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Author Topic: How To Make Molds & Casts With Instant Mold & Milliput  (Read 38205 times)

Offline Darknight

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How To Make Molds & Casts With Instant Mold & Milliput
« on: November 24, 2012, 07:39:02 PM »
There has been discussion about using Insant Mold to make duplicates and multiples of components on the forum, and I recently purchased some. After a lot of trial and error, I have been able to come up with some simple instructions which allow you to make decent copies of objects. A few opening remarks;

The copies made are not by any means perfect - they often have minor imperfections and do not reproduce detail as well as commercially-produced components or original sculpts. One may get much nicer results with resin or metal casting using silicone etc. However, those methods can be expensive - especially for a small run - and often require specialized equipment to accomplish.

Highly complex components are not well-reproduced by these methods - a full figure could not be made, for example. The best results are seem to be got from flat objects, and objects which exists mostly in a single plane (shields, swords etc.)

The minor variations in the duplicated components mean they are best used on rank-and-file models, and when partially covered by other things. I have duplicated shields, for example, which I have then put laurel wreaths on, allowing me to hide minor imperfections.

These techniques should not, of course, be used to evade copyright or perform any illegal activity. This tutorial is offered simply for informational purposes and no other.

With that out of the way, it must be said the results are rather nice and much easier than making multiples of a single item in a "factory assembly line" process in many cases. Here is the equipment you will need - all of it is readily available.



A kettle to heat water (some people maintain that a microwave can be used to heat the water; I have not tried this. I have found that the water needs to be as near boiling as possible to get excellent results, so a kettle with a theromostat switch works very well).

Milliput - I used the standard grade. Milliput works better than Green Stuff because it is softer when mixed, and more easily squishes into gaps. It is also easier to scrape excess away and can be filed and sanded more easily. You may find another putty which is good, but I had best results with Milliput.

A heat-proof dish to hold water.

A fork or other utensil to remove the Instant Mold from the water (a fork is good because it has tines which drain the water, but is not so small and sharp the Instant Mold bends under its own weight).

The Instant Mold. There are various brands of thermo-setting mold material on the market, but Instant Mold is the one I have used.

Sheets of fairly sturdy plasticard or other hard, smooth material.

Pieces to be duplicated. For the purpose of this example, I have used some pre-cast components, but one should only use this to duplicate items one has sculpted oneself.

Not shown here, but necessary, are paper towels to dry items, and superglue (for two-sided molds).



Heat the water to boiling point and pour it into the dish, putting the Instant Mold inside. It may float to the top, and I find it useful to use the fork to hold it down.



Instant Mold seems to make the best molds when you begin with a square block. If you are reusing the material (which you can do) the best thing to do is remove it from the water after a few minutes and mold it into a rough block with your fingers. The Instant Mold is quite safe to touch, but the water will be very hot, so use the fork!

When you have made the blocks, pop them back into the water to continue to soften.



There are three different kinds of molds I have discovered one can make - there is the single-sided or press mold (which is a mold of a thing which lies flat on a surface. The mold is simply filled with putty and then smoothed off). There is the double-sided mold which produces a fairly complex shape, and there is the hybrid mold which I call the "one-and-a-half" sided mold, which is made from a single-sided mold. We will discuss the single-sided mold first.

Place the item to be duplicated on a flat piece of plasticard, with the flat surface down. In the single-sided mold, the detail of the underside is not reproduced. This makes it an excellent method of making shields, icons, and other details where the rear is not important (thus, this method is not recommended for duplicating Kardashians).



Remove a block of Instant Mold from the water, and make sure it is fully softened. It should be easily maliable throughout, with no hard center. Once it is fully softened, dry it with the paper towel and squish it on the item to be duplicated.

Use smooth, even pressure. Make sure you do not have air or water pockets around the piece. You have a few moments to work this without difficulty. If it does not work, just peel it off and re-heat it and try again!



Use another piece of plasticard to flatten the top of the mold. Don't press too hard - if you do, the mold will cut through to the piece itself and cause problems. Just flatten the top. This makes it much easier to place the mold flat while filling it.



