Where to obtain organophilic bentonite clay in EU. (First steps in alum casting)

Hi guys,

For those of you who don't want to read the whole thing... I need to find a supplier for a small quantity of organophilic bentonite within the EU (preferably in Germany, or the UK while they're still in the EU :) ). I nedd to mix the so called K-bond sand. And locally I can only obtain hygrophilic (standard) bentonite.

And now for the long story...

For an year or so, I am working on a project to create a LED street lamp. This has brought me up to many challenges, and usually the answer is "learn how to do it, and do it yourself".
So after a waited for ages to receive my first prototypes from random cnc guys, and after paying a ton of money. I decided to obtain a CNC router.
After a few months of initial learning, I am now able to achieve pretty complex shapes. Still have a lot to learn though.

Ever since my first prototypes I've been in contact with several foundries that would eventually cast my shape. I learned that my model needs to have a parting plane and so on. So I started working on a plywood model for casting purposes. So I gave it my best (not much considering I am into CNC milling for less than an year) to make a good dummy with a parting line and inbuilt gating system. Had to start over several times. First time my model failed because I used MDF and it distorted its shape after cutting. Second time I used Plywood, but when I was ready with the two halves I realized they don't match. Then I found that my gantry is misaligned. Learned how to align it, and although I didn't align it perfectly, the two halves were now much more closer to a perfect match. Some sandpaper and putty did the rest. Painted it, and now I have a pretty decent shape for casting. Here are some pics:
- Before paint:
http://www.cnczone.com/forums/attach...d=357524&stc=1http://www.cnczone.com/forums/attach...d=357526&stc=1http://www.cnczone.com/forums/attach...d=357528&stc=1
- After paint
http://www.cnczone.com/forums/attach...d=357530&stc=1http://www.cnczone.com/forums/attach...d=357532&stc=1

So I while I was busy celebrating my first successful casting model the foundry that was closest to me (¬5 km) went out of busyness. The next closest one is too busy casting a large batch of some bronze stuff and have no time dealing with me. And my last resort is a guy who owns a large foundry, and his busyness is refining scrap and formulating alloys, however the only shapes he casts are ingots. To cast shapes he insists for the help of two old (and probably very experienced) guys. However those old guys work exclusively with liquid glass (frozen by CO2) molds, and refuse to do anything with greensand. And now I must prove this would work and do my own molds for this guy to pour aluminum in them.

So.... I started researching casting techniques. Had some coal lying in my yard for years, so I designed a quick furnace, cut open an old fire extinguisher. And started practicing.
My first attempt was pretty miserable, but still something. A picture below (don't laugh pls :) ):
http://www.cnczone.com/forums/attach...d=357534&stc=1
The mess that you see can be attributed to 3 factors:
- Wrong sand (used 50 micron silica sand, waaaay to fine)
- Wrong bentonite (used plain kitty litter in large granules I didn't bother grinding it)
- Too much water (The original recepie opted for 7l of water per 100kg of sand.... I ended up with over 20 liters in my mix, because the sand wouldn't stick well with less water. Tha probably has to do with the kitty litter).
- And one more... I tried using table salt for flux and sodium carbonate for degassing... Not a good solution, at least the salt. The Sodium carbonate actually did bubble out some stuff, so it might of worked.

So what happened is that the upper half of the flask couldn't hold the sand and it collapsed. So I was left only with the lower half. And I poured the aluminum in it. The spills are due to the fact that I had waay more aluminum than what was needed for only half of my model (and the backup ingot shapes I prepared)... had to pour it somewhere. And the large cavities/bubbles were caused by the tremendous amount of water in my sand mix.
Anyways I was still happy with this turd... I actually got something that kinda resembles the original design, using an absolutely wrong casting sand mixture :).

So with the lessons learned I am now stocking up for a second attempt.
First thing on my list - SMALLER FLASK! One half of my current flask filled with sand weighs over 80kg! So I ordered a new one about 60% the depth of the original one. I might further reduce the weight by other means. But for now I prefer to play safe.
Second I obtained nice sand within the range of 120 - 250 micron. This thing is actually sand (the previous one was called sand, but at 50 micron it is actually dust!)
Third, I obtained real flux and degassing tablets from the guys who is making alloys ( I live in Bulgaria, and believe me, you can't find that in the store, only at certain distributors and it is sold only in large bags, a quantity enough for melting tons of aluminum). I did a quick melt and poured a slab (lost styrofoam) and the flux worked great, the dross was now mostly powder.
And fourth, obtaining the right bentonite. Fortunately, there is a Bulgarian company now owned by a french company, that used to be called Bentonite AD (forgot the new name, sorry), and their main production are various bentonites, zeolites and perlite. So I ordered some bentonite from them that is specially formulated for foundries.

So in a week or so, I will do my second attempt with good greensand and hopefully I'll get better results.

All that sounds great. But when I recall the time I did the mixing and mulling of the first batch of sand, and this kinda drives me off. OK I'll do it one more time for the test. I might keep a 100-150 kilos of sand and recondition it once in a while. But if I want to be able to make let's say 10 molds I'll need a lot of sand, and maintaining its usability will present a problem, even with a muller!

I've read about Petrobond/K-bond, and it sounded like a better idea. Yes it still needs reconditioning after some usage, but it doesn't lose it's properties by just sitting in the box. More expensive yes, but surely better. Making half a ton of it and optimizing my flask, should allow me to make about 6 molds with risers (maybe 7). Petrobond is a US product, nowhere to be found in Europe, so I'm sticking to the K-bond recipe.
So here comes my problem. I can't find any organophilic bentonite in Bulgaria. The company Bentonite AD, actually never heard of such a thing (or at least the girl on the phone had never heard of such a thing). She explained to me that all of their bentonites are made to be mixed with water and not oil.

So now I am looking for any suppliers within the EU, who sell organiphilic bentonite (or the stuff they refer to as Bentone 34 on the forums). I have means for cheap transport from Germany and the UK, so these are the two countries where it would be best to find this bentonite. However I would consider any other country within the EU (I prefer to buy it in the EU, so I don't have to deal with customs clearance etc.). I would appreciate any input with company names, web pages, addresses, etc.