[SS2S-Main] Re: Material for Nozzle fabrication

  • From: Rick Maschek <rickmaschek@xxxxxxxxxxxxxx>
  • To: "sugarshot@xxxxxxxxxxxxx" <sugarshot@xxxxxxxxxxxxx>
  • Date: Wed, 7 May 2014 10:41:21 -0700 (PDT)

If you start the list it will be repopulated very quickly, trust me. I will be 
the first 'subscriber'.
On Wednesday, May 7, 2014 10:35 AM, Steve Peterson 
<steve_peterson@xxxxxxxxxxxxx> wrote:
Hey Rick,

I'd have started a freelist version of sugpro myself but to really
    get it going again we need the old subscriber list. I even thought
    about harvesting some old subscriber email addresses from the
    archives that are still around, but haven't felt that it was my
    perogative to just go ahead and do. Still, it *is* tempting....


On 05/07/2014 08:29 AM, Rick Maschek wrote: 
>I remember that thread on sugpro and have done something similar since I have 
>had to make a 6" graphite/phenolic nozzle for an APCP motor we are doing. 
>Having made steel nozzles on my lathe doing that graphite would have been 
>I have many things I would have liked to post on sugpro if it were still up 
>and running. When the sugarshot went down I suggested to Richard we go to 
>freelists. Putting sugpro back up would be very easy on freelists if someone 
>would like to do that.  
>Here is the link: 
>FreeLists - Free Mailing List Hosting  
> FreeLists - Free Mailing List Hosting 
>FreeLists provides free mailing list hosting for technology-related topics    
>View on www.freelists.org  Preview by Yahoo  
>On Wednesday, May 7, 2014 5:03 AM, Steve Peterson 
>mailto:steve_peterson@xxxxxxxxxxxxx wrote:
>(Can we PLEASE get sugpro up and running on freelists.org??)
>The last time this issue came up on sugpro, the
                    suggestion was to use one of those drywall sanders
                    that run the air through water before exhausting it.
                    I don't have a link handy, but as I recall the item
                    wasn't that expensive and was available at home
                    improvement stores and the like.
>On 05/07/2014 04:15 AM,  (Redacted sender monsieurboo@xxxxxxx for DMARC) 
>>Because I occasionally machine graphite and this is the first time I've seen 
>>this particular concern raised, I did an online search for info.  I'd 
>>characterize it as showing broad consensus but not unanimity.  Based on that, 
>>I've formed my own conclusion but really think anyone who creates graphite 
>>dust should review the literature yourself and assess your own operations 
>>accordingly -- always keeping safety foremost.
>>That's a fascinating and clever use of
                                graphite in mining.  LOX, like other
                                highly concentrated oxidizers, will
                                sensitize most organics so I can
                                certainly see a combination of tamped
                                graphite saturated with LOX being
                                effective.  Here we have three separate
                                cases (the mining case, graphite dust
                                dispersed in workspace air, and graphite
                                dust dispersed in the shopvac canister
                                or bag).  The fuel density and A/F
                                ratios are different for each case, as
                                is the likelihood of an ignition
                                trigger.  It's certainly interesting to
                                juggle the variables involved while
                                pondering the importance of "safety
>>I rarely cross-post but this might be a good question to pose on arocket.  
>>It's been pretty quiet over there for the past week and the response from 
>>that bunch could be informative.  Any objections?
>>Mark L.
>>-----Original Message-----
>>From: Cliff Bates mailto:cliff@xxxxxxxxxxxxxx
>>To: sugarshot mailto:sugarshot@xxxxxxxxxxxxx
>>Sent: Wed, May 7, 2014 12:54 am
>>Subject: [SS2S-Main] Re: Material for
                              Nozzle fabrication
>>    I might suggest here that carbon dust is "extremely" explosive if mixed 
>>with the proper amount of air and ignited.  In fact carbon dust was used back 
>>in the 1920's in mining to replace dynamite.  A cardboard tube of packed 
>>carbon dust was soaked in liquid oxygen for 15 minutes, then stuck in the 
>>blasting hole.  If the charge failed to go off for some reason, after 30 
>>minutes the O2 evaporated enough that the explosive aspects of the charge 
>>became inert, so it could be drilled out.  Unlike the dynamite filled holes 
>>that the "new guy" got to dig out........... alone. 
>>    Machining graphite is extremely dirty if a vacuum cleaner is not used, as 
>>someone earlier pointed out.  THE THING TO WATCH is the arcing brushes on the 
>>vacuum cleaner motor igniting the dust if the vacuum cleaner exhausts through 
>>the motor housing, as most do.  I'd strongly suggest that the vacuum cleaner 
>>bag be double bagged to assure the dust is all caught inside the can.  If 
>>not, a dust explosion could very likely occur from the arcing motor brushes 
>>as the air/carbon mixture flows by, and it will not be a nice thing.  Years 
>>ago I accidentally sucked some coal gas fumes into my 5 gallon shop vac while 
>>cleaning up after some blacksmithing.  The vacuum exploded, splitting the can 
>>wide open and throwing the lid with a 1 horse motor still attached, about 30 
