My Contribution to TDH

Thanks guys.

I've put the third thickened coat on and begun to create the key.

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The key will be used to help re-align the outer jacket to the body, I will be making a small pot to ensure that this is a nicely defined key and use the rest to coat the outside a little bit more before the final light coat.

Getting there :)
 

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The cardboard key is in, but I have had an influx of money making work, so I will have to concentrate on that first.

I've the final smooth coat to do, I'll get pictures up as soon as I get my work done.
 
Hokie Cokie!

Work's done, so here's the progress so far:

1. Final Thickened goop is put on with the cardboard Key so it has an object to lay against, the cardboard will be usefull in the jacketing stage.

Finalgoop.jpg


2. Coat of normal runny goop over the top to take out some of the hard edges. It may need another coat though.

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I am ordering some more silicone today as I still have the other items to cast!
 

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I'm being ultra cautious at the moment and will wait till the new silicone comes to put another coat over to smooth it off.

Meanwhile, I did try to do a step by step on how to make a mold for flat pieces, but I ran out of silicone completely whilst doing it, so the end result isn't very good at all :(

I will post up the steps later though, as I think it would help a few peeps here.
 
While we wait for the main helmet to be completed and because people have made mention that they want to know about the techniques I use, I thought that I would show you the simplest method for molding with silicone. Now, this has been done with extensive research into the process, so I know that that I won't be steering you wrong.

I call this method the "Drip" method and here it is step by step:

Type of objects you should mold with this method

You should only use this method if your item has a large flat area you can use as your base, so I will be using this method for the RF stalk.

1. You need a smooth base.

A flat bit of glass or large tile is best, but you can use plastics, anything that won't allow the silicone to get under it and get caught in crevaces. Trust me, it's pretty persistent stuff and if there is a hole, it will find its way in there.

2. Making the container.

Silicone needs an area with which to work in, if that area is thick enough then you can mold straight into a silicone mold without the need of a hard jacket. So you have to be generous with it. The problem is that with a variety of shape your containing box needs to vary too. depending on the size of the object you can use cups and boxes, but I found an ingenious method to make custom containing boxes.... LEGO!

DripSilicone1.jpg


I can't remember the name of the guy who put this method out there, but serious props to him and if he's here thanks mate!

Yes, Lego is probably the most diverse box making material you can use as in the picture above, you can size the box to the model. You can see that I have given it a lot of room at the sides and top, this is the level of thickness you want to be looking for.

DripSilicone2.jpg


Of course a mold is 3d, so I have put another layer of bricks to sturdy the model and have some depth to the mold. Ideally, you'll be wanting to fill this to the brim with silicone.

4. Seal off the model

This is an important step, I can't quite emphasise enough how pervasive Silicone is in its liquid form, if there is a micro fracture in your model, it will find it, that isn't too much of a problem as you can trim the model afterwards, but to ensure that you don't have to, you will need to seal off the model.

I use re-usable modelling putty or paste, it's sometimes known as plasticine.

The important part with this is to keep the lines of the model, but get the plasticine in underneath the model where the cracks are, if the putty is in there, then the silicone won't be and that will prevent skinning (Where a fine layer of silicone covers the part you are supposed to pour into).

DripSilicone3.jpg


You can be pretty rough when applying the silicone, I tend to use a coffee stirrer to push the putty under the model, use a craft knife to cut off the excess to the line and fill in and use the stirrer again to smooth off.

DripSilicone4.jpg


Till you get the above picture.

DripSilicone5.jpg


You will also need to seal off the box because, believe it or not, the silicone will seep under the lego and through the gaps in the bricks. No, I am not kidding! If you look at the white brick to the right, it still has the remains of the silicone after it managed to sneak through the gaps.

You can be rough with this on the outside as it won't affect the model on the inside, be sure to cover all the gaps between the bricks.

5. Preparing the drip method

So what is the drip method all about?

When you mix up silicone you create air bubbles between the mixture, which, if caught up against the model will produce flaws in your final model, imagine if an airbubble settled down next to the model, it would leave a hole next to the object and anything cast would have a bubble attached.

The pro method is to buy a silicone vaccuum tank, but they cost a fortune, so the cheaper method is to use gravity to remove the air trapped in the silicone.

DripSilicone6.jpg


First, cut a hole into the cup with a screwdriver or some sharp implement. Put some tape over the hole, but make sure you are able to take the tape off.

DripSilicone7.jpg


Put the model below and get the cup in a position so the hole will be able to drip silicone into the hole.

6. The drip

This method uses gravity to stretch out the silicone as it slowly drips onto the model, because the stream is so fine, the air bubbles trapped in it pop and you get pure silicone dripping into the model case.

