# What do I use to color HDPE?



## Individual

My first go to would be food colouring,

What have you used?


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## BCLuxor

Surely you would have to do this during material construction? Dyes would perhaps not work on a plastic?..


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## Pawpawsailor

I think trying to color HDPE would be an exercise in futility... Get the color you want to start with... Any color is good as long as it's white.


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## Individual

Note: I ment during the melt process I would apply this.


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## Sunchierefram

I have a bucketful of HDPE pieces, but I haven't done anything with them. But I think it'd be pretty hard to color molten plastic without using some sort of industrial chemical. It'd probably be better and easier to just find HDPE in the color you want. And of course, white's probably the easiest color to get for HDPE.


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## Pawpawsailor

In my experience the white works easier than the colored stuff. The more additives the slicker and more difficult to sand.


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## parnell

Would it work to dye it with rit dye after the fact? I know that plastics can be dyed with rit in hot water, just not sure if hpde is one of those.


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## Lacumo

My experience with HDPE is limited---I'm not one of the SSF Archdeacons of HDPE, but I've played with it enough (using #2 HDPE liquid laundry detergent jugs) to have learned a bit from my failures so far. Based on my various snafus and fubars, I can tell you a few things:

1---HDPE doesn't "melt." The use of that word implies that it morphs into a liquid or near-liquid state and I haven't seen it do that yet. The pieces in my baking pans have gotten soft, loose, semi-gooey, sticky and pliable but never anywhere near liquid. My results have been a semi-soft, semi-gooey mass that I could never have stirred around or mixed food color, dye or colored ink into.

2---Any color management or control on my part has had to take the form of carefully mixing and piling the different colored pieces of HDPE that I put into my baking pan. I can achieve a mosaic type of effect by doing that but when I use the baking-pan-in-the-oven method, I don't get that "swirled" type of effect that other HDPE players have achieved using the sandwich griddle method.

3---Don't use Tide brand plastic laundry detergent jugs. They're the right kind of HDPE, but they yield crappy results.

4---Use only flat pieces of HDPE that are cut small. In addition to that, thinner pieces are better. Thick, curved pieces tend to cause air pockets in your board and--for me--have caused throw-away results.

5---If you use the baking-pan-in-the-oven method... It's been my experience that when I take the pan out of the oven, it's imperative to get the HDPE under at least 300 pounds of pressure IMMEDIATELY to force out as much of the air pockets as possible and get the plastic squashed together so it fuses into a good solid board with smooth surfaces. Any delay or any less pressure have yielded unacceptable results.

That's the knowledge I've gained from my failure-intensive efforts so far. For more and better info, read through the "HDPE Board" thread in the tutorial section.


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## stej

Lacumo, great post. I have the same experience with each point except (3) (I have other sources of HDPE).

Especially crucial is (5) - press it asap otherwise the pieces of HDPE may remain split and don't make the solid board. And the same for (1) - HDPE is not liquid at all. Very well written. I think it is good information for anyone who has never tried "melting" HDPE, but is willing to.


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## bigdh2000

HDPE has multiple "melt" points. It does melt into a liquid that then fuses together to form the slabs like you see from various folks on this forum. However, it does not melt enough to infuse colors of any sort at these temperatures. You must have the high end extruding machines to do such and HDPE gives off harmful fumes at that level of "melt".

Many HDPE containers also have a spray on "lining" that can be removed with a good hot dishwasher cycle. If you do not remove it, you will get some of the results Lacumo mentions in Bullet 3.


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## Viper010

I have worked in a factory that made custom cables for use in marine environments... We used hdpe there to coat the outside of the cables. Depending on the color needed, we had to add 1-3% pigment granules to the colorless hdpe granules. These were first mixed in the feed hopper and subsequently mixed by the auger inside the melt chamber.

Personally, I do not think this is a process you can reproduce at home, even if you could procure the necessary raw materials.

As others have mentioned above, recycling hdpe that already possesses the color you desire is a much easier way to go.

Namely, when it is not enclosed in a pressurized melt chamber, you can not get the hdpe hot and thin enough to allow adequate mixing of color pigments, without burning it.


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## Toolshed

Big thanks guys!! Playing yesterday with a piece of hdpe BigDan sent me i was wondering about all the questions here. I had cut about an inch off one side so it would fit the pan. Took it up to 400 degrees or so so it was a hot only semi-pliable mass. Then I put it under a block of wood with a heavy vise on it....not terrible but can definitely see the need for the pressure.


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## The Norseman

Taco Seasoning!


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## birdmom

pony beads are cheap and available in many colors. because of the holes in the beads you have to pile em high and tamp them down once they soften in the oven around 400F for about 10 minutes, then add another layer of beads on top of that. keep softening and tamping to desired thickness. i don't make slingshots, but i have done this and it produces a solid, beautiful piece of colored plastic which is very easily sanded smooth or cut with a no-melt blade or jigsaw. also, a tip for baking plastic is to use a toaster oven outdoors, so you don't put the harmful fumes in your house.


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## Bob E

I had an old jug of malt vinegar in the back of the cabinet that I dumped out and cut up. The vinegar seems to have given the plastic some color.


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## Ridge Runner

If you are wanting spackle coloring just look for already colored HDPE and add chips of that in your processing.

For a single color buy a colored HDPE cutting board on Amazon for $25 to $30 and use it for 10 or more projects. https://smile.amazon.com/Carlisle-1288225-Commercial-Cutting-Polyethylene/dp/B001TAD7MS/ref=sr_1_13?ie=UTF8&qid=1546069445&sr=8-13&keywords=hdpe+cutting+board+3%2F4


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## brother goat

I work for a company that uses a lot of plastics. we actually make blade covers for knives and parts for snow machines, anyway i'm told food coloring (alcohol based) would work. a better option would be oil based colorings, but that may cause it to be slick


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