wiseman

making a mold

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has anyone tried making their own mold before? I was thinking about trying to do the alumilite vac 50. looks easy enough but $40 to try something, could be a waste of time and money. I have made silicone molds but wanting to try making an injection mold.

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My limited experience with making silicone molds is that, in order to be able to make a two-part injectable mold, I would make matching open faced wooden boxes with at least 1/2" plywood bottoms, so the two halves are well supported, and can be clamped together.  That will prevent the silicone flexing out of the way and let the plastic leak out.  I would also be sure the mold is well vented.

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Vac 50 will work fine for what you are wanting to do. I have used it and have made a few injection molds out of it. 

I have used a few things for making the boxes to pour into... corrugated plastic (cardboard made of plastic), lexan cut to make the size boxes I need and also legos. The kids are all grown and I had a bunch laying around so with those you can make any size box you need and dont have all the materials for the boxes laying around after your done. Just clean them up a little and put them back into a plastic container. You will want to use some type of release agent on your boxes and the item you are replicating. If not both will be a loss. 

1. Prepare box to the size you need, hot glue the box to a smooth hard surface (lexan is good)- make sure you have depth for both halves of the mold that you will create. The first one I did I didnt make the two halves of the mold thick enough, dont skimp on material.

2. Spray release into box, and brush onto bait

3.  mix your vac 50 (comes in two container) and pour into box

4. brush vac 50 onto the back of what you are making so that you dont get air bubbles in the mold under the bait

5. settle the bait into the vac 50 so that you have half of the bait in the vac 50, let cure just a little bit and push something like a dowel into different spots in the vac 50 for making sure the two halves will go together properly

when the mold is done and let  sit over night.

6. Clean up top half of bait and whatever you need in the vac 50

7. Spray the top of the first half and bait with release and pour vac 50 on top. Let sit till cured. 

You may have a little hassle getting the two halves apart but once you do your good. Just take you time at it, they will come apart.

 

Good Luck

 

 

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Personally, I too would be nervous about the cost too, although by the comments above, the VAC50 is a good choice of material. I would have a few practice runs with PoP  (plaster of Paris). I would include a short section of copper pipe or something convenient of the appropriate size for the injector to press against, thus protecting the brittle PoP. Plastic pipe might work but I would be concerned about the temperatures. Easy enough to do a test.

All the instructions mentioned above apply regarding the box, adequate venting, mold release etc.

There will be bubbles, so tapping the box while the PoP is wet will help release the bubbles. When both halves are cured, seal the cavities with thinned epoxy. Some use thinned PVC wood glue.

Don't skimp on mold thickness, again as mentioned previously, HUGE mistake.

Once you can make a PoP mold with little fuss, then you are ready for the BIG time. You never know, you might like the PoP mold. Done right, it will certainly give you a good quality result. If you do stay with PoP, I suggest back the mold halves with plywood, to prevent the possibility of cracking under clamping.

There are TU members who are using PoP molds that they made a decade ago or more.

Just a suggestion. PoP is so cheap, it is 'a shot to nothing' and good experience. Also, good for future prototyping lure ideas without the expense.

Dave

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 I am one of those that are using decade old molds.  :lol:

Second the PoP for practice.  I do think Durham's Rock puddy gives a better mold however but cost jumps a little.   To be honest one can create a PoP or Durham's mold that will give a bait with equivalent and in some cases better finish than some store bought plastics (sad statement).    

If you thin your epoxy to water consistency it will soak in and increase the strength of the injection site.  

 

 

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Travis - I knew I had read the 'decade' thing, but could not remember names. Most people will think that because PoP is so cheap then it must be inferior, but apart from durability of the final mold, this is not true.

I have not tried Durham's, but the general census that I have read here on TU, is that it is a superior product with the same PoP qualities.

Dave

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On ‎12‎/‎17‎/‎2018 at 5:14 PM, wiseman said:

i'm interested in the del superfluke could you send a picture and info?

mel it's been a while, welcome back!  i'm interested in how your molds are done. I can't figure out how to message you so here it is. I believe your molds are silicone? I don't think they have "regular" anymore. they have so many types of silicone. I have used high strength 2 before. do you think I could cast a multi-cavity mold with silicone, one injection port.

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I use a harder plaster than POP, but same principle, always paint a coat of plaster on the mold models to eliminate the bubbles. This "2fer" mold was sealed with epoxy spray paint, but high temp engine enamel works good too. The mold half laying down works with either of the other two halves

20171021_123623_zpsvdezsyui.JPG

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On 12/21/2018 at 4:06 PM, Roger Linnell said:

I use a harder plaster than POP, but same principle, always paint a coat of plaster on the mold models to eliminate the bubbles. This "2fer" mold was sealed with epoxy spray paint, but high temp engine enamel works good too. The mold half laying down works with either of the other two halves

20171021_123623_zpsvdezsyui.JPG

Really clever and original idea!

