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Julius Wilkko
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Discussion Starter · #1 ·
Hi!

I wanted to build a really BIG grandstand, but encountered a problem with the figures. Very big grandstand can take up to 140 small 1:32 scale figures to fill it up. Plastic spectator figures cost about £1 a piece. I would have to pay £140 to fill my grandstand with spectators. There had to be a cheaper alternative. I decided to inspect use of soft 2-part silicon moulds and plaster to duplicate Scalextric spectator figures. Step-by-step instructions below.

First you have to trim the plastic figures. Remove mould separation lines.



Preparation of the 1st part of the 2-part mould. Place modelling clay around the figures so that the lower half of the figures is covered with clay. Ensure that there are no negative angles.



Press holes to the modelling clay. These will function as guides when the two parts of the 2-part mould are connected together.



Place plastic sheets around figure/clay piece. Tape the plastic sheets together, ensure that no gaps or holes are left to the structure.



Surround the base with modelling clay. This pushes the plastic sheets towards the structure and seals the bottom.



Use some chemical to help with mould separation. Light oil, soap, or special mould separation chemical. I used a chemical which is called "Download", it forms very thin film on the surface of the part.



Silicon used with this project was Wacker elastosil M4511. Hardener is Wacker "T"-hardener. Add 3% of the hardener and mix carefully.



Pour silicon to form the first part of the 2-part mould.



Let the silicon to set for few hours and then separate the clay/figures piece from the silicon. We have now the first part of the 2-part mould.



Place the figures face down to the first mould and surround with plastic/clay. You should wax the pieces very carefully with mould release wax. This is preparation for casting the 2nd part of the mould.



Mix and pous silicone, let it set for a few hours.



Separate the pieces. You now have 2-part mould to form 1:32 spectator figures.



Prepare the top-part of the mould by drilling holes for casting and air.



Connect the pieces together and you are ready to cast your first part. Use rubber bands to keep the pieces together.



Mix plaster. 2 parts of plaster to 1 part of water.



Pour well-mixed plaster to the mould. Press the mould to remove air bubbles.



Let it dry for at least one hour and separate the mould very slowly and carefully.



After separation trim the plaster cast with hobbyknife. Plaster will duplicate the original piece quite well.



Cost of my figures now? Maybe about 0.12euros (£0.08) per 5 figures. (0.024euros=£0.0164 per 1 figure). Requires a lot of work though.

Happy casting!

Julius
 
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hi, Julius
thanks very much for your very informative how-to on molding. I have been thinking about casting some driver and passenger figures...and will borrow your techniques. Probably go with synthetic rubber mold and resin bodies, but seems like the same principle should work. it's always nice to have pictures to work from ...thanks again!!

John
 

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Julius Wilkko
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935 Posts
Discussion Starter · #4 ·
Hi!

Hornby Hobbies Ltd. owns the rights for these figures. My plaster figures will not be for sale. Stricktly for my own use. Multiple same figures? I will duplicate Carrera and SCX figures as well to get a good mix. By changing colours and figure sets on the grandstand it is very easy to create an illusion that each figure is individual little person. The whole story with some extra pictures can be found here. Text in finnish, but the pictures are self-explanatory.

Cheers!

Julius
 

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Ian
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JW,
Great step by step, I love the picture where you are tickling the guy with your paintbrush,



Personally I have been buying "Homies" off ebey to bulk out my stands much cheaper than Scalex or Carrera etc, but not in the same era either as they are very modern characters but you get them cheap.

Thanks for that

Ian
 

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Great idea.

Not got these figures myself but it looks as if it would be a simple process to separate them. With a bit of filing on the cuts you would then have individual figures which would allow more combinations on your seating.

I've never used plaster but if they were cast in resin you'd be able to cut/saw off a few heads and swap them around for additional variations.
 

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Julius Wilkko
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935 Posts
Discussion Starter · #8 ·
Thanks for positive comments!

