Groucho Posted February 9, 2016 Report Share Posted February 9, 2016 Here is something I can't figure out and need help. This could be very simple I hope. Sometimes when I inject a mold I get what I would describe as a thumb print on the sides of some worms. It's a indention like you would press your thumb on the side of a too worm worm. It can be only on one or maybe two or none at all in the pour. They are there when I first open the mold up. Is it a heat problem? or what. Any Ideas. Thanks. Quote Link to comment Share on other sites More sharing options...
rcbv Posted February 9, 2016 Report Share Posted February 9, 2016 There is some good input in this thread: http://www.tackleunderground.com/community/topic/29917-denting-problem/?hl=dents#entry237896 Quote Link to comment Share on other sites More sharing options...
fishon-son Posted February 9, 2016 Report Share Posted February 9, 2016 MY DENTS WERE FIXED BY ADDED 1 INCH EXTENSION TO MY INJECTION PORT..OFF A BEARS STICK MOLD WORKS GET..I THINK SOMEONE MAKES THEM..I MADE MY OWN.... 1 Quote Link to comment Share on other sites More sharing options...
Groucho Posted February 9, 2016 Author Report Share Posted February 9, 2016 Has anyone had any trouble with BTS molds in the 5 and 4" molds Quote Link to comment Share on other sites More sharing options...
FATFLATTIE Posted February 9, 2016 Report Share Posted February 9, 2016 I have the Bass Tackle 4" and it has a serious problem with the denting of the baits. Quote Link to comment Share on other sites More sharing options...
gone2long Posted February 10, 2016 Report Share Posted February 10, 2016 Bear sells the sprue extenders but try topping off first thats ussally all it takes, a warm mold helps too. Quote Link to comment Share on other sites More sharing options...
hpssports Posted February 10, 2016 Report Share Posted February 10, 2016 You may be running your plastic too hot. The 702 craw mold has the same problem with denting in the claws. Injecting between 300 & 320 sovles the problem in the 702. It may work with your stick mold. 2 Quote Link to comment Share on other sites More sharing options...
MonteSS Posted February 10, 2016 Report Share Posted February 10, 2016 As said get a sprue extender and you will be fine. Quote Link to comment Share on other sites More sharing options...
archery1 Posted February 10, 2016 Report Share Posted February 10, 2016 sprue extenders. just go to hardware store and get copper tubing to fit inside closed mold. Make sure u always top off molds as the plastic will suck down when cooling, Not sure of the sizes of copper tubing u need ..maybe some one will no better but the sprue extenders i made came from 2 different size copper tubing stacked onto each other The first tube goes into mold and other goes tightly around it. I soldered them together Quote Link to comment Share on other sites More sharing options...
Frank Posted February 10, 2016 Report Share Posted February 10, 2016 Yes it is a temp thing. Lower the temp to 300-310 and you will be fine. If you are using a microwave you will get temperature spikes so making bigger batches will not spike it so much. The plastic will look much thicker and almost like it won't shoot but it's fine. Not sure why a sprue extender would help with denting as this is from the gate freezing before it cools. Hollow baits are from a sprue running dry. 4 Quote Link to comment Share on other sites More sharing options...
camrynekai Posted February 10, 2016 Report Share Posted February 10, 2016 Most of my molds shoot best between 302 - 307 degrees. My stick baits I shoot at 298-300. A couple of degrees is a big variable when injecting....a couple of degrees too hot and you get dents....a couple of degrees too cold and your fine appendages wont fill. Another note.....all plastic brands have different characteristics, so you will need to hone in on what temp works best for your plastic brand/blend and the molds you are using. 2 Quote Link to comment Share on other sites More sharing options...
Groucho Posted February 10, 2016 Author Report Share Posted February 10, 2016 I didn't know you could inject at that low of temp. Quote Link to comment Share on other sites More sharing options...
mark poulson Posted February 10, 2016 Report Share Posted February 10, 2016 If your microwaved plastic comes out too hot, just stir it until it cools to the temp. you want, and then suck it up into your injector and shoot. Quote Link to comment Share on other sites More sharing options...
Frank Posted February 10, 2016 Report Share Posted February 10, 2016 I didn't know you could inject at that low of temp. That the reason I mentioned that the plastic looks thicker. At times I have shot when it is just above the jell state and it works(280ish). 1 Quote Link to comment Share on other sites More sharing options...
Groucho Posted February 10, 2016 Author Report Share Posted February 10, 2016 so i'll try shooting at lower temps before i go screwing with a file on the gates. Thanks alot Quote Link to comment Share on other sites More sharing options...
majic man Posted February 10, 2016 Report Share Posted February 10, 2016 A properly gated mold will shoot at 350 dent free. Quote Link to comment Share on other sites More sharing options...
camrynekai Posted February 10, 2016 Report Share Posted February 10, 2016 A properly gated mold will shoot at 350 dent free. I cant agree with that statement. Out of the hundreds of molds and 40 different styles of baits I have....the only one that can even come close to giving out a dent free bait at 330deg is my hula skirt mold. 350 is insanely hot for pouring or injecting....couldn't imagine the color fade and browning that would occur at them temps. Quote Link to comment Share on other sites More sharing options...
majic man Posted February 10, 2016 Report Share Posted February 10, 2016 I cant agree with that statement. Out of the hundreds of molds and 40 different styles of baits I have....the only one that can even come close to giving out a dent free bait at 330deg is my hula skirt mold. 350 is insanely hot for pouring or injecting....couldn't imagine the color fade and browning that would occur at them temps. LOL. Now your going to make me shoot a video!! Quote Link to comment Share on other sites More sharing options...
camrynekai Posted February 10, 2016 Report Share Posted February 10, 2016 LOL. Now your going to make me shoot a video!! Very much looking forward to it. Always curious as to how some achieve success with their methods. Quote Link to comment Share on other sites More sharing options...
