Machinable wax

[AdeV]

When I first started reading up about this hobby, even before I got the mill & lathe, I read about some stuff called Machinable Wax. Basically, it's a mixture of paraffin wax (candles) and low-density polyethylene (LDPE). I have a PDF which tells me how to make it, and even that many plastic milk bottle caps are LDPE (in fact, they're mostly HDPE...).

Firstly, has anyone ever made this stuff before? And if so, what did you use for LDPE? As far as I can tell, the most easily obtainable bulk source of the stuff is plastic food bags, e.g. freezer bags, from the local supermarket.

Also, what's the best source of candle wax (again, in bulk)? Cheaper to buy candles & melt them, or to just by paraffin wax - and if so, where from (I'm in the UK)?

I've attached a copy of the PDF for reference (in case it's useful). If the document is to be believed, it's almost perfect as a prototyping material - doesn't stick to the cutter, doesn't need coolant or lubricant, holds fine details, is reusable if you melt it down & re-cast. What's not to like?

[John Stevenson]

Yup, made quite a bit as we wanted some for demoing on the CNC's at shows.

Not read your pdf but I got some info from CNCZone so maybe the same.

For paraffin wax i bought some big surplus candles from Ikea for £2.00 each, massive black things. The LDPE I got as virgin material from a plastics supplier as a sample, got 5Kg for not a lot of money [ can't remember ] it comes as clear beads about 3mm diameter.

I then bought a deep fat fryer from Asda for £10, we didn't have an old one I could use.

The candles were melted first and the LDPE added and stirred in, it turns into goo straight away and really takes some time and stirring to fully dissolve, far longer than you would think so don't get disheartened. Once fully melted and mixed you can use a ladle to pour it into your mould and allow to cool naturally. We were making loco wheels so used a alloy ring on a plastic sheet, the slower it cools the less contraction.

When the chippings and old parts are remelted it melts very quickly and you can pour new parts very quickly, it's only the initial mixing that takes time.

Our parts came out black because of the candles, clear candles can be made any colour by using dye powder.
I never found a source of cheap candle wax, all the hobby sites seem to want a lot of money by the time postage and VAT has been added.

John S.

[andyf]

I've never tried it, though it does seem to offer the possibility of decoratively machined candles. For show only - Lord only knows what toxins might be released if you lit 'em.

Google UK reveals various "paraffin wax suppliers" and the going retail rate appears to be around £5/Kg for small quantities. Cheaper by the quarter ton, of course. If it were I, Fred Aldous (a craft supplier in Manchester city centre) is only 6 miles away, and I could get there using the free bus/tram/train pass I got as compensation  for reaching 60  . For a test, plain wax candles aren't expensive.


As to LDPE, old carrier bags, pedal bin bags, etc etc. If you want less flimsy stuff, I believe Visqueen damp proofing menbrane (the stuff in big sheets for putting under concrete floors) is LDPE. Perhaps you know a builder who would let you have some offcuts for experiments.

Andy

[PTsideshow]

Don't have much to add to the above other then it is made by one outfit that I know of and it is labeled for who ever buys enough at once.
There are a large supplier to the pattern making and foundry industry here in the states and recently purchased another company in Canada to expand their hobby side of the business. They have great learning video's on waxes casting for the jewelry trades(again they make a lot of brands) Here is their site look for the videos great stuff.
Freeman Supply industrial
Miapoxy is the new name for the hobby side hobby side

The video's are on both. along with great explanations of the bits and pieces for the mold making and casting process.

[AdeV]

Well, a bit of googling would suggest that, of the online retailers at least, Homecrafts Direct are the cheapest for wax (25kgs for £50 delivered, 2kg bags for £5, but there's a fixed 3.99 delivery charge which makes a single 2kg bag expensive); and BuyRite UK have LDPE @ £13 for 5kg. It may be possible to get raw plastic cheaper than that, the BuyRite product is food grade tubing (I guess, of the sort that sandwiches come wrapped in).

I was planning to cast a rectangular piece of wax to practice milling this sump I'm making; I don't mind making mistakes on a piece of re-usable wax, wheras if I botch the aluminium version it's going to cost £200 to get a new piece...

Links:

Wax
LDPE

[John Stevenson]

Still not bad prices, have you priced up the ready done wax?
I bought two blocks 3" x 3" x 3" and 3" x 3" x 10" and it was £45 delivered.

What size do you need because i still have some left and you still need to collect these faceplates / staedys if you are still interested /.

