modelmaking guides

Guide to Desktop modelling

Card modelling

Setting out the elevations

Firstly draw the different elements of your design that will make up the 3 dimensional model. If these are drawn on a computer extra details can be easily added such as brick work, window frames and colours.

Gluing Paper to card - Using spray mount as a contact adhesive

1. Spray 2 or 3 light even coats of spray mount onto the back of the paper and board and let the glue become touch dry. 2. Then apply the paper to the board working from one end smoothing out any trapped air.

Cutting guide

1. Place the card onto a cutting mat.
2. Stand up and place the ruler on top of the elevations so you are cutting on the waste side and hold the ruler firmly on the board keeping your fingers away from the cutting edge.
3. Hold the scalpel with a sharp new blade vertical and fairly upright so your cut leaves a right angle between the top surface and the cut edge.
4. Make a cut through the top layer of the board then repeat several times until you have cut all the way through the board.

Note: You will get a better cut and are much less likely to cut yourself using a sharp blade and by making gentle cuts rather than trying to cut all the way through in one go.

Gluing card to card - Using PVA glue

1. Run a thin line of pva glue along one of the edges of the card
2. Carefully place the edges of the card together
3. Hold for about 15 seconds until the joint holds
4. Leave for about 15 minutes for the glue to set
5. Repeat until the model is complete

Foamboard modelling

Cutting out the elevations Cut out the elevations as described in card modelling but take extra care to make sure the scalpel is held absolutely vertical so the edge is at a right angle to front face.

Gluing foam board edge to edge - using UHU glue as a contact adhesive

1. Run the glue down one edge of the joint
2. Touch the glued edge onto the other edge and quickly pull apart.
3. Allow the glue to become touch dry on both sides
4. Firmly place the edges back together to form a strong joint.

Making a stronger and neater foam board edge joint

1. Using one of the foam board pieces as a guide mark the thickness of the foam board on the back of the other board
2. Holding the ruler firmly gently cut through the back surface of the card and the foam and not the front surface of the card
3. Gently run the scalpel along the inside edge of the front face of the card
4. Remove the cut piece
5. With the foam board on a flat surface run the scalpel along the back surface of the cut edge to remove the last bits of the foam.

1. Run the glue along the cut edges of the foam board that you removed the piece from
2. Put the foam board together as described earlier
3. Pull apart and allow to become touch dry
4. Put together and apply firm pressure to form a strong joint
5. This will give a stronger joint as there are two gluing surfaces and neater as the foam edge will be covered

Adding card details

Cutting out the details

Print details such as window frames and stonework onto thick paper or card Carefully cut out the details, always if possible cutting towards the waste side of the design Remove the waste card slowly making sure that the details have been completely cut out.

Gluing the cards details onto the model

Run a line of PVA glue along the card.
Then with a paint brush paint the glue thinly and evenly over the back of the card detail.
Carefully put the card detail in place on the model and push down firmly when positioned correctly Repeat with the other details to build up a more detailed model.

If your elevations are on paper it is best to spray mount them onto the foam board. Spray a light even coating onto the back of the design, let the glue become tacky then apply the paper to the foam board working from one end smoothing out any trapped air. For a very strong adhesion of the paper to the board use the spray mount as a contact adhesive by spraying both the paper and the board allowing the glue to become touch dry before sticking together.

You can either draw your template directly onto stiff card or draw your design on a computer, print out the design and glue it onto the card.

f gluing the template onto the card spray glue is usually the easiest method of gluing. Spray a light even coating onto the back of the design and onto the card, let the glue become touch dry then apply the paper to the card working from one end smoothing out any trapped air. Using spray glue as a contact adhesive will give a very strong adhesion of the paper to the card.

Before you start you need to check the hot wire cutter is set up correctly.

• Make sure that the wire is under tension and not loose.
• Make sure that the wire is set at right angles to the cutting bed.
• Set the temperature control to the correct setting for the thickness of the material you are cutting.

