# Frame Bag made from Coroplast



## Bill in Houston (Nov 26, 2011)

The photo in this thread got me thinking. Why not make a hard sided frame bag out of coroplast?

It's lightweight, easy to clean, easy to work with, etc. I have not made anything 3-dimensional out of it, but I am more confident in my coroplasting skills than my sewing skills.

I would ziptie it to the frame, and maybe screw it to the bottle bosses.

The sides would have some stiffness, which would help prevent the bulging I forsee with a fabric bag. It would be easy to make it narrower near the BB for pedal clearance, and wider up near the top and near the headtube.

Anyway, what do you think?


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## monzie (Aug 5, 2009)

From my expirence with coroplast I would be hesitant to do it. It seems like leakage would be a big issue. Plus, that stuff is bulky and akward. I like the fabric because it is a little maliable and lenient for odd sized items. The coroplast is too stiff in my opinion. But, if you can solve those problems and make a great "bag"( I think case would be a better term?) then go for it! I like your enginuity.


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## Mr.Magura (Aug 11, 2010)

The one thing I would sort prior to actually making a box, would be how to glue this in a proper way.
Polypropylene is pretty hard to get good adhesion on. 

Once that is sorted, I think you're on to something.

I can only come up with one solution to join the profiles, and that is ultrasonic welding.
For a couple of boxes, that just might be a bit excessive.


Magura


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## Bill in Houston (Nov 26, 2011)

monzie said:


> From my expirence with coroplast I would be hesitant to do it. It seems like leakage would be a big issue. Plus, that stuff is bulky and akward. I like the fabric because it is a little maliable and lenient for odd sized items. The coroplast is too stiff in my opinion. But, if you can solve those problems and make a great "bag"( I think case would be a better term?) then go for it! I like your enginuity.


I am usually able to find a relatively thin gauge of it. Once I fold it and then set it with a heat gun, I hope it won't be awkward.

I am sort of puzzled about how to close the top in a way that keeps out rain and is easy to open and close. I figure some kind of flap top like the swiss one, BUT that is likely to poke out some. I will need to curve it and work it with the heat gun.



Mr.Magura said:


> The one thing I would sort prior to actually making a box, would be how to glue this in a proper way.
> Polypropylene is pretty hard to get good adhesion on.
> Once that is sorted, I think you're on to something.
> I can only come up with one solution to join the profiles, and that is ultrasonic welding.
> For a couple of boxes, that just might be a bit excessive.


I have thought about that a little bit. I have previously used Gorilla Glue, and it woked well, but that was a less demanding application. I will try shoe goo on some test strips, since it seems to stick to everything. Next try would be to try to melt it together with something like a very thin tip on a soldering iron, poking staggered holes every 1/2 inch or so. But that would end up so ugly. If all else fails, a sure solution that would look hideous would be to poke lots of holes and ziptie the two pieces together. Yuck.


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## vikb (Sep 7, 2008)

Randonneurs and bike commuters as well as recumbent riders have been making all sorts of boxes out of coroplast. It will work. You can simply fold the frame box and tape it together. The real challenge is the design and then carefully assembling it.

I don't think I'd want a frame box vs.a frame bag if I was buying them, but with my limited DIY skills I'd end up with something I could use from coroplast faster/easier than I could sew anything.

My GF uses a coroplast pannier box on her commuter bike and likes it quite a bit.

Donkey Boxx Initial Impressions&#8230; « The Lazy Rando Blog&#8230;


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## Bill in Houston (Nov 26, 2011)

vikb said:


> I don't think I'd want a frame box vs.a frame bag if I was buying them, but with my limited DIY skills I'd end up with something I could use from coroplast faster/easier than I could sew anything.


Oh, trust me, if I could sew, I would sew one instead. 

Thank you for the input.


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## monzie (Aug 5, 2009)

I'm jealous of the VO hammered fenders. I'm getting some for my rando/touring bike when I can afford them.


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## vikb (Sep 7, 2008)

monzie said:


> I'm jealous of the VO hammered fenders. I'm getting some for my rando/touring bike when I can afford them.


Sorry for the OT - check these babies out...:thumbsup:

bb1 | Flickr - Photo Sharing!


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## monzie (Aug 5, 2009)

Sexy. And Carradice, very nice.


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## Bill in Houston (Nov 26, 2011)

made a cardboard prototype tonight. photos posted tomorrow. rough calcs show it has a capacity of 528 cubic inches, or almost 9 liters. it's about 6 inches wide, and isn't in my way at all except down at the cranks. I like it so far.


