Most modern Russians have no idea how to cook starch paste and why. But some 30–50 years ago, wallpaper on the walls of 99% of houses and apartments was kept on it. A paste is a completely natural and even edible adhesive.
What is a paste and why is it needed?
Kleister is called a jelly-like mass, which has the properties of glue. It is obtained by boiling starch in water. Starch is used both in pure form and in the form of flour or even grain. In contact with boiling water, starch grains break, absorb water and form a spongy mass.
Clusters from different types of starch have their advantages and disadvantages:
Corn starch | High hardenability. Slightly cloudy. Prepared at high temperature. May not spoil for a week or more. |
From wheat starch (ordinary flour) | Medium hardenability. It does not spoil for several days. A bit muddy. Widely used in bookbinding. It is not boiled, but poured in a thin stream into boiling water. Otherwise, after cooling, the paste will lag. |
Potato starch | Transparent, clean. Low hardenability. Easily changes in the air, quickly acidic. Cooking does not require high temperatures. |
Rye flour | It has an enviable strength mixed with turpentine (gum). Resistant to damp. It can be used for pasting ovens, gluing new wallpapers on top of old ones. |
Starch paste is widely used. In small concentrations, they are used to make jelly and mashed soups. In laboratories, they play the role of reagents. But pastes are most in demand in gluing paper and cardboard: when pasting wallpapers, making papier-mâché, various children's crafts.
A paste is a perishable product. When it comes into contact with air, it turns sour, forming lactic acid. Therefore, it is used immediately after cooking. You can add salt, salicylic acid or other additives to the solution. Then the shelf life of the mass will increase.
How to weld a paste?
To prepare the glue, you will need aluminum or enameled dishes, water, starch or flour. The cooking process is quite simple:
- Dissolve starch (flour) in a small amount of cold water (1: 1).
- Pour water into a large pot and put on fire.
- When it begins to boil, pour in a thin stream of flour solution, stirring the water intensively.
- As soon as the mixture reaches the desired consistency, turn off the heat and cool the container in water (otherwise the glue will thicken further).
- Leave the paste for 1-2 hours.
- Strain through cheesecloth (sieve) to get rid of lumps.
The proportions are considered standard: 2 parts of starch to 8-10 parts of water.
Wallpaper Recipes
For wallpapering, it is preferable to use a paste made from rye and wheat flour (flour contains 75% starch).
The potato starch paste is not waterproof and easily rots in damp. In addition, the strength of the adhesive joint is very small. On such a composition, you can only stick thin paper wallpapers and use it for priming the ceiling and walls.
The denser and heavier the wallpaper, the more tenacious the adhesive should be. To increase the tenacity, an additional ingredient is added to the cooled mass (approximately 20 g per 1 liter):
- wood glue - for dark wallpapers;
- PVA glue - for light;
With wood glue and rye flour, you need to be very careful: they leave brown marks.
To impart water resistance, calcium chloride (40 g per 1 liter) is added to the paste during the cooking phase.
Starch and water are edible products. It is not surprising that the paste is attacked by all kinds of bugs and mold. It is very important to give it antiseptic properties by mixing starch with copper sulfate (1 g for every 100 g of dry matter).
Potato starch
The advantages of starch paste are low cost, transparency and speed of preparation. It is used for light wallpaper, and it does not stain.
Instruction:
- Dilute 0.5 kg of starch in 0.5 l of cold water.
- Boil 4 l of water in a saucepan and turn off the heat.
- Stirring the water vigorously, pour the solution in a stream.
- After 2 hours, pass the glue through cheesecloth.
Add salicylic or boric acid (1 tbsp.spoon per 1 liter) to the finished glue so that it does not deteriorate for 3-5 days. Otherwise, the mass will have to be thrown out after 10 hours.
From starch and flour
To prepare a paste for wallpaper starch is recommended to be mixed with flour. Then it gets tighter.
Instruction:
- Dilute 100 g of flour and 100 g of starch with 200 ml of water.
- Heat 0.8 L of water in a saucepan and reduce heat to a minimum as soon as bubbles appear.
- Pour in the flour mass, stirring constantly.
- Simmer for 3 minutes.
- Cool and strain the solution.
Estimated paste consumption:
- 10-15 g per m2 - for light wallpaper;
- 25-35 g per m2 - for heavy ones.
If starch is placed in the oven and heated for more than 2 hours at a temperature of 160 degrees, it will turn yellow and turn into dextrin. It is also used to create glue. Dextrin is diluted with boiling water in a ratio of 1: 3. For every 100 g of powder, 30 g of sugar is added. This glue dries very quickly and holds the wallpaper firmly.
Rugged paste
If you need to weld heavy-duty and waterproof glue for heavy wallpapers, use the following recipe:
- Dilute 40 g of calcium chloride in 600 ml of water and bring to a boil.
- Separately mix 400 g of starch and 0.4 l of water.
- Pour a solution of calcium chloride into a mixture of water and starch, stirring.
- Add the glue base to 4 liters of hot water. Cook for 2–3 minutes over low heat.
- Cool, let it brew for 2 hours and strain.
To check the tenacity of the paste, spread a drop between the fingers and try to smoothly separate them. The harder it is, the better the glue.
Many do not trust starch paste, preferring modern types of glue. But in vain. Prepared by technology, he firmly glues non-woven, vinyl wallpapers, not to mention paper ones. And its composition is completely safe and does not cause allergies. Natural glue often glues wallpaper in the room of allergy sufferers, small children. A paste is cheap, environmentally friendly and efficient!
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