Then using the guide on the hot wire cutter cut the styrofoam to width, length and height required.

Now pin your cardboard template onto the foam and cut out the details of the design.

note: When cutting the foam try and make sure that you use one smooth movement as you pass the wire through the foam. The temperature of the wire will determine the speed that you can cut through the foam, you need to find the optimum cutting speed.
Cutting slowly will melt the foam too much causing uneven edges, where trying to cut too fast will distort the wire and could also cause it to break.
Use some scrap pieces to get the feel of the cutter before start.

suitable metals:

• Brass
• Copper
• Zinc
• Tin (tin plate)
• Steel (not stainless)
• Nickel Silver

Standard solder 60/40 will do for most jobs. There are specialist solders for particular jobs, such as Easy Flowing for long seams or Low Melting Solder for white metal.

The latter should only be used with an iron with an adjustment for temperature.

For electrical connections use Non Corrosive Resin Cored Solder.

Fluxes - helps the solder flow & stick to the metal (key) Acid Flux will serve most purposes but it will be necessary to wash the joint after construction otherwise it will corrode. Different fluxes are available for different metals (see Carr’s Range).

Large soldering jobs require large irons, but for most small model making joints use either a 25 or 40 watt iron.

Preparation of the tip is vital: with Tin Plated Tips (Weller) clean with sandpaper or a file. Iron Plated Tips (Antex) should only be wire brushed. When the tip is clean, dip in flux then apply a little solder to tin* the tip.

*Tinning - coating a base metal with a thin coat of solder

Make sure that the joint surfaces are clean, then add flux and then solder using the iron so each joint surface has a layer of solder. Put the joint together then apply the soldering iron tip to melt and unite the solder layers to make the joint.

On long joints, start at one end and work your way along to the other end rather than spot joint.

Styrene: Flexible but rigid extruded plastic from the polystyrene family

Users: Cladding for architectural models, vac forming and quick builds

Colours: White, Black, Grey & Clear and now, red, blue, orange, purple, yellow, cream and green

Thicknesses: 0.25, 0.38, 0.5, 1.0, 1.5, 2.0, 2.5, 3.2

Sheet size: 457x 508mm upto 660 x 1370mm

Accessories: White styrene strip, shapes, ladders, spiral staircases et

'As if by Magic'

The advantages of styrene over other building materials is speed:
>>score
>>snap
>>glue!

Four tools required:

• Scalpel
• rule
• paintbrush
• liquid solvent adhesive

Measure your shape out, score the surface, snap apart, pare the edge to tidy, hold together and then using the liquid solvent apply to the joint.

Capillary action: The adhesive is a solvent that will melt a small part of the styrene, drying in air the melted styrene will solidify and seal the joint

If you don't like it, peel apart, pare the surplus melted styrene off and start again.

Don't like it much later, score the surface, snap apart, and again and off you go!

Suitable moulding materials

Choosing the mould material will depend on a number of factors:

• Original artwork (master) material and shape

If there are a lot of overhangs/undercuts on the master then a flexible mould will be needed. However, on larger, simpler shapes a rigid moulding material may be more suitable, such as resin/fibre glass.

*for life casts a non toxic and fast drying material is required: plaster, alginate, latex.

• Final casting material

Certain materials are only suitable for specific casts, for example aliginate is best only used with plaster casting. Planning your casting material is important before starting your mould.

• Level of detail required

Some reusable moulding compounds produce a lower level of detail compared to most silicone and resin moulds.

• Number of reproductions/casts required

It is important to determine how many casts you require from your mould, waste moulds (usually plaster) can be a cheap way to do a single cast. If multiple casts are required then silicone rubber is a better choice, as it can be used over and over again without deteriorating.

• Budget

Mould making can be an expensive process, understanding the requirements of the project is important before choosing materials.

Releases and Sealants

Most moulding materials will require a release agent, this is usually a spray/wax/vaseline that is applied to the surface of the master to ensure that the moulding material does not stick.

