Picture of How to make Machinable Wax at home!
Featured on Hackaday.com!  Woohoo!  But for records sake, my name is Jake: http://hackaday.com/2012/12/29/make-your-own-machinable-wax
A major issue that I ran into when I first started working with my new CNC machine was the cost of raw materials to machine. Sure, a block of plastic is not terribly expensive by itself – but figure in the cost after you mess something up and the cost becomes quite unreasonable. For this reason, I began looking into machinable wax.

Machinable wax is a very hard wax that won’t gum up a cutting tool, is soft enough to machine quickly and most importantly is completely reusable! Since I am cheap, I decided to make my own, which is actually quite simple and could be considered environmentally friendly since we use recycled plastic bags. Be aware that this Instructable is DANGEROUS! We will be melting wax
around 300* and this wax will be thick and sticky so it will literally burn your skin off faster than you can say “OUCH!”

(The basic recipe is 4 parts wax to 1 part plastic)

You will need:

- Paraffin Wax (Available at Hobby Lobby)
- Plastic Shopping Bags (HDPE or LDPE, Recycle symbol #2 or #4)
- Deep fryer WITH adjustable thermostat
- Candy Thermometer (to make sure your fryer thermostat is working correctly)
- Wood Spoon
- Leather Gloves
- Safety Glasses
- Molds (I’ve used Tins, Wood frames, and Cardboard)
- Strainer
- Wax paper is handy
- A scale to measure wax/plastic
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Step 1: Melting Wax

Picture of Melting Wax
Set your deep fryer to the “Warm” setting or 100* if applicable and add the paraffin wax. Keep stirring the wax until it is completely liquid. Once melted, you could add a crayon for color if you would like. I recommend leaving the candy thermometer in the wax to keep a better eye on the temperature.
Paraffin ignites at around 400*F.

Don't forget that what your looking at is melted wax, not water.  Hot water will splash and drip off of you, hot wax will splash and STICK TO YOUR SKIN!  So be careful....

Step 2: Melting Bags

Picture of Melting Bags
Set your deep fryer to 300*F and monitor the temperature with the thermometer. Make sure you continue to stir the wax because we do not want any hot spots that could cause the wax to ignite.

Once you hit 300*, begin adding the plastic bags, one at a time. It helps to cut them into strips so that they wont ball up, but I don’t have any data to support a specific way just yet. The more your stir this mixture, the faster the bags will dissolve (Just don't get too crazy, you could introduce a lot of air into the wax). Continue adding bags until they won’t dissolve any more.  Most of the plastic should have dissolved, leaving just a few chunks left.  With LDPE this is usually a 25% mixture, whereas HDPE bags are around 15%. Stay patient, this process can take a while.

Step 3: Casting the Wax

Picture of Casting the Wax
Once your bags are dissolved, it is almost time to pour the wax into molds.  You may have some small clumps of plastic at this point, and there are a few different ways to remove them.  The first option is to use a kitchen strainer to filter out the clumps as your pour the liquid goo into your molds.  This works very well, but I have yet to be able to re-use the kitchen strainer afterwards.  The second (and less effective) is to turn off your fryer and let the clumps float to the top.  The top of the liquid will start to solidify and make it easier to skim off the clumps with a spoon.  Either way, wear leather gloves!

If you chose option #2, turn your fryer back on and make sure your wax is liquid before pouring.  When pouring into molds, pour slowly but be committed as you do not want wax to drip down the side of your fryer.  Once poured, cover the molds with a towel so that they cool slowly.  The slower they cool, the more likely that air bubbles will escape before getting stuck in the wax.

Step 4: Machine that Wax!

Picture of Machine that Wax!
Out of the mold, the wax will have a HUGE sink mark in the middle; I usually just clamp the sides of the block and face off about ¼” to get it flat.  Then I flip the block and machine to thickness.  If you are carful and clean your vacuum ahead of time, you can save the chips to re-melt later.  I keep a container nearby where I store my wax chips.

