If they're modern medical x-rays, you can expect about 10 oz of silver, total, from your 100 pounds. If you run full sheets, you will find that the sheets will stick together, causing the stripping to go very, very slowly and complete stripping may be impossible. Since you're just playing around, I would suggest you first run the film, a sheet at a time, through an old decent paper shredder. This will make the stripping go much faster and you will be less frustrated.
Some of the newer film may be Dryview, which is developed by heat instead of by chemicals. It will strip slower and you may find that you'll have to raise the temperature of the solution considerably. Dryview is detected by briefly holding a lighter underneath a non-black clear area of the film - maybe on the border. If it is Dryview, the spot will turn black. This has to be done right. If you don't leave the flame long enough, nothing will happen. If too long, even regular film will burn and turn black, although the black color is different - it's more like a very dark brown. A second or two or three should be long enough. Some big film refiners won't buy Dryview because it's such a pain to process. Some Dryview requires special in-house secret solutions to get good stripping.
Stripping is complete when all of the black has been removed and you're left with just blue (usually) plastic.
Stripping time in a NaOH solution is a function of chemical strength and temperature. The weaker the NaOH, the higher the temperature required. A 3% solution requires about 200 F. A 10% solution, about 100 F to 120 F. With the 10% solution, you may get away with room temperature but it may go slow. Tumbling is always best in production. In your case, I would drill some holes in a small bucket, put some film in it, and slowly bob it up and down, every so often, in the solution that is contained in a larger bucket. After stripping, bob the film in a couple of buckets containing rinse water. Wear a full plastic face shield to keep drops of NaOH solution from flying into your eyes. After the silver/emulsion sludge has settled and been removed, the solution can be reused, over and over. If if slows down, you can add a little more NaOH. Never get NaOH under your fingernails or you'll be in pain for a long time. Don't ask me how I know this. Always wear good rubber gloves with no pin holes in them.
Everyone uses tap water. You could lose traces of silver as silver chloride, however. Some of the chlorine in the water can be eliminated by filling buckets with water and, with occasional stirring, letting the water stand for a few days before using it. As Harold said in a recent post, the value of the silver lost is less than the cost of distilled water.
Some of the newer film may be Dryview, which is developed by heat instead of by chemicals. It will strip slower and you may find that you'll have to raise the temperature of the solution considerably. Dryview is detected by briefly holding a lighter underneath a non-black clear area of the film - maybe on the border. If it is Dryview, the spot will turn black. This has to be done right. If you don't leave the flame long enough, nothing will happen. If too long, even regular film will burn and turn black, although the black color is different - it's more like a very dark brown. A second or two or three should be long enough. Some big film refiners won't buy Dryview because it's such a pain to process. Some Dryview requires special in-house secret solutions to get good stripping.
Stripping is complete when all of the black has been removed and you're left with just blue (usually) plastic.
Stripping time in a NaOH solution is a function of chemical strength and temperature. The weaker the NaOH, the higher the temperature required. A 3% solution requires about 200 F. A 10% solution, about 100 F to 120 F. With the 10% solution, you may get away with room temperature but it may go slow. Tumbling is always best in production. In your case, I would drill some holes in a small bucket, put some film in it, and slowly bob it up and down, every so often, in the solution that is contained in a larger bucket. After stripping, bob the film in a couple of buckets containing rinse water. Wear a full plastic face shield to keep drops of NaOH solution from flying into your eyes. After the silver/emulsion sludge has settled and been removed, the solution can be reused, over and over. If if slows down, you can add a little more NaOH. Never get NaOH under your fingernails or you'll be in pain for a long time. Don't ask me how I know this. Always wear good rubber gloves with no pin holes in them.
Everyone uses tap water. You could lose traces of silver as silver chloride, however. Some of the chlorine in the water can be eliminated by filling buckets with water and, with occasional stirring, letting the water stand for a few days before using it. As Harold said in a recent post, the value of the silver lost is less than the cost of distilled water.