[AdeV]

Hi John,

Still definitely interested in the faceplates/chucks/steady/etc., just fishing about for an excuse to head over your way on company money...

I'd be wanting a lump of wax some 10"x22"x2.5" in size - that will match the outline size of the sump. In fact, there's a couple of tabs stuck out the side too which will make it about 13-14" at one point; so it's not only not quite rectangular, but it's also huge...

The required weight of wax, if my calculations are correct, will be a bit over 8.1kg.

[John Stevenson]

won't have that much kicking about.
What about a glued up lump of MDF then use it as a pattern 



John S

[AdeV]

won't have that much kicking about.
What about a glued up lump of MDF then use it as a pattern 

I've never really liked putting wood on the mill, somehow it just doesn't seem right. Will it harm the cutters, or can I cut it with impunity?

[HS93]

Just use wood router cutters, Aldi is a good source for them they do sets of about 12 cutters for under a £10 from time to time all shapes and sizes, use them on ally as well.

peter

[andyf]

I've never really liked putting wood on the mill, somehow it just doesn't seem right. Will it harm the cutters, or can I cut it with impunity?

This rather dodges the question, because I don't know what resins etc are used to bind MDF, but I use HSS drils on it without any apparent damage.

Like wood, MDF is usually machined with carbide cutters in routers etc at very high sfm and feed rates compared to metal. If you hang around, the friction can cause scorching. But your spindle will be revolving more slowly which may help.

Some warn that the very fine dust from machining MDF can cause respiratory problems, and that a full face respirator should be used. I don't know how true that is, but it might be worth researching before you fill the shop with a haze of particles. And going by my limited experience with the stuff, everything in the vicinity, including you, will need a lot of dusting down afterwards.

Andy

[spuddevans]

Some warn that the very fine dust from machining MDF can cause respiratory problems, and that a full face respirator should be used. I don't know how true that is, but it might be worth researching before you fill the shop with a haze of particles. And going by my limited experience with the stuff, everything in the vicinity, including you, will need a lot of dusting down afterwards.

It is majorly bad for your lungs. Years ago I made a pair of floorstanding speakers out of MDF and routed a round-over on all the edges without using even a dust mask, I ended up up-chucking the contents of my lungs and stomach for most of the evening afterwards. But, lesson learned, I ALWAYS wear protective equipment when machining MDF, or when working in my dads workshop I always use his dust extraction system (its really powerful and when aimed well it collects virtually all the dust generated)

If you can mount a shop-vac close to the cutter so that it sucks up the dust as you machine, that should keep the worst of the dust down

Tim

[AdeV]

Hmmm, I'm going to make this wax I think. I don't have a respirator, or even a face mask, and the dust will make a terrible mess of everything. Besides which, I'm wondering how well MDF would show up detailing? In my (very!) limited experience of MDF, it tends to crumble away at the edges, wheras apparently this wax stuff doesn't.

So, anyway, never one to take advice , I've ordered 25kg of wax, and bought a bunch of freezer bags from Tesco. Hopefully, the wax will turn up before the weekend (if not, I may be forced to go buy some candles), and I'll try to make a small batch. If it works, then I'll just have to bite the bullet & buy some bulk LDPE from somewhere - anywhere - & make enough to prototype this sump in...

[AdeV]

So, today being Sunday, and having cleared the mill of that whopping big lump of Ali, and with Windows MovieMaker making a right meal of that video I mentioned elsewhere... I had no choice but to crack on with this machinable wax (Who am I kidding? I've been looking forward to doing this all week!).

First task, shopping:



Candles: £3 each
Freezer bags: £1.14 each

All from Tesco, obviously...

The coloured stick is from an old artist's set I have lying around. No idea why, as I can't draw for toffee. Still, that means all the coloured sticks are intact I added about 1/2 the blue one that you see to the melt. But I'm getting ahead of myself here....



The equipment is: An old toaster oven I have lying around. It's not been used in donkeys years, but seems to work OK. A brand new 20cm saucepan (less than £7 for a set of 3 from Tesco - bargain), and a jam thermometer (good for 200C/400F). The strange looking "funnel" device next to the saucepan came with the jam thermometer. With a spout type arrangement on it, it'll be ideal for refilling the various oil applicators I have, from the always-too-big oil containers... I think I've spilt more hydraulic oil than I've used...

OK, I'm rambling. On with the show... First, weigh the candle & the plastic:



Apply some simple mathematics:


 

And (with some rounding) we arrive at the conclusion that one box of plastic bags is almost exactly the right amount of plastic for 1 candle. Result!

