An article to understand the basic knowledge of silicone glass glue for broken bridge aluminum doors and windows

No matter what kind of high-end doors and windows are in use, there will be gaps that must be sealed with construction glue to ensure that the doors and windows have good performance. They are a waterproof sealant, styrofoam, and silicone glass glue. These are the products that must be used in the installation of doors and windows. Waterproof sealants and styrofoam are used in the installation of plastic steel doors and windows; while the installation of broken aluminum doors and windows will be used. Styrofoam, silicone glass glue, or the above three are all used.

Silicone sealant is a paste made of polydimethylsiloxane as the main raw material, supplemented by crosslinking agent, filler, plasticizer, coupling agent, and catalyst in a vacuum state. It passes through at room temperature. With water in the air, it should be cured to form elastic silicone rubber.

1.The classification of silicone glass glue

Silicone glass glue can be divided into two categories from the product packaging: one-component and two-component. One-component silicone glue, its curing is caused by the change of physical properties due to exposure to moisture in the air; two-component means that the silicone glue is divided into two groups, A and B, and anyone group alone cannot form curing. But once the two sets of glues are mixed, they solidify. At present, one-component silicone glass glue is common in the market. This book mainly introduces this kind of glass glue.

One-component silicone glass glue is divided into acid glue and neutral glue according to its properties. Acid glass glue is mainly used for general bonding between glass and other building materials. The neutral glue overcomes the characteristics of acid glue that corrodes metal materials and reacts with alkaline materials, so it has a wider range of applications and its market price is slightly higher than that of acid glue. A special type of glass glue on the market is the silicone structural sealant. Because it is directly used for the metal and glass structure or non-structural bonding assembly of glass curtain walls, the quality requirements, and product grades are the highest among the glass glues. The market price is also the highest.

^{Figure 1 One kind of two-component silicone glass glue: the silicone structural sealant}

2. The brief introduction of silicone glass glue

One-component silicone glass glue is a kind of ointment, once it comes into contact with moisture in the air, it will solidify into a tough rubber-like solid material. Silicone glass glue has strong adhesion, high tensile strength, and at the same time has weather resistance, vibration resistance, moisture resistance, odor resistance, and adaptability to large changes in cold and heat. Coupled with its wider applicability, it can realize the adhesion between most building materials products, so the application value is very great. Silicone glass glue does not flow due to its weight, so it can be used in the joints of overhead or side walls without sag, collapse, or run away. It is mainly used for the bonding of dry and clean metal, glass, most grease-free wood, silicone resin, vulcanized silicone rubber, ceramics, natural and synthetic fibers, and many painted plastic surfaces. Good-quality silicone glass glue will not be extruded or changed in physical properties when used below zero degrees Celsius. Fully cured silicone glass glue can remain effective when used at a temperature of 204°C (400oF), but the effective time will be shortened when the temperature is as high as 218°C (428oF). Silicone glass glue has a variety of colors. Commonly used colors are black, porcelain white, transparent, silver-gray, gray, and bronze. Other colors can be customized according to customer requirements.

^{Figure 2 The silicone glass glue}

3. The use of silicone glass glue 

3.1 The Acid glass glue

1. It is suitable for sealing, blocking, leak-proofing and weather-proofing. It is suitable for both indoor and outdoor (the indoor effect is better), and the anti-seepage and leak-proof effect is obvious.
2. Bonding various interior decorations of automobiles, including metal, fabric, organic fabric, and plastic.
3. Join the gaskets on the heating and cooling equipment.
4. Install ribs without screw holes, nameplates, and paint and plastic materials on the metal surface. 
5. Seal the window on the oven door, the flue on the gas appliance, the pipe joint, and the passage door.
6. Provide instant-formed anti-leak pads for gearboxes, compressors, and pumps.
7. Seal the cabin and window.
8. Sealing of glass windows in trailers and truck cabs.
9. Glue and seal equipment parts.
10.  Form an anti-wear coating.
11. Inlay and fill thin metal sheet laminates, pipe networks, and equipment casings.

3.2 The neutral weather-resistant glue

1. Suitable for weather-resistant sealing of various curtain walls, especially recommended for weather-resistant sealing of glass curtain walls, aluminum-plastic panel curtain walls, and stone dry hanging;
2. Sealing the joints between metal, glass, aluminum, ceramic tiles, plexiglass, and coated glass;
3. The joint sealing of the surface of concrete, cement, masonry, rock, marble, steel, wood, anodized aluminum, and painted aluminum. In most cases, no primer is needed.

3.3 The Silicone structural adhesive

1. It is mainly used for structural or non-structural bonding assembly between metal and glass of glass curtain wall.
2. It can directly connect the glass and the surface of the metal component to form a single assembly component, which can meet the design requirements of the curtain wall with a full or semi-hidden frame.
3. Structural bonding and sealing of insulating glass.

