wchilton

You can use GOOGLE to seach this forum and it will accept 3-letter searches! To search for "PVC", you just type in the word (or words) followed by "site:..." where the ...is the url of the forum. Here's an example, put everything except the quotes in the google entry field "PVC site:http://www.tackleunderground.com/community/forum/13-hard-baits/"

I haven't used Play-Doh, but I have used modeling clay. It's also called "plastilina" no 1 and is an oil/parafin based clay that does not harden. It leaves a sort of matte surface on the silicone where it touches. One nice thing is you can melt the modeling clay in the oven (around 200 deg F) and let it cool to produce a flat surface.

I tried using marbles for keys in a POP mold and they caused it to crack. Better to just impress the key into the first half and let the second half fill the impression. That way your keys shrink or expand with the mold material.

I'd also suggest working with one mold at a time. Plastic that is too hot will shrink a lot and that's what causes "dents". Plastic that is too cool, mold that is too cool, or injecting too slow can result in incomplete filling of the mold because the plastic solidifies before it can fill the small appendages. You may need slightly different temps or technique for your craw mold than for your frog mold...so that's why I'd say work with one at a time. You can heat a mold on a hot plate or skillet to help it fill better. If I do that and get the mold too hot I get a lot of flashing so think in terms of pretty warm but not too hot to touch for warming up a mold. A few rounds of injection will also warm up a mold. I also pre-heat the injector so that plastic doesn't cool too fast inside it. Last thing is your method of heating the plastic. If it's not well stirred when you pull it into the injector then no telling what temperature you're actually working with. My first time injecting I heated the plastic in a large pyrex bowl/cup on top of a skillet and it was pretty tricky maintaining temperature with that new (to me) set-up. Good Luck

One that I like a lot is hard urethane casting resin. The one I've used is from aeromarineproducts.com. It's a transparent tan color when first mixed and cures to an off-white opaque color in about 5 or ten minutes. It can be polished, but I usually just get it smooth/nonpolished and then dip in clear floorwax for a shiny surface. Keep it sealed up well, it can form bubbles if it absorbs too much water from the air.

If your master wasn't shiny, the silicone mold won't be shiny. I usually coat masters for my silicone molds with clear floor wax (several coats). Best finish for me is accomplished by dipping, draining off excess, and then can dry with a hair drier to speed things up. Be careful if your master is pourous (wood) as a hot hair drier will make the floor wax bubble and you have to start over. Has worked really well for me on baked clay.

Never tried it, but I'd expect if you put tungsten powder in the mold and pour lead in, the lead will cool before it can fully penetrate the powder and you wouldn't get a whole/solid casting. The reason for inconsistent density is going to be the tungsten settling out of the liquid lead (to the bottom). I suppose you could try pouring from a ladle so you can scoop mix off the bottom of the melting pot. It might not flow very well, though. If I were doing this, I'd consider some sort of epoxy or casting resin and cast the pieces in a silicone mold. I'd look for a resin that is very thin/low viscosity. I'd also use a mix of two or more different tungsten powder grits. With multiple size particles you get a bit better packing density. Single size "sphere packing" maxes out at about 70%.

Tall thin beakers can be had on eBay. Search for "Bomex Beaker" or "tall beaker pyrex". Anything made of pyrex or borosilicate glass is ok to heat up, just put it on some kind of hot pad (wook is ok) rather than a cold counter to minimize heat shock. A 250 ml bomex beaker is about 4.5 inches tall and a bit over 1 cup in volume.

Bluing is actually a type of iron oxide (rust) and does not by itself protect against corrosion. What it does do, is provide a thin layer of oxide that holds oil in place on the metal and the oil provides the rust protection. Some oils are a LOT better than others at protecting against rust. One that comes to mind is Bo-Shield. Unfortunately, the cold blue formulas are not a true bluing, but are a chemically-induced blue that is not as durable (or as good helping to prevent rust) as a "hot blue". For protection against salts, I'd go with a coating of some kind, possibly a thin layer of epoxy on a very clean hook? Either that or Seal Coat use for lure top coat (urethane, water-based) should work, but you'd want to test for compatibilty with soft plastics.