>>feet in the air.  Graphite/carbon dust is much more energetic than coal gas 
>>fumes, and why air powered drills are used in coal mining. 
>>    If you doubt this, take a large coffee can with a slap on lid.  Drill a 
>>hole in the side of it to fit a small 1/4" hose.  Attach a small funnel to 
>>the hose inside the coffee can and put a small amount, half a teaspoon, of 
>>flour in the funnel set up vertically.  Take a birthday candle and put it in 
>>the can.  Light the candle, then snap on the lid.  Quickly blow into the hose 
>>to mist the flour before the candle burns up all the O2 and goes out.  Be 
>>sure to be back about a meter or so from the can due to the exiting lid.   
>>    You can use this method to test various dust samples, including powdered 
>>sugar, coal, graphite, flour, corn meal, fine wood dust, etc., etc.  A larger 
>>can with the same amount of "fuel" and candle will usually produce a more 
>>energetic response than a large coffee can due to more air being available to 
>>burn the fuel.  However the idea here is not to level your shop, but just 
>>some food for thought about something that is normally not considered.. 
>>----- Original Message -----  
>>>From: Hans Olaf Toft  
>>>To: sugarshot@xxxxxxxxxxxxx  
>>>Sent: Tuesday, May 06, 2014 9:11 AM 
>>>Subject: [SS2S-Main] Re: Material for Nozzle fabrication 
>>>When using graphite for nozzles - keep in mind that it is a surprisingly 
>>>good heat conductor.
>>>On 05/06/2014 02:39 PM, Steve
                                      Peterson wrote:
>>>The Graphite Store (http://www.graphitestore.com/). Right now, 2" rod, 48" 
>>>long (medium extruded) is selling for $66.50. That much steel would be a lot 
>>>more expensive. Unfortunately, I don't see any smaller diameters in the 
>>>medium-grained; they do have smaller diameters in the fine-grained but it's 
>>>more expensive--for instance 1" diameter by 24" long is $43.90. I would not 
>>>recommend trying to machine away a 2" diameter chunk if all you need is 1" 
>>>diameter--a vacuum helps control the dust, but it's still messy. 
>>>>I used 12L14 for years before I
                                      switched to graphite and I still
                                      make steel nozzles on occasion. I
                                      never saw any erosion with sugar
>>>>If you do go with graphite you can
                                      make a "form tool" for the
                                      convergent and divergent sections
                                      which makes the turning go much
                                      quicker--just grind down a spade
                                      bit, it doesn't have to be that
                                      sharp to get the job done.
>>>>On 05/06/2014 03:59 AM,  (Redacted
                                      sender monsieurboo@xxxxxxx for DMARC) 
>>>>Strangely enough, the mid-grade (medium-grained) graphite tends to do the 
>>>>job better than the high-end, fine-grained material.  Less erosion, perhaps 
>>>>due to larger grains interlocking better and being ablated more slowly.  
>>>>And of course, less expensive.
>>>>>Graphite's definitely the
                                            way to go, but you don't
                                            want conductive, fine dust
                                            getting into any electronics
                                            (such as a benchtop
                                            mini-lathe) so try to
                                            capture the dust at its
>>>>>Mark L.
>>>>>-----Original Message-----
>>>>>From: Hayk Azatyan mailto:dmarc-noreply@xxxxxxxxxxxxx
>>>>>To: sugarshot mailto:sugarshot@xxxxxxxxxxxxx
>>>>>Sent: Tue, May 6, 2014 5:53 am
>>>>>Subject: [SS2S-Main] Re:
                                          Material for Nozzle
>>>>>Thanks for your input Jeff. Where do you recommend I buy graphite from? 
>>>>>On Monday, May 5, 2014 4:58 PM, Jeff Moore <tnetcenter@xxxxxxxxx> wrote:
>>>>>Graphite would probably be the most affordable of materials to use.  We 
>>>>>had a machinist in our local group at one point and he made a titanium 
>>>>>nozzle as a proof of concept.  That would more than likely be rather 
>>>>>pricey for this project ( his was for a 54mm motor).
Aluminum is a good material to practice on or do mockups with, but I suspect 
that it's melting point is way too low to be used as the actual nozzle.  It 
might work as a carrier for a graphite or ceramic insert though.
Jeff Moore 
Bend, Oregon
>>>>>On Mon, May 5, 2014 at 4:10 PM, Hayk Azatyan <dmarc-noreply@xxxxxxxxxxxxx> 
>>>>>Hello all, 
>>>>>>Would you all happen to know where I can get my hands on some scrap 
>>>>>>circular steel bars for rocket nozzle fabrication?And if you have any 
>>>>>>suggestions on the material I should use please let me know. I have 
>>>>>>already started using the lathe, and currently I am machining a nozzle 
>>>>>>out of aluminum. Although I will not be using this particular nozzle for 
>>>>>>flight I figured I should practice making one out of some scrap metal 
>>>>>>that I found(in this case aluminium). I know that you guys make some of 
>>>>>>your nozzles out of graphite, but for now I am learning to machine metal 
>>>>>>nozzles just for educational purposes.
>>>>>>Thank you guys!  
>>>>>>-Hayk Azatyan        

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