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#1
Old 12-29-2017, 04:52 PM
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Coroplast - the most useful material you've never heard of

In another IMHO thread, aceplace57 was looking to make dividers for an equipment bag. Various materials had been suggested including rigid insulation, foam core art board, cardboard and Masonite. I suggested Coroplast - aka corrugated plastic.

You've seen it if you've seen the bins the US Postal Service uses. The material is available in different thicknesses from 2mm to 10mm, with the 4mm version being the most common. It's also frequently used to back signs.

It's two sheets of plastic separated with ribs spaced at the same distance - 4mm Coroplast has ribs every 4mm. There are tools available to easily cut either one sheet or both, guided by the ribs, so you can easily cut and curve the large sheets into a curved surface perpendicular to the "grain" of the ribs.

It's not a lot harder to cut than cardboard, just using a utility knife, but unlike cardboard, it's rigid and won't shed fibers. People are actually making fold-up boats with this stuff!

Bends across the grain can be made with the roller tool used to insert the the rubber "spline" that holds screen in place. More permanent bends can be made by heating the material. A heat gun can be used to made smooth curves, and sharp bends can be made with a long strip heater and a jig, as seen in this video of someone making a camp food box.

The hardest part seems to be gluing it together, but a boat builder has experimented with a number of different adhesives with success.

I learned about this material when a friend made me a bag for my camera. The exterior is made from "ballistic nylon", the interior is lined with pigskin suede but the basic case is made from Coroplast. After 10 years of constant use, the case is still holding up.

Anyway, thought it would be a good idea to share this, and hope it proves useful.

Last edited by gaffa; 12-29-2017 at 04:53 PM. Reason: Link
#2
Old 12-29-2017, 04:55 PM
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Hmm, if I saw that out of context, I would just assume somebody couldn't spell chloroplast.
#3
Old 12-29-2017, 05:00 PM
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Originally Posted by Riemann View Post
Hmm, if I saw that out of context, I would just assume somebody couldn't spell chloroplast.
No, Coroplast is utterly useless at converting sunlight to energy.
#4
Old 12-29-2017, 05:11 PM
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But you can tap into The Force with Midicoroplast.
#5
Old 12-29-2017, 05:44 PM
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Oh yeah, it's great stuff. Our school prints billboards for the school fair every year on the stuff, though I didn't know what it was called. I souvenired one one year and chopped it up for a giant dice, which has survived abuse at multiple pre-teen birthday parties in the years since.

It's functionally basically a way sturdier corrugated cardboard.
#6
Old 12-29-2017, 06:02 PM
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I'd never heard of this stuff until my daughter got a fancy guinea pig cage, which uses coroplast for the low walls and the floor. It was interesting to cut and form, it has I would say a unique feel...I can indeed imagine it's useful for a lot of different things.
#7
Old 12-29-2017, 06:08 PM
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I have a collapsible hamper made of Coroplast. I did not know the name until this thread. I just thought of it as plastic corrugated stuff.
Thanks
#8
Old 12-29-2017, 06:09 PM
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Yes, good stuff. Among other things, it's the favorite material for homemade streamlined bicycle/tricycle fairings.

The actual material is polypropylene. There are double-sided tapes that work with polypropylene, like the 3M VHB tape.

I myself used it recently for making an enclosure for my 3D printer. The leftover coroplast was useful for making signs for political marches/protests.

Home Depot sells big (8'x4'?) sheets of it, by the way.

