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9/22/2017 12:11:25 AM
Posted: 8/14/2005 8:11:02 PM EDT
I have been trying to duplicate name brand fishing lures using this castin craft stuff that hardens into plastic. I wanted to make a cast or mold of the companies lures and then pour the castin craft in, to make my own. They use two peice molds that you pull apart once it dires, does anyone know of anything like this out there? Tried using clay but that didnt work it was too brittle.
Link Posted: 8/14/2005 9:46:05 PM EDT
Try bondo.

Wax and polish your lures with Johnson's Paste Wax first, then coat them with PVA (Poly-Vinyl Alcohol, aka "Green Seal"). When dry you can slop your bondo on.

Here's how I make permanent molds: www.rcgroups.com/forums/showthread.php?t=87950&highlight=1%2F2A+Sliver

Link Posted: 8/14/2005 9:59:39 PM EDT
Bondo is a horrible mold making material because it shrinks during curing and it's not all that stable by itself. Check out these links:

www.freemansupply.com/video-casting.htm

www.alumilite.com/howto.cfm

Those should help. I suggest the RTV silicone casting materials for smaller parts because they tend to flow well, they don't stick to most anything, and work best for small parts. In most forms it won't adhere to themselves once cured, so making two part molds is easy. The ones that will adhere to themselves just require a light dusting of talc powder on the surfaces where the mold will join. Just make sure that whichever you use does not have to be degassed. Degassing is where you apply a vacuum to the rubber after mixing the catalyst in to remove air bubbles. I had great luck with Dow RTV silicone rubber. I bought it for $30/jar at the local art supply store in Houston.

Remember the Alamo, and God Bless Texas...
Link Posted: 8/14/2005 10:11:08 PM EDT

Originally Posted By GodBlessTexas:
Bondo is a horrible mold making material because it shrinks during curing and it's not all that stable by itself. Check out these links:

www.freemansupply.com/video-casting.htm

www.alumilite.com/howto.cfm

Those should help. I suggest the RTV silicone casting materials for smaller parts because they tend to flow well, they don't stick to most anything, and work best for small parts. In most forms it won't adhere to themselves once cured, so making two part molds is easy. The ones that will adhere to themselves just require a light dusting of talc powder on the surfaces where the mold will join. Just make sure that whichever you use does not have to be degassed. Degassing is where you apply a vacuum to the rubber after mixing the catalyst in to remove air bubbles. I had great luck with Dow RTV silicone rubber. I bought it for $30/jar at the local art supply store in Houston.

Remember the Alamo, and God Bless Texas...




thanks guys. Would RTV silicon work good on a round lure like this?



When it comes out would it be smooth where the 2 halfs of the mold meet?
Link Posted: 8/14/2005 10:12:19 PM EDT
yeah, but if he's only making a few parts it will be perfect for him. It doesn't make sense to have the guy buy $60 worth of glue that will spoil beofre he uses all of it to make a mold from a part that might only be a trial.

Besides, with Bondo you can make a mold in 2-3 hours. With metal filled epoxies and the like you are looking at a 24hr day per coat, then the fiberglass layers to back it up.

I can make useable bodies (airplane fuselages are long and the molds especially prine to warpage) out of a bondo mold for 2 weeks after the mold is made. The trick is to keep it clamped together when not being used.

Dave
Link Posted: 8/14/2005 10:16:45 PM EDT

Originally Posted By BigB1129:
thanks guys. Would RTV silicon work good on a round lure like this?

www.hawaiifishinglures.com/images/bg6.jpg

When it comes out would it be smooth where the 2 halfs of the mold meet?



It could, your part will only be as good as the plug you use to make it... As for the seam at the parting line, this is where it pays to use a glue rather than a RTV compoud. The exception to this is if your plug were made it two halves and joined later.
Link Posted: 8/14/2005 10:19:23 PM EDT
Thats bond looks good, Is there anywhere I can buy the materials you used online?
Link Posted: 8/14/2005 11:57:19 PM EDT
Bondo can be bought in just about any auto parts store for $3 or 4 a can.

Dave
Link Posted: 8/14/2005 11:59:07 PM EDT
Tagnet.

