In order to make joints that will hold well consistently, the following points must be clearly understood.
I. Joining surfaces should be softened and made semi-liquid.
2. Adequate amount of adhesive should be applied to fill the gap between the pipe and the fitting.
3. Pipe and fittings should be installed while the surface is still wet and the adhesive is still liquid.
4. Joint strength improves as the adhesive dries. In the tight part of the joint, the surfaces tend to fuse together; In the loose part, the adhesive will bond to both surfaces.
Penetration and softening can be achieved with the adhesive itself, by using a suitable cleaner, or by using both the cleaner and the adhesive. For some materials and in certain situations, the use of a cleaner is necessary. A suitable cleaner will generally penetrate and soften surfaces faster than adhesive alone. In addition, the use of a cleaner can provide a factor of safety for the installer because, under various temperature conditions, he can know when sufficient softening has been achieved. For example, more time and additional applications may be required in cold weather.
Sufficient adhesive should be applied to fill the loose part of the joint.
In addition to filling the gap , sufficient layers of adhesive will penetrate the surfaces and remain wet until the joint is installed. You can try this yourself. Apply two separate layers of cement to the top surface of a piece of pipe.
First apply a thick layer of glue; then, next to it, apply a thin layer with the brush. Feel the layers with the tip of your finger, like every 15 seconds. You will notice that the film becomes sticky and then dries quickly (possibly within 15 seconds); the heavy layer will stay wet much longer. After a few minutes of applying these layers, check for penetration. Scrape both surfaces with a knife. The film will have little or no penetration; the thicker one will have much more penetration. If the adhesive coatings on pipes and fittings are wet and liquid during assembly, they will flow together and become a layer of adhesive.
Also, if the adhesive is wet, the surfaces underneath them will still be soft, and these softened surfaces in the tight part of the joint will tend to come together. As the solvent diffuses, the adhesive layer and softened surfaces will harden with a corresponding increase in joint strength. A good joint will receive the necessary working pressure before the joint is fully dry and the final joint strength is established. Strength develops faster in the tight (fused) part of the joint than in the loose (bonded) part of the joint.
Joining solvent welds of large diameter pipes requires special attention and our technical service department should be contacted in case of difficulty. Always close the lid of the box after making a connection and follow the instructions on it, observing any warnings.
Joints should not be moved or disturbed for 10-15 minutes. Then the jointed pipe can be used carefully. Wait 4 hours if lengths of jointed pipe are to be laid in a trench.
Wait 24 hours before proceeding to Test Pressures. It is possible to reduce this time with pipe sizes up to 50mm. Wait 1 hour for every 3.5 atmospheres of pressure. Brushes must be clean and dry before solvents start welding. Brushes are removed from use by washing them with cleaning liquid.
then it should be thoroughly cleaned. Do not dilute solvent adhesive with cleaning fluid. Use solvent adhesive and cleaning fluid in a well-ventilated area. Keep away from naked flames and do not smoke. Replace the lids of the containers. In any case, follow the instructions printed on the containers.
When laying continuous pipe, joints can be made faster than the set times stated above. The joint will not fail over long lengths provided the pipe is not bent or the previously joined joint is not dislodged.