Depending on the material of your master and your choice of mould material, you may need a release agent and/or sealant. Careful consideration should be given to the surface of your master because any excess release agent or scratches on the surface will be transferred into the detail of your mould.

Depending on your moulding material most porous or slightly damp materials, ie plaster, wood and stone, will require a sealent before a release agent is applied. Any layers of sealant or release should be allowed to sufficiently dry before a further coat is added.

Layers of wax can be applied and polished onto the surface of your master to give a high gloss finish to your mould, as well as acting as a good release.

Making a rubber mould

This is only a basic guide, there are many ways to go about making a mould and through practise and experience you will develop your own methods.

Open mould

The simplist mould ia an open mould when the master onject has one flat side, it can be placed at the bottom odf a moulding box and the moulding material simply poured over the object. Once cured the mould can be removed from the box (ensuring the walls of the box have a release agent applied) leaving a cuboid mould with the negative space of the object within it.

Multiple part mould

On more complicated shapes it is necessary to make up the mould of two or more parts that join together.

To begin, cover the entire object with a thin layer of rubber (approx 2mm). Once this has cured you can build up the thickness to between 5-10mm, ensuring that where the edges of the mould meet has a thicker covering.

Fix keys (small rounded tubes of cured silicone) to the curved surface, these will hold the rubber skin in place when you make the mould jacket, see figure 5.

You now need to make a jacket for the mould, this will hold the flexible rubber skin in place when you are casting. With a silicone mould it is best to do this with fibre glass and laminating resin or Smooth On Plastipaste, however you can use plaster bandage although this will deteriorate over time.

Firstly mark out the lines you have decided to make for the seperate parts of your mould (see figure 4). The walls of your jacket should follow the lines you have made on the rubber. Accurately make a Clay Scrim* (see figure 6) along the line of your mould and build up the fibre glass walls against these.

As you layer up the different parts that make up the jacket (see figure 7) ensure you have a barrier or release agent on the previous piece so the two cannot stick together, these also should have registration or keys (see figure 6) on them so they can be taken apart and put back together accurately.

* Clay Scrim: a wall about 5cm in height that follows the line of your mould to stop the jacket spilling over to another section of the mould. The clay should have a release agent on it as well as registration points (the registration points can be simply made by making an indentation with your thumb).

Once the jacket has cured you can remove it. Make a scalpel cut along the seperation lines marked on the silicone underneath, the rubber will come away with the jacket as it will be fixed now with the keys. Take out the master.

Once you are ready to cast the mould, use wing nuts (see figure 8) to ensure the pieces of the mould remain firmly together while casting.

Casting

To cast the object turn the fastened together mould upside down and pour the casting material into the opening. On small moulds you may need air holes in your mould to allow air to escape as you pour in the casting material.

Other Moulding Materials

Alginate

• Usually used for life casting as non toxic
• Mixed with water
• Degrades after one or two casts
• Only for use with plaster

Moulding Compounds (Polymorph)

• Less detail will be picked up in the mould
• Reusable by melting down
• Is affected by heat so best used with plaster and waxes, can be used with polyester resins but the surface will be affected

Polyurethane Rubbers

• Needs a good release agent and sealant
• Very good detail obtained
• Long curing time
• Good for concrete casting

A basic guide to mould making (773kb .pdf)

Notes before Spraying

When spraying always spray in a well ventilated area, preferably in a spray booth wearing a suitable fume mask.

The spray paint should be applied in thin even coats to give a consistent finish across the model making sure the paint does not pool on the surface using the technique as described below.

Before you start spraying shake the can well and check that the nozzle is clear. Test the paint by spraying the can off the model to make sure the paint is coming out evenly and is not spitting out any blobs of paint. You need to be especially careful with the white paint as this colour is particularly prone to this. For the colours being used for speckling make sure you are using the blue dot nozzles as these give a softer spray ideal for this effect.

Base coat (Grey Primer)

Rotate the model by 90° and repeat until you have sprayed from all 4 corners.

