[Bob La Londe]

There are a lot of different ways to handle injection and reservoir, but this one works and provides for no sprue marks on the body. Add two more pieces and you could shoot a double skirt version. Cut the flats of the angle like a flat two piece mold for the grub body. Open port to the edge of the angles. Alignment pin that and clamp. Then machine the plate and the combined flats of the angle like a seperate 2 piece mold for the skirt. Drill and thread your alignment pins or whatever.

If you made it as a two hinged mold with alignement pins in the right place you would only need one clamp to shoot this mold. For most of us it would be easier to just use two clamps. You could add another piece and make it a multicavity mold with one injection port.

I do not think the idea is patentable since a large variety of multi piece molds have been around for almost as long as people have been blowing glass, but my version of the idea is posted in the public domain.

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This post has been edited by Bob La Londe: 16 June 2010 - 01:40 AM

[Bob La Londe]

Bob La Londe, on 16 June 2010 - 01:31 AM, said:

There are a lot of different ways to handle injection and reservoir, but this one works and provides for no sprue marks on the body. Add two more pieces and you could shoot a double skirt version. Cut the flats of the angle like a flat two piece mold for the grub body. Open port to the edge of the angles. Alignment pin that and clamp. Then machine the plate and the combined flats of the angle like a seperate 2 piece mold for the skirt. Drill and thread your alignment pins or whatever.

If you made it as a two hinged mold with alignement pins in the right place you would only need one clamp to shoot this mold. For most of us it would be easier to just use two clamps. You could add another piece and make it a multicavity mold with one injection port.

I do not think the idea is patentable since a large variety of multi piece molds have been around for almost as long as people have been blowing glass, but my version of the idea is posted in the public domain.

If I was making this is a single skirt multi bait mold I'ld add another flat plate and machine the injection port and reservoir between the two plates. It would also have the advantage of being freestanding in the shooting position.

[Vodkaman]

Thanks for the reply.

The way I see the spider grub is in three parts: The thin flat legs, the fat body and the other end, the radial array of legs.

The radial legs is the part that would normaly be assembled/glued separately, but could be molded using a fluted insert. I did crude experiments with this idea, using PoP and posted it on TU. I suspect that this is where Bear got his tube mold idea, but I posted the idea for everyone.

The problem that I see for the spider grub, is where to place the injector port. If injected from either end, the thin/narrow sections may cool the plastic too quickly, possibly causing an incomplete pour, especially considering the thermal conductivity of aluminium.

The first solution that springs to mind, is to inject in the centre of the body length, the plastic flowing to each end. This would work, but would be undesirable, leaving a scar were the sprue is removed.

My idea is to inject through the centre of the insert, direct into the body, filling the flat legs and the skirt simultaneously. The advantage of this method is reduced cooling and totally invisible sprue scar. I believe this is very do-able with only the addition of the central hole through the fluted insert.

Any thoughts?

Dave

This post has been edited by Vodkaman: 16 June 2010 - 02:00 AM

[Bob La Londe]

Vodkaman, on 16 June 2010 - 01:57 AM, said:

Thanks for the reply.

The way I see the spider grub is in three parts: The thin flat legs, the fat body and the other end, the radial array of legs.

The radial legs is the part that would normaly be assembled/glued separately, but could be molded using a fluted insert. I did crude experiments with this idea, using PoP and posted it on TU. I suspect that this is where Bear got his tube mold idea, but I posted the idea for everyone.

The problem that I see for the spider grub, is where to place the injector port. If injected from either end, the thin/narrow sections may cool the plastic too quickly, possibly causing an incomplete pour, especially considering the thermal conductivity of aluminium.

The first solution that springs to mind, is to inject in the centre of the body length, the plastic flowing to each end. This would work, but would be undesirable, leaving a scar were the sprue is removed.

My idea is to inject through the centre of the insert, direct into the body, filling the flat legs and the skirt simultaneously. The advantage of this method is reduced cooling and totally invisible sprue scar. I believe this is very do-able with only the addition of the central hole through the fluted insert.

Any thoughts?

Dave

I really don't see it as an issue unless you made it as a 10-20 cavity mold or more. The curly tails are not much thinner than the tails on my Speckled Hog mold and that plastic had to flow through the entire body cavity of a larger bait first. The skirt arms would fill last probably with either injection port design. Either the add on tube or the extra plate, but they would be filling with hot plastic directly out of the injector/reservoir so again no issue. I've only got enough metal laying around right now to make one more mold and its not enough to make a skirted jig mold of this type, but I might make one just to prove the idea down the road a little ways. Rather than bolt together plates I figured I would just start with angle and then all I have to do is rough square it up to my table and surface the working flats.