This step is not necessary - the molds will harden at normal temperature. But, I like to put them in the freezer for a few minutes to really set up. You can see it sitting on top of the cranberries.



Once the mold is hardened, you can carefully remove the plasticard and the piece - it should not stick too much. The mold is quite flexible, but be careful. You now have a very nice press-mold!

You can use the press-mold method for casting objects which don't have a perfectly flat bottom - you just have to accept that the back of the piece will be perfectly flat! For some applications, this isn't a problem (this shield, for example, would work with a smooth back without any problems) or can be overcome with some careful carving and filing afterwards.



Now let's work on a two-sided mold. Begin by making sure your Instant Mold is good and soft. You will need two pieces for a two-sided mold.

The water cools fairly quickly, so you will likely need to get fresh water, newly-boiled.



This is fairly tricky to describe perfectly. Take a piece of the Instant Mold and put it on the flat surface. Then, press the component into it. Do not press too hard. The idea is to set it in there, about half-way. The surface of the Instant Mold will deform, curving down like a matress with a heavy object on it. This is make a depression all around the model.

Notice that the piece has been put near the edge of the mold, and that it actually overhangs a little. This is deliberate. If possible, make an overhang for a two-sided mold; this allows excess putty to squish out and not make a messy cast.



Here, the freezer is all-but essential. Let the piece get really nice and cold - not only does this set the mold, but also helps with the next stage. A cold surface means the fresh Instant Mold tends to harden quickly, before it can stick to the other piece.



Take the mold and piece (still in situ) out of the freezer. Use another piece of soft Instant Mold (you will likely need fresh water) to squish over the top. Try to get the Instant Mold to flow over the edges of the first piece - this makes a "key" which helps with aligning the mold later.



As with the single-sided mold, flatten the top with some plasticard.



Into the freezer with it! Here it is seen sitting on top of some nicely frosted steins.



When the mold is set, carefully pry it apart. You can use a tool to help you here. It may be difficult, but apply gentle, even pressure and it will come apart.



Now let's cast something! Mix up a blob of putty about the right size (it is better to have too much than too little, of course) according to the instructions.



For the two-sided mold, squish putty into both sides. Use a tool to press it in if you wish, and use water to smooth it off. Scrape away excess putty. The idea is to have an even layer of putty in each half, up to the level of "lip" of that half of the mold. When put together, they will make a full cast.

Sop up any excess water with a paper towel. It needs to be pretty dry for the next stage.



Apply a thin layer of superglue - any kind will do - to one side of the cast. Superglue will not stick to Instant Mold once it is cured, so it is quite safe.

If you are casting something long and thin, you can place a thin piece of wire between the two halves of the cast, to give some strength,



Squish together the two halves of the mold. Make sure they are lined up correctly. With the flat surfaces, you can easily press them together on the surface of a table. You do not need crazy pressure - too much pressure will deform the mold and make the cast thinner.



The single-sided / press mold is very simple indeed - just fill it with putty and smooth it out with a wet finger. You can leave it completely flat if you wish or, as I have done here, make it slightly concave if the application merits it (for example, a shield.) Obviously, no rear details are reproduced, and that is what one uses a one-and-a-half sided mold for.



The completed casts. The shield has a couple of small errors on it, caused by bubbles in the Instant Mold. But these are very minor, and could easily be trimmed away leaving a nice smooth surface. The helmet has been turned to show the worst of the casting line down the face - for a more detailed model, this might cause a problem. But, for a simple facemask like this it is not too serious and could easily be trimmed away.



Another picture of the components, this time showing the side detail of the helmet, which has come out very nice and cleanly. This casting would work well as a rank-and-file model, but probably not a character!



Here we see the single-sided mold with the original piece in place (truth in advertising; I have actually used a plain shield of the same size and shape. This works for this application because the rear of the shield is all I am interested in.) Notice how it fits in perfectly, and notice also the small notch I have cut out on the left side - this will work as a "key". I freeze this assembly to make the mold more solid and cold.

