robbor Posted October 4, 2004 Report Share Posted October 4, 2004 What type of silicone do you guys recomend for jig heads molds (ie lead mold)??? thanks, Rob Quote Link to comment Share on other sites More sharing options...
Art Brush Posted October 4, 2004 Report Share Posted October 4, 2004 Hi Robbor, welcome to the forums Smooth-on makes a product called "Smooth-Sil" I've used the 940 with good results. Smooth-on claims the product is good for "low melt alloys, such as tin and pewter". http://www.smooth-on.com/silicones.asp#ssil Another company called Miniture molds has a product called Quick-Sil. They calim "It will last for 1,000's of uses and can with stand metal temperatures up to 900?F without being damaged". http://www.miniaturemolds.com/mainframe.htm The photos show a mold I built with the Smooth-sil 940 with plastic backings. You could just as easily use 2 pieces of wood and clamp the mold shut in a vice. Tight lines, Shawn Quote Link to comment Share on other sites More sharing options...
robbor Posted October 4, 2004 Author Report Share Posted October 4, 2004 Thanks for the info shawn, 900 deg sounds like the stuff. Nice pics also. I am planning on making aluminum molds then just milling out where the head goes and then filling with silicone, but want something that will last and the stuff you mentioned should work. Quote Link to comment Share on other sites More sharing options...
Richoc Posted October 5, 2004 Report Share Posted October 5, 2004 You will not have the life to the mold that milling it out of aluminum will. If you are looking to do a quick copy/ proto type ......... You can get a mold made to do that with from hilts. Quote Link to comment Share on other sites More sharing options...
redg8r Posted October 5, 2004 Report Share Posted October 5, 2004 Dang Shawn, Thats a near flawless mold. Nice use of resin for backing the silicone too. Quantum Silicones also makes a high temp RTV called Q-Sil. I thought it was the same as the above mentioned stuff but what I have looks like terra cota in color & pretty rigid (high shore). quantumsilicones.com good luck Quote Link to comment Share on other sites More sharing options...
robbor Posted October 6, 2004 Author Report Share Posted October 6, 2004 Turner Jones a while back and he makes molds from silicone that last a long time basically forever(i'm not talking production though) I may have to give him a hollar again. Production spincasting uses silicone for mass producing molds??? Ther has gotta be a way with all this modern stuff. I just am not shure yet if i am going to be able to mill stuff in close allignment. I just alligned and pinned 3 blocks of alum this monring so I can do a little playing. I should very easily be able to do full alum molds for drop shot weights, tube baits, But I am really interested in making buzzbait molds and a few molds to copy the crappie jigheads I like, and then I want to play around with ice plastics and ice jigs. I am also going to try to make a fixture for soldering ice blades up like 10 at a time. But with all this I am trying to make it work with a drill press and a x-y table,I know its not going to be easy, so I figured a partial alum mold using a minimum amount of silicone to beat the allignment issues. I have only have plaster molds so far and I had a board member make me a beautiful crappie jig body mold out of all alum and may contact him again. i just have been wanting to make a few more molds so I can start at pouring plastic and lead all at once. Quote Link to comment Share on other sites More sharing options...
redg8r Posted October 6, 2004 Report Share Posted October 6, 2004 Hey Robbor, I heard you talking about milling alum with a xy table. If youre setup to mill some aluminum (basic blocks) Id recomment you research vulcanized molds. Vulcanized molds are rubber molds used in production molding. The issues with vulcanized molds are 1 they need a strong metal frame to produce 2 they need heat to cure #2 is an easy one, Ive heard of suppliers making a variety of molding rubber that you can cure in a household oven #1 is the kicker, buying the aluminum frames to contain the rubber while it cures are quite expensive, but it looks as if your gonna make some anyway, so maybe a vulcanized rubber mold will suit you well. I do know it will hold up under production runs & its the main component in spincasting low temp metals. It works kinda like a sandwich, you lay one layer of the rubber in the frame, add your master & gates, vents, etc. then lay the top layer of rubber in the frame. Press them together tight (using metal clamps) & bake until cured. pretty simple concept really & makes a tough mold. Quote Link to comment Share on other sites More sharing options...
robbor Posted October 7, 2004 Author Report Share Posted October 7, 2004 You are giving me much info. The idea about silicone mold blocks sounds good, I will look into it. I saw som of the stuff mentioned in spincasting and am shure now thats what they do, it would work fine for me. I have also heard of boiling silicone to vulanize it, but am not shure??? More reasearch. I just finished pinning 2 sets of 3/4" alum for my buzzbait molsa and some small ones 1.5" x 2" for crappie and ice jigs. So as soomn as I get some mill bits I will be in business. Quote Link to comment Share on other sites More sharing options...
