Resin casting tutorial

Here's the tutorial you have benn asking for.

Open moulds for bases and other things with a flat back.

Tool's and other need's:
Silicone rubber and catalyst
Resin
A suitable container to make the mould in. LEGO's are gold!
Disposable mixing cups/containers
Disposable sticks for mixing
A scale that can weigh very small amounts
The part(s) you want to replicate
Modelling clay

First you take the base and stick some bluetac in the bottom. Then place it firmly in the container you want to make the mould in:


Then you mix the rubber with the catalyst until it hase a nice even blue tone:



Then you pour it into the container with the base. It's best to start around the base and let it flow over the base from the sides to minimize the amount of airbubbles:


Tap it down on a hard surface to release any airbubbles that may have formed and let it harden for 24 hours:


Peel the mould out of the container without forcing it too much. It's best to loosen the sides first and the peel it out:


Remove the base from the mould and trim the edges if you need to:


Now you're ready to make some copy's:


Mix equal parts of the two resin components and mix it well for about 20 seconds:




Pour the resin into the moulds. The resin only has a working time of about 2-3 minutes so do it fast but don't stress it. Less is more:





Let it harden for 15 minutes:




Pop the hardened resin casts out and trim the edges if you need to. and you're ready to paint:







TWO-PART MOULD

Tool's and other need's:
Silicone rubber and catalyst
Resin
A suitable container to make the mould in. LEGO's are gold!
Disposable mixing cups/containers
Disposable sticks for mixing
A scale that can weigh very small amounts
The part(s) you want to replicate
Modelling clay. My Dough from a toy shop works fine(though it smells horribly sweet)


First you need your container to make the mould in. I use LEGO's as they are perfect for this. Build it uo in a shape and size to minimize the amount of rubberwaste but don't get too cheap. You dont want a hand or foot sticking out somewhere when you're finished:




Then you fill in the bottom half of the LEGO box with modeling clay and press your part about halfway down in it. Make sure there isn't any space between the part and the clay the rubber can seep into. I use a clayshaper to press the edges of the clay against the part:




Then you mix the rubber with the catalyst until it hase a nice even blue tone:



Find an old brush and start to paint the parts with your rubber. Make sure to get it into all the little holes and details on your part. I don't have any pictures of this stage but there's some similar ones further down the tutorial.

Put a lid on the box and pour in the rubber in a thin stream. The thinner the stream the less airbubbles it will make:




Leave it on a flat surface for 24 hours. IT'S VERY IMPORTANT YOU LET IT DRY FOR 24 HOURS! The rubber may seem dry after shorter time but the release agent will be absorbed into the rubber and will have no effect and possibly ruin your mould.
Also the rubber will seep out between the LEGO bricks a little bit but as long as you don't place it on your wife's antiqe hardwood desk it rub's off with a finger.

After 24 hours take the box apart and remove the first half of the mould. Remove most of the clay so you can use it again another time and use hot water and a hard brush to remove the last clay from the mould and parts. ANOTHER IMPORTANT NOTIFICATION: Don't take the parts out of the mould. It's virtualy impossible to make it fit in the mould again and the next part of the mould will seep in between the parts and the first half of the mould and again, ruin your hard work:





Rebuild your box and place the first half firmly into place. Apply the release agent on the mould but not on the parts as it may ruin any fine detail:



Put a lid on the box and pour in the rubber in a thin stream. The thinner the stream the less airbubbles it will make:




Leave to dry for 24 hours:



Take the box apart and seperate the two parts of the mould. They may stick together a little bit but should come apart with a little leverage.





This is where I forgot to take pictures and have since run out of mixing cups and pippettes but I'll try to explain it without pictures.

There's a bit of trial and error in the next stages as you properbly need to cut the mould a little bit to ensure a minimum of air bubbles forming at the top of the mould where the resin is injected.

But the mould back in your box and mix up the resin.
Use a pippette or syringe to get the the resin into the mould. If you just pour it in there will be much more airbubbles in it.

I'll finish the tutorial with pic's as soon as I get new supply's.

Wow! this is great!

I can't wait to see how you do models or pieces of a model.

How many casts can you make from one form?

Quote :

How many casts can you make from one form?

Wait! I know the answer to this one... it's a shitload, yeah?


I've found that my one part moulds would often come out not quite flat on their flat edge - having a bit of a curvature to them. In order to encourage them to catalyse flat, I tried resting a few different things on the top of the mould while the resin hardened, and found that far and away the best thing to place over the moulds was the flat side of other one part moulds I wasn't using at the time. They're good and flat, and (as you'd expect) resin doesn't stick to them at all.

Komfritten wrote:

How many casts can you make from one form?