Recycle Your Wax

When recycling your wax, I recommend using no more than 50%-75% reground wax.  This is due to the fact that plastics degrade rapidly when heated (think compost) and can start to smoke/burn/ignite if you are not careful.  Therefore, start by melting paraffin wax, adding new bags and THEN adding your recycled wax.

Good luck and be safe!
JustinDuke8 months ago

i'm going to try it with hdpe pellets: http://www.ebay.com/itm/HDPE-White-Plastic-pellets...


How did this work out for you? I have a bag of those standing around.
And what grade parrafine did you use it with?

GuillaumeF29 days ago

So i was trying to machine some very thin aluminium part and i was looking for some support material to reduce vibration, i tought of buying some machinable wax but for a fraction of the price a manage to make my own machinable wax.

I've prepare the wax with some of my friend for a school project, we were very doubtful about this instructables.... so we just tried it. the preparation of this thing was very long and a bit sketchy, since we had 4.4 kilograms of parafine. ( I would totaly recommand doing it outside or with gas mask...

In the end, i was very scares that the wax wouldn't stick enough to the aluminium but it worked way better than expected... No vibration at all during the machining ( it was somme very smooth cnc maching with nice and sharp tools, I think it helped.

So, in conclusion this wax is easy and clean to cut and it can also be use a support material, but it shrink a lot during cooling.

kwhitacre2 years ago
Oh, I almost forgot. If you recycle a clean pair of panty hose or knee-high hose you can vacuum up the pieces without it going into your vacuum. Place the nylon over the hose. Tape or clamp it to the side of the hose so it cannot be sucked up. When you vacuum it will catch the small items and you can reclaim them easily. I use this to clean up spilled beads and sewing pins. Works like a charm. But before you turn off the suction be sure to hold the end of the hose up, as everything may fall out again when the air isn't sucking it into the foot of the hose.

Or, for larger amounts, you could use a home-made cyclone between your vacuum and the hose. There's plenty of instructables on that topic.

Amazing idea. Thanks!

theres an idea

stevfuri2 years ago
What CNC machine are you using in these photos?
rawkstar320 (author)  stevfuri2 years ago
Zen Toolworks 7x7 with a Dremel 4000. Very nice little kit machine, but I highly recomend getting the 12x12. The 7x7 bed is awkwardly small.

I got the 12x12, but I still need to learn the software. They released $60 aluminum uprights recently to help rigidity.

haven't got a clue...sorry...if you describe it, maybe i can find one around here?
*sigh* Guys in the kitchen! LOL!!!!!

To avoid someones wife getting opinionated about where HER deep fryer has gone off to---git yer own! Try the thrift stores and Sal Army or Goodwill first or go directly to Craigslist. This also avoids having to sneak the thing back into the kitchen after use---and how exactly ARE you goin' to 'splain any drips????

To strain a simple and cheap solution might be to use a Chinese wok skimmer/strainer---these have a bamboo handle with a brass "mesh" (some have better mesh than others!) attached in a shallow bowl shape; These are a very few bucks and being that they are metal with a fairly wide space between could be useful for those chunks but not clog. They come in several lengths and bowl sizes. Try an Asian market for the best selection and pricing. You can also buy regular stainless strainer spoons at thrifts or other sources or even new for a few bucks---if you really want a custom size buy a large cooking serving spoon with a long handle to avoid getting burned and then drill or make "slices" across the bowl to the size you need. Polish. Done!

Great idea by the way---remember how spendy hard dopping wax was back when I used to do gems---and sealing wax the same! Prob could use your formula for these uses and carving as a to-be-cast project in addition. Thanks!
mbear valkgurl7 months ago

Just FYI: The Chinese wok skimmer is sometimes called a "spider" or "spider strainer".

beware. of buying stainless steel utensils at wall-mart. they are chromed up normal steel. try bringing in a small hard drive magnet with you. then bring it to the mangers knowledge that their breaking the law. no false advertizing, false truths, and misleading the consumers.

