Vodkaman Posted December 30, 2007 Report Share Posted December 30, 2007 This is a project that has been in my book of 'things to do one day', for quite a while. 3D legs from a 2 piece mould. I brought it forward because the subject was touched on a few days ago in a thread called, 'IKA like pours'. I have posted it separately because it has much wider applications than just copying IKA's. Quote Link to comment Share on other sites More sharing options...
KcDano Posted December 30, 2007 Report Share Posted December 30, 2007 Primo deluxe job! Dave. Quote Link to comment Share on other sites More sharing options...
Spike-A-Pike Posted December 31, 2007 Report Share Posted December 31, 2007 Vman. That almost looks something my mother-in-law developes when she trying to make homemade pasta... her cooking always leaves me feeling like something from aliens is living in my lower GI tract... Sorry, that was a tad graphic Quote Link to comment Share on other sites More sharing options...
Vodkaman Posted January 1, 2008 Author Report Share Posted January 1, 2008 How to mould 3D legs with a 2 part mould This thread is in response to the thread linked below. Hopefully, it will open up the possibilities for new designs, such as octopus, squid etc or even abstract designs that were not within the realms of feasibility before without expensive equipment. this is the lure posted by DelW in the ‘IKA like pours’ thread. http://www.tackleunderground.com/forum/showthread.php?t=11261 this shows the legs emerging from the body radially. The only way to mould these in a conventional mould would be parallel to each other in the plane of the mould joint face. This would be aesthetically unacceptable. Materials ¾ inch dia dowel. Packet of sate sticks Body master RTV RTV is used as the mould manufacture includes under cuts. However, the design can be adapted to carry the undercuts on the slug. This is more work intensive, so for this experiment I chose to cast the legs into the mould. To create the leg master, the dowel and satay sticks are cut to the length of leg required. Glue the satay sticks around the outside of the dowel. I managed 14 legs with a smaller diameter, but I did lose some definition between the legs, resulting in some trimming. The lesson is, don’t put the legs too close together, I would say minimum 1/8th, 3/16th would be better. The plan was to grind flats onto the satay sticks, but this was found to be very tedious and subsequently not necessary. I used instant super glue for this operation. The leg master must be sealed, epoxy or resin will do the job. A good coating of Pam oil or something similar will be required to stop the RTV from binding. Set the master up against the leg pattern and create your 2 part mould in the usual way. Personally, I use a split master technique, but each to his own. The slug insert is another length of the same dowel, cut a few millimeters shorter than the leg master and seal. The plain slug cylinder is inserted into the mould. Make sure a gap is left at the top for the plastic to reach the legs. The mould is now ready for the pour. Whether you can get that many legs to pour using the regular gravity method, I don’t know. I did not try, I went straight in with the vacu-venting method. This is my layout ready for pouring the RTV. If PoP is to be used as the mould material, then the undercut of the satay sticks has to be eliminated. This is done by casting the plain dowel cylinder into the mould and cutting the legs into the slug. This method would be the solution should the mould be made in aluminum. However, the long thin legs would not lend themselves readily to the heat transfer characteristics of the aluminum and an injection or vacuum method would probably have to be employed. Del would be the man to advise on this possibility. Below is a photo of the resulting lure. Scruffy? Yes, that is down to my lowly position on the learning curve, but proof enough that the technique works. By choosing more accurate and stable materials, such as a turned master, plastic rod or tube to replace the satay sticks, decent RTV, attention to detail and precise workmanship, it will be possible to produce a quality casting with zero flash. This test pour also demonstrates further the effectiveness of the vacu-venting process. http://www.tackleunderground.com/forum/showthread.php?t=11056&page=2&highlight=vacu-venting I would appreciate some feedback on this thread and the vacu-venting thread, questions, reservations, like it, hate it etc. Quote Link to comment Share on other sites More sharing options...
jmik26 Posted January 1, 2008 Report Share Posted January 1, 2008 I would like to see it in the water. I applaud you on your creativity and willingness to try new things. We tried something similar with aluminum vacuum mold and it didn't work at all, wonder if the RTV makes the difference? Keep up the good work ... Quote Link to comment Share on other sites More sharing options...
Vodkaman Posted January 2, 2008 Author Report Share Posted January 2, 2008 You can see from the legs, that some are longer than others, so the limit is being approached. RTV is a very good insulator and maybe the plastic gets to flow a tad further because of that fact. Pre-heating the aluminum would help, but I'm sure you tried that. Another feature of my mould is the size of the venting. This greatly increases the force on the plastic. The third important point is the sealing of the mould. If you block the sprue with your finger, you should not be able to draw any air through the suction pipe. Any leakage would reduce the drawing force on the plastic. Try a coating of pam oil on the contact surfaces. Personally, anything but the very simplest of pours, will be vacu-vented in my pouring studio. Quote Link to comment Share on other sites More sharing options...