I then heat another piece of Instant Mold (I actually trimmed the helmet molds of excess Instant Mold - this works well. But, if you are reusing Instant Mold, please make sure you clean it well. Soap and a toothbrush works well, and you can also scrape off the putty with a modelling tool. The putty comes very cleanly off in large pieces, but the thin "wash" which squeezes out is harder to remove. If you stick on a big slab of Milliput, let it cure, and then peel it off it will take the rubbish with it.)



Then, squish the Instant Mold on the top of the piece and first mold. Get it into the "key" notch, but be careful to not let it wrap around completely (it will be impossible to open the mold!) Flatten the top with a piece of plasticard.



Here you can see the key notch filled, allowing easy placement of the top of the mold.

To use this one-and-a-half sided mold, fill the first side with putty and smooth it off as you would for a press mold. You will want to make a suitable depression in the putty, so when you push them together the mold halves can fit. Then, simply press the mold halves together and let it cure.

The end result is very good - the better detail is got on the side of the first mold, but the detail on the rear is acceptable. Of course, for the average shield the only thing one is interested in is the curvature of the shield, not any details, so this is a minor point.
« Last Edit: November 25, 2012, 03:37:11 AM by Darknight »
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Offline Claus79

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #1 on: November 24, 2012, 10:27:33 PM »
I absolutly love you!! the internet altruism is strong in this one!  :mellow:

What do you use for putty? just regular green stuff or??

kind regards

Claus

Offline Darknight

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #2 on: November 24, 2012, 10:54:50 PM »
What do you use for putty? just regular green stuff or??

I used Milliput - it is available in the UK and the USA pretty easily. It is the old-skool putty, which people used many years ago and was the go-to thing before the ready availability of Green Stuff. It has different properties - it is more like a traditional clay than a plasticine when one works with it. Because it is a bit softer, it can fill the voids in the molds more easily. It takes longer to cure, but when it does cure it is harder (it takes about 4 hours). It is not so good for sculpting details, but is good for this kind of casting work (and bulking out for bases etc.)

EDIT : I do not speak the Danish, but this site http://www.model-hobby.dk/ claims to be oldest hobby shop in Denmark and "Modellermaterialer – MILLIPUT (5 typer)" which I think has to be positive. Denmark is, of course, a large country and so you may be far from this place. Still, one can get the putty in Denmark it seems.
« Last Edit: November 24, 2012, 10:57:14 PM by Darknight »
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Offline Silver Wolf

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #3 on: November 24, 2012, 10:57:12 PM »
 :eusa_clap:

Milliput yellow/gray is a great choice.
It's too gooey for standard modelling, but it may be perfect for casting. It's cheap and it turns rock solid pretty quick.

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Offline Darknight

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #4 on: November 24, 2012, 11:32:09 PM »
It's too gooey for standard modelling, but it may be perfect for casting. It's cheap and it turns rock solid pretty quick.

Back in the day, I did all my puttywork with Milliput - finding Green Stuff available at a hobby store was a revelation!

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You sir, are a genius.

Well, yes - but my selection of putties has nothing to do with that 8-)

I have updated the initial post with some pictures and information on making a one-and-a-half sided mold.
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Offline Hoodling

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #5 on: November 25, 2012, 06:14:50 AM »
Some good advice here, and pretty much mirrors my own experiences.

The end result is very good - the better detail is got on the side of the first mold, but the detail on the rear is acceptable. Of course, for the average shield the only thing one is interested in is the curvature of the shield, not any details, so this is a minor point.

I found this too, because it's far easier to apply pressure to the second half of the mould when the object is already resting in the other half of the mould. Best solution is to re-make the first half once you've made the second. I've found this improves matters.

I solved the problems with alignment of a 2-part mould by using a press made of lego. Allows me to apply lots of force, and keeps things lined up. Requires more Instant Mold, though.


Biggest trick remains using the right amount of putty when using a 2-part mould. I learned over time to use less than I expected, because all my components were coming over overly thick (people have talked about this before). Trial and error.

