Random Thread #1

[Tweetybird88]

Alright, my man Clint Bowyer takes first at Darlington. I hope no one here is a big jr. fan.

[mormanman]

I would guess it is food grade, why do you ask?

 

I wanted to ball mill my Mg shavings, but I am afraid that they would ignite as soon as I opened my jar, is this possible or not? Thanks.

I read here it was under like Milling Mg as the topic/thread title. Also read under the same topic/thread that you can "help" stop the possible ignition by opening the milling jar every hour or so. Thats all I know.

 

tentacles, what do you mean by bars? Like media or a rod or something?

[tentacles]

mormanman: Lift bars - pieces of (in my case) PVC glued to the inside of the jar to force the media to lift up instead of just sliding along the inside, which is what they were doing. It's a common design, more common in larger jars - 6"+.

 

I cut a chunk out of my to-be corning drum (a piece about 3" wide) earlier and just cut some 3/4" strips out of that, it's half inch thick solid PVC. Glued em in the jar on opposite sides, braced the bottom in and clamped the top of the bars while the glue dried. They work great!

 

Interestingly, the inside of the jar was polished smooth like water from the media sliding in there. It was actually glossy, and I sanded the inside after I got it to clean out the dirt and grime.

[asilentbob]

For some reason I just now realized that we have a calendar. Its pretty empty. Lets fill it up with GOOD events! I went ahead and added the 2008 PGI convention to it. August 9-15... Just copy/pasting the info available off the PGI website section with 2008 convention info.

 

Note: If when you post events they are rather pathetic in info provided, they will probably get mod edited a lot. Or just plain deleted and done over again right.

 

So yeah. Guys start posting WPAG, etc shoots!

I'd recommend some kind of format for the titles, like:

Club - Location - event

 

Edit: Added Maker faire Austin, TX 2008, and 2 homebrewing events to the calendar.

[Tweetybird88]

It's just about time for one of my favorite holidays of the year, Junk day. Lets hope I get some good stuff this year. Last year I got a nice lawn mower engine that works just fine and I managed to find a good length of two inch HDPE.

[oskarchem]

My god you guys are lucky to have junk day....

[nick2354]

Hello, I am thinking about placing a order through for some 2.5" paper shells. I am planning on using them as header's for my rockets.

 

I am wondering how much weight APPROXIMATELY a standard 2.5" paper shell consisting of rice crispies meal coated and TT stars will weigh. (I know there are so many variables, but I am looking for a 'rough' figure)

 

I have tested my rockets and I can carry 71.2 grams but cannot carry 110 grams. I havent tested any other dummy headers.

 

Any help is MORE than appreciated!

[TheSidewinder]

I'm not the rocket expert here, though others are and will probably clarify.

 

But from what you've said and what I've personally witnessed, I *think* 2.5" shells will weigh too much for the rockets you're describing.

[justanotherpyro]

When I build an easter egg shell with 1/4 inch TT stars and BP coated puffed rice it is ~35-40g. Thats a 2" shell the extra 1/2 inch might increase the weight I want to say another 20-30g. This definitely is a rough starting point but hopefully it gives you one.

[superman1451]

I've made some ruby red 2.5" shells and they all weighed in about 90 grams. But I also overpacked them abit.

[justanotherpyro]

Ruby red stars the exact same size as TT are going to be significantly heavier due to the metal content. But it is a good range to know that a 2.5 inch shell could be roughly 60-90g or so.

[nick2354]

I am thinking I will be okay. I could always use less stars and more burst. (BP coated crispies should weigh less than stars, right?)

 

I will go ahead and order the shells.

 

Thanks for all your help!

 

EDIT: Pudi, how much did your 3" shell on Pyroguide weigh. It says 70g Tigertail, but how much did the entire thing weigh?

[50AE]

Shellac - Weak binder ?

 

I just bought shellac to bind my nitrate based stars. When they're dried, they break up very easily. Inside they have small holes, like these aero delicious chocolates. Does even shellac work for cut stars, because that's my most common method to make them ? Or I must only press them ? What do you think

[pudidotdk]

EDIT: Pudi, how much did your 3" shell on Pyroguide weigh. It says 70g Tigertail, but how much did the entire thing weigh?

Notes say about 125 grams including everything.

[hst45]

Does even shellac work for cut stars, because that's my most common method to make them ?

I use shellac to bind my Ammonium Perchlorate blue cut stars, but they do seem to take a few days to dry really hard. I found this odd myself as I thought that they would dry more quickly than dextrin-bound stars, but if you try leaving them for a week I think that they will be good and hard. I hope so. Good luck.

[superman1451]

What are the dimensions for 1 pound bp rocket tooling? The rocket itself would be 3/4" ID and 7 1/2" long. I found a place where they might machine it for free.

 

Thanks for any input.

