Hydrogen balloon reconnaissance: SUCCESS! Pictures on pages 4 and 5

[Titus Wells]

I had similar plans using water rockets and a cheapy pen camera, the camera package said it could do movies but the camera has different ideas.... all it can do is act like a webcam while tethered to the usb port.

Could you hook up a wireless (bluetooth?) connection? Then you get a light, free-moving camera that won't be a great loss if it plummets groundward.

[akumabito]

Or do some ghetto engineering.. if it's too much of a hassle to get a camera up, just get the picture you want down! Aluminum foil is plenty reflective to act as a mirror of sorts. if you could just lift a large(ish) sheet over the house, you could take a picture from the ground. Picture quality would be crap, naturally, but it's the quick 'n' dirty solution!

[H. MacHinery]

re: the mylar balloon.  I think that mylar can be heat sealed, which would be better than tape for H2 retention.

[Professor Fzz]

Thanks for the ideas folks!

I'm regrouping now.  The balloon mostly stayed inflated overnight, though lost perhaps 1/4 of its volume.  Surprisingly good.  But unfortunately Balloon #1 is no more.  I tried to further inflate it this morning, and realized that when the sodium hydroxide had sprayed around last night, it had attacked the mylar.  There were quite a few holes around the filler tube, and an attempted repair with tape was not a success.  I need to buy more space blankets tomorrow.

We did do a bunch more hydrogen generation tests, including using the sides of a couple of coke cans, having burned the paint and plastic off first.  They worked OK, but also disolved surprisingly quickly.  So far I've not found anything that approaches the production rate of scrunched up kitchen foil without dissolving in a couple of minutes. 

It's very clear from the damage to Balloon #1 that we absolutely can't let foaming sodium hydroxide spray blast up the tube into the balloon (aside from it just being nasty).  It's going to need some sort of expansion chamber or bubble chamber in the tubing.   And the wine bottle just isn't going to be big enough to do the job I think.  Looks I need thicker aluminium pieces so they last a lot longer, but a lot more of them to give the surface area.

So, as a proof of concept, Balloon #1 was a success.  But in terms of equipment I'm back to square 1.

[Professor Fzz]

re: the mylar balloon.  I think that mylar can be heat sealed, which would be better than tape for H2 retention.

Any idea how I'd do that?  Tape seems pretty good at keeping the hydrogen in, but it isn't completely negligible in terms of weight.

[von Corax]

Long gloves and possibly some sort of facemask definitely reccomended!

Quite. If you're dealing with any quantity of sodium hydroxide, I would strongly suggest wearing a full-face splash shield (the sort that looks like a fireman's visor, without the helmet) as well as monogoggle-style safety goggles (the sort that look like a scuba mask.)

Have you considered using a demi john for your Hydrogen production? Fit fermentation lock until you are confident the majority ofair has been forced from the demi john, then connect your hose. You'll get a bigger volume of hydrogen from one container, but also be able to leave a buggish expansion gap to prevent the caustic soda from spurting out.

Very good idea. Bear in mind that caustic soda can etch (and even dissolve) glass, so you might want to use a plastic carboy/demijohn. (The plastic ones have gotta be useful for something...)

As would be some form of neutralising agent, (say around PH5.5?) in industrial quantities to pour over any splashes.

Also a garden hose.

[Prof Eumides Blakehurst]

Just to throw a mild spanner in the hydrogen works, but have you tried using acid production ? The standard method for 'small' quantity production of hydrogen in the labs here is to use granulated zinc and 5M hydrochloric acid. You get quite a bit of gas from a small set-up, but I haven't used the NaOH set-up you're using so I can't tell you if it's more or less efficient.

Yes, it gets hot, but it doesn't get as hot your set-up seems to get. The acid is available from hardware stores and is used for cleaning bricks when new houses are being built. Neutralised by lime or calcite/limestone when you've finished.

It's about as caustic as the NaOH you're using so the safety process you have in place should be fine. You just need a source of zinc - model hobbyists ?

[OldProfessorBear]

Back in the day, we used to use muriatic acid (hardware-store grade HCl) and a bunch of nails to make hydrogen.

Now, for all I can recall (this was ~ 50 years ago!), the nails may have been galvanized, so it may have been the zinc that was doing the job rather than the iron.

I don't know where you find bits of zinc these days, but at one time it was sold in rolled strips for binding the edges of floor linoleum and the like.

For neutralization purposes, I would keep a quantity of household ammonia, as well as some sodium bicarbonate, handy. HCl is not quite as nasty as sulfuric (doesn't absorb moisture from whatever it touches, in effect burning it). But still to be handled warily. I think, too, it's somewhat less hazardous than lye.

I would guess the hydrogen yield would be higher, BTW.