So, melt the candles:



Until they look like this:



The greenish tinge is that wax crayon. Goodness knows why it went green. You may also notice a slight issue here..... my 20cm saucepan is FAR too small to hold 2 candles AND 2 boxes of plastic bags. Doh! I transferred half the wax to a spare pan, then started adding the bags.



The PDF says "they will dissolve quite slowly". They weren't kidding. This was nearly an hour later:



Fortunately, only another 20 mins required (ish):



Although, in fact, there is some undissolved plastic in there still, which appeared when I poured it:



Those blue lumps are they. Still, we'll see how it goes... maybe I'll just use the 2nd batch (which went a lot quicker, as I just dumped as much LDPE in as I could, as fast as I could, and only stirred it occasionally) - that seemed to use all of its plastic up properly.

So, here they are, 2 slabs of machinable (?) wax... Still too warm to machine, I'll try them out tomorrow.




PS: If you plan on using decent saucepans, don't use metallic tools! Like a screwdriver, or the thermometer, to stir your liquid, as you WILL damage the finish! And your beloved (if applicable) will NOT be best pleased with you!



As far as making this stuff at home¹? Go for it. Provided you don't spill it, it's very clean. The only odour is a faint smell of candle wax - there's no molten plastic smells, and no smoke either. Very spouse-friendly  


¹ It occurs to me that, if you have a gas hob, you may be wise not to use it... I don't know how flammable the vapours which come off the pot of wax are, but I'd really rather not chance finding out...

[John Stevenson]

Ade,
Next time chop the bags up into small pieces and you have more edges for it to dissolve.

If you do a remelt now it will melt very quickly, it's the initial mixing of the plastic and the wax, we bought a deep fat fryer for £10 from Asda solely for this so we wouldn't get shot.

Yours looks a lot better than ours because our candles were black to start with but they were only £1 each from Ikea on clearance.

There is another ingredient you can add to harden this mixture off, can't remember what it is you will have to do a search on the candle making sites. We never got any or used any but the bought stuff we have is harder than what we made.

John S.

[PTsideshow]

Hardener
Candle hardener is a synthetic wax which has a melting point of around 90 degrees C. Because of its high melting point it is a very hard wax. Adding a small quantity (usually only 1 part hardener to 100 parts wax) to moulded candles tends to make them harder and possibly last longer. It also makes the surface of the candle shinier and makes the candle more cloudy and opaque. Dipping tapers in wax containing hardener helps prevent dripping by putting a harder outer shell on the taper wick acts as a ‘cup’ for the liquid wax when the candle is burning. Because of its high melting point it is best to melt hardener with a small quantity of wax before adding it to other pots of candle wax.

Plasticiser
Plasticiser is also a synthetic material which like hardener has a high melting point. Because of this it is best to melt plasticiser separately with some wax before adding it to other pots of candle wax. It makes the wax go more pliable at temperatures just below its melting point and makes it thicker once melted. For this reason it is good for sculpturing effects where you want the wax to be less brittle. It is also used in dip and carve candles as it allow the successive wax layers of the candle to be cut and twisted while still warm.

You also can use Micro-crystalline wax, Micro-crystalline waxes are excellent materials to use when modifying the crystalline properties of paraffin wax. The microcrystalline wax has a significant effect on the branching of the carbon chains that are the backbone of paraffin wax. This is useful when some desired functional changes in the paraffin are needed, such as flexibility, higher melt point, and increased opacity.

And John beat me to it about chopping up the LDPE bags into smaller sizes.
 

[AdeV]

Thanks for the hints & tips chaps, always appreciated 

I think the second batch went faster because, after all the bags melted into a congealed blob, I picked it up & allowed it to droop off the screwdriver/stirrer a few times, which I think effectively increased the surface area. At least, it dissolved very quickly after that. The first batch, I added 2-3 bags, let them dissolve, added 2-3 more, rinse & repeat; I think that's why it took so long.

John - did the harder stuff machine better than your home-made stuff? If so, I'll get some hardener, it seems to be cheap enough. I'm guessing there's already some in there mind, as these are commercial candles (same as yours).

[John Stevenson]

Doing the thumbnail test the bought stuff is noticeably harder but we were making loco wheels about 80mm diameter and all the spokes were coming out nice.

Oh one thing keep this stuff sealed up we now have loco wheels with missing spokes, the mice like this gear 

John s.

