Rondinax/Sputnik Developing Tank

Hi

I have just bought a developing tank which is almost identical to the Rondinax, it's a Sputnik, the only difference being the Sputnik has no thermometer. The problem is the locking knob on the side of the tank which releases the winding knob is stuck fast and cannot be turned. I don't know whether this is how this earlier model was designed or it has just become rusted, has anyone any ideas how to release the knob? Being made of Bakelite (I think) don't know whether WD 40 would be safe to use.

Any help would be appreciated.

If you're not sure about WD40 on the plastic / Bakelite of your tank, I would apply a few drops on an unimportant area, and leave for ~3 days, before cleaning off and examining for damage / absorption. I'm not sure that WD40 is a lubricant; I think the "WD" indicates a "water disperser" - check the web for better information.

Maybe a few drops of Liquid Wrench silicone spray (It's meant for plastic and vinyl) and gentle wiggles.

Submerge it in a tub of warm to very warm water water for about an hour and try to turn the knob.

Helios 1984 said:

Maybe a few drops of Liquid Wrench silicone spray (It's meant for plastic and vinyl) and gentle wiggles.

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I notice that the OP is in the UK - there are a number of similar silicone sprays available here under different names (check out Amazon or Ebay); most seem to be intended for use on plastics, and are even certified as safe for use with food manufacturing machines. I've used them on car plastics, etc. (and my wife has borrowed them for things like stuck zips). Take care if you're trying warm water, I once distorted an old plastic dev tank through trying to clean it in too hot water.

Hi

Thank you all for your advice, I have now removed the screw (very badly rusted) and a replacement is on its way. Just hoping the thread on the tank is still in order.

Stivi said:

Hi

Thank you all for your advice, I have now removed the screw (very badly rusted) and a replacement is on its way. Just hoping the thread on the tank is still in order.

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Let us know how it goes with the Sputnik.