I ran across these last week. Office Depot as a whole series of boxes they call "Really Useful Boxes". They come in a lot of different sizes from a few inches up to file-box size. For use in making molds, these have a nice flat bottom and are externally re-enforced to hold their shape (all square inside with no indents or out-dents). Even the bottom of these has sort of a honeycomb re-enforcement on the outside to keep the bottom flat. Price is not bad, depending on size.

I bought the orange, minimum shrinkage stuff. Also, some dark blue that was even harder, but I never worked with the dark blue. Recommend getting flakes or pellets rather than in block form. The blocks came in a disposable "tin" that was stuck to the wax. You'd have to use a hand saw to cut up the blocks for melting smaller amounts, a knife won't do it very easily and electric saw melts the wax and then it sticks to the blade.

I've played with it, but not a lot since most of my molds are silicone. Here's what I know. First, found an on-line source at "http://www.ottofrei.com". The wax I bought (years ago) is casting wax and it is really hard. Almost like plastic. That's actually a good thing if you want to carve it since it maintains it's shape. Many of these waxes are formulated to minimize shrinkage during cooling. They also have a fairly distinct melting point, so if you try to heat a model to get the finish to smooth out it's real easy to melt the whole thing. Also, when they do melt, they are very liquid so they run/drip. For these hard waxes, you're probably going to have to heat up your hard mold to get the models out and the models will not be re-usable. I've also had some success using regular hot-melt glue for models. This was for silicone molds, the stuff might stick to POP if you heat it enough to melt it. However, hot melt glue gets soft and flexible before it melts. You could probably use hot melt glue with POP if you sprayed it with silicone release agent before pouring the POP and then don't heat the mold enough to melt the hot melt but just enough to make it soft for removal. Forget about ever trying to carve hot-melt...it's too gooey. I haven't tried either of these to make a POP mold. Would recommend a quick test with single model to work the kinks out of the process before trying a multi-cavity mold.

I'm pretty sure you're having a mixing issue. Measuring by syringe makes getting the proportions right fairly easy. You might try mixing a bigger batch, even if you're not going to use it all. Also, make sure and scrape all sides of the mixing container to involve every bit of the epoxy in the mixing. I generally don't worry about having a little bit left over because then I can "test" the left-overs for full cure at any time and it doesn't mess with the lure finish. If some part of the mixing cup cures and another part does not, you didn't mix it well enough. I use disposable mixing cups (1 or 2 oz) from a restaraunt supply store...no clean-up and left-over epoxy stays in the cup to cure so it can be inspected to check for problems. If mixing is perfect, all the left-over epoxy will cure and can be pulled out of the cup in one piece.

The best method of mixing I've found is to use a rotary tool that can be run SLOW. If you go too fast the epoxy will fling off the mixing rod. By "slow" I mean slow for a rotary tool, maybe in the 100 to 500 rpm range. I use a Foredom tool with a foot pedal so can control the speed. The handpiece has a small chuck (like a drill chuck) and I just chuck up a 2-3 inch piece of bamboo meat skewer. I tilt the mixing cup and then stir around through the epoxy with the spinning rod. As with mixing by hand, I "scrape" the sides of the cup with the tool and make sure to involve every bit of the epoxy. Since I've started using this method, never had a problem with curing. The two epoxy components have different densities, that's why the volume ratio is different than the weight ratio. It's like the difference between oil and water. The oil is less dense so it floats on top of the water, except for the epoxy, the two liquids will mix/disolve each other so they don't separate.