Rotate the model by 45° and spray as before 2 more times to give a total of 6 thin coats. This should given an even grey surface finish but apply more coats if required.

4th coat	5th coat	6th coat

The road surface

Creating the road tarmac surface is done by speckling the beige, white and black paint onto the grey base.

You need to let the paint fall onto the surface rather than spraying it directly onto the surface as with the base coat, this is what creates the speckled effect. If you are using a spray extraction system turn it off so as not to interfere with this process.

Start by spraying the milk coffee paint over the top of the model so the can’s nozzle is not directly pointing towards the surface at around a 60° angle in a swift zig zag as before allowing the droplets of paint to fall onto the model’s surface.

Then for white spray, from all 4 corners then horizontal and vertical (6 coats) finally for the black spray, from all 4 corners then horizontal and vertical (6 coats).

This should give you a reasonable representation of a road surface but you can add more coats if you feel the colour is not quite right for your model.

The pavement surface

Firstly gently brush of the dust that will have accumulated from the speckling of the road colour. Then mask the road using masking tape and speckle the pavement colour as the road colour to the following ratios using the same method as the road surface.

Milk Coffee - 4 times from each corner then 1 horizontal and 1 vertical (6 coats)

Speckle with white paint	after 12 coats of white paint

White - 4 times from each corner then 4 times from horizontal and vertical then 4 times from each corner again (12 coats).

This should give a reasonable representation of a pavement colour. Peel back a bit of the masking tape to check how the road looks against the pavement, if you feel it is not quite right add speckled coats.

The grass surface

Before masking the pavement throughly brush the dust from surface to ensure the masking tape adheres to the surface. Mask the paved areas pushing the tape down firmly.

When all the pavement has been masked paint the grass areas with the flock adhesive making sure that this is applied as evenly as possible. Then using a flour sieve, sieve the flock onto the adhesive making sure it is completely covered.

Leave to dry for about an hour then tap off the excess flock collecting it for further grassing projects. Carefully start to remove the masking tape between the pavement and the grass.

It is important that the adhesive is still soft as you remove the tape so it leaves an even line. Be careful not to touch the flocked surface as it will mark or will be damaged until the adhesive is fully dry.

Once all the masking tape has been removed leave to dry for about another 2 to 3 hours, when dry any loose flock can be knocked off and vacuumed.

Products used

Creating roads & pavements (706kb .pdf)

A basic guide to using airdry dough - how to make a daffodil

The Petals

Roll out a small ball of Air Dough to about 1mm thick then place the templates on the Air Dough and cut out the petals with a knife. Score lines into all the petals using a skewer to represent the veins as shown in the picture.

The Trumpet

Place the template of the trumpet on the air dough and cut out with a knife. Roll the skewer firmly across the top of the trumpet to create the ruched edge effect. Then wrap the cone round to create the trumpet finishing it by placing a small ball of dough at the bottom of the cone.

Adding the Petals

Add three petals to the base of the trumpet arranging them at 120° intervals. Then in the gaps arrange the other three petals to complete the flower.

The Stems

Fix piano wire into the base of the flower to create the stems using a small ball of dough to fix in place. Then paint the stem green with acrylic paint.

The Products Used

A basic guide to jig making

A jig for cutting

This is a basic guide to jig making using the example of a card picket fence on the garden model shown here.

Cutting the Pickets

1. Using a ruler and knife mark a number 4mm divisions on either end of the card.
2. Line the ruler up to the knife marks made on the card and cut the card making a series of shallow cuts until you have cut all the way through.
3. Repeat this until you have cut all the strips.

note: The first strip cut is often a slightly different width to the others so may have to be discarded.