Last edited by scr4; 12-29-2017 at 06:10 PM.
#9
Old 12-29-2017, 06:13 PM
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Originally Posted by gaffa View Post
Bends across the grain can be made with the roller tool used to insert the the rubber "spline" that holds screen in place. ...
I've found that a pizza cutter works OK in a pinch.
#10
Old 12-29-2017, 06:56 PM
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Originally Posted by scr4 View Post
I've found that a pizza cutter works OK in a pinch.
One of the pages suggested those, but only after dulling the blade with a grinder.
#11
Old 12-29-2017, 06:58 PM
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Originally Posted by Sveltington View Post
I have a collapsible hamper made of Coroplast. I did not know the name until this thread. I just thought of it as plastic corrugated stuff.
Thanks
Coroplast is a trade name, corrugated plastic is the generic term.
#12
Old 12-30-2017, 02:36 AM
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Quote:
Originally Posted by Maserschmidt View Post
I'd never heard of this stuff until my daughter got a fancy guinea pig cage, which uses coroplast for the low walls and the floor. It was interesting to cut and form, it has I would say a unique feel...I can indeed imagine it's useful for a lot of different things.
Our guinea pigs have it for their floor as well. Though in their case it was leftover election signs from a local pollie, cut to fit. It has lasted almost 10 years so far and is in better shape than the wooden hutch itself. And very easy to clean.
#13
Old 12-30-2017, 08:51 AM
ftg ftg is offline
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How much weight can this stuff take? E.g., if you walk on it will there be footprints left in it? If you drop something (somewhat lighter than a bowling ball?) on it will it be left dentless?
#14
Old 12-30-2017, 11:35 AM
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I run a water stop for the marathon. As of this year we're using it as the divider when we stack cups 3 layers high. Works much, much better than the cardboard we used to use as it doesn't loose it's integrity when there's a spill & it gets wet.
#15
Old 12-30-2017, 11:50 AM
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Quote:
Originally Posted by ftg View Post
How much weight can this stuff take? E.g., if you walk on it will there be footprints left in it? If you drop something (somewhat lighter than a bowling ball?) on it will it be left dentless?
It'll get dented up if you walk on it. If you want to experiment with it, you'll find endless samples along the roadway and attached to poles from people who put up signs like "We Buy Houses", "Lose Weight Now", and many others. Often during political season you'll see much larger 4'x8' sheets, which are thicker and more durable than the smaller signs seen more often.

Although these signs are often illegally placed along shoulders and right of way, it's also illegal for you to pull them if you haven't been authorized by your city. Use appropriate caution as necessary.
#16
Old 12-30-2017, 11:51 AM
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A friend had a project where he needed to add dividers to cheap plastic drawer units. He had a low budget for this but wanted something sturdier than oak tag.

We shopped Lowes and bought enough corrugated plastic to do the job easily. It was very cheap, cuts easy and hot glue works find for applying to plastic drawers.
#17
Old 12-30-2017, 12:48 PM
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I've been watching videos. Learning how to work with this material.

It's certainly more durable than foam board.

I'm reconsidering my original plan to cover the dividers in fabric. I thought fabric would protect the foam board. That's not a concern with Coroplast.

Last edited by aceplace57; 12-30-2017 at 12:52 PM.
#18
Old 12-31-2017, 12:12 AM
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Quote:
Originally Posted by aceplace57 View Post
I've been watching videos. Learning how to work with this material.

It's certainly more durable than foam board.

I'm reconsidering my original plan to cover the dividers in fabric. I thought fabric would protect the foam board. That's not a concern with Coroplast.
If I were doing your project, I'd be sandwiching two pieces together, one oriented side to side, one oriented up and down. That should make the dividers nearly indestructable. I haven't seen it in videos but you can melt the rough ends to smooth it out (have really good ventilation.) Hot glue looks to be the best thing for bonding joints and seams, and the glue is cheap enough - maybe a bead along the top of each divider to smooth them out.

Last edited by gaffa; 12-31-2017 at 12:13 AM.
#19
Old 12-31-2017, 03:03 PM
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Here's a guy who made a camper to haul behind his recumbent bike out of Coroplast. He got four sheets of it free that were formerly campaign signs! He managed to make it airstreamed, and even has a space for a stove and the whole thing weighs around 60 lbs.
#20
Old 12-31-2017, 03:30 PM
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Originally Posted by gaffa View Post
He got four sheets of it free that were formerly campaign signs!
That's where I get all mine. I sealed up a broken window in my shop, and use it to winterize the sides of my swamp cooler.

That guy ain't running for Sherriff anymore, anyway.
#21
Old 12-31-2017, 08:57 PM
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Originally Posted by Gatopescado View Post
That's where I get all mine. I sealed up a broken window in my shop, and use it to winterize the sides of my swamp cooler.

