Gun applied sealants and adhesives
When you walk into a DIY store, you will be confronted by shelves of gun applied sealants to fill gaps and glue. Unlike traditional fillers, most of these stay flexible and will not shrink, keeping gaps filled and, where relevant, waterproof. They usually are available in 'standard-sized' tubes designed to fit in a cartridge gun, this has a trigger operated piston that squeezes the sealant from the tube, through the nozzle and into the required position. There is one popular adhesive which is not in a standard length tube, it's longer and does not fit a 'standard' gun.
To choose the right sealant for the job, you need to think about which features you need in the sealant, the important features include:
- the type of material it will adhere to;
- the size of gap it will fill;
- its degree of mould resistant;
- how waterproof it is;
- whether it can be overpainted, or not;
- whether it can be used indoors and/or out of doors;
- whether it is solvent based or gives off fumes when curing;
- what it is like when it cures, i.e. solid, flexible or very flexible.
When using a sealant, always make sure that the surface is sound, dust free, and dry, the sealant is 'squeezed' onto the surfaces and it often depends on gentle surface contact to create a bond.
Types of sealants
General purpose Water based sealant
General purpose, water based sealants are sealants for indoor use, such as filling gaps along skirting boards, around door and window frames etc. They are usually supplied white as it can be over painted with emulsion or solvent-based paint as soon as the surface has cured.
Some waterproof sealants are water based.
General purpose Silicone based sealant
Silicone sealants produce a waterproof seal that can be used indoors and out. Most manufacturers offer it in white, translucence and possibly a choice of colours. These sealants give off a distinctive smell until it cures.
Kitchen and Bathroom sealant
These are usually designed to seal areas where water seepage is likely (around a sink or bath etc). They need to be waterproof and mould resistant. Usually available in white.
For external use, silicone sealant is used as a water-resistant sealant and joint filler, formulated specifically to seal between wooden or UPVC door and window frames to the surrounding material. Silicone cannot be over painted but is available in a number of colours.
For internal frame sealant, water based sealant can be used and it can be over painted once the surface of the sealant has cured.
Roof and gutter sealant
An all-purpose exterior sealant that can be used to seal leaking joints in guttering and downpipes as well as stopping leaks in flat roofs. Generally it is only available in black.
A number of adhesives are available for application via a 'sealant' gun. They are able to provide both gap-filling and high strength adhesive in one pack. They tend to be suitable for a very wide range of materials, i.e. wood, metal, brick, plaster, ceramics, glass, plaster, concrete, uPVC etc.
A number of sealant are now available in easy-to-use aerosol dispensers making the use of a cartridge gun unnecessary. The sealant is extruded from a nozzle when the cap on the container is depressed, giving good fingertip control.
Always read and follow the instructions on the sealant cartridge before using it.