Offline Quickbeam

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #6 on: November 25, 2012, 06:41:05 AM »
I don't like using instamold unless it is for tiny things. For anything bigger than the stuff you guys did here I would make a silicone rubber mold and use resin.
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Offline King

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #7 on: November 25, 2012, 09:02:39 AM »
Guys how about the liquid greenstuff to fill out a mold?  Wouldn't that avoid lots of pressing and squishing of the detail?  Just my 2c here.
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Offline jullevi

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #8 on: November 25, 2012, 12:15:48 PM »
Guys how about the liquid greenstuff to fill out a mold?  Wouldn't that avoid lots of pressing and squishing of the detail?  Just my 2c here.

Sorry but it is not going to work. Liquid green stuff shrinks a lot when it hardens and if applied too thick, the middle does not harden at all. Unlike normal green stuff, it needs air to harden. The name is misleading because LGS has nothing in common with GS except colour.

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Offline Darknight

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #9 on: November 25, 2012, 01:03:50 PM »
The end result is very good - the better detail is got on the side of the first mold, but the detail on the rear is acceptable. Of course, for the average shield the only thing one is interested in is the curvature of the shield, not any details, so this is a minor point.

I found this too, because it's far easier to apply pressure to the second half of the mould when the object is already resting in the other half of the mould. Best solution is to re-make the first half once you've made the second. I've found this improves matters.

That is a very good idea; my comments were directed at the one-and-a-half sided mold, where the first mold initially made works better. With two-sided molds, I haven't noticed a significant difference between the two sides.

Quote
I solved the problems with alignment of a 2-part mould by using a press made of lego. Allows me to apply lots of force, and keeps things lined up. Requires more Instant Mold, though.

Requires a LOT more Instant Mold in many cases - I experimented with this, but eventually realized that if one gets a good key it is not necessary. Then again, most of what I am doing is single-sided or one-and-a-half sided molds; the two-sided stuff I have found is a lot of faffing and (unless it is a very rare component) almost not worth doing.
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Offline ZeroTwentythree

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #10 on: November 26, 2012, 02:33:56 AM »
Has anyone tried two part epoxy glue for casting bits with Insta Mold? I know it's usually a bit thick/viscus, but was wondering if the epoxy with the longer set times would have enough time to settle into details, etc.


Offline Quickbeam

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #11 on: November 26, 2012, 02:43:34 AM »
Has anyone tried two part epoxy glue for casting bits with Insta Mold? I know it's usually a bit thick/viscus, but was wondering if the epoxy with the longer set times would have enough time to settle into details, etc.
I have. It's really not much better in my opinion but insta Mold is kinda bad in the first place. And be careful because you might get the halves stuck together
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Offline GamesPoet

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #12 on: November 26, 2012, 02:48:44 AM »
Just saw this product this past Friday.  I did a double take, and then read the packaging.  I was intriqued, and will likely buy it to try it out.

It was good to see this thread on the product as well, much appreciated. :icon_cool: :::cheers:::

- - - - -

Quickbeam ... why are you saying the Insta Mold product is bad?
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Offline Darknight

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #13 on: November 26, 2012, 02:50:49 AM »
I have read that people have used super glue and accelerator to cast small parts, building it up in layers - but the heat generated (the same with resin) can be detrimental.

Instant Mold gives nice results provided you are prepared to accept a certain degree of variation and imprecision in the pieces made. I am using it to make shields simply because the flat, smooth surfaces are easy to repair and sympathetic to the mold. Anything more complex I would not recommend unless it was a rare or expensive component (as many single pieces from plastic kits end up being) you need a fair number of.
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Offline Quickbeam

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #14 on: November 26, 2012, 03:26:22 AM »

Quickbeam ... why are you saying the Insta Mold product is bad?