I thought about injecting into the side of the body. I agree. That would leave an ugly sprue mark. I thought about the tail, but it would also be hard to hide. The only real answer is to shoot it from the head/skirt end. To do that needs 4 pieces. Either a tube reservoir for a single cavity mold or a 2nd plate for a multi cavity mold.

To make it a double skirt would require two more pieces setting side by side so they can seperate from around the bait.

I can also visualize a Mister Potato Head version of this so you could swap tail designs, skirts for arms, stack two piece skirt plates and arm paltes, etc...

To be honest though the actual basic bait doesn't intrigue me all that much. Like I said I might make a mold like this down the road just to prove the idea. Right now I want to make a couple more of my Speckled Hog molds, and then start on a zipper body curly tail mold and a zipper body oval tail mold. Also scaled up and scaled down versions. Well, that and I would like to remake my jerkbait mold to be more organic and less industrial looking. Maybe make a buzz tail version of it to be injected with microspheres for a topwater bait.

[powerworm]

i happen to know where the idea for the mandrel in the tube molds came from! it was in louisiana but a little farther north than bear!!

[carolinamike]

Guys are we talking about a bait with a skirt attached to the front all in one piece? If so, check out Power Team Lures, the Texas Rig Jig is a one piece front skirted bait. I've had the pleasure of seeing these molds and they are complicated monsters, but really fun to work with.

[Delw]

Vodkaman, on 16 June 2010 - 01:57 AM, said:

Thanks for the reply.

The way I see the spider grub is in three parts: The thin flat legs, the fat body and the other end, the radial array of legs.

The radial legs is the part that would normaly be assembled/glued separately, but could be molded using a fluted insert. I did crude experiments with this idea, using PoP and posted it on TU. I suspect that this is where Bear got his tube mold idea, but I posted the idea for everyone.

The problem that I see for the spider grub, is where to place the injector port. If injected from either end, the thin/narrow sections may cool the plastic too quickly, possibly causing an incomplete pour, especially considering the thermal conductivity of aluminium.

The first solution that springs to mind, is to inject in the centre of the body length, the plastic flowing to each end. This would work, but would be undesirable, leaving a scar were the sprue is removed.

My idea is to inject through the centre of the insert, direct into the body, filling the flat legs and the skirt simultaneously. The advantage of this method is reduced cooling and totally invisible sprue scar. I believe this is very do-able with only the addition of the central hole through the fluted insert.

Any thoughts?

Dave

Dave a spider grub has a 90º skirt, using the tube meathod dont work properly for the spider grub with skirt.

Bob,
Yamamoto and others major manufacters dont glue them with glue they use hot plastic and fuse them together. there is many reasons forfusing them rather than shooting them all in one shot. the main reason is cost as not every one use's skirts on there grubs.

running a 90 degree skirt is the only way to use a spider grub other wise you wont get the flare.
putting the molds all together you have a pretty big and wide mold.

There are approx 63 of these on the market, but there is limitations running this type of one piece mold

[Vodkaman]

Quote

Dave a spider grub has a 90º skirt, using the tube method dont work properly for the spider grub with skirt.

I had suspected that this might be the case. This certainly makes the mold a lot more complicated. Thanks Del.

Dave

[Bob La Londe]

Vodkaman, on 17 June 2010 - 11:34 PM, said:

I had suspected that this might be the case. This certainly makes the mold a lot more complicated. Thanks Del.

Dave

I know I didn't take the time to do a proper drawing, but the mold concept drawing I posted is a 90 degree skirt. I've since refined the idea in my head. More along my Mr Potato Head thoughts. I may make this mold sooner than I originally planned now. I'm kinda getting excited about some of the options. Now I need to put together another metal order or go buy a few pieces at list price just to play with.

[Delw]

Vodkaman, on 17 June 2010 - 11:34 PM, said:

I had suspected that this might be the case. This certainly makes the mold a lot more complicated. Thanks Del.

Dave

Dave the mold is not complicated at all, matter of fact its very simple. the problem is being cost justifable.

for example it can be made in 3 pieces, which is no problem but the material needed to make it is a huge waste and cost quite a bit do to the size,
if you have a 2" 3/4" skirt then you will need a min of 1.5" thick material for each side. the cost of that material is what is NOT cost justifiable when it comes to hobbiest. you can also make it in 1/2" thick material but then you have more pcs to deal( the person machine the molds not the end user) with and more cutting time. The end user will still get a 3 pcs mold. thats for a single skirt for a double skirt add 2 more pcs's.

now if you want 2 or more cavites you need to add 3" for every cavity. all of a sudden for a 4 cavity mold you have a 12"+ wide pcs of material that is 3" thick and about 4-6" tall depending on the length of the grub you want. you could be talking 20-30lbs of material. for just 4 cavities ( unless you use a T shaped one with 1/2" plates but then the cost of machineing and putting together addes the price up as well.

by the time it all ads along with effecientcy your wasteing money and time and space on a production level. plus you thro other things into the mix like you want the skirt a different color etc etc. Slide bars work in this type of mold but it still cost more to add slide bars and also what iff the customer doesnt want skirts on them, then you have to cut the skirts off. so serpeate molds end up being the right way each time.

