Jump to content
eastman03

First mold questions

Recommended Posts

So I’m finally going to make my giant hybrid paddle tail musky lure.  My one problem based on my rough calculations is I don’t believe I have enough rtv silicone.  It is going to be an open pour mold. It is flat on “top” (which is obviously face down here).  So I’ll kinda seal it down to the base. Make a mold box, but as you can see because the boot part of the tail is so tall, most of the bulk of the mold will be wasted down the length of the tail just to get the depth.  So my question is can I pour the silicone and simply put something in that area (like a block of wood?) to fill in some of the volume. 
obviously this isn’t the best option, and my apologies if this has been asked a thousand times. But mold making material is like hens teeth where I live, and I kinda don’t want to make a smaller tail lol.  What do you guys think?

 

 

447878EA-F764-4DDE-890C-6584E6B59024.jpeg

  • Like 1
Link to comment
Share on other sites

Ok first tip smooth on silicone is about half the price compared to Alumilite silicone in Canada. If I remember right the last 11lbs bucket was $160

I don’t recommend it but yes you can reinforce your silicone mold with a wooden box. I made the mistake of making a mold too thin when I first started making silicone hard bait molds. Bracing it with wood and clamps made it still functional. Thin molds suck and I no longer skimp on my molds

Make a test mold out of POP to prototype and if you like it buy some more silicone and make a good mold is my advice 

Edited by Hillbilly voodoo
  • Like 2
Link to comment
Share on other sites

7 minutes ago, eastman03 said:

Ok interesting. Good idea. Thanks! Don’t want to skimp on a mold. This was part of a soft bait kit that came with a bit of everything. Gotta start somewhere!

My skimpy mold was made because I started with a hard bait kit lol

I did a little messing around with the idea of hybrid baits recently but have decided to step away from it for now. Made a couple POP after reading about it and they work. I am taking on too many different lures and need to focus so it many be a long time before I revisit it

good luck

  • Like 1
Link to comment
Share on other sites

@Hillbilly voodoo is totally on the ball here. Do NOT try to skimp on molds, a lesson we all learn during the process.

Initial prototyping with PoP is also an excellent suggestion, if nothing more than getting used to the process. Never dispose excess down the sink, just though I would throw that gem in there.

The acetic acid cure silicone comes in the standard tube that you buy that cheap injector for, used for sealing baths and windows. You have to read the small print to see if it mentions acetic acid. If no mention then walk away.

When you pour it, the smell of vinegar is very apparent. A splash of water mixed in will make it cure very fast. Do testing to get a feel for the product.

Dave

Link to comment
Share on other sites

With some slight modification can easily make this into a POP mold and results will be really no different than a RTV for something as featureless as a tail.   

I would also highly recommend making the tail in POP first with tails.  You may find out your current design doesn't perform the way you think.  It can be a two piece mold.  

 

  • Like 1
Link to comment
Share on other sites

So i'm looking into making a pop mold based on recommendations, and I think that is a great idea for prototyping.  And that way I don't have to skimp on a real silicone mold and have regrets.  I'm just curious @Travis what you mean with some slight modifications?   What do you think I would need to change to make a pop mold instead of a silicone mold?

Link to comment
Share on other sites

It appears your tail is rounded.  If you mold in POP it will lock the master in place.  Based on your picture if you were to mold it as a one piece currently it looks like it would be locked in place as the top of the tail rounds over.

DSC_0090-1.jpg.6b1a8dfff176427d77bf79a9eb58d8b3.jpg

So in the bait above I screwed it to acrylic for my base and then built with legos the mold box around it.  If I had used POP it would have run around the undercut area created at the tail/base interface and locked the bait it (eye recess and gill also).   I molded this one with RTV first (not ideal and tail didn't move near as much as I would like).  

DSC_0101.jpg.8a99a7f8818be6fe8bd4ed3d0110d074.jpg 

It is easy to see in the molds how far the RTV surrounded the tail because it was rounded at the top.  If I made a two piece mold with the seam running across the back and side could have used POP.  Just easy to not look at the master and think about locking it in place on the first few.

 

 

Edited by Travis
  • Like 1
Link to comment
Share on other sites

Travis is spot on. In engineering it is called the draft angle. You have to be able to remove the master from the hard PoP mold.

There are solutions to this dilemma.

A soft clay master, but difficult to get a nice shape.

A three layered master, were the center layer can be extracted first.

Construct the wide parts with soft clay.

