Matt Moreau

Making Swimbaits From Resin...help!

67 posts in this topic

Well try I did to get cork or saw dust in the bait to get it to float better and no luck. Alot of bubbles from these products. One thing I did try is to put the micro baloons in and let it settle. The air trapped when I mixed it in floated to the top ,then hit it with heat gun to pop the bubbles. Now when I mixed it together there were far fewer small bubbles. They came out almost perfect. After all that I found that my mold had some thing that I did not like in it so I fixed that. All in all I hope some one will learn from this. When casting from resin like this these problems are something that happens and are not foreign . Call any of the manufacturer and ask them they will know exactly what you are talking about when you tell them of these types of problems.

Next I will put them in the oven and try to cure them. I will do it with half to see if it is any better . Over the last few weeks I picked up a small hand held micsoscope to see what these bubbles might be. From this all I could see is Bubbles that are 95% under the surface. Filling these is hard because they want to push out what you try to put in from the pressure. But if you clean it with a stiff nylon brush the fill it seem to stay in and not push it out. Just a thought cause this is what we do at work to get rid of this problem. Good Castings All.

Has anyone tried vibrating the mould after you've poured? I don't pour baits, but we do that with concrete to make sure there are no voids.

A hand held vibrating sander held against the mould, or the batch of resin before you pour, for a few seconds might help to get air bubbles out.

Edited by mark poulson

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Has anyone tried vibrating the mould after you've poured? I don't pour baits, but we do that with concrete to make sure there are no voids.

A hand held vibrating sander held against the mould, or the batch of resin before you pour, for a few seconds might help to get air bubbles out.

I have tried pounding it on the counter and rotating it in a circle. The best thing ive done is put it in a pressure tank so it keeps it from expanding and compresses the air that is there. The amount of heat they produce is the real problem it makes the bubbles expand. I dont think concrete does that does it. Reducing the amount of bubbles from how you mix does reduce the amount in the end. Like I said before I have some samples that are perfect and I would like my castings to look like these.

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I think there are two origins of bubbles in a mold.

1. Bubbles generated during mixing of the resin. They will of course be somewhere in the mold.

2. Bubbles which emerge by air that is getting encolsed in the mold during pouring...for example in a fine detail where air gets trapped.

Another thing I was thinking about is if a blank with a high proportion of microsperes is able to produce bubbles under the clear coat either. Would be interesting how stable these microspheres are before they explode and degas under heat...

So vibrating the mold would prevent bubbles with origin 2.

The best way to prevent bubbles with origin 1 would be prepare the mixed resin under vacuum...this pulls the bubbles out of the mix. But this would presume a long curing time for the resin...otherwise it will cure under the vacuum...

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I think there are two origins of bubbles in a mold.

1. Bubbles generated during mixing of the resin. They will of course be somewhere in the mold.

2. Bubbles which emerge by air that is getting encolsed in the mold during pouring...for example in a fine detail where air gets trapped.

Another thing I was thinking about is if a blank with a high proportion of microsperes is able to produce bubbles under the clear coat either. Would be interesting how stable these microspheres are before they explode and degas under heat...

So vibrating the mold would prevent bubbles with origin 2.

The best way to prevent bubbles with origin 1 would be prepare the mixed resin under vacuum...this pulls the bubbles out of the mix. But this would presume a long curing time for the resin...otherwise it will cure under the vacuum...

I have done the vacumn thing and it makes them worst ( expanding not compressing). The bubbles are so fine that they will not burst unless you break the surface tension. As we were talking about before the mold is very important to mold in a way that the bubbles end up in a spot that is easy to fix or end up in a cavity that will not be a part that you will use.

Glad you joined this thread Luretrekker

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do any of you guys use that make two part molds use the clay that comes with the rtv? I have made a mold before and using this but it was with great difulculty. the problem i have with it it is around the fins gills and mouths. any advice? also how do you guys make a one piece mold? do you just suspend the bait?

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do any of you guys use that make two part molds use the clay that comes with the rtv? I have made a mold before and using this but it was with great difulculty. the problem i have with it it is around the fins gills and mouths. any advice? also how do you guys make a one piece mold? do you just suspend the bait?

What I do is make a box big enough for the part. Then I drill holes for my pour holes and vent and glue them in the master. Then try to guess where I want my bait to hang then hot glue two sticks across to support the bait. Add more hot glue to the sticks and the box to hold the bait down in the box. Pour your rtv in the side away from the part and let the rtv climb up on the part until full. After it is dry I take apart the box and remove the sticks. Then I cut the mold with a sharp knife between the pour holes and down both sides just enough to get the part out. The rtv will flex alot so dont be shy pull and tug till it comes out. Most of mine are cut 1/3 of the way around so the rest is good as your master. I also try and put the holes as far up as you can to prevent air trapped in the corners. A very important thing on details in the master you might want to brush the rtv in these areas so you will not loose the detail. then put in box and fill.

I have only done one two part mold and it was not to my liking.

These are only the quick and dirty ways I do it cause I did not even add the vacumn and pressure parts.