Making the Picket Jig - from 1mm styrene

1. Cut a piece of styrene big enough to make the base of the jig, in this case 30 x 120mm
2. Cut a 10mm strip of styrene to form the sides of the jig
3. Make an approximately 35° angled cut on the end of the 10mm strip
4. Mark the length of the picket on the styrene measuring from the pointed end and make a right angled cut using an engineers square
5. Using the cut piece as a guide cut the same 35% angle on the 10mm strip

6. Then using the cut piece mark the length on the 10mm strip
7. Cut the 10mm strip to the same length using the engineers square.
8. Glue one of the angled pieces onto the base with plastic weld.
9. When dry place a strip of the card against the glued styrene and glue the other piece of styrene onto the base making sure the pieces of styrene match up exactly.

Using the jig

1. Place the card strip in the jig and using your knife like a guillotine against the jig snip the end off the card.
2. Making sure the card strip does not move cut the other angle on the end of the strip
3. Then again making sure the card strip does not move cut the strip to length completing the picket.
4. Repeat until there are enough pickets to make the fence.

A jig for gluing

Cutting the rails

1. Using a ruler and knife mark a number 3mm divisions on either end of the card.
2. Line the ruler up to the knife marks made on the card and cut the card making a series of shallow cuts until you have cut all the way through.
3. Repeat this until you have cut all the rails.

Making the gluing Jig - from 1mm styrene

1. Cut a piece of styrene big enough to make the base of the jig, in this case 300 x 50mm
2. Cut a two 15mm strips of styrene to form the top and bottom of the jig
3. Cut a 9mm strip of styrene which will space the rails apart
4. Cut a 10mm strip of styrene which will be used to make sure the pickets are level when glued
5. Glue the first 15mm strip onto the base using plastic weld making sure that it is glued exactly along the edge of the base

6. When dry place one of the rails against the 15mm strip and glue the 9mm strip against it.
7. When the 9mm strip is dry place another rail against it and glue the other 15mm strip to the base
8. With a pencil mark 9mm divisions along the top of the jig
9. Using the engineers square draw lines across the jig from the division marks made
10. Glue the 10mm strip to the bottom 15mm strip

Assembling the picket fence

1. Place the two rails in the jig
2. Using the pencil marks as a guide and put a dot of glue on each rail
3. Glue a picket onto the rails using the lines to keep the picket straight and the 10mm strip at the bottom to keep all the pickets level
4. Repeat gluing the pickets until the fence is complete

Products used

How to make a Tombstone

Step 1 First of all choose a shape for your tombstone and sketch the shape onto a piece of Styrofoam. Then use a knife to carefully cut around the shape and remove the excess parts. Step 2 Once you have cut the shape you can then start to make it look more realistic. By cutting out small bits, smoothing edges and scuffing the surface you can ‘age’ the tombstone. Then add detailing such as a cut a ledge, an epitaph or carvings.

Step 3

Once you are happy with the look of your tombstone you can seal and strengthen. One great product to use for this is called Foamcoat.

Foamcoat not only strengthens and seals but can also be used to add texture. Once dry it can be sanded and carved. You can also start to add colour at this stage by adding a small amount of Black Acrylic to the Foamcoat. Ensure you have completely covered the Styrofoam before proceeding.

Step 4

Once the Foamcoat is fully dry it’s time to paint the Tombstone. Apply a base coat using a Grey spray paint. You can hand paint using acrylic but it’s easier to achieve a stone effect with spray paint.

Leave time to dry before adding the detail.

This is best accomplished by using the dry brush technique. Add paint to you brush then remove most before applying in layers. This gives a lighter and more realistic finish. Use this approach to highlight the edges, ledges and any other detailing. To create moss effects, dry brush with green paint then add small amounts of PVA, sprinkle with Green texture and gently pad down with your fingers. Once dry, dust off any remaining texture. Continue using these techniques until you are happy with overall effect.

Extra finishing touches

Make a base for it to stand on (we used a thick piece of wood).

Use the off cuts of Styrofoam to make the mounds at the base of the stone, secure using UHU Por.

Mix up earth coloured acrylic paint and then add Cork texture to create soil effects. Add more green texture to create further moss effects.

Materials used

4D_guide-Tombstone.pdf (154kb.pdf)