Spike-A-Pike Posted January 2, 2008 Report Share Posted January 2, 2008 Dave. Do I even want to guess the vacuum source being used for your testing? Remember what happened the last time you were playing with acetone. You got off lucky with just a headache and blurred vision. The RTV we used to seal aircraft panels with had at least 2 or 3 hazard warnings on it. It’s only Jan 1, 2008… I’d like to ring in 2009 in about a year with you. Quote Link to comment Share on other sites More sharing options...
Vodkaman Posted January 2, 2008 Author Report Share Posted January 2, 2008 With the mould sealed correctly, the volume of the drawn air is the volume of the lure being cast. For the stuff that I have cast so far, this amounts to about 30cc. Weigh out an ounce of water in cup to get a feel for the amount of air involved. It is not possible to breath it in. It is more like blowing a kiss at your wrinkly grandma. Cured RTV is inert and cannot be any more of a problem than keeping it in the same room all day. The whole issue can be avoided with the use of a vacuum pump. I am estimating that a fish tank pump would be strong enough to do the job. It is more important to make the suction pipe a long one and made of clear plastic. So far, I have never managed to draw the plastic out of the mould, but why take the chance. Another safeguard for both the above hazards, would be to introduce a DRY reservoir half way up the pipe. This could be a hard plastic bottle, with one pipe in and a separate pipe out. Thanks for your concern Bruce and I am looking for a pump For testing, also I am only doing a few test pours for TU, once the pour works, I move on to the next project, which is probably back to hardbait lips. Quote Link to comment Share on other sites More sharing options...
Spike-A-Pike Posted January 2, 2008 Report Share Posted January 2, 2008 Vman. I think a 50cc Manual Taper Tip Syringe would work very nicely until you get a pump. It would allow you to push or pull air out. http://jensenglobal.com/cgi-bin/jgd1/JG50MT-5.html Quote Link to comment Share on other sites More sharing options...
Vodkaman Posted January 2, 2008 Author Report Share Posted January 2, 2008 Yes, that would work. The important thing is that it has to be operated with one hand. A cake icing syringe would do it. Totally hands free would be an added bonus though. Stability is one of the most important aspects of the process. The mould should be fixed in such a way that it cannot accidently be pulled over by the pipe. Pushing is out of the question, as has been demonstrated on more than one recent thread. This would involve the hot plastic in the syringe. The beauty of the vac-venting system is that the hot plastic is poured in the normal way, except into an oversized sprue or funnel. It then disappears inside the mould and is not seen again until the mould is opened. Quote Link to comment Share on other sites More sharing options...
KcDano Posted January 2, 2008 Report Share Posted January 2, 2008 How about a stream of air direct over the top of vacuum hole. Quote Link to comment Share on other sites More sharing options...
Vodkaman Posted January 2, 2008 Author Report Share Posted January 2, 2008 Yes, that would introduce a vacuum by using venturi theory. Not sure it would be strong enough though. Everything has to be tested, this is all new. I would like to get more information from weighinalimit as he has worked on this problem with success. Can you show any pics of your setup, moulds and pours? Quote Link to comment Share on other sites More sharing options...
hazmail Posted January 2, 2008 Report Share Posted January 2, 2008 VM- I just came across this thread, great work and so simple, which are always the best solutions. I love the way you thought out that mold and left the 'core' in place. pete Quote Link to comment Share on other sites More sharing options...
Vodkaman Posted May 16, 2015 Author Report Share Posted May 16, 2015 Deleted images added. Quote Link to comment Share on other sites More sharing options...
CNC Molds N Stuff Posted May 17, 2015 Report Share Posted May 17, 2015 This is a mandrel type mold. Isn't it really a variation of what some guys are doing with tube molds now? Quote Link to comment Share on other sites More sharing options...
Vodkaman Posted May 18, 2015 Author Report Share Posted May 18, 2015 Bob - indeed it is, in fact that is how I molded it, by making a wooden mandrel with the legs cut into it. Again, like the hairy worm and the spider, they were tests to try to find the limit of the pouring capabilities of the method. This being a complete pour first time, past the test, but did not find the limit of the technique. All these test models, the masters are made of a child's modelling clay or plasticine. Never intended to be fished. Dave Quote Link to comment Share on other sites More sharing options...