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## monzie (Aug 5, 2009)

Can't wait to seethe pictures.


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## Bill in Houston (Nov 26, 2011)

well, the gallery on here doesn't work the way i would expect. it takes my photos and assigns other people's random photos to them. so hopefully you can see the photos that are attached. 
first is the completed prototype from the left side of the bike. 
the next few show the size of the inside of the box. for the final execution, i will remove the bottle cage. just didn't feel like messing with it tonight. 
then there are two that show the view from the right side with the flap open, and with the flap closed. on the one with the flap open, you can see what a 16.9 oz waterbottle looks like standing inside, for scale. 
and then the last really shows off what a disaster my wife's garage is, and shows what the box looks like from the top.
the box will be good for carrying dense, compact things. water, fuel, stove, etc. the weight will be down nice and low and should ride nicely.


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## oromis (Jul 13, 2011)

How did this ever turn out? did you make another box out of coroplast?


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## Bill in Houston (Nov 26, 2011)

not yet! but hopefully soon.


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## annoying crack (Jan 15, 2010)

*Duct tape*

I know there is a guy here in Belgium who makes all his bags in layered duct-tape. He says it's very easy to work with, waterproof, easely repairable, easy to find and relatively cheap. And it seems to work. I'll see if I can still find links to the stuff.


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## Lone Desert Walker (Sep 15, 2011)

I like the idea. I have installed a lot of donkey boxes (like the one above on the surly) and tryed them out. They are super tough. I think they use some kind of heat type spot welder to join them together. I have always wanted to mess around and try to weld coroplast together because you could make darn near anything out of it. I like the duct tape idea too though, you could just wrap that cheerios box with duct tape and be done. Cant wait o see photos of the finished product.


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## vikb (Sep 7, 2008)

bee said:


> Hey! This is pretty awesome. Is it custom made to your dimensions?


Donkey Boxx, a durable, versatile bicycle pannier

Nope. There is only one size. She had a serious crash that destroyed her fork amongst other things. The bike slid on the Donkey Boxx which survived with only a bit of abrasion. I was pretty impressed.


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## bee (Apr 7, 2008)

vikb said:


> Randonneurs and bike commuters as well as recumbent riders have been making all sorts of boxes out of coroplast. It will work. You can simply fold the frame box and tape it together. The real challenge is the design and then carefully assembling it.
> 
> I don't think I'd want a frame box vs.a frame bag if I was buying them, but with my limited DIY skills I'd end up with something I could use from coroplast faster/easier than I could sew anything.
> 
> ...


Hey! This is pretty awesome. Is it custom made to your dimensions?


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## Bill in Houston (Nov 26, 2011)

*Whatcha gonna do with all that junk?*

Put all that junk in your bicycle trunk!

Finally finished it. Didn't take much time to build once I set my mind to it.

The volume is about 9"x16" by 5" wide, which is 360 cubic inches, which is 6 liters.

It will mount to the top tube with zipties or velcro straps, and it mounts to the bottle cage mounts on the downtube.

Pics show side view, top view, and view with door open. The hole in the box could be cut to be a bigger, but my first concern is keeping stuff from jostling out. As it it, I can get a big water bottle through it, so I'm happy with it.

The flap on the front edge of the door keeps puddle splash out. The whole thing is rainproof.

I'll try this for a while, and then see how much wider I think I could make a large capacity version.

Oh, the raw materials are shoe goo and an illegally posted campaign sign, which explains the blue writing inside. .


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## Mr.Magura (Aug 11, 2010)

Not too shabby Mr. B.

This just might give some inspiration for future projects in this end.

Magura


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## Bill in Houston (Nov 26, 2011)

Thank you, sir. 

I have 4 giant sheets of coroplast now, so I need to get creative too. I need a good solution for a bar bag, so maybe that will be next.


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## Lone Desert Walker (Sep 15, 2011)

Looks good.


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## TigWorld (Feb 8, 2010)

Nice one.


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## verslowrdr (Mar 22, 2004)

Bill in Houston said:


> ...Oh, the raw materials are shoe goo and an illegally posted campaign sign, which explains the blue writing inside. .


Your ideas are intriguing to me, and I wish to subscribe to your newsletter.
:thumbsup:


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## matt1976 (Sep 9, 2007)

Fabulous!