Perhaps you are unaware but there are different kinds of stainless steel, some of them magnetic.

I have a container of paraffin wax in the freezer. I'm guessing that it will harden and be machinable long enough to make a test cut of a CNC file. What am I missing?

nerd129 months ago

I needed some sealing wax, so I decided to try this to make it, but it didn't work. I found a large plastic bag marked as #2 HDPE, and it didn't melt in the wax even when it was boiling. I don't know what temperature it was at, since I don't have a thermometer. It just got really soft at best. Is there any other way to do this? Perhaps by mixing hot melt glue into the wax?

mcottew1 year ago

Can this wax be used for the lost wax method of casting aluminum? also, since I intend to use it for a DIY cnc mill, how hard is it? i'll be using 5v stepper motors and a cheap rotary tool, so it will be a fairly weak machine. I just need to know if this is best, or if just regular paraffin would work best. Incidentally, excellent instructable. Many props!

Machine1 year ago

That's a very nice instructable and thanks for all the sensible cautions and it is easy to see that you have thought carefully about the text of this instructable.

Baughb1 year ago

I didn't see it elsewhere, so I'll mention it: Please do your heating and pouring outdoors. This is similar to deep frying a turkey, and if you haven't heard stories about that....

afaul1 year ago

LOL Ok, I will admit right off, I did this the ghetto way. I knew it was ghetto, and although I didn't have a fire it was freaky.

What I used:

  1. Soup pan on gas stove.
  2. 2 boxes of Gulf Wax (paraffin wax for canning)
  3. some grocery bags. #2 typ
  4. Food thermometer (yes at least I was that smart)

I made the HUGE mistake of being scared, because I knew better but did it anyway, of having the wax directly on the pan bottom in the very beginning, so I put in like 1TBSP of water to keep the touching surfaces below 212F

This was ok for that, but after I hit 212F melting the wax the water wanted to boil and I had to continually stir it and keep it around 212F until the water was mostly evaporated. It kept wanting to "burp" and splash wax! (duh, looking back at it)

This made me scared of the process as I worked the temp up higher. I ended up putting a bag in well below 300 just to help contain the bubble bursts from splashing all over the stove, which they did anyway.

I never got it all the way to 300, but was close. Probably about 265F. The bags began melting in but never really totally did so. I have a lot of particles in there now. This would be fine for milling, but I am injecting this stuff with a food syringe into silicone jewelers molds I have made. I'm going to use the wax casts to make plaster casts and melt the wax out and pour aluminum in. I have already done this before, but didn't do the wax step in between and had a lot of problems because my parts are irregular and it's pretty much impossible to make a two part plaster mold.

So anyway, since the plastic didn't totally liquefy I'm not sure it will melt out of the plaster molds once they are hardened and I heat them to creat the void for the molten aluminum. I may have to burn away the plastic bits and it may contaminate my casts. We will see.

If it does I'll have to remelt this and strain it really well. Then it should be fine.

So, what did I learn from this kids? No water, don't use a pan because it's too hot right at the bottom.

I'm lucky I did this really slowly or I know I would have had a splash and a fire. I probably won't do the bag thing again and just use paraffin wax for my casting. I just thought the plastic would strengthen the wax so it wouldn't be so easy to break the piece when I take it out of the silicone mold.

Speaking of which, it should be cooled off by now. Time to see if it worked!

inciteman1 year ago

I used the fiberglass mesh for windows screens and it worked fine! About $7 for a roll! 36" x 84"

Good Instructable. You can also get paraffin from almost any grocery store in food canning section. How well does it match your expectations for clean cutting? Does it leave any significant residue on the cutter?
rawkstar320 (author)  AndyInAnnArbor2 years ago
It cuts very cleanly, the only problem to watch out for is swarf sticking to the part. The cutter stays nice and clean, much more so than cutting UHMW PE actually.

