P glycol and BZT

[Maine-iac]

Is there any reason to choose poly over propy? I can order propylene glycol at the pharmacy for about $10/pint. Does it have a strong smell or other potentially unpleasant qualities I should know about before I order it?

Propylene glycol is sold as "green" or "environmentally friendly" antifreeze in some autoparts stores. I got a gallon for under $12. It works fine in any developer I've tried it with.

Larry

 

[Gerald Koch]

The problem with using antifreeze in developers is that it contains other chemicals such as rust inhibitors. One never knows what effect they will have. Even though one brand or batch may not cause problems is no guarantee that the next one will not. I always recommend buying pure propylene glycol. The Chemistry Store sells it for $17.38 plus shipping. Yes it is more expensive than the antifreeze but worth the peace of mind.

 

[Ryuji]

A common cheap corrosion inhibitor is sodium nitrate or something similar. These compounds are readily soluble in water but not so in glycols.

Sure, componds like benzotriazole and its derivatives are also used as anticorrosion agents, and I'm not excluding that possibility...

 

[Maine-iac]

The problem with using antifreeze in developers is that it contains other chemicals such as rust inhibitors. One never knows what effect they will have. Even though one brand or batch may not cause problems is no guarantee that the next one will not. I always recommend buying pure propylene glycol. The Chemistry Store sells it for $17.38 plus shipping. Yes it is more expensive than the antifreeze but worth the peace of mind.

You're probably right. Maybe I just got lucky with the particular brand, but I've experienced no adverse effects from the gallon of antifreeze I got.

Larry