Jeanetta Posted March 9, 2022 Report Share Posted March 9, 2022 Hi! I’ve encountered a newish problem, although it’s happened only a few times so more am wondering more out of curiosity than panic. Shortly after throwing, the odd mug will get this vertical cracking phenomenon. I used to think it was that I was throwing too thin in that spot, however this particular mug has really even decent thickness throughout so I don’t suspect this is the problem here. My next guess is maybe It’s related to my using reclaimed clay. I toss all scraps/duds in a bucket with water and then overtime dry and wedge it out, so maybe could it be that I didn’t integrate everything well and this is causing the problem? Interested in thoughts and ideas, I love and value the wisdom of this community. With thanks, Jenna Link to comment Share on other sites More sharing options...
Jeanetta Posted March 9, 2022 Author Report Share Posted March 9, 2022 Ps : sorry for the sideways photo….the cracks really are vertical!! Link to comment Share on other sites More sharing options...
dhPotter Posted March 9, 2022 Report Share Posted March 9, 2022 This is from @glazenerd maybe this will help... Additive for Reclaim Clay How do you determine the level of ball clay the recipe had to begin with? The Slip Test When you throw the original clay: how much slip comes up and on your hands? Coats just the inside of your palms and oozes through your fingers over time.... lower levels. Coats your palms, and oozes; have to clean a few time while throwing.... mid levels Oozes quickly and constantly cleaning off hands....... high levels. Most of the reclaimed scraps is from trimming; which has been stripped of the fines; which includes ball clay, silica, and feldspar. That would alter the properties of recycled clay: because it is the ball clay primarily that holds moisture in a clay body. The fix: blend 80% ball clay (Om4 or FHC), 10% silica, and 10% feldspar. Add 1 cup (dry) per gallon of slurry. The testing comes when you throw it after it has been reclaimed: how much slip comes up when you throw? Adjust to suit your taste. Normally within 30 days there is a marked difference, which improves over the next 90-120 days. After about 6-8 months, the process begins to reverse because the clay is actually starting to loose water: dehydration. Link to comment Share on other sites More sharing options...
Min Posted March 9, 2022 Report Share Posted March 9, 2022 If you save the throwing water (and splashpan sludge) with all the lovely fines that sink to the bottom of it add that back into your reclaim bucket., this is often enough to prevent recycled clay being short. Link to comment Share on other sites More sharing options...
Hulk Posted March 9, 2022 Report Share Posted March 9, 2022 ...I'm seeing a quarter cup of Nerd's fix added to two or three gallons of slurry makes a noticeable difference - a bit more plastic, slightly more drying time. Link to comment Share on other sites More sharing options...
JohnnyK Posted March 9, 2022 Report Share Posted March 9, 2022 When throwing, I use 2 buckets...one for throwing water which, after a couple of sessions, I set aside to let the clay fines settle to the bottom of the bucket. Then I siphon off the water and pour the remains into my reclaim bucket. The second bucket next to my wheel I use to scrape my hands of excess slip and also collect any "live" trimmings while I'm throwing. I have a lid for that bucket (which is about a gallon size) and cover it when not in use. When it gets near full, I squish the clay around to blend it somewhat and then scoop it out onto a couple of plaster bats to dry a little before wedging and storing in plastic bags for the next throwing session, or for use in my extruder... Link to comment Share on other sites More sharing options...
Jeanetta Posted March 11, 2022 Author Report Share Posted March 11, 2022 Thanks everyone! I’ll try these tricks n’ tips! Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.