You can buy paraffin at the grocery store, but it is about 50% cheaper at hobby stores....strangely enough.
grocers buy it in bigger bulk than the hobby stores will ever get it.
It's really not a food/non food grade issue as much as the way the market works in the distribution/consumer interaction. Anyway, you should that there are multiple formulations of paraffin wax differentiated by the hardness, melting point, narrowness of the cut (how much of the block is X type of paraffin versus Y type of paraffin), and so forth. You can buy paraffin wax that melts at 125F (for containers) and wax that melts at 180F (for hurricane shells and embeds). You can even modify the melting points through the use of additives (microwax - which is essentially plastic) etc etc etc... In the application you are talking about here I'd try to make sure you are using a relatively high melt point wax suitable for pillars/hurricanes. If you get into this you can buy wax in 50# boxes for around $80.

Oh, as for the melting pot - it's a good idea. When I first started candlemaking I bought a presto pot ($25), tapped a hole near the base, and installed a spigot. Made it a lot easier to transfer the wax into a pour pot.
Not so strange...the paraffin sold in grocery stores is food-grade, (it's found in the canning section) whereas the wax sold in hobby stores is for candle making.
rawkstar320 (author)  bruce.desertrat2 years ago
Good point.
n1cod3mus2 years ago
shame paraffin wax is so hard to get hold of here in the UK and if you can get it, its massivly expensive.

still a good instructable, would be great for lost wax casting of metals.
try using beeswax instead. pafafin wax is a oil based product . if u used beeswax instead u'd have a better made block.
You can get 1kg of pelleted paraffin wax on ebay for £5.95 inc. P&P - that's not too expensive.
every time i have gone looking its always expensive, prehaps i wasnt lucky enough to come across a good price when ever I have looked on ebay. I'll keep my eye out
jmpg n1cod3mus2 years ago
most candles are paraffin wax as beeswax is far to expensive. If the candles contain carnuaba wax or some other nut derivatives it will be harder than paraffin wax, which will be a benefit in this manner.

When you melt the candles just pull the string/wick out of the molten wax.

I've also used electric frypans to melt wax as they have a thermostat also.
Thats exactly what i was thinking.
Pjstone2 years ago
If I could offer a suggestion! When you pour a liquid from one container to another the pour creates air bubbles....so...I would like to suggest that you use a cook secret (I am a cook by trade) of pouring the melted wax over the back of a wide spoon or a wide piece of wood that is held on a slant or just leaned into the container you are pouring into. This reduces splashing and possible burns...and less air bubbles should give you a really good product!
try using a vibrator off some kind as well. too get the air bubbles out as well.
veeguy2 years ago
Fantastic Idea! I have both a CNC router and a milling machine. I had a quantity of machinable plastic, foam and wax free samples I have gone through. I was *shocked* by the prices of machinable waxes and plastics. I needed some 4" X 4" X 6" blocks, and they wanted $65.- each!

The main problem I can foresee is sneaking the french fryer out of the kitchen and into my basement "Little Shop of Horrors".

-And your spelling and grammer is OK by me. The complainer is obviously a frustrated English teacher.
i dislike (pc correctors) they dont like when other pple mispell.
rawkstar320 (author)  veeguy2 years ago
That price is unreasonable, look into machinablewax.com if you want to buy it. Amazon and eBay dont have any good deals on machinable wax for some reason.
cjs12982 years ago
Hello, I am only 14 and in need of cheap material. Unfortunatly I do not have a deep frier. Is there an alternitave to a deep frier? My best guess is a camping stove and an old pot. I have a candy thermometer, so is there some possible way that I could measure the inital temp of the propane stove?
try to experiment first. try getting a dutch oven. and the propane stove part 4 a turkey fryer. that should help u out. by the way u should also have safety gear on hand as well as using it. face shield (full) respirator of some kind, to block the wax / plastic fumes from entering yr lungs. gloves (work gloves, welding gloves are better. long sleeve style excellent, to protect yr arms.) long pants that cover yr work boots. god forbid please dont wear any thing thats made from plastic type materials. unless u wanna go to the emergency room, and explain to them how you tried to remove 1 - 3 layers of yr own skin. other than that happy smelting. if u like that u can do the same thing with aluminum soda cans, pie tins, empty beer can (that yr parents have emptied (or better yet pick them up off the street youill help yr help city out as well.
Dowaine cjs12982 years ago
they also sell plastic meltars that you could probably use
rawkstar320 (author)  cjs12982 years ago
do NOT use a camp stove. Check out Goodwill/salvation army for a deep fryer WITH thermostat.

