Pebbles instead of glass beads?

Merlin · 2006-10-20T11:09:51+00:00

Hallo ... diese Glasperlen, um die Luft aus der Entwicklerflasche zu verdrängen, hat Impex ja nicht im Angebot. Gibts dafür einen Grund? (außer das die - de...

Merlin

Hello ... Impex doesn’t actually stock those glass beads for displacing the air from the developer bottle. Is there a reason for that? (Apart from the fact that they’re – I reckon – quite expensive?) My idea the other day was to use pebbles as a displacement agent, provided they’re really clean. Is there anything wrong with that? They shouldn’t soak up the liquid, should they... The reason I don’t want to use Protectan spray is simply because you can’t tell whether you’ve sprayed too much or too little... Kind regards, Martin

Renate

Hello, Glass beads are available in the children’s section of any department store. We used to call them ‘knickers’. ‘Marbles’ is perhaps a more familiar term. They aren’t expensive, but they are certainly more expensive than pebbles. You can buy 25 kg of pebbles at a DIY store for €4. You can also find glass beads in craft shops. The problem with pebbles is their surface. It is often porous and therefore difficult to clean. Metal ions could also leach into the solution, and it is impossible to predict the effects of this. But that doesn’t necessarily have to be a problem. If in doubt, give it a go. Best regards, Renate

RalphRogge

The reason I don’t want to use Protectan spray is simply because you can’t tell whether you’ve sprayed too much or too little...

Hi Martin, you really can’t go far wrong with that... when using the original Protectan, 50 ml of air is displaced per second of spraying. So with one bottle, you can displace a huge amount of air. And even if you put just a tiny bit too little into the developer bottle, the surface of the solution you’re trying to protect is still protected, because the inert gas is heavier than air... And lots of lab users actually use glass beads :D just because Protectan is too expensive... have a look here: Alternatives to Protectan (Franz has gone on and on about it there).

Merlin

[...]You can find glass marbles in the children’s department of any department store. We used to call them ‘knickers’. ‘Marbles’ is perhaps a more familiar term.[...]

I can’t see the wood for the trees :D I’d (almost) have paid a fortune for a few measly marbles 8

DirkGeiger

[...]And even if you put just a tiny bit too little into the developer bottle, the surface of the solution you want to protect is still protected, because the inert gas is heavier than air[...]
That’s right, Protectan has the advantage over marbles in that a single ‘protective layer’ is sufficient. With marbles, I have to displace all the air.

Gases mix completely within a short time – a heavy gas does not form a protective film on the developer’s surface. The only advantage of a heavy protective gas is that it’s easier to flush the air out of the bottle when filling it (it ‘flows over the top’ – with a light inert gas, you’d have to hold the bottle upside down...). After a short time, there is a homogeneous gas mixture in the bottle that no longer separates on its own. Regards, Dirk

huehnerhose

Hi! I use Protectan too – if you spray it into the bottle and watch the neck, you can see air swirls rising from the top of the bottle... at first they look a bit 'fluffier', and when only gas is coming out, it just drifts lazily along the outside of the neck... Maybe I’m using a bit too much Protectan – but apart from the gas and the solution, there’s certainly nothing else in there (at least for now). Best regards Sebastian

HansDerHase

Hello ... Impex doesn’t stock those glass beads used to displace the air from the developer bottle. Is there a reason for that? (Apart from the fact that they’re – I reckon – quite expensive?)

I bought my glass beads at Ikea. They sell them there for decorative purposes; the tin of 1

MirkoHaesslich

I can only agree with Hans. I’ve been using my Ikea glass blocks for about two years now – without any problems. Best regards, Mirko