[Space] Inert gasses

Shannon Lee shannon at scatter.com
Fri Jan 15 15:21:39 PST 2010


So, just to re-iterate:  the part of the fill that's hard is that the thing
you're filling gets more and more buoyant as you fill it; it's not at all
hard to fill a balloon with a heavier-than-air gas, beacuse it just sits
there; but an 8-foot balloon full of helium is very awkward to handle.

The balloons you guys got look a lot easier to deal with than the ones we
were using, so you may not have the problems we did, but I don't think
you're going to see an accurate "practice fill" with the co2, unless maybe
you rig the balloon to a pully with 17# of bricks on the other end?

It seems to me that if you want a real practice fill you have to spend the
extra $50 or whatever and get helium.

--S

On Fri, Jan 15, 2010 at 3:04 PM, Christie Dudley <longobord at gmail.com>wrote:

> Great call there!  I went ahead and called Atlas and they not only had way
> better prices, are open Saturday and rent the regulator, they had some
> interesting things to say about which gas to use.
>
> Costs:  N2 $28.77, CO2 $23.90, rental $0.26/day, reg $40-$100 to buy,
> $8/month to rent.
>
> They also deliver for a charge of $20.
>
> The guy also explained to me why we don't want to use CO2.  It apparently
> changes volume considerably when it expands and contracts.  Also we'd have a
> hard time making it not come out as snow and freezing up the regulator and
> all sorts of other problems.  The guy there indicated that it'd definitely
> be far more trouble than the $5 we'd save on it.
>
> He also explained to me that the balloon filler would be much slower using
> nitrogen than helium.
>
> So I guess if we want to go this route (which sounds appealing) we'd not
> need to decide "rent or buy" before tomorrow.
>
>
> Christie
> _______
> Getting to the bottom of the hill is convenient. The view from the top of
> the hill is stunning. Where would you choose to live?
>
>
> On Fri, Jan 15, 2010 at 2:17 PM, someone wrote:
>
>> Atlas Welding in Berkeley will rent you a regulator along with your gas; I
>> dunno if they have co2, I know they have helium.
>>
>> --S
>>
>> On Fri, Jan 15, 2010 at 1:45 PM, Christie Dudley <longobord at gmail.com>wrote:
>>
>>> I talked to airgas and praxair.  They each like to have an account.  They
>>> also have different sized tanks for the nitrogen.
>>>
>>> Airgas was $41.03 for N2 and $43 for CO2.  Their tank rental was
>>> $0.85/day.
>>>
>>> Praxair was $40 for N2 and $35 for CO2.  Their tank rental was $0.12/day.
>>>
>>> We will also need to buy a regulator, as these guys don't rent them at
>>> all.  I inquired about the low end regulators:
>>> Airgas starts around $130-140
>>> Praxair starts around $90.
>>>
>>> Both places said you needed to set up an account with them because tank
>>> rental is done monthly.  Praxair was clearly the better deal so I asked them
>>> about terms.  They said that if we absolutely needed to have the stuff today
>>> then they could work it out with a $250 credit card deposit refundable when
>>> the tanks are returned.  Tanks would have to be returned Monday morning.
>>>
>>> So...
>>>
>>> 1) Is it worth the $35-$40 to go for the fill test this weekend?
>>> 2) We're ready to buy a regulator?  This would be what we would want to
>>> use for the helium as well, but not flammable gases like propane, as it
>>> won't be reverse threaded.
>>>
>>> Christie
>>>
>>> _______
>>> Getting to the bottom of the hill is convenient. The view from the top of
>>> the hill is stunning. Where would you choose to live?
>>>
>>> _______________________________________________
>>> Space mailing list
>>> Space at lists.noisebridge.net
>>> https://www.noisebridge.net/mailman/listinfo/space
>>>
>>>
>>
>>
>> --
>> Shannon Lee
>> (503) 539-3700
>>
>> "Any sufficiently analyzed magic is indistinguishable from science."
>>
>
>


-- 
Shannon Lee
(503) 539-3700

"Any sufficiently analyzed magic is indistinguishable from science."
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