clay lover Posted February 25, 2012 Report Share Posted February 25, 2012 I have a new 5" square Scott Creek exstruder, my first other than a hand held, and while I am very pleased with the process for making solid extrusions, I am having major trouble with the hollow ones, of all sizes, the larger they are, the worse the problem is. the sides of the extrusion collapse inward and the entire pieces curls upward. I'm having my partner pull the handle and I sit under the barrel and pull and stretch on the exiting clay, trying to get it straight. The sides of the extruded piece are uneven, one side is twice as thick as the other, no matter how straight I start the center die piece. The problem is the same with softer, harder and well wedged clay. None of that makes it better. Any suggestions will be appreciated. Link to comment Share on other sites More sharing options...
Chris Campbell Posted February 25, 2012 Report Share Posted February 25, 2012 I dont have this brand name but my design looks the same. The extrusions should come out with all sides even if the die has even sides. The beginning few inches tend to curl up but the weight should then make the extrusion fall straight. You should not have to pull it at all ... I only guide mine and take some of the weight. I would call the manufacturer and ask for some tech support. Link to comment Share on other sites More sharing options...
clay lover Posted February 25, 2012 Author Report Share Posted February 25, 2012 I dont have this brand name but my design looks the same. The extrusions should come out with all sides even if the die has even sides. The beginning few inches tend to curl up but the weight should then make the extrusion fall straight. You should not have to pull it at all ... I only guide mine and take some of the weight. I would call the manufacturer and ask for some tech support. I did and I was told it would get better with practice. Well and good, but I've practiced, hung upside down under it, cursed, put shims in the housing trying to hold it more stable and therefore unmovable. I start out with the center piece even in the housing and as soon as the clay comes through, it goes off center enough to cause a difference in the wall thickness, hence the crookedness to my way of understanding. After some close examination, I discovered the center post that holds the center die was not evenly set in the center die hanger,so I called them asking if they had a straighter one. I was sent one some better and the problem improved slightly. I'm still working and over handling little hollow pieces and truly fighting to get larger pieces to be usable. I bought the 5" to be able to make larger work, but the crookedness has an even greater effect on larger works. I'm hoping someone with lots of extruder time will have a suggestion. Link to comment Share on other sites More sharing options...
Mark C. Posted February 25, 2012 Report Share Posted February 25, 2012 I dont have this brand name but my design looks the same. The extrusions should come out with all sides even if the die has even sides. The beginning few inches tend to curl up but the weight should then make the extrusion fall straight. You should not have to pull it at all ... I only guide mine and take some of the weight. I would call the manufacturer and ask for some tech support. I did and I was told it would get better with practice. Well and good, but I've practiced, hung upside down under it, cursed, put shims in the housing trying to hold it more stable and therefore unmovable. I start out with the center piece even in the housing and as soon as the clay comes through, it goes off center enough to cause a difference in the wall thickness, hence the crookedness to my way of understanding. After some close examination, I discovered the center post that holds the center die was not evenly set in the center die hanger,so I called them asking if they had a straighter one. I was sent one some better and the problem improved slightly. I'm still working and over handling little hollow pieces and truly fighting to get larger pieces to be usable. I bought the 5" to be able to make larger work, but the crookedness has an even greater effect on larger works. I'm hoping someone with lots of extruder time will have a suggestion. I have an older scott creek 4 inch barrel-I have not made hollow stuff for years but did at one time. The center hole is a 3 legged tripod which you can spread the legs so that they are against the barrel and is in center and cannot move- when the cap is on. What ever the system that puts the center die in center( it will not be the same 3 legs for a square barrel) make sure it cannot shift as thats what causes the uneven wall thickness you are experiencing. I looked at this model and the hollow core shapes on the web but no where was the center holder shown-so I cannot see how it works. One tip is I like to spray with mist the setup as its starts. Mark Link to comment Share on other sites More sharing options...
minspargal Posted February 25, 2012 Report Share Posted February 25, 2012 Mark is right it sounds like your little tripod thing is too loose in the barrel or the die part you screw on is not centered. My guess if you put shims in, your tripod thing is too small for the barrel. Call the Scott people again. Link to comment Share on other sites More sharing options...
Guest The Unknown Craftsman Posted February 25, 2012 Report Share Posted February 25, 2012 Here are the die holders for the round and square barrel extruders, respectively: It appears that the tripod is used in the round barrel extruders, and not in the square barrel models, which claylover has. "I start out with the center piece even in the housing and as soon as the clay comes through, it goes off center enough to cause a difference in the wall thickness, hence the crookedness to my way of understanding." Do you mean the center piece of the die goes off center, or the clay? Is this happening consistently, is the thicker wall always on the same side of every extrusion, or does it change from extrusion to extrusion? Link to comment Share on other sites More sharing options...
Mark C. Posted February 25, 2012 Report Share Posted February 25, 2012 Here are the die holders for the round and square barrel extruders, respectively: It appears that the tripod is used in the round barrel extruders, and not in the square barrel models, which claylover has. "I start out with the center piece even in the housing and as soon as the clay comes through, it goes off center enough to cause a difference in the wall thickness, hence the crookedness to my way of understanding." Do you mean the center piece of the die goes off center, or the clay? Is this happening consistently, is the thicker wall always on the same side of every extrusion, or does it change from extrusion to extrusion? That square jig looks to have some play in it side to side-looks like a few shims will fix that.It needs to not be able to move any direction. On a whole other note that round barel jig look nothing like my scott creek one from the 70's Mark Link to comment Share on other sites More sharing options...