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This might be a bit misplaced. I have made some casting of baits with polyester inside a RTV mould. It was a bit to mess and smelly for me. Furthermore the baits cracked as soon the hit a rock. So I started to cast them out of hot glue with a glue gun. The positive side is that its quick to work with, no nasty smells and clean. The baits becomes extremely durable and hot glue floats so it’s only a question of how much weight that is needed to get the baits swim right. The down side is that there is a limit of how big parts or baits one can do. It’s a bit like casting lead, with bigger baits a preheated mould makes things a lot easier. Also one should use a glue gun with highest possible working temperature and capacity. A 20°C change, up or down, of working temperature of the glue that’s comes out of the gun can make a huge deferens when making a bit bigger baits with lots of metal inside the mould.

Regards, Robin

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This might be a bit misplaced. I have made some casting of baits with polyester inside a RTV mould. It was a bit to mess and smelly for me. Furthermore the baits cracked as soon the hit a rock. So I started to cast them out of hot glue with a glue gun. The positive side is that its quick to work with, no nasty smells and clean. The baits becomes extremely durable and hot glue floats so it’s only a question of how much weight that is needed to get the baits swim right. The down side is that there is a limit of how big parts or baits one can do. It’s a bit like casting lead, with bigger baits a preheated mould makes things a lot easier. Also one should use a glue gun with highest possible working temperature and capacity. A 20°C change, up or down, of working temperature of the glue that’s comes out of the gun can make a huge deferens when making a bit bigger baits with lots of metal inside the mould.

Regards, Robin

Ya polyester is alot like using glass for a bait not a good choice. We are using casting resin that is made to reproduce products from a mold. The hot glue idea is new to me at least. As for me I have used hot glue and it smells more than the resin I am using. It is pretty much odorless. As for polyester it would be only be good if it was reinforced by some type of fibers. I use polyester at work and the last thing I want to do is bring it home. The only thing that come home is things without odor.

How well does paint stick to the glue.

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I have painted some of the glue lures over d the years with spray paint and it has stayed on very well, but then I not fishing with this lures for especially toothy fish (sea run brown trout). But once I started with the hot glue I quickly figured out that for my purpose the best solution was to melt the colour in to the lures during the casting itself. I do this by putting projector pens or Sharpies inside a thing called Blow Pen that is like a mouth driven airbrush made for kids. With the Blow Pen its possible to coat the inside of the mould with the amount a colour need. Once the colour in place, I sometimes spread some pearl flecks inside the mould before, I put in the wire harness and close the mould. I inject the hot glue and after a couple of minutes I have almost an ready bait with colours and maybe some flecks melted into the surface. All it needs is some trimming with and it’s a quick job with a gas burner to get a smooth finish. Some stick on eyes, split rings and it s done.

If you want more solid colours, there are lots and lots of opaque and translucent hot glue sticks in different colours on the market. Some are even glow in the dark, some are fluorescent and some contains different amounts of glitter flecks. I have made some with opaque fluorescent lime green glue, pearl flecks and an airbrushed-in-the-mould black back that came out really nice.

The lure on the picture is just plain hot glue and an airbrushed-in-the-mould green back made for clear water conditions on the coast.

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Very nice shrimpy . Have you ever done jointed swin baits like that?

Frank, I started a few projects with jointed baits a long time ago but wasn’t really happy with the baits performance. I made something that locked like a Rapala Sliver wobbler with a Tomic shaped front/head to get a bait that would resemble a sand eel and. I glued the wire connection between the parts with CA glue and then coated the small area where the wires meet with some epoxy just to get some space in the mould. I cant really see any other limitations with the hot glue other than the size of the bait or part of the bait one can do I one go. I have mainly made sand eel like plugs and lip less wobblers with a length up to 4,5 inch and a diameter up to about 0,5 inch. And I have never had any problems with getting those amounts of glue into the mould.

In the beginning when I started to cast with hot glue I was lucky enough to have an “industrial grade” glue gun that I had been give by a friend who used them at work. The gun was more or less in the end off its lifespan but for my normal purpose (fly tying) it was perfect because it had an adjustable temperature ranging from 285ºF-445ºF. When I started to use it for the casting the higher working temperatures really came to its right together with the high melting capacity per minute. After a year or so it throw in the towel and when I started to look around for a replacement I realised that the asking price for the one I had used was about $260 here in Sweden. That was a bit over the top for my budget at that time so I went for a high grade consumer gun that hade a working temperature of 403°F and an asking price of about $35. Since then, 11-12 years ago, I’ve go through a few these guns and the temp is okay but every know and then I miss the capacity of the first glue gun. If I would aim to make big baits I would certainly consider a pro gun that in North America probably don’t cost more than $150.

One thing to bear in mind is that there are glue sticks and there are glue sticks. Many of the round ones I run into here are 11 or 12 millimetre. If a gun is made for 12 millimetre sticks you really shouldn’t try force an 11 millimetre stick into it as there is a big risk that the glue will be pressed backwards towards the feeding mechanism and then flood it and make a general mess and sooner or later stop then feeding of the glue stick. Also one should try to figure out which is the recommended working temperature of the glue stick. If this doesn’t match the glue gun one could be in for some trouble.