I don't know for sure about the oil. I've read that mineral oil (baby oil, etc.) is not compatible with soft plastic and will harden it, but vegetable oil is probably ok. The garlic scent will not scare the fish away and may even attract them. Instead of garlic powder, I would crush a few fresh garlic cloves and let them soak in your oil for a week or more to "flavor" the oil with actual oils from the garlic. Also possible to use coffee as a scent/flavor in an oil but it may darken the oil a bit.

I've made several silicone molds and you can get away with a lot. The silicone is so stretchy you can remove rigid originals that have some undercut and removing soft plastics is even easier because they stretch. I made one little "shad" shaped paddle tail where the paddle is at least twice the width at the bottom as at the top. Baits don't fall out of the mold but a little pull/stretch and the tail pops right out. The thing I would advise being careful about is getting good adhesion of the top of your "master" to the bottom of the mold form. I use a sort of rubbery two-sided tape on the whole top surface. This prevents silicone from getting under the master and gives you a nice, clean edge on the mold. I've also gone around a master with a thin sealant of some type (thin epoxy or casting resin) and that gives a really clean edge to your mold.

My guess is it's a hot-stamped foil. The pattern comes from a die that has those scale patterns on it. Try a google search on "hot stamping" or an ebay search for "hot stamp foil" and you'll learn/see what's available in that category. Also interesting is an ebay search on "holographic adhesive" which will show you some adhesive-backed holographic films but not necessarily scale patterns.

Many of the suppliers/advertisers on this site for soft plastic lure making sell quality glitters that can take heat up to 350 degrees or better and are oil/solvent compatible so they will retain color in solvents. They're available in different colors, flake sizes, and shapes. I've also used glitter from paintwithpearl.com which is more expensive, but they have some very fine (small) flake if you're looking for something like that.

The difference between a dye and a pigment is partly just a difference in particle size. Dye particles are very small, so they don't diffuse light (ie. transparent colors) while pigment particles are about 1000 times larger. The smaller dye particles can "flow" easier with liquids in the plastic so they may bleed. Also, being a smaller particle, it has greater tendency to react chemically and that is why some will fade (ie. loose color). The thing you want to make sure of is that whatever colorant you use is compatible with oils and can withstand the temperatures that are reached. Oil based or solvent based colorants should be ok, just be careful (as you are) with solvents that smell strong or could be flamable. People here have used melted crayons, oil-based art paints, etc.

RTV is a little more dense than water. I usually just figure it in water weight/volume and add 10%. It's easiest to figure in cm because 1 cubic cm of water is 1 gram. For the trout worms you'll want about 1/4 inch between baits and another 1/4 inch around the outside edge (minimum) so figure 3.5 inch length for 3 inch worm and 2 inch width to accomodate 4 or 5 worms. That's 7 cubic inches x 2.54 x 2.54 to convert to 45 sq cm. Figure 1 cm thick (makes it easy) and your mold will need 45 cc + another 10% so 50 grams of RTV. A pound is 454 grams so you'd get 9 molds of that size out of the pound of RTV. That's not a very large mold, and they can require a lot more very quickly. I've made a few single-cavity fluke-type molds (5-inch or so) and I'm usually starting with 150 grams of RTV for one those.

Syringe is a good idea. They are typically marked in ml. Approx 20 drops in on ml so you would need a 15 ml syringe for 300 drops. You'll want to "calibrate" whatever you use (drop size will depend on the container you make the drops from) so you'll have to do some drop counting into the syringe at first to get your measurements right. Use the smallest syringe that does the job. A 10ml syringe would work in your case to measure 10, then another 5 to give you 15 ml total. There are some available from hobby shops for measuring glue, etc. You don't need them to be sterile so no need to pay for that. Here's one on-line source http://www.mcmaster.com/#syringes/=gckdqj . I've bought them on eBay.

Dipping can leave a more glossy finish, but I think most of what you are seeing is because of the glossy finish on the molds being used. It's also sometimes possible to improve the gloss by using very light application of oil to the mold before pouring or injecting.

