Figure 3-84.-Corrugated fasteners and their uses. (which have a plastic base) and mastics (which have an asphalt, rubber, or resin base) are the two major categories  of  adhesives. The method of applying adhesives, their drying time,  and  their  bonding  characteristics  vary.  Some adhesives are more resistant to moisture and to hot and cold temperatures than others. SAFETY NOTE Some  adhesives  are  highly  flammable; they should be used only in a well-ventilated work  area.  Others  are  highly  irritating  to  the skin   and   eyes. ALWAYS   FOLLOW MANUFACTURER’S     INSTRUCTIONS WHEN USING ADHESIVES. Glues The primary function of glue is to hold together joints in mill and cabinet work. Most modern glues have a plastic base.    Glues are sold as a powder to which water must be added or in liquid form. Many types  of  glue  are  available  under  brand  names.  A brief  description  of  some  of  the  more  popular  types  of glue  is  listed  below. Polyvinyl  resin,  or  white  glue,  is  a  liquid  that comes in ready-to-use plastic squeeze bottles. It does a good job of bonding wood together, and it sets up (dries)  quickly  after  being  applied.  Because  white glue is not waterproof, it should not be used on work that  will  be  subjected  to  constant  moisture  or  high humidity. Urea resin is a plastic based glue that is sold in a powder  form.  The  required  amount  is  mixed  with water when the glue is needed. Urea resin makes an excellent bond for wood and has fair water resistance. Phenolic resin glue is highly resistant to tempera- ture extremes and water. It is often used for bonding the  veneer  layers  of  exterior  grade  plywood. Resorcinol  glue  has  excellent  water  resistance and  temperature  resistance,  and  it  makes  a  very  strong bond. Resorcinol resin is often used for bonding the wood  layers  of  laminated  timbers. Contact cement is used to bond plastic laminates to  wood  surfaces.  This  glue  has  a  neoprene  rubber base. Because contact cement bonds very rapidly, it is useful   for   joining   parts   that   cannot   be   clamped together. Mastics Mastics  are  widely  used  throughout  the  con- struction  industry.  The  asphalt,  rubber,  or  resin  base of mastics gives them a thicker consistency. Mastics are  sold  in  cans,  tubes,  or  canisters  that  fit  into hand-operated  or  air-operated  caulking  guns. These adhesives can be used to bond materials directly  to  masonry  or  concrete  walls.  If  furring  strips are required on a wavy concrete wall, the strips can be applied with mastic rather than by the more difficult procedure of driving in concrete nails. You can also fasten insulation materials to masonry and concrete walls  with  a  mastic  adhesive.  Mastics  can  also  be used to bond drywall (gypsum board) directly to wall studs. They can also be used to bond gypsum board to furring strips or directly to concrete or masonry walls. Because  you  don’t  use  nails,  there  are  no  nail indentations to fill. By   using   mastic   adhesives,   you   can   apply paneling with very few or no nails at all. Wall panels can  be  bonded  to  studs,  furring  strips,  or  directly against concrete or masonry walls. Mastic adhesives can be used with nails or staples to fasten plywood panels  to  floor  joists. The  mastic  adhesive  helps eliminate squeaks, bounce, and nail popping. It also increases the stiffness and strength of the floor unit. 3-61