One of the many features of a Witt flexible drop in tank liner is the ease of repair. Of the two methods of repair, the adhesive method is the easiest and probably the most common. However, it is paramount that the right adhesive be used.
The adhesive is essentially liquid PVC resin combined with a solvent. The solvent will flash off and bond the two pieces of PVC together. The PVC resin in the adhesive has to be compatible with the type of PVC you are trying to weld together. The types of adhesives that bond rigid PVC or PVC pipe together will not work with flexible PVC. Trying to repair a flexible PVC liner with these types of adhesive will never work.
You need to use an adhesive labelled specifically for flexible PVC. The label will either read “For Flexible PVC” or say “For PVC Sheeting”. The two most common brands are IPS Weld-On 795 and Oatey X-15. You should be able to find one or the other at any local hardware or plumbing supply store.
Once you have obtained the correct adhesive you should be all set to repair the liner. We always send the scrap pieces from the fabrication of the bottom corners along with your liner so you will have repair pieces if needed. If you no longer have them we can easily supply you more. Also, any formulation of flexible PVC will adhere to any other formulation of flexible PVC. As long as the formulation of the repair piece is compatible to the chemistry and temperature of the environment it will be exposed to that formulation can be used.
One last point regarding the adhesive. The adhesive has a finite shelf live. Sometimes, we receive specifications that ask for a repair kit of material, cleaner, and adhesive to be supplied. Depending upon the brand of adhesive, the shelf life will be between 12-24 months from date of manufacture. By the time the adhesive gets from being made it will sit on the shelf of the distributor before coming to us. Then it may sit on our shelf for a period of time before finally being put into the repair kit. At this point, the shelf life could already be down to 6 months or even less. By the time an incident occurs requiring the use of the repair kit, most likely the adhesive is unusable. We strongly recommend simply holding on to the scrap pieces we send and then taking a quick trip to the hardware store for fresh adhesive if needed.