3.4 Various silicone glass glues are subject to the following restrictions when used

1. It is not suitable for construction in a place with long-term flooding;
2. It is not compatible with materials that can ooze grease, plasticizers, or solvents;
3. The frosty or damp surface cannot be glued;
4. It cannot be cured in a completely sealed place (silica gel needs to be cured by moisture in the air);

^{Figure 3 The use of silicone glass glue} 

4. The surface of the substrate is not clean or firm.

4.1 The acid glass glue has the following restrictions:

Acid silicone glass glue will corrode or cannot bond copper, brass (and other copper-containing alloys), magnesium, zinc, electroplated metals (and other zinc-containing alloys), and it is recommended to make masonry materials and ferrous carbide substrates Do not use acid glass glue. It will not be good if used on materials made of methyl methacrylate (PLEXIGLAS), polycarbonate, polypropylene, polyethylene, and TEFLON (Teflon, polytetrafluoroethylene). Bonding effect and good compatibility. Acid glass glue is not suitable for connections that move more than 25% of the joint width. Ordinary acid glass glue should not be used on structural glass (except for acid structural glue). In addition, it should not be used where there is abrasion and substantial disadvantages. Use acid glass glue. The surface temperature of the base material of the silicone acid glue exceeds 40℃ and it is not suitable for construction.

4.2 The neutral weather resistant adhesive has the following restrictions:

The neutral weather-resistant adhesive is not suitable for structural glass assembly; the substrate surface temperature exceeds 50 ℃ and is not suitable for construction.

4.3 The silicone structural adhesive has the following restrictions:

The surface temperature of the base material of the silicone structural adhesive exceeds 40℃ and it is not suitable for construction.

^{Figure 4 The acid silicone glass glue}

5. How to use silicone glass glue

5.1 Use: One-component silicone glass glue can be used immediately. It can be easily shot out of the plastic bottle with a glue gun, and the surface can be trimmed with a spatula or wood chips.

5.2 Sticking time: The curing process of silicone adhesive develops from the surface inward, and the surface drying time and curing time of different characteristics of silicone rubber are not the same (for the detailed description of the curing time, please refer to the fourth "technical parameters" Content), so if you want to repair the surface, it must be done before the glass glue surface is dry (acid glue, neutral transparent glue should generally be within 5-10 minutes, and neutral variegated glue should generally be within 30 minutes). If a color separation paper is used to cover a certain area, it must be removed before the skin is formed after the glue is applied.

5.3 Curing time: The curing time of glass glue increases with the increase in bonding thickness. For example, acid glass glue with a thickness of 12mm may take 3-4 days to solidify, but within 24 hours, there is a 3mm outer layer. Has been cured. When bonding glass, metal, or most woods, it has a peel strength of 20 pounds per inch after 72 hours at room temperature. If the place where the glass glue is used is partially or completely closed, then the curing time is determined by the tightness of the seal. In an airtight place, it is possible to remain uncured forever. If the temperature is increased, the glass glue will become soft. The gap between the metal and the metal bonding surface should not exceed 25mm. In various bonding occasions, including airtight conditions, the bonding effect should be fully checked before the equipment after bonding is used. During the curing process, the acid glass glue will produce a smell due to the volatilization of acetic acid. This smell will disappear during the curing process, and there will be no peculiar smell after curing.

5.4 Bonding:

A. Wipe the metal and plastic surfaces completely to remove oil stains. Then, except for the plastics, rinse all surfaces with acetone first, the rubber surfaces should be polished with sandpaper and then wiped with acetone. When using acetone, please observe the precautions for using this solvent.
B. Spread the glass glue evenly on the surface of the ready object. If you are bonding two surfaces together, you can place one side first, and then squeeze the other side with enough force to squeeze out the air, but be careful not to squeeze the surface. Out of glass glue.
C. Place the bonded device at room temperature and wait for the glass glue to cure.

5.5 Sealing: When silicone glass glue is used for sealing, follow the same steps as mentioned above. Forcibly squeeze the glass glue into the joint surface or gap to make the glass glue fully contact the surface.

5.6 Cleaning: The glass glue can be wiped off with a cloth or paper towel before it is cured. After it has been cured, it must be scraped off with a scraper or scrubbed with solvents such as xylene and acetone.

5.7 Matters needing attention: Acidic glass glue will release irritating gas during the curing process, which is irritating to human eyes and respiratory tract. Alcohol-based neutral glue releases methanol during curing. Methanol has the potential to cause cancer and is a known skin and respiratory allergen. The volatilized gas can cause inflammation of the eyes, nose, and throat. Therefore, this product should be used in a well-ventilated environment, avoid getting into the eyes or long-term contact with the skin (after use, wash your hands before eating and smoking), and do not swallow this product. Keep out of the reach of children; the construction site should be well ventilated; if accidentally splashed into the eyes, rinse with clean water and seek medical advice immediately. There is no danger in the fully cured glass glue.

5.8 General guidelines: Before use, please read the correct construction method and use of glass glue carefully. Please pay attention to the instructions on safe use and health hazards.

^{Figure 5 How to use silicone glass glue}

6. The silicone glass glue storage

Storage and storage period Glass glue should be stored in a cool, dry place, below 30℃. A good quality acid glass glue can ensure an effective shelf life of more than 12 months, and a general acid glass glue can be stored for more than 6 months; a neutral weather-resistant and structural glue can guarantee a shelf life of more than 9 months. If the bottle has been opened, please use it within a short time; if the glass glue is not used up, the plastic bottle must be sealed. When using it again, you should unscrew the bottle nozzle to remove all blockages or replace the bottle nozzle.

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