The copies made are not by any means perfect - they often have minor imperfections and do not reproduce detail as well as commercially-produced components or original sculpts. One may get much nicer results with resin or metal casting using silicone etc. However, those methods can be expensive - especially for a small run - and often require specialized equipment to accomplish.
This really. I mean it's by no means terrible. But I would much rather make a Silicone mold to cast 4 resin shields at a time even if they take a while. Comes out much nicer and lasts quite a while (the mold).
I like using Instant Mold if I need just quickly one or two more of something or if I make something myself and want to just duplicate a couple.
« Last Edit: November 26, 2012, 03:30:49 AM by Quickbeam »
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Offline Commander Bernhardt

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #15 on: November 27, 2012, 12:13:28 PM »
Great tutorial!

and for those who care: Oyumaru is the original name for instant mold! it's exactly the same product but much cheaper: http://stores.ebay.com/Kenncer-Online-Store-by-icanucan/Oyumaru-Moulding-stick-/_i.html?_fsub=3049778017&_sid=61436737&_trksid=p4634.c0.m322 (I got mine here)

and for those that don't trust the japanese: http://www.ebay.com/itm/Rapid-Mold-Sticks-great-for-making-an-instant-push-mold-/251184962192?pt=UK_Toys_Wargames_RL&hash=item3a7bca5a90

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Offline Darknight

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #16 on: November 27, 2012, 12:41:49 PM »
for those that don't trust the japanese

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Offline humanityunited

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #17 on: November 28, 2012, 03:16:48 PM »
Great tutorial Darknight! Thanks for sharing!  :::cheers:::
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Offline SorenJ

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #18 on: November 28, 2012, 06:27:45 PM »
Biggest trick remains using the right amount of putty when using a 2-part mould. I learned over time to use less than I expected, because all my components were coming over overly thick (people have talked about this before). Trial and error.

You need to make an outlet where the excess greenstuff can go once you apply pressure. It is key to reducing moldlines. You then have to remove the outlet from your finished product with a knife. This is actually why many of the GW figures, or other injection molded items, have all those anoying sprue connections.

Have anyone tried using greenstuff for a mold instead of Instant Mold?

Offline Darknight

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #19 on: November 28, 2012, 06:34:26 PM »
Have anyone tried using greenstuff for a mold instead of Instant Mold?

I tried it. It is just not as good, for many reasons. The end results were acceptable for certain applications, but not anything people might actually look closely at . . .

I would recommend springing for the $20 Instant Mold (you can likely get it cheaper, too).
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Offline Delthos

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #20 on: November 29, 2012, 01:12:34 AM »
Biggest trick remains using the right amount of putty when using a 2-part mould. I learned over time to use less than I expected, because all my components were coming over overly thick (people have talked about this before). Trial and error.

You need to make an outlet where the excess greenstuff can go once you apply pressure. It is key to reducing moldlines. You then have to remove the outlet from your finished product with a knife. This is actually why many of the GW figures, or other injection molded items, have all those anoying sprue connections.

Have anyone tried using greenstuff for a mold instead of Instant Mold?

I've made lots of greenstuff press molds. The only thing is you need to use a little petroleum jelly as some mold release on both the item you are making the mold of and also on the mold when you cast things in it. Works great for making small things.
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Offline Commander Bernhardt

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #21 on: November 30, 2012, 10:43:00 AM »
I've used olive oil :D
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Offline Eltrummor

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #22 on: April 20, 2013, 03:45:55 PM »
Awesome ship! How/where did you make/buy it? 
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Offline steveb

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #23 on: April 20, 2013, 11:43:18 PM »
I've used olive oil :D

cheap cooking spray works real well and is fast.     I used to cast small bits using silly putty, spray the putty press item in it, then removed item and put in liquid crazy glue, hit it with a spritz of accellerator and poof! instant piece.  Instant mold is better, but I haven't tried using crazy glue yet, it would probably reproduce details quite well.  steveb

Offline techbuilder

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Re: How To Make Molds & Casts With Instant Mold & Milliput
« Reply #24 on: November 04, 2015, 06:00:37 PM »

All you images on this amazing article you wrote are gone.
Any chance for the images to be restored?