That guy ain't running for Sherriff anymore, anyway.
I imagine that the day after an election, you could volunteer to go around picking up those big yard signs and disposing of them, and you would get people falling all over themselves to thank you.
#22
Old 12-31-2017, 10:55 PM
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Hmm. I have 200 campaign signs in my garage waiting for the next election in 4 years. I never thought of cutting them up and using them for projects! Good to know...I definitely have signs to spare.
#23
Old 01-01-2018, 01:06 AM
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Quote:
Originally Posted by gaffa View Post
If I were doing your project, I'd be sandwiching two pieces together, one oriented side to side, one oriented up and down. That should make the dividers nearly indestructable. I haven't seen it in videos but you can melt the rough ends to smooth it out (have really good ventilation.) Hot glue looks to be the best thing for bonding joints and seams, and the glue is cheap enough - maybe a bead along the top of each divider to smooth them out.
I'm going to Home Depot this week. See how stiff this material is. Doubling it up may be a great idea.
#24
Old 01-01-2018, 02:06 AM
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It's called Corflute around here I think and I didn't know about it until fairly recently either. I mostly see it used for signs and billboards of various sizes at schools, markets, fetes, community events, etc, and of course during election campaigns. It can be printed with really vibrant colours too, it's great stuff!
#25
Old 01-01-2018, 06:48 AM
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Originally Posted by Gatopescado View Post
I sealed up a broken window in my shop, and use it to winterize the sides of my swamp cooler.
Sorry to jump in at this point, but swamp cooler? winterize?
#26
Old 01-01-2018, 07:05 AM
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Technically, the material is high impact polypropylene copolymer. Coroplast is the name of the extruded twin-wall plastic sheet products and also name of the company.
#27
Old 01-01-2018, 12:43 PM
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Originally Posted by Santelia View Post
Sorry to jump in at this point, but swamp cooler? winterize?
A swamp cooler is a substitute for an air conditioner. Works by evaporative cooling. Fine for dry climates. Not a good idea in humid climates.

Like an AC wall unit, it's a good idea to cover them in the winter to make them last longer and reduce heating losses.
#28
Old 01-01-2018, 01:44 PM
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Originally Posted by Santelia View Post
Sorry to jump in at this point, but swamp cooler? winterize?
Quote:
Originally Posted by ftg View Post
A swamp cooler is a substitute for an air conditioner. Works by evaporative cooling. Fine for dry climates. Not a good idea in humid climates.

Like an AC wall unit, it's a good idea to cover them in the winter to make them last longer and reduce heating losses.
I live in a Wonderland! Hot as shit in summer, and cold as Hell in winter. If you don't seal and cover the swamp cooler, you would just vent all the heat straight up through the roof. I use the coroplast to cover the sides, wrap it up in shrink-wrap stuff, then cover it with a canvas cover and wrap that in rope to keep it from getting torn up in the wind.

Lots of wind here. Like I say, a Wonderland.

Last edited by Gatopescado; 01-01-2018 at 01:44 PM.
#29
Old 01-02-2018, 09:41 AM
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Quote:
Originally Posted by Maserschmidt View Post
I'd never heard of this stuff until my daughter got a fancy guinea pig cage, which uses coroplast for the low walls and the floor. It was interesting to cut and form, it has I would say a unique feel...I can indeed imagine it's useful for a lot of different things.
I bought a big sheet of it from a sign shop 11 years ago to make a guinea pig cage from scratch. Easy to work, durable, strong.

I just bought a sheet Sunday from Home Depot to make a light table for bottom-lit photography. $20 for a 4' x 8' sheet (may not have been Cloroplast brand).
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#30
Old 01-03-2018, 05:22 AM
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Quote:
Originally Posted by ftg View Post
A swamp cooler is a substitute for an air conditioner. Works by evaporative cooling. Fine for dry climates. Not a good idea in humid climates.

Like an AC wall unit, it's a good idea to cover them in the winter to make them last longer and reduce heating losses.
Thanks
#31
Old 01-03-2018, 07:03 AM
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I was getting ready to make a bunch of arrow cases for my flight arrows, an entire set only weighs about 3 oz. This would be perfect for that. I normally use veneer but this would be a lot easier to work with.
#32
Old 01-03-2018, 12:38 PM
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Originally Posted by HoneyBadgerDC View Post
I was getting ready to make a bunch of arrow cases for my flight arrows, an entire set only weighs about 3 oz. This would be perfect for that. I normally use veneer but this would be a lot easier to work with.
If you made a box like this one, you would wind up with quadruple thickness at the ends. And it would only weigh a couple of ounces.

Last edited by gaffa; 01-03-2018 at 12:39 PM. Reason: Count
#33
Old 01-06-2018, 07:41 PM
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So it turns out that when a snowplow hits a coroplast sign (which, if you're curious, read "#2069") and it's -8, the sign shatters into a bunch of little pieces.
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