Hi all,

I just built an outdoor kitchen with King Starboard (HDPE sheetgoods primarily for marine application). The installers are having issues with the hinge plate screws holding tight on the sunnier days (it's baking on a rooftop in New York City, even in April).

Does anyone have any recommendations based on experience with this product? My current recommendation to my guys is going to be to drill out the screw holes and insert typical 8mm dowel inserts with epoxy.

Thanks all.

Consider switching out your #7 x 5/8 screws with 5mm x 14mm system screws. If you're using wing plates, put an additional screw in the tail for insurance. Even thickened epoxy doesn't adhere well to PE unless you rout out a big enough pocket with lots of scratches & fissures to give it something to grab.

Thanks for the reply Jared. We're going to try swapping for better suited screws first and see if that solves the problem.

If not, we'll move on to a more invasive solution, likely the dowel inserts plus TAP Poly-Weld which is rated for polyethylene use... you made an excellent point about epoxy doing us little good!

Epoxy won't stick to polyethylene. The plastic epoxies aren't actually epoxy. They are methylacrylate also known as Plexus adhesive.

I would try the system screws or the largest diameter self tapping screw that goes thru the hole in the plate. Bigger coarser threads are your friend in soft plastic.

I built a few food shops with the same Starboard.
Used the 175L8100 hinge plate with some success , it has the large system screws. Drilling the system and shelf pin holes was a disaster. You would have to clean each of the 23 drill bits off by hand or the next hole would be larger and conical shaped. I gave up on system hole drilling for shelves , changed to the old shelf standard with a dado. For hinge plates drill through panel and use twin application screws. They call it starboard because you see stars when picking up to load sheet on saw.
Ed

Your having problems because of expansion/contraction and the fine thread of the screws in relation to the HDPE. Most all from Starboard to Vycom specify no screws. Switch to threaded inserts and machine screws (brass inserts and stainless machine screws). The increased diameter and extremely coarse thread on the inserts keep them put. Its not a pretty solution but screws in HDPE and heat dont play well together.

https://www.mcmaster.com/bolts/flat-head-binding-barrels-and-screws/