Milk Top Bowl

Intro: Milk Top Bowl

Hi

This insturctable will go through how I turn milk bottle tops (and various odd ones) into blanks for working with, mainly for turning but you can work it just like timber so your imagination is your limit :)

To start off with you need LOTS, just to be clear here LOTS of milk bottle/coke/fabricsoftner tops I get various places like cafes, staff canteens an family to save them for me just ask whoever you can.

A mold, this should be near the shape/size you want to use less caps, in my case im making a bowl so i used a bowl. If you want to be safe have one that you can melt into at 200 celsius because trying to melt it and move molds is unplesnt the lids retain loads of heat and stick to most surfaces so its just asking to cause serious burns.

An oven to melt it in. an expensive bit of kit but if you look hard in the kitchen (the place you take the lawnmower apart when it breaks before you manly shave the lawn) you might be as suprised as me that you already have one. (same applies to the mold the next cake my wife bakes will have plastic in it...)

And a work shop or tools to create! in this case a lathe was all i needed

STEP 1: Wash and Dry

This is a really important step if you don't want material that smells of old milk and this is also a good time to remove any of the little silver seals stuck in the lids.

STEP 2: Fill Your Mold

Fill you mold with the caps and back as hot as you can. The lids are HDPE which is a recyclable thermoplastic (can be heated and reshaped) which softens at about 120 Celsius but we want to go as molten as possible so high heat (I was at the 220c mark) these will liquify for lack of a better word and sink to the bottom so keep topping up with caps till you reach your desired fill level, at this point if your very well equipt stick it in your vacuum chamber to get the air out but alas is don't so i must suffer air pockets in my work (its good you sell them and proof of fully hand made recycled item) now switch the oven off and let the blank cool slowly in there to stop it warping this will take 8 hours plus if its a large blank.

STEP 3: Remove the Blank

this was a gamble as i usually do this in loaf tine paper cases so the just lift out but this time i decided to see if glass would keep it loose, it didn't until i stuck it in the oven at 200 for 5 minutes then up ended it which should work on all smooth molds? but wont leave the mold completely clear. this can be remidied if really needed with more heat just burn it out after scraping any big bits off the hot surface.

STEP 4: Make!

Whatever you want to i've done pens, bottle stops, garden dibbers and now a cereal bowl.

This isn't a wood turning tutorial (i can do one at some point if its wanted) but I will take anyone interested through my process (everyone works differently especially with turning)

I mount the blank between head tail stock as centered as I can by eye (brilliant tool impossible to buy a new one even from screwfix so put a protective case on yours such as goggles) and then make it true round from said centers and the shape i want before cutting a rebated dovetail in the base for my chuck jaws to expand into and grip.

clean the base as you wont have it spinning at 2000rpm and accesable at the same time after this.

spin the blank round and grip with the jaws and turn out the center which ever method you prefer as the all work on plastic do a clean pass on the outside and the rim aswell and make it all nice and clean and then out have a bowl.

STEP 5: Done

my first suggestion is save the shavings or any other type of HDPE you can get as they can all be melted together.

second suggestion is be really creative with ideas and if you can implement them let me or others in the comments know about them so we can try them.

third is tell me off for grammar and spelling as needed as I'm more comfortable with a chainsaw then with writing stuff.

And lastly if you like this idea or instructable spare me a vote?

All the best making and breaking and thanks for reading

Comments

[kthlnworth]

Omg, I have been searching forever for someone who is doing plastic tops or any top other than beer and coke tops.

I have loads upon loads of baby food tops I have been saving from the screw off kind. (Because I recently lost all my teeth and baby food is a. Huge option) Well I have lots of colors and I already did one soak. But for a bowl I will do another.

Do you recommend one of those hobby ovens you can cook in from the garage with the doors open? I have read melting plastic in your kitchen can set off bad fumes.

Also, how do I find out if my top will melt. I know it is recyclable but is it meltable? Just wondering?