The deep fryer I use is only $20 at walmart, I convinced my wife to let me getting it by selling her on the idea of making her own candles. :-)
Go to a thrift store and get a used deep fryer. Go to several. Check back every week until you find one.

Avoid open flames around boiling oil.

I have had success with a new hot plate I bought at Walgreens for $10. I opened it up and bypassed the temp switch, and now I use it to melt lead. If you keep the temp switch working, it should be able to melt plastic well.

For low temp melting, electric is WAY easier to work.
4cylndrfury2 years ago
Awesome writeup. Ive done this before with an electric hotplate and an old soup pot, but the electric fryer with a thermostat seems waaay better. One piece of advice, keep a lid nearby that will seal tightly to the pot on the fryer - you can put out an accidental fire with the lid if a hot spot occurs and you get an ignited pot of wax. Dont ask me how I know...
we all know now. u accidentally let it heat up too high.
BMcDanel1 year ago
HDPE melts at 266F LDPE melts at 248F. Running it at 300F is a bit hot for these materials. You may be able to reuse this more if you melt it at a lower temperature.

You can get HDPE or LDPE pellets for about $5/pound. These are used in injection molding as well as making your own filament for 3d FDM printers.

Investment casting is another option for this, you would mill your shape then coat with a 50/50 sand and plaster of paris mixture. Multiple light coats bring out more detail. Invert your mold and heat to its melting point and everything will go out the sprue (you did make a sprue right?). pour in your molten metal and let cool. Smack with a hammer and the plaster breaks off (which can also be reused if you grind it back into powder). You now have a metal object cast from the wax one.

This can save on milling time since you can run higher feed rates, save on bits, etc. You do lose the temper so you would want to investigate how to restore that if its important (each alloy is a little different).
jeiclin1 year ago
Thanks so much for this - very interesting!

Do you think this wax would be suitable for hand carving? I'm looking for something like jewelry wax (although I don't need quite the same level of fine detail), which is prohibitively expensive.