Use your imagination.

Once you have a soft plastic master, you can make a multiple pour PoP mold.

Dave

  • Like 1
Link to comment
Share on other sites

It looks like your master would be fine as a two piece based on the picture but angle may be deceiving.   The seam will run across the back and belly but master should pop right out.  I typically will drive a screw into the exposed half to pull the master out as can easily be patched if needed.   Then as Dave pointed out use the soft plastic bait as a master.  You can then make one piece molds wit it. 

Another option  for prototype is you can mold with bondo body filler.  The mold has a little give before it finally sets but just keep checking the consistency/temp of the mold to demold.  I made a lot of crank bait molds that way over the years with no issues.

 

Edited by Travis
  • Like 1
Link to comment
Share on other sites

Like Travis says, a two piece mold will solve your problem, easily done with a PoP mold.

Once you have produced a few  masters from the 2-piece mold, a one piece mold could be achieved. But if you reach that level of expertise, I see no reason for not sticking with two part molds. A far superior product.

Dave

  • Like 1
Link to comment
Share on other sites

Well this thread was full of great advice, and I ignored it all. Haha. Stupid virus has me working from home (which lets me help with the kids, so no complaining here, just happy to be working), anyway I decided to just go ahead and see if I could make a mold with what I got. I did a simple open pour mold with the alumilite silicone. Knowing it wasn’t enough I filled in gaps with 100% silicone to get enough depth.  Then I let that set up and filled in the remainder with silicone. It was a huge mess but I was bored. 
Now today I used an old pot and my torch to carefully melt some of the alumisol! I got it up to 350, and stirred it the whole time. Then I added three drops of the red dye, and a bit (probably to much) pearl powder. And after letting it cool I had my FIRST ever soft plastic pour.    Man this could get addicting!!  Need some other supplies to do it more consistently, but it was an awesome first result. 
And now I can visualize this big lure finally coming together!  I used screws in this particular lure, and a corkscrew wire in another one, anyone have any tips as to what works best? What glue would you use to join them, regular super glue?

 

E64C638D-7E31-48C3-9FEB-C3145A9F1F33.jpeg

92243A51-DAAB-4332-A3A2-2B32E81312B6.jpeg

Edited by eastman03
Link to comment
Share on other sites

Thanks Vodkaman.  Hillbilly, keyed joint? Are you referring to giving the end of the wood and rubber a interlocking shape, like dovetail, to allow more glue surface area?   I studied the new rapala hybrid that just came out, and they kind of inset the soft part into the hardbait.  Of course it's incredibly well done and beautiful.  They really do a good job, but my issue with all the off the shelve lures is either they are too small (like the rapalas), or they are a giant one piece rubber, like the svartzonker mcrubbers.  Those giant rubber baits are cool, but hard to find for me, expensive and they still get destroyed by a few fish.  I can tell some of the brands have resorted to stronger, tougher rubber, but I feel that has taken away from the tail action.  I want real soft rubber to give a nice big slow wobble on a slow retrieve, so that is what led me down this rabbit hole of pouring my own soft baits.  I can have a tough wooden body and all the benefits of that, but a real soft replaceable tail for a nice slow wobble.   Now that I've opened up this aspect of lure making, I have a million other ideas I want to try lol.  

Link to comment
Share on other sites

The method I had planned for a similar 9” bait was as followed 

1)take a 1/2 spade bit and drill a 3/4 inch hole in the front section hard section 

2)glue a half in by 3/4 piece of dowling on the master for your rubber tail. of course be sure it will line up the joint evenly front and back

this way you will have a rubber peg coming off of your tail that fits into the hard front section. This will give you a pressure fit and larger glueing surface. It will also line up your two halves nicely 

I have seen variations of this along with dove tail and slot/rail style joints used on hybrid baits 

The rapalas hybrid joint I think is more about giving a solid anchor point for the hook instead of running a wire leader from the front and sinking the hook into the rubber or a corkscrew/spur peg

 

  • Like 1
Link to comment
Share on other sites

Cool, great idea! I was thinking about some sort of joint sticking out, but once again, I just wanted to get moving haha.  I'll test out this tail/lure design, and then look toward a better method of joining them, thanks!

Has anyone ever dipped an entire hybrid lure in clear plastisol? I know soft plastics are often dipped after to give them a 3d look and to 'seal' them.  But an entire lure! lol now i'm just talking crazy.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...


×
×
  • Create New...
Top