SGat1r5
Link Posted: 8/15/2005 12:04:35 AM EDT
There are also some great RTV urethanes available for mold making. There is one manufacturer in Houston that makes it specifically for casting...I need to dredge up the literature on it. What was really cool was the shrinking/expanding line. You could take your pattern, cast the mold and then soak the mold in water to get a mold that is 50-100% larger than the pattern.

For lead jigs, neither silicones nor urethanes will work.
Link Posted: 8/15/2005 12:40:22 AM EDT
THAT is F-ing cool!
Link Posted: 8/15/2005 9:48:58 AM EDT
They have a website! Industrial Polymers

The president gave me a tour and molding assistance on my project. He also showed me the extensive line of examples they have cast.

The urethanes he has range from dead hard solids to jelly-like molds. The products are easy to handle and have almost no odor.
Link Posted: 8/15/2005 9:49:17 PM EDT
[Last Edit: 8/15/2005 9:55:00 PM EDT by BigB1129]

Originally Posted By Keith_J:
There are also some great RTV urethanes available for mold making. There is one manufacturer in Houston that makes it specifically for casting...I need to dredge up the literature on it. What was really cool was the shrinking/expanding line. You could take your pattern, cast the mold and then soak the mold in water to get a mold that is 50-100% larger than the pattern.

For lead jigs, neither silicones nor urethanes will work.



I am only making plasic heads out of casting resin. Does RTV urethanes work good with casting resin? I would like the molds to keep the same shape.



Sorry a little confused which product would I want from industrialpolymers to make molds of existing plastic lure heads and then using casting resin to reproduce them? It would also be cool If I could make the same heads but in a soft rubber plastic from. Does anything they sell do that?
Link Posted: 8/15/2005 10:09:50 PM EDT
Tagging this one, because I've wanted to know myself.
Link Posted: 8/15/2005 11:10:33 PM EDT
Didnt realize it at the time but I bet theres tons of gun stuff that you can mold and duplicate
Link Posted: 8/15/2005 11:27:53 PM EDT

Originally Posted By BigB1129:
I have been trying to duplicate name brand fishing lures using this castin craft stuff that hardens into plastic. I wanted to make a cast or mold of the companies lures and then pour the castin craft in, to make my own. They use two peice molds that you pull apart once it dires, does anyone know of anything like this out there? Tried using clay but that didnt work it was too brittle.

Does a fishing lure really cost enough to make this a worthwhile proposition?
Link Posted: 8/15/2005 11:33:08 PM EDT

Originally Posted By BigB1129:

Originally Posted By Keith_J:
There are also some great RTV urethanes available for mold making. There is one manufacturer in Houston that makes it specifically for casting...I need to dredge up the literature on it. What was really cool was the shrinking/expanding line. You could take your pattern, cast the mold and then soak the mold in water to get a mold that is 50-100% larger than the pattern.

For lead jigs, neither silicones nor urethanes will work.



I am only making plasic heads out of casting resin. Does RTV urethanes work good with casting resin? I would like the molds to keep the same shape.



Sorry a little confused which product would I want from industrialpolymers to make molds of existing plastic lure heads and then using casting resin to reproduce them? It would also be cool If I could make the same heads but in a soft rubber plastic from. Does anything they sell do that?



Yes, nearly anything is possible. Too bad you are in NY and cannot take a trip to see how it is all done. For molds, it is best to have some rigidity in the mold material but to also have a good deal of elasticity to remove the cast product. This limits the amount of draft necessary in the pattern, meaning you can cast round objects with relative ease. The mold will flex to remove the cast object and not damage the mold.

The project starts with a mold box. This is where you pour the mold compound. It needs to be twice as thick as the object you are replicating, also known as the pattern. The mold box needs to be very smooth and coated with a release agent. Silicone is good for all but silicone molds, these are best with a wax. But the important element is very smooth walls. Plastic works well. A "tree" or casting channel is also needed. This is just a rod or "tree" of rods connecting all patterns in the mold. This is used to fill the mold with the product used in casting the finished product.