Just checked that plaster costs 2.8euros (£1.9) per kilogram. Set of 5 figures requires about 30grams of plaster so I will be able to manufacture 33 pieces of 5-set figures out of 1Kg plaster. The problem is that minimum bulk packaging of plaster for that price is 25Kg sack. I guess I´m gonna use plaster for that GRAND Grandstand also. I will get back with pictures as soon as I get something finished.

Cheers!

Julius
 

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QUOTE (John Cahill @ 20 Apr 2006, 16:42) <{POST_SNAPBACK}>hi, Julius
thanks very much for your very informative how-to on molding. I have been thinking about casting some driver and passenger figures...and will borrow your techniques. Probably go with synthetic rubber mold and resin bodies, but seems like the same principle should work. it's always nice to have pictures to work from ...thanks again!!

John

John can you please tell me about synthetic rubber mold. Is there a trade name for this product or where would you get it...craft shop? Same with raw resin. What would this be called from a shop and in what quantities does it normally come, eg small bag or Miniskip load.

Julius - Fantastic article by the way. Can't wait to give it a try.
 

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Julius Wilkko
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935 Posts
Discussion Starter · #11 ·
Hi!

GLF483, others, here´s some useful additional notes:

- Use very soft silicone as mould material. Check Wacker M4511 datasheet and get similar stuff.
- Use mould release wax when you are manufacturing the 2nd part of the 2-part mould
- Cut air-holes to each leg and each back of the head. Hollow sharpened metal tube is a good tool.
- You don´t have to use any release agent when casting plaster with silicon mould
- When casting, brush first figure faces at the mould with plaster. Otherwise you risk losing noses.
- I recommend getting an injector for moulding. This way you can force the plaster inside the mould.
- Let the plaster set at least one hour before opening the mould, otherwise you risk breaking the figures.

Cheers!

Julius
 

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Hi Julius,

Thanks for sharing that with us. I have done quite a bit of resin casting of small spare parts for scalex cars, and was about to start trying to copy some of the spectator figures for the same reason you are.

I was also considering using plaster instead of resin for the figures, because they are much larger than the other parts I have cast, expecially the 5 seated figures in a row. Besides the high cost of the resin, I wasn't sure I could fill such a big mould with resin before it starts setting.

Now that I know plaster works OK, I will give it a try myself. I have some old plaster of paris lying around somewhere (the kids used it for making stuff), so it won't cost me anything to try 9apart from the cost of the silicone for the moulds of course, but I would need that anyway, no matter what material I use for the casting).

Thanks again Julius, love your work!
 

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QUOTE (brisbiker @ 20 Apr 2006, 14:00) <{POST_SNAPBACK}>
John can you please tell me about synthetic rubber mold. Is there a trade name for this product or where would you get it...craft shop? Same with raw resin. What would this be called from a shop and in what quantities does it normally come, eg small bag or Miniskip load.

brisbiker,
My apologies...missed your question the first time! *grin* Lately, I like to use urethane for my mold masters, and then mold in resin. If the shape is complete and requires deforming the master quite a bit to extract the finished part, I find urethane (especially fairly soft urethane such as Shore A 20) to be excellent and durable. The reason I mention flexibility is that often I can "cheat" and make parts that would normally require a 2-sided mold but with a simple 1-sided mold. Recently I have moved to Smooth-on products. I like their Vyta-flex urethane for molding and their Smooth Cast products for resin. The urethane comes in a variety of hardnesses, the resin comes in a variety of cure-times. They also have a wide range of products worth reviewing, all high quality in my experience. Also be sure to get some of their "Universal Mold Release" when casting resin in urethane. Please ask if any other questions...
best regards,
John
 

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two suggestions from my years of casting
1. would be to add a rinse agent into your plaster. here in the States we have "jetdry" for dish washers. add that to release the bubbles form the plaster while it sets. its a "wet water" technique.

2. buy a "lady massager" of some type and duct tape it to the board where you pour your plaster so that the bubbles rise to the top.
 

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Thanks for sharing Julius, though I'm not in the people process of my track just yet, this will come in very handy when I do get there. I am definatly going to try this with pit crew figures.

thanks again

Arman
 
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