sure you don't melt the plastic.

That may be one reason why Saand above has success with hot glues.

sid, you might be right there,

the hot glue does heat up the coroplast plastic enough to almost melt, i squirt in a large enough amount of hot glue so that it can heat up the plastic enough to bond well.

Bond Coroplast/Glue Coroplast instead use Leather Rivets
 

Tried to bond 4mm Coroplast together with Formboard CA, goop and sheet metal rivets to no avail. Found leather rivets at Tandy Leather to work great.
They also have Chicago or bookbinding screws. These are about 5 bucks for 10 or rivets which are a nickle a piece (5 dollars for 100). You have to buy the setting tool for another 5 bucks and thats it. I cant pull it apart!!
I use the 1/4 size for two pieces of 4 mm coroplast.
This was for a sign project, but give a try. The Manager at Tandy did one for me before I bought and seeing is buying.

The manufacturer recommends silicone caulk. I overlap 4mm pieces, poke two holes about a inch apart, then loop a zip tie through the holes and tighten.