Would this melt if held in the hand too long or get sticky? How brittle is it? Any help would be very, very appreciated!
DRH20142 years ago
Have you tried burning the wax off of the strainer? If you get a metal colander you can just burn of the wax. (Outside of course)
st_indigo2 years ago
I just finished my CNC router build and found your excellent instructable while researching machinable wax. I am going to give it a try soon. Thanks for the clear instructions and thoughts on safety.
Horsehockey2 years ago
Great Instructable. Looking forward to more of your good ideas. Have you tried melting gallon milk jugs? I buy water in the gallon jugs. On the bottom they are marked HDPE. I have daydreamed of a way to get them into a plastic state so they could be pressed into a mold. I see that you are working at 300 degrees. Wonder what it would take to melt the thicker material. You have provided me with a wonderful starting place.
Thanks for the inspiration to get me started.
jamesb212 years ago
why can't normal shopping bags be used? and can other biodegradable bags be used for example TDPA (produced by EPI)??
There should be an instructable:http://www.instructables.com/id/HomemadePlastic/
You shred up old shopping bags into hot oil, then use a stick to stir it around until it's very soft, then ladle it out into a mold and press out any oil in it. Voila! One block of "free" HDPE plastic. You can mold up a lot of different shapes and parts with this method.
Dowaine2 years ago
why is it colored and could i use crayons for the wax
RangerJ2 years ago
cbegliomini2 years ago
In your recipe you talk about "4 parts wax to 1 part plastic": do you refer to weight or volume?
kwhitacre2 years ago
Wow. I read this eagerly as I need to create some wax masters for lost wax casting. The wax in all of the art world is expensive. I am considering trying your machinable wax for this purpose. I noticed only the good directions, cautions and photos. I did not notice spelling or grammar until I read it in the comments. Please dismiss the untoward comments. I LOVE your post. It is great info and timely for me. I, too, would like to hear more about your CNC.
mdlee19582 years ago
Hi. I am really impressed with this instructable. I am just starting out as a hobbyist in machining I am curious if you have tried the "Lost-wax" casting method with this wax?
Squee mdlee19582 years ago
At the school I go to we "lost wax" cast with waxes, plastics, and plenty of other odd things (sticks, leaves, styrofoam. anything burnable, really). This wax should burn out fully, but of you are concerned increase the length of your burnout (we normally do a 6 hour burnout for jewelry-scale, and a ~36 hour burnout for larger-scale castings.
I would think it depends if a residue is left when the wax is burnt off, I would try burning a small piece of the plastic used , if it burns to nothing it might be OK . I'm curious to know how rawkstar came upon the idea of adding plastic to wax , not something I would have thought of.
Felixg2 years ago
thanks! It is great info.
regards, Felix
Fabulous ible..well done... To catch/save/collect your trimmings use a catch pot.. I machine a lot of brass and that produces heaps of fine (sharp) swarf... The catch pot is the answer.. Take your ordinary vacuum cleaner and add a catch pot between the end of the hose and your work.. I use a 10 liter (2 gallon ) plastic paint pail for the catch pot. Make 2 holes in the lid.. one for your vacuum cleaner hose and another for the blunt end of a vacuum cleaner hose from the local recycle centre. The pointy end of your (recycle) hose goes to your work. So.... when the swarf is vacuumed up it goes into the catchpot and is trapped. Oh dear... I feel an ible coming on.
zakamooza2 years ago
why the bags ?
tiagolramos2 years ago
i use a Crème Brûlée Burner to clean metal mesh's.
I burn it to carbon then remove it.
the metal usually handles more then 20 cleans
stayputnik2 years ago
Where did you get that dremel end mill bit? I'm having trouble finding a similar one online...

Nice 'ible, by the way... I'm going to try this!
rawkstar320 (author)  stayputnik2 years ago
Dremel bit #654, 1/4" straight flute. (actually, its 0.225")
Thank you!
Great instructible. I'm looking forward to making a batch. Your setup looks great too.
Machine2 years ago
This is a nicely written instructable - you've got a good skill at this and you've made creating the machinable wax blocks a lot easier. Thank you.
lahines2 years ago
You can raise the paraffin wax melting point by adding stearic acid available at candle making supply craft stores.
cjraabe2 years ago
This looks so interesting, I'm trying to think how I could use machinable wax. For straining the finished product, how about squares of metal screen (door screen) bent over a metal form? Or what have you tried to clean your strainer?
Edgar2 years ago
A Zillion Gizmo Makers around the World will make good use of this, and not only for CNC, but also, Lost Wax Casting on Aluminum... :D
Good Job! :)
Went to my Blog post:
blindpig2 years ago
Like the clear description and pics.I've tried this a couple of times and always had trouble getting the plastic bags to disolve before the wax started vaporizing. Someone suggested trying candle type paraffin insted of canning paraffin as the canning variety was much softer than candle wax(sounds right to me)and I'm about to give'er a try.
rawkstar320 (author)  blindpig2 years ago
Remember, it only takes 300* to start disolving the bags. Also note that this process is not instantaneous, the first time I did this it took me nearly two hours and not all the clumps will disolve.
acoleman32 years ago
i learned on a machinists forum that you can use cheap cutting boards for this too since they're hdpe. they're not free, but you can pick them up at the local dollar store for a dollar plus local tax.
rawkstar320 (author)  acoleman32 years ago
Unfortunately, cheap cutting boards (that I have seen) are almost always polypropylene. These are typically advertised as "Poly Cutting Boards."