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Wow, I just read through this entire topic. Thank to everyone who contributed! It will save me hours of R&D of my own.

I just started making molds for a 5 peice 4 inch swimbait I have been working on over the years. I started using a SmoothOn product and had serrious bubble problems. I recently tried Alumilite Amazing Plastic (AP) and Amazing Clear (AC). The AC actually worked the best, probably because of the long working time, but it takes 7 days to fully cure, and tensile streangth is low.

I thought I would add some microballoons to the AP and get apporximatly the same wieght as the PVC Board I made the master out of, but unfortunately I was wrong. I am mixing 1 part balloons to 1 part resin by volume. I was trying to see how many balloons I could add to maintain a desirable durability of the bait. I am sure this will vary depending on the baits design, but any suggestions? Can I achieve the same weight as PVC or is this a dream?

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Great read. I was wondering if anyone has ever tried to powder coat resin lure? Seems possible and would cover any defects while being very durable.

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I am now in the process of making swim baits with two products. One is from tap plastics and the other is Alumilite. They are about the same product as far as casting goes. The one from tap is local. I have alot of these baits out there for some on the water R&D and have had no one complaint about breakage or even paint problems for that matter.

Here is my take on the mold process. It sound easy to say I am going to make a mold and cast a swim bait,But that is because you have not done it yet. When you make a mold it is very important to understand how you will go about it. Like you I was going to make a two part mold, all three pieces in one mold. Boy was that a mistake it came out so bad it is not good enough to be a paper weight( more embarasing than anything else). But I did learn that if I was going to make a mold it would be a one piece. Now all my molds are one piece. Less clean up of the parting lines. Use the firmest rtv silicone you can get away with and try not to stir air in the rtv so you dont get bubbles in the mold. I use a vacunm to remove what I put in now.

As for the resins it is nice to have a thin 2-3 minute pot life one. I use a scale to measure the portion and when I add microballoons I add them to the thin product while it is on the scale. Most of mine are made with 10% mb by weight which work for me. Then I add a split shot to the belly of the mold to keep it running true. Plastic cups are the ones I use for mixing,I use two one with the thin part with the mb then one for other part. I pore the thin one into the thicker one and stir with a FLAT stick to prevent putting small air pockets into the mix(champain bubbles if you think about it). Open the mold and pour in to the point of over flowing then release slowly to let as many bubbles out as you can. Wait longer than you think and then remove the part. Sand the parting lines and pore spouts install hard where and paint.

As for bondo it is not a good product for this as it is to soft and pourius. All it is is polyester resin and mb. No strenght there.

I have not seen other products like this at any store other than tap plastics. This stuff is pretty special not your every day resins.

When you go and pull the trigger on this I would put most of my work in the molds because remember if you rush your molds all the imperfections will be in every part you cast untill you make a new one. My blue gill head is on the fourth one but it is real good now.The tail is on the third one and i will redo tommorrow. But alot of rtv also it may seem to be alot but it goes fast.

Just my 2cts on the subject. And yes it is fresh on my mind. Hope this helps

I agree completely with frank.

i have made swimbaits from resin and it is a grueling process. My first one i made i was so excited, to try out and learned my bait swam sideways. In my opinion i would separate the two piece lures individually. make a mold for each piece as i have tried both ways. Although it may seem more expensive because it requires more silicone, it delivers more consistency than making a one piece mold and then cutting the resin. As far as resins go, i have used Alumilite and Taps plastic so i can only speak on those products. Alumilite is heavier and taps plastic is more buoyant. I keep a record log of how much microballoons, weight, i use when i pour, so i can get a more consistent action.

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Multiple molds for multiple pieces is the way to go. I tried 3 and 4 piece molds interlinked. The main problem that occurs is gas venting as the resin cures. You notice that after you pour the resin is pushed out of the mold. With multi-piece molds, each piece pushes into the next piece.

I documented each lure section for my swimbaits on excel, weighing each piece out and I also mixed my resins methodically and precisely. I measured the resin using 20ml syringes and measured the filler with a good scale. I never could get my pieces to have consistent weights, and the trends for each pieces consistency didn't correlate with the other pieces within the same mold.

So yeah, its much better to just make multiple molds from my experience and mix a batch of resin for each piece for the most consistency.

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I put some expanding foam in a box and let cure. After I cut out a block about 3/8 X 3/8 X 3/4. I suspended it in the mold of the head piece of my swimbait using a metal wire, making sure it would not interfere with the hook hanger, line tie, or pin. I poured the resin into the mold using the same ratio of micro-balloons as I have been using. I compared the weight of this new piece to ones I previously poured without the foam insert. I was able to knock 3 grams of the weight of the head piece. It now weighs the same as the master carved from PVC.

Weights:

PVC = 7g

Resin, micro-balloons, foam = 7g

Resin, micro-balloons = 10g

The body segments are to small to safely add the foam to, but Friday I should be able to determine if lightening the head piece, then counter-acting with additional ballast, improves overall movement of the bait.

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