[ULTRABUF]

It's just about time for one of my favorite holidays of the year, Junk day.

One of my favorite holidays as well. We actually have 3 of them, one for each part of town. This is the first year I didnt really go out though, I was busy with track. We had our conference championship meet yesterday, which we won, but which also prevented me from enjoying the fruits of the third and final Junk Day of the year.

[nick2354]

I can get my self some high strenth plastic tubing (I thinks it's HDPE, but my dad says its stronger than HDPE, if that is possible, the walls are 8mm wide and the tube is used for gas piping I think)

 

I can get some, but I need to find out what room should be left when I have placed a shell inside it.

 

1mm, 2mm, 3mm or a Tight fit.

 

Since no one seems to talk about it, I take it that it is not very important as long as its not off buy large amount like 1cm or so. I guess I will have to calibrate the lift charge to suit mortar width, because logic would say "snugg" fit, less lift required and "loose" fit, more lift required.

 

Basicaly my question is:

What is the maximum amount of left over room, once a shell is placed inside the mortar?

 

 

Im sorry If this post makes no sense, I cant think of a way to word it better.

[justanotherpyro]

No it makes sense, and you're right it isn't something widely talked about. The shell should be snug though and should be able to slide down under its own weight. You should not have to push it down, and even worse, force it down. Now if it is just barely not wanting to go down by its own and you have to poke it a little with your finger or shake the tube slightly to get it to fall then thats O.K. but like I said a good fit is a shell that can slide down by its own weight. It shouldn't have a lot of wiggle room, but a millimeter or two is better to chance then having to shove the shell down the mortar.

[tentacles]

Rule of thumb is, shoving the shell into the mortar = no more mortar + mine effect.

 

 

Randomly, I picked up a new heat gun yesterday. I got my hop plants and was getting dirt to bury them in, and the place had a nice looking unit for $30. It claims 50-650C digitally set temp. I tested the 50C with my mercury thermometer - it stabilized at 49.3C, not bad! I'll do more testing with my thermocouple and see how well it works. It's actually very nice, 6 fans speeds and all temperature controlled.

[mormanman]

Rule of thumb is, shoving the shell into the mortar = no more mortar + mine effect.

Not all the time no more mortar but most of the time and it is to much stress for the mortar so probably the next time you shoot it there will be no more mortar.

 

Although the mine effect is pretty I don't like the prices of mortars.

 

I also have a question for mumbles that I've been wondering for a while now.

So mumbles, in your signature it says your have 2,113 lbs for powder for sky painting in your workshop. Is this true or have you been pulling are legs b/c thats alot of powder?

[Mumbles]

I'm sure the amount isn't exact, but it's probably in the ball park. At one point I did indeed have over 2,000lbs of chemicals, thus the time I made the signature. It'd be hard to guess what I have now, but still a significant amount.

[tentacles]

So I'm considering how I'm going to be welding my go kart frame together, talked with my dad about it, and he recommends either MIG or TIG. I'm stumped as to which one to go with. Really, with either I need argon shielding gas (not such a big deal) and for either I'd need some new equipment. The TIG *could* be done just by picking up a torch and some supplies, although I think I'd rather pick up a nice cheap/small inverter welder with torch and all. The MIG welder would cost about the same, although the cheap ones are all sketchy about whether or not they come with all the gear to hook it up to gas (rather than simply using flux core wire).

 

Any welders on the board, any thoughts?

 

Here's a link to the TIG unit I'm considering.. http://www.harborfreight.com/cpi/ctaf/Disp...temnumber=91811

 

There's a variety of MIG units that would work, but they all have lower duty cycles than the inverter TIG unit.

[JCrewPyros]

I am not a professional welder... But I have had some welding classes and also welded at a machine shop for a few years...

 

In my experience it would be preference... If you want a nice clean weld then use a tig... I would use a mig personally... I can get fairly clean welds with minimal grinding to make something look nice...

 

The only time we used a tig was when we needed something to look nice... Or welding aluminum... Which when I was at UTI they had the spool guns for aluminum welding and those things friggin rocked... I could lay down the nicest bead with one of those and they all passed the strength test for cars... So I am certified for aluminum and steel welding on cars...

[asilentbob]

I have an AC arc stick welder and oxy-acetylene equipment, however, I have like no practice. I'm strongly considering learning and practicing a bunch on both over the summer and hopefully getting certified so that I have yet another fall back skill.

 

I've more or less planned out my scalable ball mill / star roller. Its pretty damn cool on paper. The distance between the rollers and the number of rollers can be changed by sliding rollers around and locking them down with wing nuts. I'm going to have it made with metal and welded together... probably get my dad to do it so I wont screw it up. The motor powering it will be 1/4HP so it will be able to handle several milling jars at the same time no problem. Will probably add some wood to the bottom since steel on concrete isn't wise around pyro.