Although the curtain material is a relatively strong and durable material in that it can and does withstand the “tests” of time, operators of this type of equipment will on occasion need to perform repairs due to damage sustained during operation of the vehicle. In most cases, the repairs can and should be performed by company personnel in order to minimize down-time, cost, and/or damage to loads. In this tutorial, we will attempt to walk you through the repair process with a step by step approach. We strongly suggest that having read the following you practice a repair before you actually work a curtain.
The curtain material consists of three parts:
- A polyester thread mat which gives the curtain it’s strength and provides the rip-stop characteristic
- A PVC coating
- An acrylic laquer top coat
The PVC coating is basically much like the PVC compound used to make plumbing pipe, main difference being in the curtain material plasterizers are added to soften the PVC and make it pliable.
Three different approaches or processes for repairing curtains are being used:
- Glue methods
- Stitching using traditional machines
- Heat gun process
At Center-Line, we strongly recommend the latter or heat gun method for best results. We have found that glues leave an undesirable cosmetic appearance and do not result in a truly strong bond at the patch. Stitching the patch has the same problems of appearance and strength. Users of the heat gun process however report clean, neat looking repairs that have the strength needed to last. This method is perhaps best explained by understanding that in the production process, as the curtain itself is built, the pockets for straps or biason strips and various reinforcement pieces are bonded together either by hot air (1500 degrees plus) or dielectric welding. Both of these methods use the PVC compound as the bonding agent.
On-site repairs can be performed in a matter of minutes given that the following equipment or tools are available:
- An industrial heat gun with no more than a 2″ tip and a heat range up to 1500 degrees
- A 100′ grounded extension cord
- A silicone rubber roller
- Pair of industrial quality scissors
- Patch material
- Denatured alcohol
Note: These items are available in the form of a repair kit from Center-Line.
The Repair Process
Step one: Assessment
You must first assess the extent of damage to determine if a patch will in fact be successful or if the curtain has been damaged to the extent of requiring the abilities of the factory. For instance, if the damage is a small hole or tear in the curtain body it can be done on-site. However, if the tear includes damage to post pockets or an original weld, the curtain should be sent to an authorized curtain repair station.
Step Two: Curtain Preperation
The curtain material must be cleaned on both sides at the damaged area. To avoid further damage we recommend using denatured alcohol.
Step Three: Prepare Patches
All patches should be installed on the inside of the curtain. Patches installed on the outside are vulnerable to windflow while on the road and do not provide the desired cosmetic appearance. The patch material should be cut to overlap the hole at least 2-3 inches on all sides. For best results, round the edges to avoid “corners”.
Step four: Prepare to Patch
The heat gun should be allowed sufficient time to heat to it’s hottest setting or 1500 degrees.This is very important in that the PVC coating must be broken down to a molten stage before the patch will actually adhere to the curtain body. A second person will now be necessary to proceed holding a flat, rigid surface or board at the damaged area on the outside of the trailer. This provides a firm, flat surface for the man inside that will actually install the patch. Be sure the board is free of any dirt, grime, or paint as the heat tends to bond such materials to the curtain body.
Step five: Patching
Place the patch over the damaged area in the desired location. Now place the heat gun tip between the two layers of material at center and using the roller begin pressing and rolling parallel to the gun tip until the bond occurs. Continue the process working to the outer edges until finished. Do not hurry this process!! Remember, the PVC coating must be broken down by the heat and the roller must be used to “push” the two layers together. Short cutting or under heating will result in patches that are not effective>
Perhaps the most important element of this procedure is PRACTICE. We strongly recommend that you practice before each repair operation to familiarize yourself with these steps and perhaps most importantly, gain confidence.
Every member of Center-Line is here to aid and assist you in any way possible. Should you have a question concerning this or any other item, don’t hesitate to contact us. Patience, questioning, and practice will quickly make all of this second nature to you, don’t be afraid.