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## Bill in Houston (Nov 26, 2011)

verslowrdr said:


> Your ideas are intriguing to me, and I wish to subscribe to your newsletter.
> :thumbsup:


Write your address on a triple ring square taper crank set, and send it to me at... 

thanks!


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## De La Pena (Oct 7, 2008)

So how tough is this stuff? Is it brittle? How do you believe the box/bag and the mounts will hold up in a crash?


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## Bill in Houston (Nov 26, 2011)

you've seen it before - its the stuff little signs on the side of the road are made of. it is amazingly tough. you could stomp on the box, and then just bend it back to shape. 

I will need to be careful on the mounts. i think that is where it is most likely to fail. if the load isn't spread enough, the ziptie or velcro will tear the material. so i will use some kind of large washer or other piece of metal to spread the load. 

hopefully this weekend i will get it fully mounted up, stuff it full of full soda cans, and go ride some bumpy stuff. the cans are heavy and will bounce around plenty and be a good test.

results posted as soon as i get them.


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## Bill in Houston (Nov 26, 2011)

The box mounts to the frame in two spots. There are two screws thru large washers, then thru the box, and into the bottle cage mounts.

The second mount is at the top of the seat tube, and i just poked a couple of hole in the box there, reinforced it with a piece of metal, and secured that top rear corner of the box to the top of the seat tube with a short little bungee thing I had.

Today I tested it out. I put 6 cans of soda in it (all that would fit) and went for a 21 mile gravel grind. I also threw in a couple of very steep climbs. I hardly noticed the extra weight (4.5 lbs). The box rode nicely. The cans inside didn't bang around except on really rough stuff. My legs only touched it occasionally, and not in an annoying way. I still have all my calf hair.  

All in all this is a winner to me. An easy way to carry a decent amount of heavy stuff down nice and low, in a weather/splashproof box. 

If you'd like to build your own, and have any questions, just ask.


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## Johnny Chicken Bones (Jul 13, 2005)

REVIVE!!!
Who has made their own frame bag from COROPLAST!?

It's been done. Not to death but i know there are more DIY homemade Coro bags out there. 
What's the most clever way to close the box? 

Photos if'n you got em. 
(please)
-JCBs


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## Bill in Houston (Nov 26, 2011)

I ended up using the bag above on a trip or two before that bike got stolen. The bag worked well. I ended up making a closure with one of these, I think .
https://www.amazon.com/BC6B-100-Bungee-Stretch-Cord-Black/dp/B01G5CNK1C

I cut the hole in the side bigger for easier access.

Stuff kind of rattled around inside of it, which could be fixed with better packing. But I can see how that noise would most annoy people.


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## Johnny Chicken Bones (Jul 13, 2005)

Any suggestions for how you used the shoegoo to join the edges? 
I'm picturing a small (1.5" flap) folded over, then glued to it's neighboring side. 
Perhaps I'll get a large enough piece to that the top narrow portion and both side panels are all the same piece. 
Only requiring attachment for the bottom edge along the downtube, and a potion along the seat tube. 

1.5"


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## Bill in Houston (Nov 26, 2011)

Yes, exactly. Make a crease in the coroplast to give you a 1.5" flap, and heat-set it with a heat gun.



Johnny Chicken Bones said:


> Any suggestions for how you used the shoegoo to join the edges?
> I'm picturing a small (1.5" flap) folded over, then glued to it's neighboring side.
> Perhaps I'll get a large enough piece to that the top narrow portion and both side panels are all the same piece.
> Only requiring attachment for the bottom edge along the downtube, and a potion along the seat tube.
> ...


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## PL Scott (May 29, 2014)

I built mine about 3 years ago and still use it. I used zip ties to hold it together.

Here it is (almost got the #3 perfect) on a 202 mile bikepacking ride from sacramento, to south lake tahoe and then to Truckee. Picture from the original Echo summit looking into South Lake Tahoe.


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## Bill in Houston (Nov 26, 2011)

Hey, that's pretty awesome.


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## PL Scott (May 29, 2014)

Thanks Bill! I call it a frame box. If I made another one, I'd make it 1/2 wider to accommodate some of my gear, with the goal of eliminating a backpack. That would still give leg/feet clearance and then I could design a better opening. As built, to open it you must take it off the bike as the opening is at the shock area.

I've put about 400 miles on it, but I use only when my ride is more of an adventure, fishing, experimenting with different types of gear and exploring ride. 

