Wet film thickness

Take wet-film thickness for each coat applied and confirm that they are such as to yield the specified dry-film thickness. 

As stated above, high performance coatings based on epoxies, vinyls or chlorinated rubbers are used almost exclusively on all large ships. A general development in these materials has been the introduction of highly thixotropic types that can be airless sprayed at wet film thicknesses of 300 im or more, that do not run or sag on vertical surfaces. This enables the requisite film thickness to be applied in fewer coats, saving time and reducing application costs. 

Films of PATE were cast on copper plated circuit boards. Typical solutions contain from 8% to 17% PATTE solids and 0.02% Flourad FC 135 surfactant. No other additives, such as adhesion promoters, sensitizers, viscosity modifiers or stabilizers, were employed in the formulations. Films of 0.001 to 0.008 inches wet film thickness were cast on abrasively cleaned circuit boards and then oven dried for 5 minutes at 105 °C. Thus, in each case the... 

Polymer films of approximately 1000 microns wet film thickness were laid down with a bar applicator on PTFE coated glass panels and the solvent allowed to evaporate at ambient temperature for a standard period of seven days. A typical plot of solvent weight loss with time is shown in Figure 2. The thickness of the wet film was dictated by the need to have adequate mechanical strength in the dry films in order that they might be suitable for subsequent mechanical test procedures. Dry film thicknesses were approximately 300 microns as measured by micrometer. The dried polymer films were examined by dynamic mechanical thermal analysis (DMTA) (Polymer Laboratories Ltd.). Typical DMTA data for a polymer and paint are... 

Two-roll reverse For additional control over adhesive coating can handle wet film thicknesses from 1 to 20 mils... 

Table III. Response of Amylose Films to Wetting (Film Thickness 10 fi)...

In most cases the consistency of the polymer film at the end of spinning ranges from a highly viscous liquid to a wet solid. The as-deposited film is therefore usually treated by post-spinning bake at a higher temperature or in vacuum to remove any remaining solvent in order to produce a dry solid film. Two film thicknesses are therefore to be distinguished. The as-deposited wet film thickness h or H(H = where hg is some initial thickness,... 

The dry film thickness h or H is usually the experimentally and readily measured one in industrial practice although techniques are available for measuring the wet film thickness. On the other hand, h or H is the theoretically predicted one. This distinction between wet and dry film thicknesses enables the delineation of effects of solvent evaporation those effects during spinning which are due to a finite Ag and those effects due to post-SCD drying which can be measured by il. ... 

Figure 3. Calculated dimensionless wet film thickness profiles for Newtonian and non-Newtonian liquids at selected dimensionless spinning time T defined in ref. (12).

Wet film thickness The thickness of the liquid coating as it is apphed. 

ASTM D1212 Wet film thickness of organic coatings. 

Figure 49.7 (a) Steel surface profile monitoring equipment (b) Dew point monitoring equipment (c) Wet film thickness gauge (d) Elcometer adhesion tester. Photos by Metal-weld, Inc. 

Experimental data on falling films have suggested that this theory provides a very conservative measurement of minimum wetting film thickness as it is derived from the principle of the stability of dry patches rather than the breakdown of films. In general, it was observed that films could be maintained down to close to an order of magnitude lower than the above equations suggest, although under very contrived conditions. 1 Based on this, it can be assumed that... 

Ramshaw, and Burns et al.) has shown that wetting films for p values within the metastable film region can be obtained. In particular, the use of preflooding of the disk or the use of surface roughening can push the limit of the wetting film thickness down to the lower end of the metastable film region, further details of which will be discussed in the later sections. However, the above wetting parameter calculations can be used to examine how likely it is for a process to achieve a stable wetted disk surface. 

Churaev et al. (1994) recently published actual results on the relationship between wetting film thickness h and disjoining pressure 11, from which the macroscopic contact angle of the liquid on the substrate can be calculated. Today a compact monolayer is known as a French pancake, a bilayer a Swedish pancake and thick films as an American pancake. To sum up, wetting films and their transitions are combined with dynamic processes which elucidate rather complex and yet unsolved issues. 

The tests for determining wet film thickness are primarily intended for paint, but can also be used for the much thicker gel coats. A wheel gauge or a comb gauge may be used neither will give more than an approximate measurement, hence the fairly wide range of... 

Wet film gauge Device for measuring wet film thickness of coatings. 

Wet film thickness Thickness of the liquid coating film immediately after application. 

The distance between the carrier surface and the bottom of the doctor blade is the most important variable in determining wet-film thickness. The other three primary variables (viscosity, reservoir height, and carrier speed) have less impact than the doctor blade... 

No. Substrate PHA-type PVC Pigment Wet film thickness" Curing conditions... 

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