Thanks for your help!
ChattyK

[bick577]

thank you. Such a fun idea

[danzo321]

Mixing ought to free some of the air bubbles but you might prefer the blotchy color

[Tomahawk92]

I think it would be very hard to mix, it doesn't liquefy. It just gets goopy.

[matt.sims.37266]

Yeah if you slowly mix the same way as resin it should relive the bubbles but the colours won't stay separate so you end up with a dirty brown :(

[lovethebackwoods]

Matt, it's a beautiful bowl! I am an art and language arts teacher, among other ventures, and we use those colored caps for all sorts of things, however, I've never done anything like this. I can't wait to get started. Thanks for your clear instructions and great photos! I enjoyed reading this. Your Instructable makes sense so just ignore the whiners!

[Fredfly]

1.the lids are LDPE (the actual bottle is HDPE)

2.the bowl can give you cancer, melting plastic can make the plastic dangerous.

[matt.sims.37266]

1 I don't know where you come from but here in England they are all HDPE (they even just changed the colour to allow for easy recycling so big coverage there)
2 no melting plastic is perfectly safe and won't effect your health burning plastic on the other hand will.

[gingerbaker]

It's not necessarily the plastic itself which is dangerous, but the plasticizer compounds which may be present. These, if present, are estrogenic and definitely carcinogenic.

See: http://www.ncbi.nlm.nih.gov/pubmed/19463926

[noahspurrier]

No. You're thinking of a different type of plastic (PVC, most likely). HDPE doesn't contain plasticizers. It's a totally different chemistry.

[funny1048]

yes its definetely pvc this plastic has plasticizers in it to make it more flexible hdpe is completely safe

[chancefour]

Is there a concern with fumes? Seems like there would be some trouble there at that temperature. No?

[funny1048]

nope hdpe is very inert and has very low toxicity even lower than paraffin when i melted the hdpe there was almost zero smell its a very safe plastic just be sure it's hdpe remember never melt down pvc or styrofoam these types of plastics are very toxic and will produce very dangerous fumes

[matt.sims.37266]

I've had none (touch wood) unless the plastic ignites in which case tonnes of smock but I think the ignition point is near the 300c

[chancefour]

Thank you. Do you know of an adhesive a person can use on this material? I would love to use PVC cement as it melts the two surfaces together, but I am not sure it works on this kind of plastic or the other part of the milk bottle plastic. Have you tried to bond one piece to another?

[matt.sims.37266]

As said below I would agree. The surface when smooth let's most adesives peel away with not much resistance a scratched surface and superglue would be your best bet or if it's small pieces it's possible to "weld" then with a kitchen blow torch

[chancefour]

Thank you.

[noahspurrier]

It's won't work. HDPE is resistant to the solvents used in most PVC/ABS cements. Same for acrylic cements. HDPE is usually welded by heat. There are some contact cements and epoxy cements made for HDPE, but these form mediocre mechanical surface bonds. There is no penetration, to borrow the welding term...

Look at it this way, many PVC and acrylic cements and solvents are distributed in HDPE containers, so that should be a clue that you're using the wrong glue for HDPE.

[taur561]

just as a matter of interest , if you take your wife's used cooking oil and heat it up to just below smoke point ( the stage when it burns and smokes ) , then drop your plastic caps into that , they become soft and gooey like thick syrup and can be removed with tongs from the oil and rolled or shaped over a bowl to give a similar effect . Afterwards you wipe off the oil and wash with soap to remove the oil . Just work carefully as hot oil can seriously burn you if you get it on your skin . The benefit is you have no fumes except the smell of cooking oil as though you are frying fries . Still a good idea as you are recycling waste . Here in Africa they are now making plastic logs and plastic planks from waste . Makes great outdoor furniture , garden bridges etc and never rots or gets eaten by termites .

[funny1048]

oil actually isnt needed at all all you need is an oven which you set to 330-340 degrees f the hdpe will flow without any kind of smoke or burning as long as you take it out when it all melted and the bottle caps are actually made using a process called injection molding which means bottle caps have a high flow rate when melted and therefore will flow into a mold without any kind of pressure