I started to design a saddle box based on a design I found in the bikepacking.net forums. Never finished it since I got a great deal on a Revelate viscacha.

For my next bike (now in the market for), I will get a custom frame bag. But for DIY and lost cost, the frame box has more than paid for the zip ties. I found the coroplast sheet in a store's dumpster, so it was free.


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## Johnny Chicken Bones (Jul 13, 2005)

I'll take any photos of the joints on that box PL Scott. 

After an edge is folded over- how flexible does it remain? 
Could I fold the side over and still open/close it easily? And w/o damaging that corner over time 

I have a handful of thoughts on this. For now am considering maybe lacing the edges if they aren't glued. 
Maybe use some magnets to keep the door/flap closed. 

Not even sure what bike this will go on! The fat/bike packing rig has a bag. The CX/Gravel/Adventure/Rando (or what they used to call a "bike") has a top tube bag already. Maybe it'll turn into a full size box for that one. 

Dunno. Just like the idea of low cost and DIY. 
Found panels on Amazon (black) for cheap. 

-JCBs


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## Johnny Chicken Bones (Jul 13, 2005)

(nevermind... 3 seconds of Google and I found the answer. Heat before the bend)

4 sheets of black coroplast. 
18"x24". $20. 

When making a corner- should I heat it before the bend, or after making the bend?

-JCBs


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## PL Scott (May 29, 2014)

Pictures in next post.

Think about where you want the door. I had limited side surface space and made the door on the box edge next to the shock. To access, I have to take it off the bike.

Determine total width of box. Make sure no pedaling problems occur by testing the width with something. The total width must account for the coroplast sheet thickness.

Zip ties are spaced evenly to prevent ripping of the sheet. The heads must be outside so you can trim and file the sharp edges. If inside, you can’t access them and they can tear fabrics such as a puffy jacket.

For bends, you can use glue or heat it. If glue/magnet is used for attachments, it should be very strong to overcome the coroplast’s natural recovery to original shape. I used the zip ties because I felt that glue would not be strong enough. I used a bug screen roller tool to make a bend so it would not cut the coroplast. This seemed to work fine. The box is not water proof, though.

I built it as a prototype but it fit so well that I didn’t make another. Did it in a few hours after my hernia surgery!


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## PL Scott (May 29, 2014)

close up of box. Straps are placed so they don't interfere with a top tube bag, or a bottle cage under the down tube.








close up of door attachment. velcro strap used for electrical cord organizing.








close up of the tip that fits at the top tube angle.








close up of door attachment, unattached.








Picture of saddle box template, no credit to me, I was using for another DIY project.








There's good stuff in the DIY forum of bikepacking.net.

Have fun!!


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## Johnny Chicken Bones (Jul 13, 2005)

Well done PL. Great photos. Thanks for taking the time to upload them. Not like MTBR makes photos easy to manage. 


I've wandered around the Bikepacking.net site. Just never for coroplast. 
Will see what I can find.


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## Johnny Chicken Bones (Jul 13, 2005)

I have hacked out a rickety cardboard model. Once you start this project- it's pretty easy. 
Even designing on the go turned out OK. 

One thought- I see many folks made their frame bags (out of any material) w/o the lowest corner as a corner. They chop off that last low few inches and made the bottom flat instead of being a corner. Any idea why? 
Maybe less interference w/ a F der?


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## PL Scott (May 29, 2014)

My thought is that with a flat bottom it is easier to store items. A corner is not efficient for non-soft items. You can stuff clothing like a shirt,socks and puffy jacket into a corner using all the spacing. 

For my box, next time I would leave the corner above my shock entirely free because that is a handle area when you must lift the bike over trees and the like. I’ve seen some forum posts where the sewn bag is built to get your hand around the top tube. It is genius!


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## fotooutdoors (Jul 8, 2010)

Johnny Chicken Bones said:


> I have hacked out a rickety cardboard model. Once you start this project- it's pretty easy.
> Even designing on the go turned out OK.
> 
> One thought- I see many folks made their frame bags (out of any material) w/o the lowest corner as a corner. They chop off that last low few inches and made the bottom flat instead of being a corner. Any idea why?
> Maybe less interference w/ a F der?


There are a couple reasons that I can think of. You don't need as precise of lengths if you cut the corner off. Also, you can make a wider bag of you get it above the chaining. Personally, unless you want a wider bag/box than can be accommodated with your chaining, I would lean toward keeping the bottom corner, but that's me.