[helios]

Really titchy little molecules, yer average Hydrogen.

You might have to face the sad fact that the answer is to use that boring, inert old Helium. (Damn!! No explosions!!)

Dr. Q.

Hmm, I though that helium was a smaller molecule than hydrogen, seeing as helium floats around as He, but hydrogen is H2, giving it twice the size?

No, surprisingly. Helium is double the mass, and (I would assume, from Physics last year) double the size of Hydrogen. The fact that the Hydrogen is in a pair merely results in a similar sized package.

[Adan Shepard]

"Any idea how I'd do that?  Tape seems pretty good at keeping the hydrogen in, but it isn't completely negligible in terms of weight."

A couple ideas for heat sealing your envelope;

1st off if you can find a Seal A Meal unit for plastic bag food storage these work real well for plastic seam welding, these can be found at thrift stores real cheap or maybe on ebay. I'd say this is the best way to go and opens up a whole world possibilities to you about welding seams on plastic sheeting

2nd a soldering gun this takes practice to get the right a mount of heat but not so much that you burn holes in your envelope, some soldering guns have heat controls that might help with getting a good weld

3rd I have heard of using a steam iron like whats used for pressing cloths to weld seams but it is pretty unwieldy

4th sometimes shipping places send packages that are heat sealed to keep them water and air tight they might be able to weld it together for you, it's pretty much the same idea of the Seal A Meal just on a larger scale

Hope this helps, Adan

[Professor Fzz]

Quite. If you're dealing with any quantity of sodium hydroxide, I would strongly suggest wearing a full-face splash shield (the sort that looks like a fireman's visor, without the helmet) as well as monogoggle-style safety goggles (the sort that look like a scuba mask.)

I have indeed been using monogoggle-style safety goggles.  Definitely don't want sodium hydroxide in the eyes.  On your skin, it isn't pleasant (that soapy feeling as it slowly starts dissolving your skin), but so long as you notice it and wash it off fairly quickly, it isn't really a problem (at least not at the concentrations I'm using - about 50g in 400ml of water; about the same concentration you'd use for drain cleaning).   The main problem is if you get it on your skin (or in your clothes) and don't notice, as it doesn't hurt.  That's what you have to watch out for.  I certainly wouldn't use it without a good water supply nearby though.

Very good idea. Bear in mind that caustic soda can etch (and even dissolve) glass, so you might want to use a plastic carboy/demijohn. (The plastic ones have gotta be useful for something...)

The wine bottle I've been using is showing no significant signs of etching after several hours of hydrogen production, so this doesn't seem to be a problem (unless you wanted to use it for food afterwards).  Plastic would be dangerous though - one of the main problems is keeping the reaction cool enough.  Without the bucket of water, there's a good chance you could boil the sodium hydroxide solution, and that would be bad.  A plastic container would run the risk of melting, which would be equally bad.

[alfa1]

Every Easter my family get together...

Since time is an issue here, I suggest you at least find out now where to get (at the last minute) some Helium.   As I understand it, its readily available at shops that cater for parties, for the obvious blowing up of balloons.
Nothing wrong with a backup plan.

I did some kite photography some years back.    Had a cheap film camera with an automatic winder, and used a very ordinary model airplane remote control setup to fire the shutter.   Stripped it down to save weight, had the servo pull a string attached to the shutter mechanism.   
Two issue encountered...
1. Shutter speed.   It was fixed at a slow 1/60th of a second on this camera.  Having the camera attached to the kite made too much vibration, and all shots were blurred.    Having the camera suspended below the kite on a string worked much better.

2. Pointing.   Hanging on a string, the camera would turn, even with a fin attached, and so made most shots have some rotational blur.    I suspect with more time I could have tweaked it for optimised performance, but I got the fun I wanted and never tried.

Yours will need testing as well.    You dont have a lot of time.   You dont want to be testing out the camera, attachment mechanism, remote control, all on the easter weekend. 

[jringling]

To prevent the NaOH bubbles from entering the envelope, might I suggest adding another bottle into the setup. Set up another bottle with two tubes , one longish (to the bottom of the bottle) to let the gas in and another shortish (close to the top of the bottle) to let the gas out. Any foam or liquid would enter the second bottle and stay at the bottom while the gas exited from the short tube into the balloon... This would be similar to sediment bowl or a vacuum setup to prevent liquid from entering the pump.

Very crude drawing:

Spoiler (click to show/hide)

[OldProfessorBear]

Somewhere in here

http://camerahacks.10.forumer.com/index.php

you will find some posts from people who did some aerial photography using hacked "one-time-use" digital cameras.

Perhaps you'll be able to adapt some of their techniques ...

[Professor Fzz]

To prevent the NaOH bubbles from entering the envelope, might I suggest adding another bottle into the setup.