I've been using the Norpro silicone measuring cups for microwave heating for a while now. Out of the box, they still have a few problems. They are a bit TOO flexible so you have to fill them no more than 1/4 to 1/3 full. That's not a problem for me because I only pour in small batches anyway. Another problem is they do get pretty hot, especially at the bottom where the plastisol is. I started playing with ideas for insulating these cups. Here's a pic that shows the test subjects. On the left is the first triel in which I used some high temperature insulation (expensive). While good for much higher temps, it's really overkill and would need to be much thicker to be ideal. The cup was still "floppy" so I added the large bead of silicone at the top in an attempt to make it easier to grip. That's just ordinary silicone caulk from the hardware store, good to about 400 deg and has worked fine in the microwave. For the middle cup I found this fiberglass "paper" that's about 1/8 inch thick. The black thread is wrapped around to hold it in place since I didn't want to make it a permanent addition this time. The insulation is much better, two layers on the bottom half and also two layers on the bottom of the cup were used. This cup barely gets warm during use, but the way it's constructed left it still too floppy and the tension on the thread actually starts to close/deform the cup when it gets heated up. The right-hand picture is my latest and probably final solution. For this one I first made an "insert" to put inside the cup while applying the insulation. I just used cardboard and then some paper to get a fit. First I glued (with silicone) two layers of the same 1/8 inch insulation to the bottom. Then used strips about 1 inch wide, starting from the bottom and overlapping each previous strip. This give a 2-thickness (of insulation) everywhere and creates those ridges to make the cup easier to grip. The strips were held in place with rubber bands until the silicone cured. After it was al done, I added "drip protection" using some old RTV mold making silicone. While using that second cup I poured from the wrong side a couple of times and if the insulation isn't covered with silicone liquid plastisol soaks into it and makes a mess. This last cup is pretty solid, not at all floppy, and is still flexible. It also keeps the plastisol HOT much longer than the bare Norpro cup. I've been able to pour, allow the mold to cool, remove baits, and pour a second time without re-heating, and this is with a very small batch of about 1/4 cup. For those of you using pyrex cups on a griddle, you could probably use this same insulation material, just leave the bottom of the cup exposed so heat comes through. I still have some glass beakers that I plan to insulate for microwave use as well. I got the fiberglass insulation material from mcmaster carr. They call it "fiberglass paper", but it's 1/8 inch thick material. They have other fiberglass paper that's not this thick so check carefully. This stuff comes in a 10 foot roll for around $20.

I drop them into cold water right out of the mold just to get them to cool quickly and set the shape. That way, I don't have to lay them out perfectly flat/straight. I only leave them in the water for about 10 min or so. I've left them overnight and they turn milky (like yours) but I think they cleared up after a while drying out. After water cooling, I remove and lay them out flat, but I think shape is pretty much set by then.

I would definitely use a mold release of some kind. Don't know what to recommend but probably PAM or one of the other standby's mentioned on the forum would be fine. One thing you'll have to think about is that the casting resins are VERY THIN until they set. The one I've used is almost water-thin. You may have a problem with resin running out the edges of a 2-part mold and you also will need to make sure and put release on the mold faces (not just the cavity) to prevent resin from gluing the faces together. Maybe just a little bit of modeling clay around the edges of the cavity would help control that "leakage". You could also try a grease or petroleum jelly as a sort of sealant. You could also try to pour a plastisol (melted soft plastic) "gasket" around the cavity and maybe have less of a mess...just a few thoughts. If you can get the urethane casting resin to work I think you'll like how it behaves once it has hardened. It's easy to shape by sanding, very much like wood, in fact, but with no grain to have to deal with. The stuff I use is a bit oily when I first demold so I've wondered if it has some sort of release agent "built in". When you first remove from the mold and it is a bit flexible it can be cut with a sharp pen knife so that's also an opportune time to do some trimming, might save you some work. Good luck and let us know how it works out. Warren