Expanded polystyrene (EPS) is rated by its weight per cubic foot. For example, 1lb, 1.5 lb, The higher the rating, the stronger the foam.
NOTE: VIRGIN FOAM, opposed to recycled foam, is much stronger even though it may carry the same rating.
Cover Duck is one of very few that actually uses virgin foam.
Plastic materials used for this can vary. 1mill., 2mil., 3mil., or 4mil. can and have been used. The thicker the material, the longer it will take for the vapor to penetrate and begin to saturate the foam.
Cover Duck uses virgin 4mil. plastic, and we hand heat seal it, as other companies use tape.
The metal reinforcement channels help the foam from warping, and add to the strength of the foam. T-Bars or any other lateral reinforcements will score/weaken the foam, and are not suggested. The most important rule that pertains to the metal reinforcement is to be sure that the metal is not placed in a position where it can rub through the vinyl. The metal should be embedded in the foam and should not be able to be felt from the top or bottom of the cover.
Feel a Cover Duck cover; you will not feel any metal
For a top quality spa cover, you want only the highest grade of marine vinyl. There are manufacturers that will try to use automotive or other types of non-marine vinyl. This type of vinyl has no resistance to mold and no UV protection built into them. Even those who do use marine vinyl can take advantage of you by:
- Using SERVICE GRADE MARINE VINYL
- Cutting down on the UV INHIBITORS
- Cutting down on the MOLD RESISTORS
- Using seconds or factory rejects
Cover Duck uses only the highest grade MARINE VINYL (1500 HRS/UV).
POLYESTER thread is the only thread to use on outdoor items. UV will eat up NYLON thread and COTTON thread will rot. Can you tell which thread it is by sight? No way! But, you will know in a year or two when the thread begins to break. And of course, NYLON and COTTON are cheaper!
Cover Duck uses only BONDED & LUBED PREMIUM POLYESTER THREAD.
The thicker the laminate, the better the cover is, because it lessens ripping. We have seen 7,9,10, and 11-oz. laminate used. Laminate can be single or double layered. The most important factor in laminate is the scrim used. Polyester Scrim is the only way to go. You can’t see the difference, but if nylon laminate is used, you will know because it shrinks and the seams will rip.
Cover Duck uses 11oz. POLYESTER SCRIM DOUBLE LAMINATE.
Heat Seal Gasket
Cover Duck uses a gasket in the hinge to keep the steam from escaping. You will not be happy without it
Cover Duck uses CORROSION RESISTANT ZIPPERS. When you try to unzip a three-year-old Cover Duck cover it will work like new!