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well, I picked up some durhams! so while i'm off work for x-mas i'm going to try it. here goes nothing.i will let you guys know how it comes out thank you for the info.

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Yes, report back, good or bad, so others can learn. It may take a couple of goes to get the procedure right. Careful with clean-up. Do not use your kitchen sink unless you know a cheap plumber.

Dave

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2 hours ago, wiseman said:

well, I picked up some durhams! so while i'm off work for x-mas i'm going to try it. here goes nothing.i will let you guys know how it comes out thank you for the info.

That stuff goes off pretty quick

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well, my mold set up. I've got bubbles on the bottom half not terrible. I can't figure out how to paint the model, if it is coated with a mold release.WIN_20181223_141827.thumb.JPG.eab277e629371b50bfc456141f210448.JPGWIN_20181223_152835.thumb.JPG.a8681c118585c35ea5f6d158e6e6c64f.JPG

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6 hours ago, wiseman said:

well, my mold set up. I've got bubbles on the bottom half not terrible. I can't figure out how to paint the model, if it is coated with a mold release.WIN_20181223_141827.thumb.JPG.eab277e629371b50bfc456141f210448.JPGWIN_20181223_152835.thumb.JPG.a8681c118585c35ea5f6d158e6e6c64f.JPG

you need a vent for each cavity. at the tail of each bait, cut a line straight out to the end of the mold. This allows air to . shoot the plastic  little warmer and slower

 

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the mold turned out good. I did get air bubbles on the lower half but not bad. I tried to work out the air buy placing a vibrating sander on the bottom of the mold box for a few seconds, and the bubbles came to the top that may have been why I got bubbles on the surface of the lower half.I used glue stick for the sprew and copper wire for the gates. I think I should have drilled a hole in the end of the baits for the wire, the heads of the baits were a little deformed from pushing the wire in. I did vent it at the end of the tails, used a file while the mold was still warm. overall this worked pretty good I did shoot it once. the baits came out dull but were the right shape and very little flash. I know I still have to seal the mold with epoxy or engine enamel that should take care of the dullness of the baits. durhams is overall easy to work with, it sets up hard like ceramic. I also drilled the injection port with a 5/8" drill bit while the mold was still warm, I don't think I would want to try it now since it is hard as stone. I want to thank everyone for their input on this subject. I think I have enough info to get to it, and I hope this helps others with their questions. YOU GUYS ARE A GREAT SOURCE OF INFORMATION! THANK YOU!

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On 12/23/2018 at 7:50 AM, Roger Linnell said:

I'm not just a pretty face, lol

a91d713e-71ed-4d3b-b2bc-fb9b20ca4b9c_zpshrzgremp.JPG

20171108_055315_zpsk5ykrtyw.JPG

Very nice, kinda surprised there is not a higher concentration of flake at the bottom of the tails.

I have heard some people say that is a detriment with a centrifugal type of pour.  However, these pics show otherwise.

What do you use to spin the molds, if you dont mind me asking?

Also I like that you made a single tail and a double tail mold that both fit the one top piece

 

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7 hours ago, kage_killa said:

Very nice, kinda surprised there is not a higher concentration of flake at the bottom of the tails.

I have heard some people say that is a detriment with a centrifugal type of pour.  However, these pics show otherwise.

What do you use to spin the molds, if you dont mind me asking?

Also I like that you made a single tail and a double tail mold that both fit the one top piece

 

They aren't spun, just injected

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On 3/6/2017 at 1:22 PM, jigginpig said:

Nice. 

 

On 12/19/2018 at 8:07 AM, MEL said:

GO FOR IT. I HAVE BEEN DOING IT FOR 25 YEARS +. ALUMILITE  REGULAR WORKS FINE

P1010709A.jpg

 

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MORE ON MOLD MAKING

To make a mold one has to have something to mold.  Most all of my bait designs were to make a bait that fits one of the Do-It leaded molds.  I start with two pieces of 0.032 brass shim stock.  These are fastened  togeather with double sided cellophane  tape.  The outline of the bait

is then sawed, filed , etc. your satisfaction.  The body of the bait are then made up of 1/32 strips of basswood glued together to the thickness 

P1010736a.thumb.jpg.cf413de7ae34691a2d9e5e80eea2706b.jpgP1010739a.thumb.jpg.d47f7e34af5be645733fa4fd654f8eb7.jpgrequired. Each 1/32  strip is coated with a color before gluing.  This will facilitate  shaping the body. When the body is finished  The model is

then separated  into the two halves and mounted into the cavity.  Sprues are the added and your are ready to mold.  Most of my molds are

made with polyurethane  resin [ RC-3, VAC50, specialty resin.com].  I usually make a dozen bait molds of each design.  This only a hobby

for me and I don't sell baits.  Usually make baits 2 or  3 times a year or as required.

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