gone2long Posted May 22, 2011 Report Share Posted May 22, 2011 (edited) I have an injector question but before I start this is not intended to bash any manufacturer in any way so please refrain from doing so. I have a 6 oz Basstackle injector and love it but I seem to have difficulty with an approximately 1 inch plastic plug at the end of the injection cycle i.e. I'll inject 4 multi cavity molds and when done I cannot purge anymore plastic from the injector, when I take the tip off there is a 1 inch pug of plastic left in the tube, I do cycle the injector before my 1st shot and it seems to occur from the beginning through to the end no matter how hot the molds and injector get. So I guess what I'm asking is is there something that I'm not doing to assist in this or is this pretty much the norm? Edited May 22, 2011 by mrbilky Quote Link to comment Share on other sites More sharing options...
squirrel3495 Posted May 22, 2011 Report Share Posted May 22, 2011 I have an injector question but before I start this is not intended to bash any manufacturer in any way so please refrain from doing so. I have a 6 oz Basstackle injector and love it but I seem to have difficulty with an approximately 1 inch plastic plug at the end of the injection cycle i.e. I'll inject 4 multi cavity molds and when done I cannot purge anymore plastic from the injector, when I take the tip off there is a 1 inch pug of plastic left in the tube, I do cycle the injector before my 1st shot and it seems to occur from the beginning through to the end no matter how hot the molds and injector get. So I guess what I'm asking is is there something that I'm not doing to assist in this or is this pretty much the norm? I purge in between every mold. It's a pain but it keeps everything hot. Hope it helps. Quote Link to comment Share on other sites More sharing options...
powerworm Posted May 22, 2011 Report Share Posted May 22, 2011 what you are seeing here is the plunger scrapping the plastic from the inside of the injector as it has cooled. unfortunately you have a pretty thick wall this is just a guess; as i have never seen 1 in person but thats my guess. i do have a lot of bears injectors and i only get about a 1/16-1/8th inch of a plug as you say even when it is hot and my tips dont come off after i figured out why they cam off!! ( it was operator error!!) Quote Link to comment Share on other sites More sharing options...
gone2long Posted May 22, 2011 Author Report Share Posted May 22, 2011 what you are seeing here is the plunger scrapping the plastic from the inside of the injector as it has cooled. unfortunately you have a pretty thick wall this is just a guess; as i have never seen 1 in person but thats my guess. i do have a lot of bears injectors and i only get about a 1/16-1/8th inch of a plug as you say even when it is hot and my tips dont come off after i figured out why they cam off!! ( it was operator error!!) PW I think your right that was what I was thinking that the inner wall would "set" at full draw and when I pressed the plunger down I was getting the bulk of this layer. Quote Link to comment Share on other sites More sharing options...
Frank Posted May 22, 2011 Report Share Posted May 22, 2011 I have an injector question but before I start this is not intended to bash any manufacturer in any way so please refrain from doing so. I have a 6 oz Basstackle injector and love it but I seem to have difficulty with an approximately 1 inch plastic plug at the end of the injection cycle i.e. I'll inject 4 multi cavity molds and when done I cannot purge anymore plastic from the injector, when I take the tip off there is a 1 inch pug of plastic left in the tube, I do cycle the injector before my 1st shot and it seems to occur from the beginning through to the end no matter how hot the molds and injector get. So I guess what I'm asking is is there something that I'm not doing to assist in this or is this pretty much the norm? It take a tremendous amout of heat to get a Basstackle injector to have a thin plug. That being said when you get it there it is real hot and very uncomfortable to use that way. I have put my Twinjector in prestos and never had to clean them until was done but that is when I am shooting gallons. Thin wall injectors heat faster but loose heat just as fast. I did it like you are for a long time and still do. If you inject faster you might get a smaller plug but then there maybe other issues with that. Frank Quote Link to comment Share on other sites More sharing options...
Vodkaman Posted May 23, 2011 Report Share Posted May 23, 2011 You have established that the problem is heat loss. Insulation is the next step. Two or three layers of heat shrink tubing, shrunk around the barrel would help. The HST I have will fit over a 1.5" diameter tube, but I am sure it is available in larger sizes. Dave Quote Link to comment Share on other sites More sharing options...
FuzzyGrub Posted May 23, 2011 Report Share Posted May 23, 2011 As an injector newbie, using a BT 3 oz version, I get about a 1/4" to 1/2" plug. I did try a couple of things to minimize, but the results were inconclusive, ie no detectable improvement. As a newbie, my first thought was that the air rushing into the back of the injector, along with the plunger rod was cooling the back of the plunger, causing the plug. I made an insulator spacer out of some phenolic circuit board and put between rod and plunger. As said, no noticeable improvement, but left it in place. The second thing I tried was a PVC sheath around the outside of the barrel. While the PVC is not a great thermal insulator, the thought was it would prevent direct exposure to the 60 degree air in my room. It would also be something that plastic would still peel off of vs a sock. The problem I had with that, was once the barrel heated up, the tight fitting pvc pipe started to slide on the barrel. Instead of finding a way to hold it on, I just removed it. I might try some other experiments with this, next season. Quote Link to comment Share on other sites More sharing options...
gone2long Posted May 23, 2011 Author Report Share Posted May 23, 2011 yeah I have several single port muti cavity molds so I collect alot of large sprues so it's not like I don't have to remelt anyway just thought I'd ask to see if I was missing a step. Carry on men. Quote Link to comment Share on other sites More sharing options...
