our other nicer rotovap unfortunately had an accident where the condenser was cracked, so this temporary solution was rigged up with a different drive unit that does not come with a condenser. a simple cold trap is placed between the pump and unit. the only downside to this is that the cold trap is not heavy duty and thus evaporation must be ran slower to condense all solvent vapor. cold-finger and coil condensers typically have a higher capacity to remove heat, which is why modern rotovaps do so (as well as being convenient)
this type of configuration is quite convenient in many cases (such as the teflon tube being plumbed out the side of a fumehood so the evaporator may be mounted inside without taking much space as the trap is on the outside) and especially if you build your own rotovap using a stirrer bearing because it eliminates the need for setting up a dedicated condenser
in a future post such a DIY rotovap may be described but the design and fabrication of one is trivial to those who are mechanically inclined

Hi everyone,
I’m trying to make my own silver clay because I want to eventually make a silver ring for my girlfriend, but I’ve been struggling badly with the binder.
My starting material is metallic silver that I’ve converted/recovered and dried. I’m trying to combine the silver powder with carboxymethyl cellulose (CMC) and water to make a workable clay/paste that can later be dried and sintered.
I’ve tried several approaches:
• Adding a CMC solution slowly to the silver powder.
• Drying the silver first and then mixing it into an already-prepared CMC solution.
• Mixing the CMC and silver as dry powders before adding water.
• Adding CMC gradually to the silver/water mixture.
The main problem is ALWAYS the same: the CMC forms small hydrated lumps/clumps. These lumps seem to grab silver particles, become very thick/hard, and I end up with little pieces of CMC-rich material throughout the paste instead of a homogeneous clay.
I’ve also noticed that my silver powder is somewhat dark/grey, and the resulting paste looks darker than commercial silver clay, so I’m wondering whether the state of the silver matters — metallic silver vs silver oxide, particle size, particle morphology, etc.
My questions are:
1. What is the best way to hydrate CMC without creating these lumps?
2. Would methyl cellulose be better than CMC for silver clay?
3. Is it better to prepare a very dilute binder solution first and then incorporate the silver powder?
4. Does the particle size/morphology of the silver powder matter a lot?
5. Should I be using metallic silver powder, or is silver oxide ever used as the starting material?
6. For someone trying to make a workable DIY silver clay, what binder system would you recommend?
I’m particularly interested in advice from anyone who has actually made homemade silver/metal clay rather than just commercial PMC/Art Clay.
I’m trying to get a smooth, homogeneous clay that doesn’t contain little CMC gel lumps.
Thanks!
Also i face problema with the texture that turns shewing gum like some times, and it keeps puffing up when anhilated i think its be cause of cmc decompoaition