The first step is to cast the bottom of the mold. Coat mold box and pattern with release agent. The mold box is half-filled with the mold compound and then the pattern is set onto the surface of the molding compound and carefully forced HALFWAY into the compound along with the tree, also coated with release agent and also only halfway submerged in the mold compound. It is allowed to cure completely without moving the pattern. Then the top surface of the molding compound is coated with release agent and the mold box is completely filled with molding compound. After a full cure, the top is removed and the pattern/tree are removed. THe mold should now fit together, allowing highly detailed replicas to be made. Care is needed when fitting the mold halves together to match the sides and also to achieve the proper clamping force. Too little and the mold leaks. Too much and the molds are deformed, producing a mishshapen product. Experiment.

Now for the specifics. Hardness and or flexibilty is measured using the Shore Durometer scale. Anything in the 40-70 "A" scale will be adequate. This range is a soft rubber but for your application, it will be fine. Working time is important, longer is better so go with the Truecast GTS65 Slow.

For making the actual product, you could use your casting resin or go with any of the RTV urethanes for more flexible patterns.. Yes, the GTS could be used although they are not as durable. The softest is like that of plastic worms (0 Shore A) and it works up to hard rubber (80 Shore D). If you chose a flexible product, you will need a "backbone" in the mold to attach the hooks and tie eye. But since the molds are flexible, knife slots can be cut in the mold to hold these items. Just make sure plenty of release agent coats these modifications to the mold.

And some important notes. Cured urethane will NEVER come out of clothes. No solvent will touch it. It is on your skin until it wears off. And it takes a LONG time to wear off.

For highest quality, vacuum degassing is a big help. I mix the two components and then give them a 2 minute vacuum degassing step before pouring. All bubbles expand, rise and break, leaving NO bubbles in the finished product. I use a Mity Vac hand pump and home made vacuum chamber.

Give them a call. The president was a most interesting fellow and taught me most of everything I know. He even took me through my first urethane casting.
Link Posted: 8/16/2005 12:29:02 AM EDT
[Last Edit: 8/16/2005 12:31:19 AM EDT by BigB1129]

Originally Posted By Keith_J:

Originally Posted By BigB1129:

Originally Posted By Keith_J:
There are also some great RTV urethanes available for mold making. There is one manufacturer in Houston that makes it specifically for casting...I need to dredge up the literature on it. What was really cool was the shrinking/expanding line. You could take your pattern, cast the mold and then soak the mold in water to get a mold that is 50-100% larger than the pattern.

For lead jigs, neither silicones nor urethanes will work.



I am only making plasic heads out of casting resin. Does RTV urethanes work good with casting resin? I would like the molds to keep the same shape.



Sorry a little confused which product would I want from industrialpolymers to make molds of existing plastic lure heads and then using casting resin to reproduce them? It would also be cool If I could make the same heads but in a soft rubber plastic from. Does anything they sell do that?



Yes, nearly anything is possible. Too bad you are in NY and cannot take a trip to see how it is all done. For molds, it is best to have some rigidity in the mold material but to also have a good deal of elasticity to remove the cast product. This limits the amount of draft necessary in the pattern, meaning you can cast round objects with relative ease. The mold will flex to remove the cast object and not damage the mold.

The project starts with a mold box. This is where you pour the mold compound. It needs to be twice as thick as the object you are replicating, also known as the pattern. The mold box needs to be very smooth and coated with a release agent. Silicone is good for all but silicone molds, these are best with a wax. But the important element is very smooth walls. Plastic works well. A "tree" or casting channel is also needed. This is just a rod or "tree" of rods connecting all patterns in the mold. This is used to fill the mold with the product used in casting the finished product.

The first step is to cast the bottom of the mold. Coat mold box and pattern with release agent. The mold box is half-filled with the mold compound and then the pattern is set onto the surface of the molding compound and carefully forced HALFWAY into the compound along with the tree, also coated with release agent and also only halfway submerged in the mold compound. It is allowed to cure completely without moving the pattern. Then the top surface of the molding compound is coated with release agent and the mold box is completely filled with molding compound. After a full cure, the top is removed and the pattern/tree are removed. THe mold should now fit together, allowing highly detailed replicas to be made. Care is needed when fitting the mold halves together to match the sides and also to achieve the proper clamping force. Too little and the mold leaks. Too much and the molds are deformed, producing a mishshapen product. Experiment.

Now for the specifics. Hardness and or flexibilty is measured using the Shore Durometer scale. Anything in the 40-70 "A" scale will be adequate. This range is a soft rubber but for your application, it will be fine. Working time is important, longer is better so go with the Truecast GTS65 Slow.

