Fill-Its
- Low cost, light weight, machinable backfill material.
- Specifically designed to be compatible with all Haprez laminating systems.
- When used with Haprez laminating systems, a strong, durable, backfill is achieved with excellent physical properties.
- The Fill-Its have been chemically treated and dried to promote adhesion.
A Fill-It/Haprez matrix machines just like wood, without the grain. When milled, a curled chip is produced, versus dust, when machining conventional polymer plastics. Fill-It matrices are strong and will hold threads well. It can be drilled, tapped, sanded, planed, and all Hapco's Polymer systems bond tenaciously to Fill-Its.
Fill-Its can be used at various ratios, allowing the user to control cost and properties.
Typical Properties
| Mix Ratio by weight (starting point) | 300 parts by volume to A/B mixture |
| Mix Ratio Range | 200-600 parts by volume to A/B mixture |
| Thermal Conductivity | Poor |
| Specific Gravity | .63 |
| Type | Free flowing small granules |
| Machinability | Excellent |
| Color | Tan / Brown |
Fill-Its are best mixed with the low viscosity Haprez laminating systems; such as HAPREZ 3742 and HAPREZ 3745 LV. The final choice of a HAPREZ system and the volume mix ratio of Fill-its and Haprez, depends on the final application and properties required.
The following is a reference chart on mixtures of HAPREZ 3742 and Haprez 3745 LV, Fill-It mixture. Again, the final selection of Haprez, Hapcure mix ratio, and ultimately the Fill-It ratio used, will depend on the application and physical properties required. Hapco recommends that the user try various combinations before final manufacture, by mixing small amounts and testing.
FILL-IT COMBINED WITH HAPREZ 3742 OR HAPREZ 3745 LV
Click to view and print the full Mixing Chart
| Fill-Its/Haprez Ratio | 2-3 Parts | 4-5 Parts | 6-7 Parts |
|---|---|---|---|
| Cost | Low | Very Low | Lowest |
| Strength | Highest | Medium | Medium/Low |
| Porosity of casting | Dense(no voids) | Some voids | Voids throughout Will pass air @ 7:1 |
| Shrinkage per linear inch* | 0.0020-0.0050 | 0.0010-0.0030 | 0.0005-0.0020 |
| Thermal conductivity | Poor | Very Poor | Poorest |
*Varies depending on curing agent, mass and ratio.
DIRECTIONS FOR USE
SURFACE PREPARATION TO PREVENT ADHESION:
To prevent adhesion to the mold, use a Grease-It™ release agent. The following are recommended; GREASE IT II, GREASE IT IV, GREASE IT WAX P or LT. For best results, apply in a few thin coats, drying between coats. Porous surfaces, i.e. wood, plaster, etc, must be sealed thoroughly before release is applied. Use multiple coats of a good coating, such as: a high-grade lacquer or urethane lacquer.
SURFACE PREPARATION FOR ADHESION:
For applications where adhesion is desired, the surface must be cleaned, abraded and dried. Sandblasting and mechanical roughing are the preferred ways of abrading surfaces to be bonded. For added adhesion to metals, use Primer 200. Make sure all surfaces are clean, dry and free from moisture.
MIXING:
After HAPREZ and HAPCURE have been mixed, add to pre measured Fill-Its and mix well. Some common techniques for mixing are; by hand, a dough mixer, a high viscosity pail mixer, or a cement mixer. For best results, use plastic or coated containers. Pour and tamp in place. To reduce and/or eliminate air entrapment, use a simple vibrating table or clamp on vibrator while pouring and tamping in place. Always use rubber gloves for protection when hand mixing.
SURFACE COATING:
Brush apply a first coat of HAPCOAT surface coat, taking care to eliminate all trapped air bubbles. Use a hair dryer, moving quickly over the surface while brushing, to help eliminate air bubbles. Allow to tack up, and brush on a second coat of Hapcoat, Hapcast, or Hapflex. After the second coat tacks up, apply the FILL-IT/HAPREZ mixture.
OPEN CASTING:
Pour in a thin unbroken stream into the lowest point in the cavity or mold. This will help break up some of the air entrapped during mixing.
SURFACE CASTING:
When using the surface casting method, use Hapco's RAPIDFIL , MINIFIL and/or RAPIDSHOT Dispensing Equipment for fast, reliable, and efficient dispensing.
SHRINKAGE:
Shrinkage or dimensional variation is largely influenced by 5 factors:
- 1. Mass ( total volume and thickness)
- 2. The temperature of the material
- 3. Maximum temperature reached during the exotherm (reaction). The faster the material, the higher the exotherm, the greater the shrinkage.
- 4. The temperature of the mold.
- 5. The thermal properties of the mold material.(Insulator vs. Conductive)
The stability of the mold material and geometry, thickness, and total volume of the part vary in each design, therefore, the customer responsible to test and determine the shrinkage factor to be used. The values in the brochures are for comparative reference only.
CLEAN UP:
Cured polymers are most difficult to remove. Cover your work area with a drop cloth and clean tools and equipment immediately after use.
PRECAUTIONS:
Skin or eye contact with polymers should be avoided. The use of gloves and eye protection are strongly recommended.
All polymers, as a general practice, should be used in well-ventilated areas. Spot ventilation is most effective. Contaminated clothing should be removed immediately and the skin washed with soap and water or waterless skin cleaner. Should accidental eye contact occur, wash thoroughly with water and
consult a physician.