Guest The Unknown Craftsman Posted February 25, 2012 Report Share Posted February 25, 2012 "That square jig looks to have some play in it side to side-looks like a few shims will fix that.It needs to not be able to move any direction." That was my thinking at first, too, Mark, but then I noticed that the barrel and the bridge have holes in them, into which fit the quick release pins; so the bridge really should be centered and held firm. I say "should..." Link to comment Share on other sites More sharing options...
Mark C. Posted February 25, 2012 Report Share Posted February 25, 2012 If the jig is firm that the washer/bolt is loose or not centered-which all can be remedied-either re drill the washer and tighten the whole bolt and washer. Mark Link to comment Share on other sites More sharing options...
clay lover Posted February 25, 2012 Author Report Share Posted February 25, 2012 If the jig is firm that the washer/bolt is loose or not centered-which all can be remedied-either re drill the washer and tighten the whole bolt and washer. Mark There is MUCH play in the housing set up. Scott Creek rep says that is necessary for the assembly to be user friendly??? The washer is tight. I used shims yesterday both inside and outside the square collaring that holds it all in place, didn't make any improvement to outcomes. I can't figure out how the center die could shift when extruding, with all the play in the collar taken up with solid shims, but it did. I hang upside down look and measure spacing all around the center die, it looks centered, then I extrude clay and the walls are uneven and the extrusion twists and curls. I'm ready to give up and sell it. I am hoping someone on here with the same item, 5" Scot Creek, will come back with some advice. Yes, there are 4 cotter [pins spaced evenly around the 2 sides of the square collar, they fit through the center die support which is an H shaped heavy aluminum device. Link to comment Share on other sites More sharing options...
Mark C. Posted February 25, 2012 Report Share Posted February 25, 2012 Clay-L How about when you are starting to extrude you hod the extrusion in hand and guide it straight down . You may have to let it curl a little first-also one last item The plane where the washer sits is very important-if its to high up or to low as compared to the outer plate this will cause problems-should be about flush with outer dies. I think just a little fine tuning will fix this- Mark Link to comment Share on other sites More sharing options...
Guest The Unknown Craftsman Posted February 25, 2012 Report Share Posted February 25, 2012 I agree, Mark, a little tuning could easily solve this problem - but it appears that clay lover is only willing to accept help from a select group of people, so what is the point in asking questions, posting pictures, making suggestions? I, for one, am wasting my time trying to help... Oh well, you can lead a horse to water... Good luck solving your problem, I'm sure someone will come along that has the answer. Link to comment Share on other sites More sharing options...
clay lover Posted February 26, 2012 Author Report Share Posted February 26, 2012 Mark, thanks for that tip, I didn't think about the height match being critical, looked at everything else. there is a lot of right left play in the H shaped housing, that movement therefore moves the carriage bolt that the center die is fastened to. With the nuts tight, that is the only way the center die could move, the way it looks to me. BUT, having the center die too high or low would make some extra space that might allow other irregularities to happen. May....be.... I will try this tomorrow, with height matchup as exact as I can get it. That's the great thing about this forum, enough potters will figure out most things, here's hoping tomorrow produces even walls and straight extrusions. Link to comment Share on other sites More sharing options...
neilestrick Posted February 27, 2012 Report Share Posted February 27, 2012 If the center die is not centered, or the whole die shifts, the uneven wall thickness will cause the extrusion to come out curved (more resistance on one side). Any movement of any of the pieces will cause this problem. Everything must be tight! Link to comment Share on other sites More sharing options...
clay lover Posted February 28, 2012 Author Report Share Posted February 28, 2012 Neil, there is a lot of 'slop' in the system. Just designed that way. The 5" square has the pins on either side and there is much potentiial for left right movement. The Round 4' is better designed, IMHO. What I did last night was shim the sides of the barrel-collar so that the L-R shifting was stopped. I also discovered, that the holes for the cotter pins don't match up exactly from the collar through the barrel and then on through the die holder. I had been checking the die height un assembled and it was a perfect height match. When I put the system together, the center die holder was lifted slightly and then the die outer edge and inner didn't match. Small amount, but I listened to Mark's suggestion. So what had help a lot was to secure the center die slightly lower than even, so the height mis match was compensated for. Extrusions done with that adjustment and the shims were significantly more even. Tonight I will put it to the big test by running a set of the largest hollow dies. Much thanks to all suggestions, and Mark, your comments sent me back to examine the height question, that seemed correct, but in use was not. Happy Potting! Link to comment Share on other sites More sharing options...
msartqhs Posted February 28, 2012 Report Share Posted February 28, 2012 Hi: Extruders are a bit of a headache, aren't they! Great when they work...but--- SOMEWHERE, I remember reading, (when I first got ours), that if your channel holding the clay above the templates is not PRISTINE---no little bits of clay stuck anywhere....it will slow down the movement of the clay through the tube and cause it to curl in the opposite direction. I try to always clean it well, and spray alittle WD-40 inside to insure an easy slide. Good luck! Madeline Link to comment Share on other sites More sharing options...
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