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Posted
I agree, from what I've seen so far, the wax works very well. It's interesting, when you first incorporate the wax into the clay, you end up with a powder that doesn't look any different from plain clay. Yet uder extreme pressure, such as your nozzle press setup, the wax somehow comes to life, and turns the matte powder into a shiny ceramic-like disk, with some serious strength. I've tried both paraffin and toile bowl ring wax, and they both seem to work nicely.
Posted
I would think that the wax under fire would melt and give a liquid type of body to the clay allowing it to be torn apart by the high pressures. Like dirt and water. But I guess it doesnt happen thata way.
Posted
I thought the same thing. Interestingly enough, I think it has done the opposite somehow. My nozzles stopped eroding after I started adding wax. Definitely try it out.
Posted

I never really see any of my rockets ever again if they dont CATO. Have to do some static tests. Usually my static tests are done with sticks on them :)

 

How much wax to how much clay?

Posted
Well I used the formula from ned gorsky that he recently wrote for skylighter. Its in the newsletter archive. His formula contains grog which I was also using. So you should be able to figure it out. I think its like 30%. Good luck.
Posted
I think one of the keys (and it is kind of a pain to do, but necessary) before incorporating the wax, the powders must be brought to temp, or the wax simply solidifies upon contact and makes for wax balls rather than a smoothly integrated mix.
Posted

Some others use a toilet bowl wax. There is a wax ring that seals a part of the piping. I believe it is the main exit pipe actually. There is a tutorial about it on passfire. It is dissolved in mineral spirits or something like that, and kneaded into the clay to distribute it, and allowed to dry. One might be able to dissolve paraffin in something as well, perhaps mineral spirits as well. I don't recall any solvents off the top of my heat.

 

Alternatively, one might be able to just do it in a heated pot on a hot plate. Add the clay and the wax, heat and stir until distributed.

Posted
Well Dan Thames adds wax to his bp rocket fuel. I have done it several times per his instructions. Melt the wax in a beaker or like, them dump in a certain amount of lacquer thinner, it seems to be that it instantly turns all the wax into fine particles as its cooled. Then just dump into comp and stir up. Im sure this would work. Wax may be soluable in camping fuel if heated a bit.
Posted
A quickfix to the wax problem is to heat the bentonite/grog/whatever in a oven or electrical skillet, and add the warm wax/solvent to the HOT clay mix. Stir around, let it cool, rice it, let it dry and its done.
Posted

Best nozzle formula I've *personally* seen, is the one in Dave Sleeter's book. I don't have it handy, sorry, but it was Bentonite, Grog, and Paraffin Wax. (If someone can provide the exact formula, I'd appreciate it.)

 

(A quick note: Some folks outside the USA have different terms for what we call Paraffin Wax here.)

 

Basically, you heat the Bentonite and Grog in a metal bowl for a half-hour in an oven set to 350(?) degrees F, then melt the wax in a saucepan and mix it into the clay/grog mix, stirring it briskly and thoroughly until completely cool. When done, it looks like plain clay/grog. You can't see that it has wax in it. But when you press or ram it, it forms a very hard and shiny nozzle, as Swede noted for his method. It's what I've used for my BP motors since day one.

Posted
You might want to check your facts before referencing them. Just a suggestion. Ned's article stated 8%. I thought I saw another post here with the 30% wax, and I thought it was rediciously high.

 

Heres the link for the curious:

http://www.skylighter.com/skylighter_info_...sp?Item=107#mix

Sorry about not having the exact info at the time I was sorta busy or I would have gone look it up myself. Thats why I mentioned the article and said I wasnt sure about the ratio.

 

What I did was grate the wax blocks on a fine cheese grater then weighed out the shaving to the right ammount. I then mixed these in with the bentonite /grog then baked in an oven untill heated through. This helped incorporate the wax allot better because it was all evenly distributed allready. However it still took a bit of stirring to get it perfectly incorporated because the shavings seemed to not want to fully soak into the clay without a little stirring.

Posted

I learned the "nozzle clay mix" from Sleeters book as well. I find myself going back to his book for missed tips often, maybe I should READ the book, not only look at the pictures :D

 

I'll find the right ratio if needed, just not on my top ten list at the moment.

 

And the solvent/heating has two uses: It dissolves/melts the wax, and it acts as a carrier for the wax when mixed in the clay.

This makes the wax spread evenly in the clay, and gives a better result than just heating wax and mixing. The downside is that the solvent takes time to dry. And NEVER use a high flammable solvent!!!

 

Nuff said

Posted
A non-flamable solvent for wax exists!?:o
Posted
What I did was grate the wax blocks on a fine cheese grater then weighed out the shaving to the right ammount. I then mixed these in with the bentonite /grog then baked in an oven untill heated through.

Now THAT sounds like a handy and effective way to do it. Hard paraffin wax blocks should grate nicely, and you skip the dangerous and messy step of melting the wax separately, or dissolving it in a solvent.

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