Craftsman Bio Process flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Dew point margin

The substrate temperature must exceed the dew point by at least 3 C before coating. A smaller margin allows condensation to form on the surface and causes poor adhesion or blistering.

Substrate moisture content

Water present in wood or masonry, measured with a calibrated meter. Excess moisture trapped under a bio coating causes blistering, peeling, and delayed cure.

Mill scale removal

A flaky oxide layer on new steel that must be removed before coating. Bio coatings cannot bond reliably to mill scale, which later breaks away and takes the film with it.

Pot life

The usable time after mixing a two-component coating before it becomes too thick to apply. It shortens as temperature rises and is not extended by adding thinner.

Mixing ratio by weight

The proportion of base to hardener stated on the product data sheet. Weighing rather than measuring by volume prevents cure failures caused by small ratio errors.

Shelf life of bio coatings

The period a sealed container remains usable when stored in the stated temperature range. Expired material may not cure or may show separation and must be rejected.

Masking before application

Covering adjacent surfaces that should not be coated. Bio coatings cure hard and are difficult to remove from glass, metal, or finished surfaces after the fact.

Surface profile

The roughness created by abrasive preparation, measured in microns. Too smooth a profile reduces mechanical key; too rough a profile can leave peaks exposed above the film.

Wet film to dry film

Wet film thickness equals dry film thickness divided by the volume solids fraction. A 60 percent solids coating at 100 micron dry film needs about 167 micron wet film.

Recoat window

The time interval during which a second coat bonds chemically to the first. Exceeding it requires abrasion of the surface before recoating to restore adhesion.

Wet edge

The still-fluid boundary of a brushed or rolled section. Keeping it wet prevents lap marks where fresh coating meets material that has already begun to set.

Spray tip selection

The nozzle size chosen to match coating viscosity. High-solids bio coatings typically need a 1.8 to 2.5 mm tip for an even pattern without spitting.

Two thin coats rule

Applying two coats within the specified thickness range gives better coverage and fewer defects than one thick coat, which risks solvent entrapment, runs, and blistering.

Flash-off time

The interval between application and the point when solvent has largely evaporated. Insufficient flash-off before baking or recoating traps solvent and causes pinholes.

Gentle stirring

Mixing bio coatings slowly by hand or with a low-shear paddle. High-shear mixing pulls air into the product, producing foam and pinholes in the cured film.

Maximum surface temperature

The upper limit, often 35 C, above which application should stop. Hot surfaces cause rapid drying, uneven flash-off, and visible lap or blister defects.

Tool cleaning

Washing brushes and rollers with the cleaner named on the data sheet immediately after use. Once a bio coating cures, it cannot be dissolved from tools.

Dry film thickness gauge

A magnetic or eddy-current instrument that measures cured coating thickness on metal. Readings are averaged across the area to confirm the specified range is met.

Cross-cut adhesion test

A lattice of cuts through the film, covered with tape and pulled off. The result is graded 0 for no loss to 5 for heavy detachment.

Pull-off adhesion test

A loaded dolly glued to the coating is pulled until failure. The recorded value and failure mode show whether the coating or the substrate bond failed.

Solvent rub test

Rubbing the cured film with a solvent-soaked cloth to check cure. Softening or color on the cloth indicates the coating has not fully cured.

Holiday detection

A high-voltage spark test on conductive substrates that reveals pinholes and thin spots. Voltage is set according to the coating thickness being inspected.

Nonconformity

Any measured or observed result outside the acceptance criteria, such as thickness below the specified minimum. It must be recorded, repaired, and re-inspected.

Visual defect log

A record of runs, sags, pinholes, orange peel, and misses, each with location and size. It supports repair decisions and later certification review.

Ambient condition record

Temperature and humidity logged at the start, middle, and end of each session. These readings show whether the coating was applied within the allowed envelope.

Acceptance criteria

The measurable limits, such as thickness range and adhesion grade, agreed before work begins. Results are judged against them, so they must be written and unambiguous.

Certification evidence package

The collected preparation records, batch numbers, application logs, and inspection results. A certificate is issued only when this package is complete and criteria are met.

Batch traceability

Linking each coating batch number to the location and date where it was applied. It allows later investigation if a defect appears in a specific area.

Inspector qualification

The current credential held by the person performing inspection. An expired qualification invalidates the inspection record for certification purposes.

Repair re-inspection

A repaired area is assessed by the same protocol as new work. It is not automatically certified on the basis of the repair alone.

Written deviation approval

Permission to depart from the specification, granted in writing before work proceeds. Verbal approval is not accepted as evidence during certification review.

Record retention period

The time certification documents must be kept after project completion, commonly set by contract at 5 to 10 years. It supports later warranty or dispute claims.