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## Johnny Chicken Bones (Jul 13, 2005)

As a kid I was a hack w/ scissors, glue, and crayons. It wasn't like I thought I'd be an artist and the lack of 3rd grade skills would be hampered. 
But I do remember looking around the room at the other kid's projects and wondering if I had been dropped as an infant. 

Fast forward to my 48 years current self and my coroplast project. 
It looks like our cats collaborated in the construction and argued long about how to complete it. It also looks like they had knocked back a few Yaeger bombs before beginning their work. 

Not sure my ego will allow me to post photos of this hack job but it does look like it'll work great. 
I couldn't get the stuff to bend with the heat gun so in the end I just laminated it's corners w/ Tyvek tape (it's amazing) and then some duct tape. 
And you know what? It will be wonderful. Durable. And plenty of waterproof (mostly). 

Time will tell, and when it does, I'll tell you. 
Thanks for your help.
-JCBs


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## Bill in Houston (Nov 26, 2011)

How is it working out for you?


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## Johnny Chicken Bones (Jul 13, 2005)

No issues with the construction. 
I don’t like the square edges this construction has. Nothing terrible, just not comfy to occasionally rub a leg against. 

There’s a great ease to stuffing items into my soft zippered frame bag but this one holds plenty. 

You can over stuff a soft bag more. It’ll bulge. These dont- these just threaten my shoddy edge construction. 

Would I do it again? Yep. 
What would I change? Hmmm....
I’ll think on it. 

THanks got asking. 
-JCB


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## Megashnauzer (Nov 2, 2005)

https://bikepacking.com/plog/inside-hunter-cycles/
this guy made a frame bag out of coroplast. it looks doable for us unskilled diyers. i just ordered a 4'X8' coroplast panel.


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## Johnny Chicken Bones (Jul 13, 2005)

Mega-
Funny you would post that. The Hunter article is a fantastic write up- really worth the read. 
There's a small sea of frame builders that come and go but Hunter has been here for sometime now. 

Their write up about that insane trip (and it's river crossing) was what got me interested in the coroplast about a year ago. Those shots of his bike just looked so clever and simple- low cost. Durable. Pretty perfect on most fronts. 
On a recent trip to Spain I actually kicked down for a fabric frame bag since it's easier to roll up for the airline portion of the trip. 

-JCBs


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## Megashnauzer (Nov 2, 2005)

coroplast is here. i got the cats some jeagermeister so we're going at it this afternoon.


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## Johnny Chicken Bones (Jul 13, 2005)

I had issues w/ some of the corners on my corro-box. Heat or no heat didn’t make a huge difference. In the end it worked, but not w/ the rounded corners I’d hoped for. 
Send some photos when you can. 

And as for supplies- I nabbed a stack of campaign signs last election. Now I have ample coroplast though I can’t say that all the signs reflect my election hopes. 

-JCB


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## H0WL (Jan 17, 2007)

Johnny Chicken Bones said:


> And as for supplies- I nabbed a stack of campaign signs last election. Now I have ample coroplast though I can't say that all the signs reflect my election hopes. -JCB


Reading through this thread, I was planning to note that the best time to harvest coroplast is immediately post election cycle. Some candidates use 4' x 4' signs or even larger and aren't prompt about removing them.


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## lentamentalisk (Jul 21, 2015)

Some might argue the best time to harvest coroplast is DURING the election cycle


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## Johnny Chicken Bones (Jul 13, 2005)

Too True Lenta. 
Too True.


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## H0WL (Jan 17, 2007)

lentamentalisk said:


> Some might argue the best time to harvest coroplast is DURING the election cycle


I agree, but wanted to present myself as a conscientious citizen.

On the coroplast topic, I've been considering making a sunshade/visor/brim thing for my helmet out of coroplast. It's an amazingly versatile material.


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## Megashnauzer (Nov 2, 2005)

here's a picture of the coroplast frame box. i can't say i did a great job on it but this is just a prototype. super easy to work with coroplast. i used superglue and some stick-on velcro to put it together. it's screwed to the bottle cage holes in the down tube and tied to the seat tube. underneath the plastic cover on the top tube are some grommets to secure it after everything is loaded. it will hold my sleeping pad, hammock, tent poles and ground cloth, water filter system and a pump and probably some smaller bits. it cost maybe $30 but most of the stuff could be scrounged.


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