HDPE boards are much more expensive. :(
I've cast 6in machinable wax blocks in the past and here is what I have learned to get rid of the dip in the middle. 1. Let the wax cool/de-bubble in your pot to a few degrees above the congealing point. Wax expands up to .1cc/cc per 25deg C so letting it cool will let the wax shrink a bit before you cast it. 2. Use mold release on you mold. The lets the wax desperate from the walls slowing thermal transfer. Kitchen spray works OK. 3. Let the mold cool after casting as slow and uniform as possible, try for 6-8 hours. I use a 1inch foam board on all sides. If everything goes right, you will have a block a few mm smaller than your mold with only a 5mm dip or so
RandyKC2 years ago
Thank you.
Would overfilling the mold cut down on the need to resurface before machining?

Are there any considerations when clamping the wax blocks down? I see you clamp down the edges in your pictures. How do you judge how much to clamp down this material?
rapier1 RandyKC2 years ago
So I'm a candlemaker and the main issue with the shrinkage is the way that the crystalline structure of wax reforms after being melted. Rapid cooling can lead to cavities, deep wells, and the like. Slowing the cooling process allows for a more even reformation of the structure which aids in an even rate of contraction. You can't avoid the contraction though (not entirely true but the additives necessary for low shrinkage would make the wax unsuitable for this purpose) - only the shape of it. In candlemaking we deal with the shrinkage either by melting/cutting the bottom of the candle flat or topping up the mold. Do get good adhesion between the layers though you need to do the second pour at a higher temperature than the first pour. Since you are already working at 300F you'd probably need to repour at 325F to 335F. You still may end up with a shear layer. As such - machining the ingot flat really seems to be the best move.
rawkstar320 (author)  RandyKC2 years ago
Overfilling doesnt really work, the sinkage is due to the large amount of volume in center. So overfililng actually increases the depth of the sink.

I have tried several methods, as long as your finished part does not get crushed, anything works.
r_harris22 years ago
Have you tried a combination of melting and burning to clean the strainer? I am thinking of maybe an oven and/or hot air gun to melt the wax and allow as much as possible to run off, followed by burning the wax off with a clean burning flame such as a propane torch.

I use a wire probe over and over in a plastic casting process that I do, and the plastic builds up, and I find that a few seconds with a torch reduces the buildup to a carbon coating that can be wiped off. A strainer would be more difficult to clean, but if you can reduce the gunk to carbon soot, you might get it off with soap and water and a brush, or maybe a cycle in the dishwasher.
Good call. Strainers are cheap but should be cleanable as you describe. Also something just occurred to me... cheap off cuts of flyscreen maybe? Not sure it it works vis a vis fibreglass melting temps etc ...
Unless it changed recently, window screen is also available in aluminum. That's what the old screens were made from.
We had some success reducing "shrinkage" by cooling very, very slowly. We prepared our wax in a lab oven though, so it was easy to control.
aglaranna2 years ago
Has anyone tried using the wax for casting? How well does it melt out of a mold?
Kdemon2 years ago
This is great, would this wax hold up for casting after being milled?
ehrichweiss2 years ago
I suggest buying a roll of aluminum screen and make a frame you can put small pieces on for filtration. You could use the hot-air gun method to clean it as best you can but if that failed you just rip that off and put a new piece of screen onto the frame. It'll definitely be cheaper than kitchen strainers, even if you were to buy them at a dollar store.
Why does your wax go from white/clear to pink?
rawkstar320 (author)  2ManyProjects2 years ago
I added a crayon. I think I mentioned it at the beginning of Part 2, right after the wax was melted.
StaticDet52 years ago
In one of your images, it looks like you've got a large chunk of steel wool (it's the towel). It got me thinking: Could you use steel wool to filter the plastic chunks out? It's cheap, you can adjust the "filter level" by using more steel wool or compressing it more.