DaveMc1 Posted February 10, 2016 Report Share Posted February 10, 2016 (edited) I cant agree with that statement. Out of the hundreds of molds and 40 different styles of baits I have....the only one that can even come close to giving out a dent free bait at 330deg is my hula skirt mold. 350 is insanely hot for pouring or injecting....couldn't imagine the color fade and browning that would occur at them temps. 16 cavity stick molds, I routinely shoot with the temp controllers hovering around 170C (338F) with the actual plastic around 330. Never have I had a denting problem, maybe, and this is a huge maybe, I get 5-10 out of 1000 stick baits with a dent. Further, ZERO colour issues, including white. Only fading I've ever seen is with specific dyes, all other dyes and pigments I have no issues with. It seems that as soon as I went with my own mold (I specified the layout, runner and gate design as well as the cavity design) I had no issues with dents. For the OP. The reason they dent as Frank noted is the gate is too small for the bait. Plastic expands as it is heated and then contracts as it cools. To prevent the baits from getting dents as they cool you need a fresh supply of hot plastic to feed the cavity as it cools. If the gate isn't large enough it will freeze off before the bait is cool enough and the only thing it can do is shrink and pull from the side causing the dents. One fix is to shoot your plastic cooler as it will actually contract less. Another is to hold pressure after filling the cavity. If the gates are that magic size they will sufficiently feed the cavity as it cools. Also remember, you still need to bring your plastic up to proper temperature of 350 when you initially cook it, then back the temperature off to your shooting temp. Edited February 10, 2016 by DaveMc1 2 Quote Link to comment Share on other sites More sharing options...
gone2long Posted February 10, 2016 Report Share Posted February 10, 2016 so i'll try shooting at lower temps before i go screwing with a file on the gates. Thanks alot Be advised this is after you hit the golden stage when the plastic has gone through its conversion so you need to bring it up before you can shoot it lower. 1 Quote Link to comment Share on other sites More sharing options...
camrynekai Posted February 10, 2016 Report Share Posted February 10, 2016 16 cavity stick molds, I routinely shoot with the temp controllers hovering around 170C (338F) with the actual plastic around 330. Never have I had a denting problem, maybe, and this is a huge maybe, I get 5-10 out of 1000 stick baits with a dent. Further, ZERO colour issues, including white. Only fading I've ever seen is with specific dyes, all other dyes and pigments I have no issues with. It seems that as soon as I went with my own mold (I specified the layout, runner and gate design as well as the cavity design) I had no issues with dents. For the OP. The reason they dent as Frank noted is the gate is too small for the bait. Plastic expands as it is heated and then contracts as it cools. To prevent the baits from getting dents as they cool you need a fresh supply of hot plastic to feed the cavity as it cools. If the gate isn't large enough it will freeze off before the bait is cool enough and the only thing it can do is shrink and pull from the side causing the dents. One fix is to shoot your plastic cooler as it will actually contract less. Another is to hold pressure after filling the cavity. If the gates are that magic size they will sufficiently feed the cavity as it cools. Also remember, you still need to bring your plastic up to proper temperature of 350 when you initially cook it, then back the temperature off to your shooting temp. 330 and 350 are worlds apart when it comes to expansion and breakdown of plastisol. a 350 pouring/shooting temp is considered unusable in my shop and will always be considered just that. 1 Quote Link to comment Share on other sites More sharing options...
DaveMc1 Posted February 10, 2016 Report Share Posted February 10, 2016 330 and 350 are worlds apart when it comes to expansion and breakdown of plastisol. a 350 pouring/shooting temp is considered unusable in my shop and will always be considered just that. It's far less of a difference than 300 and 330. Ive seen virtually no difference in the final product between a bait shot at 330 and one shot at 350. No matter how you shoot the plastic it does have to come to 350 in order to completely change over and set properly. Quote Link to comment Share on other sites More sharing options...
camrynekai Posted February 10, 2016 Report Share Posted February 10, 2016 (edited) No matter how you shoot the plastic it does have to come to 350 in order to completely change over and set properly. That is basic 101. I was just talking about shooting/pouring temps. Need to remember that 99 percent of the members on this site are purchasing shopping cart items from suppliers.....the other 1 percent are purchasing custom made molds that don't have any inherent issues with runners and gates.. The shopping cart style molds are great for the most part...and with a bit of direction can make some AWESOME!!! baits....without drilling, filing or any other mods. For example, the BTS series of Craw trailers (BEST EVER) have thin claws which I defy anyone to get the claws to come out dentless regardless of what you do with the gates and runners.....with those particular appendages its all about the Shooting temp. try shooting them at 330+ and let me know how you make out Edited February 10, 2016 by camrynekai 1 Quote Link to comment Share on other sites More sharing options...
majic man Posted February 10, 2016 Report Share Posted February 10, 2016 Oh. I thought we were talking stick baits here, apeendages on the end of thin claws is a different ball game. As you claw is becoming your gate for the raised edge. 2 Quote Link to comment Share on other sites More sharing options...
