Polyester Resins

Casting (SPR-41F) and Laminating (SPR-29L, SLR-22)

CASTING
SPR-41F Specifically designed for casting Water Clear, High Impact resistant parts in thin or thick sections.
Recommended MEKP Catalyst levels: 0.5 – 1.5%-- depending on part thickness.

LAMINATING
SPR-29L Clear (Bluish Tint) Laminating Resin with UV stability. Excellent for initial coat for Bonded Bronze (Cold Casting) @ 2% MEKP Catalyst level—parts can be sanded, polished and buffed.

SLR-22 General Purpose Laminating Resin to make mother-molds when supporting thin walled latex, urethane or silicone rubber molds. Use in conjunction with Fiberglass Mat, Cloth or Chopped strand fibers for reinforcement. Recommended MEKP Catalyst levels: 1 – 1.5 %

SPR-41F
Properties:
Color: Water Clear
Viscosity: 470 cps
Specific Gravity: 1.20
Cubic Foot: 70 LB
Recommended Catalyst Levels: 0.5 – 1.5%

Typical Cure Data:
Commercial Promoted Resin 50G @ 72F (22C): 1% MEKP
Gel Time (min): 16.0
Exotherm Time (min): 35.5
Peak Exotherm (F): 285
Barcol Hardness (3/16” Casting): 40-45

De-mold the part as soon as possible. A noticeable shrink void can be a sign of material solidifying—immediately remove part from the mold and store in warm, dry area (80F) and allow part to gradually cool and finish curing.


Casting Suggestions: (SPR-41F)
Because of wrinkles, sticky surfaces, discoloring, bubbles and cracking, a working process must be developed. All the above problems are caused by inconsistent heat control during cure.

1) Molds (Silicone) should be preheated to 100-125F for 30 minutes.
2) SPR-41-F must be 80F, it can be warmed up in a hot water bath (Place container in a plastic bag).
3) Add MEK-P (RCHP-90) at 1% level to start. If material gets too hot (wrinkles) you can reduce levels to 0.5%.
4) Your target goal is to create an even exotherm (chemical reaction of heat that dries the resin).
5) Any parting lines can be wet sanded with 400/600 sandpaper, dried then buffed with polishing compounds.
6) De-mold times will change with size, shape or amount of RCHP-90 (do not try to rush the process by adding higher levels of catalyst).
7) Full properties will not develop for 24 hours at 80F. Heat distortion factor is 130F (Time at constant heat).

CATALYST: MEKP (RCHP-90)
MEK Peroxides are clear colorless solutions in dimethyl phthalate used principally as an initiator for the polymerization of unsaturated polyester resin systems:
RCHP-90 is a general purpose polyester catalyst. Use for normal room temperature cures of laminating and casting polyester resins. Catalyst Ratios of .5 to 2% are typical depending on which system is used as well as ambient conditions.

Typical Properties:
Active Oxygen: 8.9 +/- .01%
Color and Form: Colorless liquid
Specific Gravity @25C (77F): 1.155
Flash Point (SETA C.C. ): 200F (93C)
Styrene Insoluble (1:1 mix): Clear Solution
Solubility: Insoluble in water/soluble in most organic solvents.

ACCESSORIES
Tooling Gelcoat  Use for creating high gloss, durable fiberglass molds

Bondo  Use for patching and plugging parts or mold tooling

Polyester Pigments
Blue, Black, Red, White and Yellow

Release Agents
PartAll Film #10 (PVA)—Sprayable Polyvinyl Release
Partall Hi-Temp—High Temperature Wax
PartAll Wax #2 —General Purpose Wax

Fiber Reinforcements
Fiber Veil  Surfacing Mat, lightweight for thin pieces
Fiberglass Cloth  4oz and 10oz
Fiberglass Mat  3/4oz and 1.5oz
Chopstrands  Add to Laminating Resin to create trowel-on paste for mother molds

The information and data contained herein are based on information we believe reliable. Each user of the material should thoroughly test any application and independently conclude satisfactory performance before commercializing. Suggestions of uses should not be taken as inducements to infringe on any particular patent.