He he, I do believe a shitload is a good answer. Though I read somewhere that a mould will loose detail after 20-30 casts because of the heat the resin generates.

lakedaimonioi wrote:

I've found that my one part moulds would often come out not quite flat on their flat edge - having a bit of a curvature to them. In order to encourage them to catalyse flat, I tried resting a few different things on the top of the mould while the resin hardened, and found that far and away the best thing to place over the moulds was the flat side of other one part moulds I wasn't using at the time. They're good and flat, and (as you'd expect) resin doesn't stick to them at all.

Yeah the backsides does not come out completly flat but I just sand them down if they are wobly. It's a good idea about placing another mould on top. I'll try it out later

Seems simple enough... now... how you do a TWO part mold?

Relaxe dude. The rubber has to cure for 24 hours. The first halves are ready but I haven't had time to do the second ones yet.

Patience is a virtue

mudboy wrote:

Komfritten wrote:

How many casts can you make from one form?

He he, I do believe a shitload is a good answer. Though I read somewhere that a mould will loose detail after 20-30 casts because of the heat the resin generates.

lakedaimonioi wrote:

I've found that my one part moulds would often come out not quite flat on their flat edge - having a bit of a curvature to them. In order to encourage them to catalyse flat, I tried resting a few different things on the top of the mould while the resin hardened, and found that far and away the best thing to place over the moulds was the flat side of other one part moulds I wasn't using at the time. They're good and flat, and (as you'd expect) resin doesn't stick to them at all.

Yeah the backsides does not come out completly flat but I just sand them down if they are wobly. It's a good idea about placing another mould on top. I'll try it out later

I can't remember if it was on this forum or another, but I saw mention of resin wearing out molds as well. It was a topic about Hirst Molds IIRC, the guy was casting like crazy (floor tiles I think) and they started to fit together wonky. Casting your own = no problem, just keep your original blank. Using Hirst Molds...better make a copy of the mold before working in resin.

Updated with two-part moulds

Thanks.

Very nice tutorial. I would really like to try some casting myself but don't really want to order up huge tubs of material. The things I would like to cast would be pretty small. Very interesting work though. I'm looking forward to seeing more of the finished leg and torso casts.

Looks like you need to figure out a way to make a cheap vibration table to help move the air bubbles too.

Yeah I was thinking about using a vibrator from a (dare I say it) dildo but a massage thingy would properbly be better.

MUDBOY!!! It is called a Personal Vibrator Massager...




Now... back on topic. Can you show a raw cast? I would like to see how much flash it has. THANKS!

I was thinking it but it might be a little to strong of a vibration, not to mention expensive and your wife will probably kill you unless it's yours.

I was thinking electric toothbrush the 8 dollar ones or 2 of them one at each side.

I was thinking of doing this for some stuff i was doing with Heirst molds.

Dysturbed wrote:

I was thinking it but it might be a little to strong of a vibration, not to mention expensive and your wife will probably kill you unless it's yours.

Worst image ever.

Sometimes, I put my setting moulds on top of my washing machine during the spin cycle. I don't know if it does any good, I haven't really had any problems with air bubbles in my moulds yet.

Wow! Nice tutorials!
You actually made it look easy!

Gatlag Stonetooth wrote:

Wow! Nice tutorials!
You actually made it look easy!

Once you get the hang of it, it really is easy

Mordheimer wrote:

MUDBOY!!! It is called a Personal Vibrator Massager...

Now... back on topic. Can you show a raw cast? I would like to see how much flash it has. THANKS!

Here in Denmark we have a saying: En spade er en spade! It translates roughly to: A spade is a spade! We call things what they are

I get a fair amount of flash but nothing that can't be removed with a knife:

NICE CASTS!

Wow! great work.
I will be bugging you for advice in June or July as I want to try this out.

No problem.

Mudboy:

Have you tried out this for a mold?



http://www.ebay.com/itm/wargames-conversion-fantasy-4-blocks-of-instant-mold-miniatures-/251039204878?pt=UK_Toys_Wargames_RL&hash=item3a731a460e

Yes I have a few sticks and they are great for replicating things with greenstuff. I haven't had much succes with it myself but I saw a guy on theboringmordheimforum who made some very nice copy's with it. Linky

It properbly won't work with resin though as you heat the sticks to make the mould and the resin generates heat when it hardens.

Dozer have used them... he was happy with them. He said (if I remember) that you make a heat-bath... boil some water, then put a dry pan in it so it heats slowly and evenly, put the stuff there. It softens alot, so you take the original and press it (half way) and let it cool. Remove the original and you have 1/2 mold. it becomes HARD, so you can take come GS and press it on the mold. Once it dries, remove with some TLC. The mold will not crack easily, so you get LOTS of use out of it.

The best part is that you can 're-melt' the mold and re-use it... same original or a new one! Dozer said it was nice to make simple stuff that you need few copies, but not for mass production (because you need to punish yourself pressing GS! )