For making the actual product, you could use your casting resin or go with any of the RTV urethanes for more flexible patterns.. Yes, the GTS could be used although they are not as durable. The softest is like that of plastic worms (0 Shore A) and it works up to hard rubber (80 Shore D). If you chose a flexible product, you will need a "backbone" in the mold to attach the hooks and tie eye. But since the molds are flexible, knife slots can be cut in the mold to hold these items. Just make sure plenty of release agent coats these modifications to the mold.

And some important notes. Cured urethane will NEVER come out of clothes. No solvent will touch it. It is on your skin until it wears off. And it takes a LONG time to wear off.

For highest quality, vacuum degassing is a big help. I mix the two components and then give them a 2 minute vacuum degassing step before pouring. All bubbles expand, rise and break, leaving NO bubbles in the finished product. I use a Mity Vac hand pump and home made vacuum chamber.

Give them a call. The president was a most interesting fellow and taught me most of everything I know. He even took me through my first urethane casting.



Thanks alot, Making the mold sounds easy. When I mix the casting resin it heats up and the bubble go away, so I dont think I need to degas it. How long will the molds last for? will they sell to me in small quantities or do I have to go to a retail store to find thier product
Link Posted: 8/16/2005 12:14:14 PM EDT

Originally Posted By BigB1129:

Thanks alot, Making the mold sounds easy. When I mix the casting resin it heats up and the bubble go away, so I dont think I need to degas it. How long will the molds last for? will they sell to me in small quantities or do I have to go to a retail store to find thier product



The molds are quite durable. Most damage come from abrasion which scratches the mold and makes release difficult which leads to tearing etc. Degassing the urethane will make for tougher molds since voids can lead to weak points and adhesions but there are ways around this. Filling all voids with wax is one way of repair. But any event, the molds are easy to make. They should easly last for 20 castings.

The smallest kit they sell is half-gallon. Get a good scale for measuring the components as this is more accurate and enables precise mixing of small batches. You do not need to mix the whole batch in one setting. It keeps well if stored properly, there are NO solvents to evaporate. The only thing is moisture which will cause bubbling. Yhey sell an aerosol product called Purge It which displaces moisture on opened cans, enhancing shelf life. Get it. Also, get a can of their mold release. It works very well for all plastic casting and doesn't "bloom" like some waxes.



Link Posted: 8/16/2005 3:22:06 PM EDT
tag for later
SRM
Link Posted: 8/17/2005 1:48:31 AM EDT
Very Useful WeissLuft!
Link Posted: 8/17/2005 2:02:56 AM EDT
Tag
Link Posted: 8/17/2005 3:40:17 AM EDT
I'm looking for some mold makers in PA. Got lot's of stuff I want to make.
Link Posted: 8/17/2005 12:47:50 PM EDT
Link Posted: 8/18/2005 3:10:40 AM EDT

Originally Posted By Keith_J:

Originally Posted By BigB1129:

Thanks alot, Making the mold sounds easy. When I mix the casting resin it heats up and the bubble go away, so I dont think I need to degas it. How long will the molds last for? will they sell to me in small quantities or do I have to go to a retail store to find thier product



The molds are quite durable. Most damage come from abrasion which scratches the mold and makes release difficult which leads to tearing etc. Degassing the urethane will make for tougher molds since voids can lead to weak points and adhesions but there are ways around this. Filling all voids with wax is one way of repair. But any event, the molds are easy to make. They should easly last for 20 castings.

The smallest kit they sell is half-gallon. Get a good scale for measuring the components as this is more accurate and enables precise mixing of small batches. You do not need to mix the whole batch in one setting. It keeps well if stored properly, there are NO solvents to evaporate. The only thing is moisture which will cause bubbling. Yhey sell an aerosol product called Purge It which displaces moisture on opened cans, enhancing shelf life. Get it. Also, get a can of their mold release. It works very well for all plastic casting and doesn't "bloom" like some waxes.






I called them today and ordered a kit in a quart size and their mold release. They were nice and helpful. They also said I need something to coat the object I am making a mold of? Do you know what that is I forgot what they said? Ill post back with my result to let you guys know how it goes. Thanks
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