SciCron Technologies Mar-Con ® 600 abrasion resist
plastic substrate has a crosslinked coating which has
excellent abrasion resistance, chemical resistance, and
clarity. Mar-Con 600 coated plastics can be fabricated
into a wide variety of flat surface configurations including
glazing, partitions, doors, enclosures, shields and access
panels. They can also be used for fabricated items such
as boxes, displays, display cases, and key pads.
However, the cross-linked, cured, Mar-Con 600 coating is
not designed for heat bending. Attempts to bend Mar-
Con 600 coated plastics usually result in cracking and
crazing of the abrasion resistant coating. For applications
requiring heat formed or bent configurations, plastic
substrates with SciCron Technologies Forming Grade
Mar-Con ® 551 coating are recommended.
This Bulletin suggests fabrication guidelines for Mar-Con ®
600 coated plastic sheet products.

General Precautions
Although the Mar-Con ® 600 surface is much more
abrasion resistant than the base plastic, the polymer
coating can be damaged if the plastic sheet is handled
roughly or carelessly. As a general rule, all fabrication of
Mar-Con 600 coated plastics should be undertaken as
carefully as is practical to avoid unintended damage.
Whenever possible, fabrication procedures should be
carried out with the protective masking left on the sheet
surfaces to minimize the possibility of damage. Work
surfaces should be free of chips and debris which might
scratch the plastic.

Note: Some plastic substrates occasionally contain
internal stresses which can cause cracks or crazing
during fabrication. In such cases, it may be necessary to
anneal the plastic before fabrication.

Cutting and Machining
It is unlikely that the presence of the Mar-Con® 600
coating would necessitate any significant change in
typical cutting and machining procedures during
fabrication. Generally, the same techniques, cutting
blades, machining tools and tool speeds are used as
would be used normally with the base plastic. Wet
sanding, buffing and scraping procedures can be used for
edge finishing but flame polishing is not recommended for
finishing Mar-Con 600 coated plastics.

Caution!
1.0 Use of inappropriate equipment and tools, not
designed for plastic fabrication, can result in melting,
cracking, or shattering of the plastic substrate duringfabrication procedures. This can damage the plastic
permanently and could result in serious injury to
equipment operators. Always observe appropriate
safety precautions when fabricating SciCron
Technologies products. Contact SciCron Technologies
or your distributor for information about appropriate
equipment and fabrication procedures.

2.0 Procedures that excessively heat the plastic, like laser
cutting and flame polishing of cut edges, can induce
stresses in the plastic. This can cause cracking or
crazing at the cut edges if the edges subsequently come
into contact with solvents. Therefore, these fabrication
techniques should be avoided, particularly if the edges
are to be glued with a solvent cement. Flame over-spray
during flame polishing can also cause immediate cracking
or crazing of the coating at the sheet edge leading to
delamination of the coating at that edge

Solvent Welding
Because the Mar-Con® 600 surface is very chemical
resistant it is not softened or removed by short term
contact with solvents commonly used in solvent based
cements. As a result, the Mar-Con 600 coating must be
mechanically removed from the substrate to achieve a
good adhesive bond. Sanding or routing techniques can
be used to remove the Mar-Con 600 coating and prepare
the substrate surface for a solvent cement.

Acrylic and polycarbonate substrates can be bonded with
methylene chloride based cements while PVC substrates
can be bonded with cements containing acetone, methyl
ethyl ketone (MEK) and tetrahydrofuran (THF).

For best results, note the following recommendations:

• Observe appropriate safety precautions when using
  solvent cements. Provide adequate ventilation during
  application.
• Cut edges should be flat, square and smooth and
  should fit together well. If the edges contain stresses
  induced by cutting or machining it may be necessary to
  anneal the plastic before allowing the stressed edges to
  come in contact with a solvent cement.
• Clean the surfaces to be bonded with isopropyl alcohol
  (IPA), if necessary, to remove any residue.
• Apply the welding liquid to both surfaces. Join quickly
  (a few seconds) after application.
• Clamp the pieces together and hold for one to three
  hours allowing the bond to develop some green strength.
  The length of time needed to achieve enough green
  strength to move the pieces will vary with cement type
  and ambient conditions. Although high bond strength is
  achieved in 24 to 48 hours, the bond continues to
  strengthen for several weeks.