Machinable wax

[John Stevenson]

There was a thread recently on here about this stuff and I bought some but so far haven't machined anything in it because as soon as I get a CNC done it's out the door and my two mills out out on load / demo.

In the last few days over on the Mach3 Yahoo group there has been a couple of posts from OZ from a guy who makes his own

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We make the stuff, it's easy to do. 25% LDPE (Australian milk bottle tops) 75% paraffin. Melt, mix cast.

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So forget all the H&S bull$hit about kerosene and explosions what I want to know is what else is LDPE or equivalent in the UK ?

.

[moldmonkey]

John,

In the states, most molded plastics have the material code and and recycle symbol molded in. Not 100% definitive as the company I used to work would occasionally change materials without changing the mold engraving.

I just poked around the frig and didn't find any LDPE products and I don't know resins well enough to give examples off the top of my head. Found lots of products from my old company. Dirty rotten @#$#$, that they are.

[bob_s]

low density polyethylene = LDPE

[John Stevenson]

low density polyethylene = LDPE

Yes but what products.

Where's Peter Neil when you want him .................PETER.........!!

.

[bob_s]

plastic bags, zip-loc seals
tops for milk bottles, tupperware containers, water service plastic tubing
most cheap plastic crap as opposed to expensive plastic crap

[moldmonkey]

I did some more poking around and found lots of HDPE. Milk jugs, aspirin bottle, coffee "can". I believe the lids we made for fast food/gas station drink cups were a LDPE/HDPE blend. Like I said I am not a resin expert but I don't see where it would have to be LDPE. I found lots of PP-polyproplene products which is what we switched molds to without changing the engraving right away. It was a cheaper resin at that time.

[aboard_epsilon]

look underneath of plastic containers ...
there is usually a recyling symbol on them ......with the intials of the plastic underneath it .

WIKI

LDPE is widely used for manufacturing various containers, dispensing bottles, wash bottles, tubing, plastic bags for computer components, and various molded laboratory equipment. Its most common use is in plastic bags. Other products made from it include:

• Trays & general purpose containers
• Food storage and laboratory containers
• Corrosion-resistant work surfaces
• Parts that need to be weldable and machinable
• Parts that require flexibility, for which it serves very well
• Very soft and pliable parts
• Six-pack soda can rings
• Extrusion coating on paperboard and aluminum laminated for beverage cartons.
• Computer components, such as hard drives, screen cards and disk-drives.

[Evan]

Cheap kitchen cutting boards are probably the best bang for buck.

[JRouche]

I was looking at a thread on the cnc zone and a guy was milling a piece from a blue wax. Looked pretty dense and the fine details were sharp and clear. What I liked was his ability to gather up all the chips and he could recycle them.. JRouche

http://www.johnbearross.com/prototyper.html

[Ken_Shea]

This is very interesting, sure had not heard that it is that uncomplicated to make.
JR, believe I saw the same video, a model tank of some sort, looked as if it had real fine detail.

He had 34 hours of machine time on the finish pass, kinda felt sorry for the guy.

[darryl]

What about ordinary plastic sheet- drop sheet as it's sometimes called, or just poly in its various thicknesses.

I'm wondering just what part or parts of a hard drive are poly-

[Rich Carlstedt]

LDPE is usually clear and stretches somewhat.
Many plastic (clear) bags or sheets are LDPE.
The White-ish bags are stronger and are HDPE, a completely different material in melt temperature and characteristics.
Rich

[toastydeath]

You should be able to buy LDPE in pellets from a plastic supplier. Rather than using LDPE with who knows what plasticizer in it, you can use fresh material.

[Holycross]

Machinable wax.

John,

The yahoo group:

http://groups.yahoo.com/group/aussie_9x20_owners

In the files section are a couple pdf's on home made machinable wax.


Mark

[Peter N]

Yes but what products.

Where's Peter Neil when you want him .................PETER.........!!

.

Some of us have to sleep ya know..

The largest uses of LDPE in the UK are in containers and packaging films. The milk jugs typically bought from supermarkets are LDPE, as are the lids for them, and most of the 1 gallon/5 litre containers for engine oils etc. Cling film and film wrap is another major use, but these are sometimes co-extruded with another material like EVA or a micro-adhesive film.
LDPE contaners will be translucent-opaque. The crystal clear ones are not LDPE but will be either Polyester (PET) or PVC. Many lotion bottles and cheapo washing up liquid bottles will be LDPE. Kitchen chopping boards are likely to be a blend of LD and HD to give a 'medium' stiffness product, as LDPE is a more flexible material.
Milk crates and beer crates and the large diameter blue underground water pipes are all HDPE (Hgh Density Polyethylene) which is stiffer and more rigid than LDPE. Washing up bowls and buckets will usually be a Polypropylene co-polymer (PP with around 5% Polyethylene).

Most plastic carrier bags are LLDPE (Linear Low Density Polyethylene) which has a branched chain molecular structure and far higher tensile strength the LD or HD.

That's an interesting idea mixing LDPE with paraffin. I have no idea if it would work or not, but the Aussies and Kiwis have always been incredibly inventive and capable of making stuff from the most unlikely sources, so on balance I'd be inclined to give him the benefit of the doubt.

One thing to be very careful of. LDPE has a melting range from around 100-120deg C, and when molten it is very, very, sticky, and will cling onto your skin like napalm and burn the hell out of it as you cannot easily rub it or pull it off, so if you're planning on trying this take precautions.Maximum continous service use temperature of LDPE is around 65deg C, ad I imagine this would be considerably lower when blended with paraffin, so watch the cutter speed and temperature.

If you need some virgin LDPE I have it in 25Kg bags here (pellets) so could easily pop a few Kgs in the post for you to try.

Peter