You will need to mix up some silicone in one cup and then pour it into the second cup with the hole. If you want to try be conservative with your silicone (as it costs a fortune!!!) then you can use rice to fill the model to the brim, then empty the rice into a cup and mark off the height, this is the rough amount you'll need. Though I usually have another project that I can use the silicone for.

Also do not use thickners or quick cure agents with the gel or it will clog up and harden long before you have used it all. It needs to be pure drip. I've never used thinning agents, so I couldn't tell you if that would speed up the time from cup to mold.

DripSilicone8.jpg


Take off the tape and watch in wonder as the silicone slowly pours out and becomes a fine stream of liquid. Make sure you manouever the model so that the drips do not touch the model as this could trap air between the two, you want it to hit the space around it and allow the silicone to slew over the model.

You will also have some useable bi product in the other cup, I tend to hang over the model with the mixer cup upside down, you usually get quite a bit dripping out into the model.

DripSilicone9.jpg


You may get little bits on the model while you are adjusting but they should be ok.

Note also how I have positioned the model on the tile, so it's closer to the edge, this will prevent you having to invent ways of getting the drip cup as far away from the edge as possible, if it's closer to the edge then you don't have to put the cup out so far and thus prevent family members and/or pets knocking it over.

Oh and make sure you do it in a room without a breeze, the drip is affected by the slightest breath let alone a breeze! :)

DripSilicone10.jpg


Finally here you see the silicone beginning to slew around the model, you want to fill this to the brim. In my case I didn't have enough and had to abort the process.

Once it is done LEAVE IT ALONE on the floor for about 3-4 hours, then move it to higher ground.

That's about it, I will try again with the new silicone when I have it and will show you the end result.

Hope that's help you in your modding needs :)
 

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And with the silicone coming yesterday I was able to finish this off:

moldrfstalk.jpg


It is thick enough so it will not need to be jacketed.

And also put another thickened layer on to smooth things out:

moldpenultimate.jpg


One more layer and I'll be ready to make the jacket
 

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Thanks for your comments :)

Right, last coat of silicone is now on and it's time to prep for the Fiberglass jacket.

I've been doing a little trimming of the key to ensure that the fiberglass goes on as smoothly as possible, this is using a craft knife to cut a straight edge and the unwanted parts of the silicone is peeled off across the top and bottom.

trimmedtop.jpg


The other thing I did is a lesson from my last attempt. I found it difficult to realign the base of the mold to the jacket when I took it all apart and put it back together again and I felt that I needed to find a way to ensure proper alignment.

So what I have done is cut peg holes into the base lip of the silicone. What will happen then is that the resin and fiberglass will be pushed into the hole creating a peg. This will mean than when I come to marry the two together once the model is removed I will know exactly where the model should be placed and make it quicker to align the mold and the jacket together correctly.

trimmedbottom.jpg


I will hopefully be able to get started in the next few days, but the weather has been pretty poor here.
 

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I haven't had a chance to comment in this thread, but I wanted to say that this is probably one of the best casting WIP threads I've ever seen.

Major props Saz!
 
Thanks for your kind words guys! It is appreciated.

I had a little spare time so I have begun to mold the RF hood, I'm taking a bit of a risk with this (Vader :D) as I am using the flat drip method shown above and I hope to work it back out of the silicone without breaking it!

It is actually good if it is difficult to get your item out of the mold because it means that the thickness of the silicone won't have allowed the resin to warp the model and model warping is downheartening!

Skupilkinson, if the weather here doesn't improve I'm going to have to stink the house out with resin :(

Not my first choice, I can tell you!

I'll be going onto two part casting sometime later as I need to get the earpiece and viewfinder part of the RF to mold. Mind you, I'll be doing that purely from theory that I have researched (which is why I left it till last :D)!
 
Whoops! Ahhh, the amount of ear bendings our love of Starwars has caused mate! Nevermind, If I were you I'd convince her that Torchwood was real and the smell of resin prevents attack by Plugarths from Nord.

Though you might do well to run if she calls the men in white coats :lol:
 
Popular? You mean with the wife?? LOL! She tolerates my hobby, I think it's fair to say. :) we have enough space here though that they aren't dotted all over the house. She's a good one. :)
 
Right, the RF top cover came out of the mold pretty easily, which has me a little worried that the rubber might be too thin, only way to find out is a test piece.

The other problem is it's going to be hard to get mold release into the mold. I may have to try another method if this doesn't work.

I also had an excess of silicone, which I poured onto the bucket mold for more smoothing, so it's still a bit tacky.

Might be tuesday before I can start jacketing this bad boy.
 
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