Now having said that I have customers that only shoot them with skirts and out of production pots so many 1 cavity molds work fine for them (they are all about production and have more than one person working for them). as they DONT sell the grubs with out skirts( one customer does but he has only grub molds)


You know manufacturing really well as your involved in it daily so I am pretty sure you understand that sometimes while things can be made to do something in one process its not always best in the long run.

This post has been edited by Delw: 18 June 2010 - 12:08 PM

[Bob La Londe]

Delw, on 18 June 2010 - 12:07 PM, said:

Dave the mold is not complicated at all, matter of fact its very simple. the problem is being cost justifable.

for example it can be made in 3 pieces, which is no problem but the material needed to make it is a huge waste and cost quite a bit do to the size,
if you have a 2" 3/4" skirt then you will need a min of 1.5" thick material for each side. the cost of that material is what is NOT cost justifiable when it comes to hobbiest. you can also make it in 1/2" thick material but then you have more pcs to deal( the person machine the molds not the end user) with and more cutting time. The end user will still get a 3 pcs mold. thats for a single skirt for a double skirt add 2 more pcs's.

now if you want 2 or more cavites you need to add 3" for every cavity. all of a sudden for a 4 cavity mold you have a 12"+ wide pcs of material that is 3" thick and about 4-6" tall depending on the length of the grub you want. you could be talking 20-30lbs of material. for just 4 cavities ( unless you use a T shaped one with 1/2" plates but then the cost of machineing and putting together addes the price up as well.

by the time it all ads along with effecientcy your wasteing money and time and space on a production level. plus you thro other things into the mix like you want the skirt a different color etc etc. Slide bars work in this type of mold but it still cost more to add slide bars and also what iff the customer doesnt want skirts on them, then you have to cut the skirts off. so serpeate molds end up being the right way each time.

Now having said that I have customers that only shoot them with skirts and out of production pots so many 1 cavity molds work fine for them (they are all about production and have more than one person working for them). as they DONT sell the grubs with out skirts( one customer does but he has only grub molds)


You know manufacturing really well as your involved in it daily so I am pretty sure you understand that sometimes while things can be made to do something in one process its not always best in the long run.

Whats wrong with using uneven leg angle instead of solid stock? I don't think it costs all that much more by weight, and certainly not as much as a piece of solid stock to do the job. I face every piece first anyway so minor irregularities shouldn't be a huge issue. Also, I think it would really need to be done in four pieces to work well. Especially for a multi cavity mold. I don't really care about the marketability or production efficiency of it directly, but I have some ideas about that too. One of my Mr Potatohead ideas came from something you said.

[Delw]

Bob La Londe, on 18 June 2010 - 01:26 PM, said:

Whats wrong with using uneven leg angle instead of solid stock? I don't think it costs all that much more by weight, and certainly not as much as a piece of solid stock to do the job. I face every piece first anyway so minor irregularities shouldn't be a huge issue. Also, I think it would really need to be done in four pieces to work well. Especially for a multi cavity mold. I don't really care about the marketability or production efficiency of it directly, but I have some ideas about that too. One of my Mr Potatohead ideas came from something you said.

What is a "uneven leg angle" if your meaning like tube molds are made using a cut mandrel, than your not talking about a TRUE spider grub with a REAL skirt( like a yamamoto grub with skirt) a true SKIRT is 90º to the bait. this has everything to do with the action in how a skirt works on a grub.

[Bob La Londe]

Delw, on 18 June 2010 - 03:31 PM, said:

What is a "uneven leg angle" if your meaning like tube molds are made using a cut mandrel, than your not talking about a TRUE spider grub with a REAL skirt( like a yamamoto grub with skirt) a true SKIRT is 90º to the bait. this has everything to do with the action in how a skirt works on a grub.

LOL. I think we are not talking about the same thing. Instead of using a solid piece of aluminum stock for the body like you were saying why not use a piece of aluminum angle. You can buy it with one leg one length for whatever length body you want and one leg a different length to accomodate whatever wdith skirt you want. Buy whatever thickness you want to work with. Its a lot less aluminum than doing it out of a solid piece of stock those dimensions. And it will result in a nearly perfect 90 degree skirt depending on your ability to clamp the work piece.


For example:
http://www.onlinemet...tural_Angle.cfm

Really. Like I sketched it.

