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: The foam on the inside of the cover is sealed in polyethylene. Hopefully
: the polyethylene is heat sealed closed rather than taped. Over time,
: the off gassing of chemicals and ozone break down the polyethylene
: causing it to become porous. Steam and evaporating water then
: penetrate through the polyethylene.
: Polyethylene.... Polyethylene in itself is water proof. Kind of. The
: manufacturing process (detailed below) produces small
: "beads" of the material that are then compressed together
: into blocks. While the beads are water proof, moisture can penetrate
: in between the beads.
: To "dry out" a cover, you'd need to remove the polyethylene
: and put the foam in a protected area for 6 months to a year. It might
: dry out in that time. But then you'd need to properly reseal the foam
: in the polyethylene. We use a $20k machine for this sealing process.
: The Manufacturing Process of EPS foam
: Expanded Polystyrene, or EPS for short, is a lightweight, closed cell,
: rigid, plastic foam insulation material produced from solid beads of
: polystyrene. EPS's properties of low thermal conductivity, high
: compressive strength and excellent shock absorption properties make
: it an ideal material for many uses. Expansion is achieved
: by virtue of small amounts of pentane gas dissolved into the
: polystyrene base material during production. The gas expands under
: the action of heat, applied as steam, to form perfectly closed cells
: of EPS. These cells occupy approximately 40 times the volume of the
: original polystyrene bead. The EPS beads are then molded into
: appropriate forms suited to their application.
: There are 3 manufacturing stages to attain EPS foam blocks:
: Polystyrene granules (resin) are expanded by free exposure to steam to
: form larger beads, each consisting of a series of non-interconnecting
: The raw material resin used to manufacture EPS is received in the form
: of small beads ranging from 0.5 to 1.3mm in diameter. These small
: beads are formulated and manufactured by the suppliers to contain a
: small percentage (4% - 5%) of the naturally occurring gas pentane.
: This gas is impregnated throughout the body of each small bead. The
: pre-expansion phase of manufacturing is simply the swelling of the
: small bead to almost 50 times its original size through the heating
: and rapid release of the gas from the bead during its glass
: transition phase.
: After expansion, the beads still contain small quantities of both
: condensed steam and pentane gas. As they cool, air gradually diffuses
: into the pores, replacing, in part, the other components. Most
: manufacturers run the finished beads through a dryer to remove any
: surface moisture. Then they're stored in large open storage bags for
: an aging process. Besides the steam and gas in the beads there are
: also areas of internal vacuum in the millions of cells created. This
: vacuum must be equalized to atmospheric pressure otherwise this
: delicate balance may result in the collapse, or implosion, of the
: bead. This process of aging the expanded beads allows the beads to
: fill back up with air and equalize. This aging can take from 12 hours
: to 48 hours, depending on the desired expanded density of the
: bead.After this process they're ready to be formed onto solid blocks
: of foam.
: The molding process involves taking the loose expanded beads and
: forming them into a solid block mass. A mold is filled with a
: specific amount of beads. A vacuum system evacuates any residual air
: from the mold. The vacuum is relieved by live steam which flows over
: the entire mass of beads in the cavity. This vacuum process softens
: the polymer structure of the bead surface and is immediately followed
: pressure compressing the beads and more live steam. The latent heat
: from the steam and subsequent pressure increase cause the beads to
: further expand. Since this is a confined environment, the only way
: the beads can expand is to fill up any voids between them causing the
: soft surfaces to fuse together into a polyhedral type solid
: structure. Pressure is released after a predetermined time and the
: loose beads are now fused into a solid block of foam. The density of
: the foam has been predetermined by the amount of pressure exerted on
: the beads while in the mold.
: Following a short cooling period, the molded block is removed from the
: machine, and after further curing and conditioning, may be cut or
: shaped as required using hot wire elements or other appropriate
Sounds like I've gotta start shopping for a new cover. Thanks guys!
PLEASE NOTE: We are Roberts Hot Tubs Inc. (manufacturers of traditional wooden hot tubs)! If you found this webpage through a search engine while searching for a different brand of spa, we are not them! We simply appeared in your search due to that name being talked about on this particular web page. The phone number below will reach Roberts Hot Tubs, not the manufacturer of the brand of spa you're searching for. This is a public forum and you're more than welcome to post a question asking for contact or other information for a particular brand of spa. Almost certainly someone will be able to assist you.