Filling is undoubtedly a technique that is often used to finish foam creations. How else would you fill holes and cracks you get so easily in your foam? Also scratches and other blemishes can be easily removed on a finished model if it ever turns out wrong. Of course putty filling also requires a correct approach and the right techniques. In the following instructable you can find some tips and tricks to make it work.
Step 1: What Do You Need?
- Putty filler
- Putty hardner
- Object in (Styro) foam
- Putty knives in different sizes
- Paint brush/toothbrush/air blower
- Polystyreen plate
- Sanding paper
- Sanding block
- Paint thinner
Step 2: Preparations
Make your shape out of Styrofoam. Sand the surface and finish with fine sanding paper (+-400). The surface should be clean, dry and free of grease. It's a good idea to brush off the dust with a brush (or even vacuum cleaner ). If you don't clean your shape, the dust will make the filler lumpy and difficult to spread out.
Step 3: Making Putty Filler
Description MoTip Fine Putty: 2 component fine putty to level small irregularities in surfaces of steel, aluminum, wood, concrete and polyester. Fine Putty is easy to sand, elastic and resprayable with all lacquer systems. Fine Putty has a very fine structure and excellent adhesion and is resistant to chemicals and weather influences. MoTip Fine Putty can be applied in layers with a thickness up to 0,5 centimetre.
Take the desired amount of putty to cover your shape. Don’t take too much because you only have a few minutes (3-5 min, depending on which brand you use) to work with it. Add the required amount of harder with the putty: In this case 2,5% of the total amount should be harder. For a small amount a few drops should do the trick. Tip: It’s better to use less hardener if you want to work with it a little longer. The less you use the longer it will take to dry. Quickly mix the harder and putty together.
Step 4: Putty on Forms
Apply the putty in the desired layer thickness (MoTip Fine Putty can be applied in layers with a thickness up to 0,5 centimeter) with a spatula, your fingers or other tools. Try to follow the same grooves you created as this gives a more even surface. You can use the putty for a few minutes until it gets too hard to work with (depending on how much harder you added). Don't try to finish the surface to perfect; it's normal that the structure is rough. The drying time depends on the ambient temperature.
Clean your tools after you've used them (with paint thinner). Do not store the surplus material, mixed with harder, in the can.
HINT: You can make your own work tool on a polyethyleen plate. Cut out your desired shape with a cutter. It helps to work equal and quickly for shapes with more difficult
Step 5: Sanding
Wait until the putty had fully dried before you start sanding (approximately 30 minutes, depending on the ambient temperature). Don’t use sanding paper that’s too rough because you will remove too much putty. End with fine sanding paper for a smooth finish.
Repeat this process until the surface is completely smooth and you're satisfied with the result. You can put as many putty layers as you want.
Step 6: Spray Putty
Once your shape is smooth you can finish with spray-putty to cover the whole surface.
Spray instructions: Before use, shake the aerosol for 2 minutes and spray a sample. The distance to the surface to be treated should be approximately 25 to 30 centimetre. Apply the spray putty in several thin layers. Wait until it's completely hardened (about 2 hours) before applying the next layer and shake the aerosol again. The drying time depends on the ambient temperature, the humidity of the air and the thickness of the lacquer applied.
After hardening you need to sand, either wet or dry (grain 400). Repeat this process until you’re satisfied with the result. After use, clean the valve (turn aerosol upside down and press the nozzle for approximately 5 seconds).
Step 7: Finishing Touch
After you’ve finished your shape with the finest sanding paper, you can give it the finishing touch.
Before applying a finishing coat, apply a primer. Use the same procedure as the spray putty. Wait until the primer is completely hardened (about 2 hours). You can sand the primer, wet and dry (grain 400). Use your desired (spray)-paint to finish your shape. Apply the same instructions as the primer.
Your shape is now finished.