This post has been edited by Bob La Londe: 18 June 2010 - 05:37 PM

[Delw]

Bob La Londe, on 18 June 2010 - 05:32 PM, said:

LOL. I think we are not talking about the same thing. Instead of using a solid piece of aluminum stock for the body like you were saying why not use a piece of aluminum angle. You can buy it with one leg one length for whatever length body you want and one leg a different length to accomodate whatever wdith skirt you want. Buy whatever thickness you want to work with. Its a lot less aluminum than doing it out of a solid piece of stock those dimensions. And it will result in a nearly perfect 90 degree skirt depending on your ability to clamp the work piece.


For example:
http://www.onlinemet...tural_Angle.cfm

Really. Like I sketched it.

Your talking about angle iron/alum nothing wrong with it as long as its 1/2" or thicker perside, however the price per foot is more than flat stock.
so it would be less costly and time consuming to use flat plate. due to less machine time( in tooling and set-up) and the price of material.

This post has been edited by Delw: 18 June 2010 - 05:49 PM

[Bob La Londe]

Delw, on 18 June 2010 - 05:48 PM, said:

Your talking about angle iron/alum nothing wrong with it as long as its 1/2" or thicker perside, however the price per foot is more than flat stock.
so it would be less costly and time consuming to use flat plate. due to less machine time( in tooling and set-up) and the price of material.

Ok fair enough. It sure did seem like you were wanting to either build it out of more pieces which would mean more machine time or a solid piece of stock which would mean more metal weight. Also, you have to recall I don't go through a lot of metal so I have to buy it from guys like On Line Metals or Metals to Go. All I can compare is their plate price to their angle price. 3 x 5 plate ($639 apx for 144") costs more than 1/2 x 3 x 5 angle ($317.88 for 300") for example.

Not sure how making an angle out of flat plate would be less machine time than using a piece of angle. I just have one small CNC machine so everything I can do to reduce machine time is important to me. Maybe your thought was to not assemble it at all? Just pins and even more clamps?

[jacobsbaits]

I've been watching this post from the start, and I'll have a mold for that bait available within two weeks.

[Bob La Londe]

jacobsbaits, on 26 June 2010 - 09:48 PM, said:

I've been watching this post from the start, and I'll have a mold for that bait available within two weeks.

I'ld already have one, but I ran out of metal to play with and won't have any more in until next week.

I'm glad you are running with it. You are one of the commercial builders who was willing to share some info that has been helpful to me. Well that, and I bought one of your molds just to analyze it and figure out how to make mine better. LOL.

I've actually been doing some design work in the old CAD CAM software for a more complex version of this mold. Basically to have interchangeable tails, shoot with our without skirt, shoot multiple skirt, or shoot one section, and then add a section to shoot another color. It would be prohibitive for most bait junkies to buy or to make for sale, but for myself it will be a fun exercise. My simulations are showing a lot of machine time. The one nice thing is by planning it in sections if I screw up one section I do not have to start over.

The idea is I can make craw, single or double curly, or beaver tail sectional molds that will be interchangeable with the main body. Then have an interface that is stackable at the other end to shoot a straight grub body, or stack skirt plates for a miltiple skirt bait. Its not universal, but with less machine time then individual molds I'll have a mold I can shoot 10-12 different baits with. My planned prototype design is 4 cavity. I bought enough angle to make two of them so wish me luck.

I might even break down and spend some real money for a trunnion table and 4th axis for my machine so I can pin it accurately.

This post has been edited by Bob La Londe: 26 June 2010 - 10:50 PM

[jacobsbaits]

Bob, I think we're on the same page. The sky is the limit on the bait possibilities that a mold like this can make. I'm thinking, a universal skirt mold that will mount on top of a variety of body molds.

[carolinamike]

Guys, why not do a core pin in the front of the grub just like you would a skirt in a tube bait? As far as making the skirt flare you could make the core pin as fat as you'd like, make your injection hole at the side of the bait in order to fill the skirt and the grub. You could make multiple core pins so when you shoot, just pull core pin, bait and all out and put a new core pin in and keep on shooting. Seems like this would be an easier way of going about it.

[CaptRodney]

jacobsbaits, on 27 June 2010 - 10:32 AM, said:

Bob, I think we're on the same page. The sky is the limit on the bait possibilities that a mold like this can make. I'm thinking, a universal skirt mold that will mount on top of a variety of body molds.

Man once these molds are made I cannot wait to see them... You guys rock I sold my CNC last year used it for pool cue building for a month too much learning curve. BTW if you know anyone thats in need of Bobcad, I think Videos with dongle to operate I had 2 licenses and kept one I need to get rid of. Anyway not trying to rob your thread, back on topic... What sort of price point do you think you would have to have on one of these molds single cavity.