Richoc Posted October 7, 2004 Report Share Posted October 7, 2004 Pressure and heat are used to make the molds for spincasting.(vulcanized) We use both rubbers and silicones. They do not last for ever. Shrink from the masters to production mold is the hardest thing to deal with. There is a new 0% shrink out there but as yet I have not seen it in use. It is black and a liquid, that cures at room temp. Just to good sounding to be true. One bad thing when using the (blue) silicones for producition is the the jigs will not take water basied paint right from the mold. They need to be cleaned to get the paint to stick. Quote Link to comment Share on other sites More sharing options...
Art Brush Posted October 7, 2004 Report Share Posted October 7, 2004 Thanks for the kind words guys Great post Rich. Do you have any links to the products you mentioned? There is a new 0% shrink out there but as yet I have not seen it in use. It is black and a liquid, that cures at room temp. Just to good sounding to be true. Any photos you can post of what the molds look like is also helpful. I've only done a few test casts with the smooth-sil 940 and there are a few things to note. The rubber contracts when it's filled with hot lead. I think the 900 deg stuff might work better. The plastic backing is necesary as it makes the mold clampable and also keeps the mold block in form. Do you guys know if the aluminum casing is a standard thickness to fit in all rotocast machines? Tight lines, Shawn Quote Link to comment Share on other sites More sharing options...
Richoc Posted October 7, 2004 Report Share Posted October 7, 2004 The thickness of the molds varys with the companys machine, but most will take a 1"thru 4" thick mold. And 9" thru 18" diameter. There is no metal frame needed to cast. It is only needed to make the molds. Here is link to one of the supply places for the spincasting ind. http://www.contenti.com/ Mold compounds will lead you through the various compounds. There are a few others but this site shows the most to the viewer. Will not openly post a pic. of a mold. ( mold maker would hunt me down) If you thinking of going this way, lots to talk about. PM/email me. Lots to share before a jump is made. Really like that buzzhead. Spinning them would make a least 12 at a time, in like 30 seconds. Quote Link to comment Share on other sites More sharing options...
dlaery Posted October 7, 2004 Report Share Posted October 7, 2004 Here is a pic of the bottom half of a gray silicone mold with a 2-1/2 oz shad head. I make my own molds with a vulcanizer. I'm looking for a way to make a mold of a single jig so I can make 20 to 30 jigs to use to make a production mold. I don't like to use the vulcanized molds for my models, because they shrink and then when I make another mold for production, they shrink again. I called miniaturemolds in Art Bush's message about the Quick-Sil. The guy I talked to said it wouldn't shrink. : It had a clamping frame to press the silicone around the part. That sounded interesting. I'm still trying to get the Durhans water putty to work. Quote Link to comment Share on other sites More sharing options...
Richoc Posted October 8, 2004 Report Share Posted October 8, 2004 Making the masters is always the trick. My guy uses a carbon allow material to machine the masters molds out of. Cuts like butter, but costs like gold. And has the knowledge to make the master the right proportions to have it come out correct in the final mold. Each generation of molds, not made from the master, makes the part smaller. Holding the masters is very important, treat them like family jewels. One tip is to pour the masters out of tin. It doesn't shrink when it cools, and has a lower melting temp than the lead. Masters come out great and long lasting. Quote Link to comment Share on other sites More sharing options...
Art Brush Posted October 8, 2004 Report Share Posted October 8, 2004 Awesome information guys. The shop I worked in would make a disk mold similar to the one in Dleary's pic. Not the same application though. I bring this up for guys who don't have cnc mills. For hubcaps a company would send a blue print of 1/5th of a hubcap. A clay model was made from the blueprint. A mold was then made from the 1/5th model. The mold then produced 5 identical parts that were assembled into a disk. The hubcap models were wet sanded then sent to a shop for chrome plating and brush metal accents. This also is how the alignment for the center placement of the chrystler star is achieved. So in applying that knowledge to lure making a disk mold can be fashioned the same way. I've considered building one small enough to fit in a 5 gallon pail with a motor mounted in the bottom with a speed controll knob. Taking all precautions and being built for slower rpm castings for soft plastic lures and squirley tails. Also crystal clear diving bills to fit premoulded lip notches. NOT LEAD lol. Rich I will definatley get in touch when I get a few things caught up. Dleary please post your results if you order the Quick-sil and how well it performs. Tight lines, Shawn Quote Link to comment Share on other sites More sharing options...
