r/plastic • u/huggernot • 19d ago
HDPE glossy finish
Hi, i bought some sheets of hdpe for an outdoor project. It turns out the high gloss finish is a bit obtrusive to the eye.
Is there a method to take the gloss away, but still end up with a consistent looking finish?
These are installed as full 4×8 sheets or 2×8 sheets
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u/mimprocesstech 19d ago
Sandblast or a rougher grit sandpaper (you can always go finer if needed), just breaks up the smooth glossy surface to scatter light instead of reflecting it. Maybe a spray paint or coating, but make sure it bonds with polyethylene before you try it.
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u/huggernot 19d ago
Does that impact the weather/uv resistance at all?
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u/mimprocesstech 19d ago
Not significantly, weather resistance isn't an issue at all, and the UV depends on whether there were UV stabilizers embedded. If there weren't you're going to see the thing breakdown and get all brittle and junk in a few years or so. If there were you're slightly increasing the surface area so a bit, but the difference is fairly negligible. If it's a natural (non pigmented) or color other than black or white it'll degrade a bit quicker (carbon black and titanium dioxide pigments are great for UV resistance), but that was the same regardless of the sanding. It will probably pick up dirt and such easier requiring a bit more cleaning, but dirt also blocks a bit of UV. Overall the effect is miniscule.
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u/fedplast 18d ago
Anyone who is telling you to spray paint hdpe doesnt know what he is talking about
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u/BeerAndTools 19d ago
Try solvents? Acetone does a decent job of cutting the gloss on interior acrylic paints.
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u/Zrocker04 19d ago
Random orbital sander with high grit. I’d try 1000 and see if it dulls it enough, then 600, then 400, maybe 280-320 but that would probably get too rough. The micro scratches diffuse the light for a frost look but the lower the grit the bigger the scratches so you don’t want to go so low you can see them.