[AdeV]

Well, tonight was the acid test. And, wow. I am impressed. This stuff is LOVELY to machine - and that's my crappy 1st batch, not the super-smooth looking 2nd batch...

As always, lots of photos for you to download - the film is free after all

First up, I rig a really dodgy contraption out of newspaper and welding rod, to catch the bits. These first cuts are quite hefty, and since the whole idea of this wax is it's reusable, it seems a shame to have to pick it up off the floor later. Especially as the floor is covered in tiny bits of aluminium, steel, WD40 and other nasties:


As you can see, the corner is snapped off. That was where I did the "how much pressure will this stuff take in the bench vice" test. The answer is: Not a hell of a lot...

Ready to machine now. 20mm end-mill in place, 1500rpm, maximum feed rate (dunno, rather swift anyway).



Shortly:


I tried it in the bandsaw, it cut nicely & didn't clog the blade. Roughed out a rectangular piece, lobbed it in the vice, and got with squaring it up:


The wax machines very nicely indeed - and, as could be expected, without any of the aggro of metal. No chatter, no coolant required. The end mill stayed clear throughout. I did chip a corner at one point, but I didn't notice when. So basically, I just tried a selection of tooling on it:
 - 50mm carbide-tipped shell mill (successful, no clogging)
 - 3/4" end mill, blunt (seen above) - cut nicely, very smooth finish. Maybe because it's blunt? No clogging
 - 6mm and 3mm ball-end mills (again, success with no clogging. Drove the 3mm at 4600rpm, high feedrate, no problem
 - 1/8" radius cutter - easy peasy
 - 2" slitting saw on home-made arbor, running at a ferocious 550rpm. Cut very well, with a tiny amount of clogging on some teeth, probably running it a touch quick.
 - Wrote on it with a Sharpie marker. It even took that, although it was smudgable for some time afterwards

Anyway, the end result can be seen below:





I am well made up with this wax stuff. It's quite fragile, especially the fine details (I accidentally broke 2 of the fins shortly after taking the last photo), but it holds its own really well. It's definitely going to be useful in prototyping this sump - and many parts yet to come.


One happy camper, check. 

[John Stevenson]

The wax machines very nicely indeed - and, as could be expected, without any of the aggro of metal. No chatter, no coolant required. The end mill stayed clear throughout. I did chip a corner at one point, but I didn't notice when.

It will chip as you exit a cut, if doing a slot try cutting from both ends so it's supported in the middle where the two cuts meet.

A lot of plastics are like this Tufnol is an absolute bastard unless you have a sacrificial piece on the exit.

John S.

[No1_sonuk]

I have some candle-making stuff around here somewhere.

Can ordinary candle moulds be used with this stuff?

[AdeV]

I have some candle-making stuff around here somewhere.

Can ordinary candle moulds be used with this stuff?

I don't have any candle moulds, so I can't give you a definitive; but, having said that, I don't see why not. When molten, it's very just like plain candle wax, only gloopier.

[No1_sonuk]

When I track the stuff down, I'll try it.

[PTsideshow]

Yes and no, it will depend on the material the mold is made out of. There are additives that are used in candle making to make the candle easier to release from a mold. There are also the micro-crystalline waxes that will make the wax harder. They also have low temp melt plastics that can be added to the wax to adjust the properties of the wax.
To get the wax out of the mold you can place it in the freezer for a while and the candles come right out.


These are 1/12 scale miniature 12 layer hand dipped joined by the wick Williamson style dollhouse candles me and the wife made and wholesaled 30 years or so when the miniatures were smoking hot!  The other shorter candles are the votive candles, actual size 5/16" tall and 3/16"dia the pillar candles are 7/16" dia and 5/8" tall.

The molds I used were the telescoping brass tube sold in the hobby shop. Cut to length so the wax would pull back in as it set up. And froze them to pop the candles out easy. as they didn't have all the stuff for additives like today.

The problem is that almost every distributor of the supplies has their own names for the items.
The addition of the LDPE doesn't make good burning candle.
 
Here are a couple of pictures of the displays for the product

The display photo that was on the leaflet, the white pillar candles toward the center of the photo. Are hand painted Christmas pillar candles. All are 1/12" scale miniatures

The display rack that the store got when carrying our candles to sell.
This was back in the day BC(before computers) the photo's were damaged by water spots and foxing but you can get the idea.

[Bernd]

Amazing Glen.

Is there something you haven't done or know about? 

You just amaze me with you knowledge. Ya, I know, you read a lot. 

Bernd