Finally, about how long does it take to go from melting the paraffin to the pour? I'm not really interested in the cooling process (I'd just let them sit for the night). About how many bags are you talking about, as well? I have dozens. Do I need hundreds?
rawkstar320 (author)  StaticDet52 years ago
Steel wool might work, but the large "vertical" surface area/travel might cause the wax to solidify before getting to them old. You really want the wax as hot as possible when cast so that any air bubbles can escape.

Its been a while since I used the walmart bags but I did 2lbs of wax and needed ~40 bags. I used a mixture of walmart bags and some garbage bags (0.5oz) to get my mixture for more recent batches.
Orngrimm2 years ago
Hey cool!
I dont have nor need a CNC, but this "hard wax" should solve some other problems i had in the past with soft wax-castings.
Thanks for the 'ible!
Great idea. I have been trying to think of a way to reuse old grocer bags. This seems like the perfect fit.
Lorddrake2 years ago
have you tried "cleaning" your strainer with a propane torch?
id think a good heat gun would do the trick. blow HOT air in from the top, it will soften and or melt the wax and blow it through the strainer
A good batch of Acetone may do the trick also. Not sure if Acetone works on wax, but it certainly works on plastic.
Just be careful with the Acetone around the fryer. It is VERY flammable.
rawkstar320 (author)  drobertson1232 years ago
Propane sounds like a fire hazard...not sure about the acetone plan, but it might be something to try.
How about doing what you should do when you get wax in the carpet. Apply heat to the surface and mop it up with kitchen roll or some other wipe.
Put the strainer above a heat source, melt the wax, then dab it off 'till it's gone.
Just a guess.
That's a really interesting idea. I hadn't heard of nor thought about machining "wax" like that before, but it does seem to solve a lot of problems. Do you use it as a test piece to make sure your cutting path is correct and then go on to cut the part in other material, or do you use it in a "lost wax" kind of casting process?

Have you tried other wax additives like Stearin and Carnuba?
In the CNC machining trade, Machinable Wax is commonly used for proving out a complex program before trying it in metal. You are saved from (some) tool crashes, you get to see if the part is right, and it can be machined at a considerably higher rate than metal.

I've been wanting some to try, and too cheap to buy it. Many thanks, rawkstar, for the recipe!
rawkstar320 (author)  gyro_john2 years ago
No problem! Good luck and be safe!
For dissolving paraffin, you need a non-polar solvent like mineral spirits or hexane. Acetone, which is a polar solvent like water or alcohol won't work (like dissolves like). Polyethylene is also non-polar, but not nearly as soluble in hexane, so it may not clean the screen completely. Mineral spirits and hexane are also very flammable, so be careful.
Great instructable. Thank you for this!!!

Considering I have a home built CNC machine and I am very cheap, this is perfect.

Have you tried using this wax for investment casting? I am just curious if the hot metal burns the plastic in the wax mixture and creates chunks.

One thought I had for your straining issue was to use a larger holed colander lined with
cheese cloth. The cheese cloth should catch the larger plastic chunks and the larger holes should allow you to clean the colander for re-use. You may not want to use it for food again, but at least you could skip the expense of a new strainer each batch.

Thanks again for this.
rawkstar320 (author)  drobertson1232 years ago
Usually investment casting involves burning out the wax ahead of time in a kiln/oven. The only time we investment cast directly onto the form material is when we use foam.

But, no, I have not tried it yet. :-D
rimar20002 years ago
Very interesting and useful info, thanks for sharing it. I have not a CNC machine, but this hard wax can be used to turn, carve, modeling, etc.