That's a good idea - I'll try that in my next setup.  I wonder if it might be even better to bubble the hydrogen through water?  That would cool the gas, and (hopefully) reduce the water vapour carried with it.  If the balloon is taped, water inside isn't a great idea.

[akumabito]

Make yourself a condener? http://en.wikipedia.org/wiki/Condenser_(laboratory)

Should be fairly easy to et one up and it would take care of most of the water while also cooling your hydrogen.

[jringling]

Make yourself a condener?

Should be fairly easy to et one up and it would take care of most of the water while also cooling your hydrogen.

fix maybe...
http://en.wikipedia.org/wiki/Condenser

[akumabito]

yeah, dunno what happened, the link got fubar'd, but it's all good now.

[Professor Fzz]

Just to throw a mild spanner in the hydrogen works, but have you tried using acid production ? The standard method for 'small' quantity production of hydrogen in the labs here is to use granulated zinc and 5M hydrochloric acid. You get quite a bit of gas from a small set-up, but I haven't used the NaOH set-up you're using so I can't tell you if it's more or less efficient.

It may be worth trying hydrochloric acid and zinc, but I'm slightly concerned about what to do with the zinc chloride produced.  It's fairly toxic, so makes for a more difficult waste disposal problem.

[jringling]

Just to throw a mild spanner in the hydrogen works, but have you tried using acid production ? The standard method for 'small' quantity production of hydrogen in the labs here is to use granulated zinc and 5M hydrochloric acid. You get quite a bit of gas from a small set-up, but I haven't used the NaOH set-up you're using so I can't tell you if it's more or less efficient.

It may be worth trying hydrochloric acid and zinc, but I'm slightly concerned about what to do with the zinc chloride produced.  It's fairly toxic, so makes for a more difficult waste disposal problem.

Isn't zinc chloride a component of dry cell batteries? Could you collect the residue and leave it at the local recycling center that accepts spent batteries?

In school, the mad scientist science teacher used to produce H₂ with an acid (muriatic maybe?) and calcium carbonate? or was it some other calcium compound.... I don't remember, but it was fairly "safe" as he would have a beaker going with a trash bag overtop to collect it. When it was full, we would go outside to light it...

Actually, the first time he did it, it was at his desk behind a shield... it caught his deck on fire and when he ran to the other science rooms to assure the other teachers we were fine, a couple of us ran to the front to fan the flames... fun times in 6th grade science...

[Professor Fzz]

I don't know where you find bits of zinc these days, but at one time it was sold in rolled strips for binding the edges of floor linoleum and the like.

From hunting around online, it appears that in the US you could always use one-cent coins.  Just give them a good scraping with the dremel to remove some of the copper plating first.  No such luck with British coins.

[jringling]

A few weeks ago I bought a sacrifical zinc anode at a boat store. "Pure" zinc... it worked well for the electroplating I was doing...

[OldProfessorBear]

I don't know where you find bits of zinc these days, but at one time it was sold in rolled strips for binding the edges of floor linoleum and the like.

From hunting around online, it appears that in the US you could always use one-cent coins.  Just give them a good scraping with the dremel to remove some of the copper plating first.  No such luck with British coins.

*facepalm*

Silly me.

Actually, the copper is so thin that it probably isn't worth scraping off. And copper probably works for this anyway.

(Dang. Where are all my chemistry books?)

[Prof Eumides Blakehurst]

Copper will also work giving a residue of copper chloride (the last time I used that stuff was for a copper ion laser).

The zinc chloride residue shouldn't be any nastier than tinning flux for soldering, so there should be waste disposal for it readily available. Or you could do a lot of soldering! 

[Professor Fzz]

I think we're getting there on the hydrogen production side of things! 

I'm still using sodium hydroxide, but here's the new setup.  The demijohn contains about 1 litre of water and about 150g of sodium hydroxide crystals.  That leaves a lot of expansion room, but even so a lot of spray and water vapour is carried up the tube.  The smaller stainless steel sugar pot contains about 4cm of water.  This is to cool the gas.  It works really well - it condensed a couple of cm of liquid by the time the aluminium was used up.  In fact this got so hot it needed cooling itself, as it was ceasing to do its job and some significant condensation was starting to occur in the second tube.  Adding the bowl of cooling water solved this problem.

By the way, the label on the demijohn says "Do not use for temperatures greater than 40C".  Hmm.  Never did hold much store by these warning labels 

I only inflated a bin bag balloon tonight, but there was more than enough hydrogen produced in one batch to fill several bags.  Balloon #2 isn't as pretty as Balloon #1, but it serves to prove the concept.  It can lift about 10g payload.  Lifting a 200g camera and a long piece of kite line still looks challenging, but we're a lot closer than we were. 
Thank you to everyone for all the suggestions!