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Home  >>  Products  >>  Drying Time/Gelation  >>  BK Drying Time Recorder

BK Drying Time Recorder

6 -12 - 24 Hour Speeds.

Conforms To ASTM D5895



Measures and Records the Drying Time of Surface Coatings, etc. BK Drying Time Recorder Item No. DT-BK3 shown. CE Approved.




Stages in the Drying Process Defined as:

  1. The first stage is a pear-shaped impression corresponding to the time taken for evaporation of solvent.
  2. The second stage is the cutting of a continuous track, corresponding to a sol-gel transition.
  3. The third stage is an interrupted track corresponding to the surface-dry time.
  4. A fourth stage is where the needle no longer penetrates the film, corresponding to the final drying time.

A typical white enamel would have a drying time expressed as follows: 1-1/4 ----3-1/2----4 (hours)

Although all stages recorded are significant it is often sufficient to express a drying time in terms of set-time and hard-dry time, thus: 1-1/4 - 4 (hours). Brass weights, each weighing 5 g, may be used to apply greater pressure on the needles and thus record the through-drying properties of alkyds, varnishes and paints. The 3-SPEED BK DRYING RECORDER will give useful information about the gelation times of many two component surface coating materials and about the properties of such films.


Method of Use

  1. Select the required speed by turning the speed control knob in a clockwise direction and sliding in or pulling out to the required speed. Release knob.
  2. Apply film to the test strips and place them on the Recorder.
  3. Lift the release lever on the back of the needle carrier and slide it to the starting position.
  4. Lower the needles on to the test strips.
  5. Switch on and the needles will now commence the run along the strips. On reaching the end of the travel, the carrier automatically stops. Switch off.
  6. Individual glass strips may be removed from the machine simply by depressing one end at the strip so
  7. that the opposite end tilts clear at the holder.


Determination of Drying Time

The drying time of alkyds, varnishes or paints is determined by adding the requisite drier and thinning to a viscosity at which the material is normally applied. The finish is allowed to stand at room temperature for 24 hours to "mature". A test strip measuring 12" x 1" (which may be of plain or ground glass or of other suitable material) is prepared by casting a film upon it by means of a special applicator which is accurately ground at one end to deposit a wet film thickness of 1.5 mils and 3 mils at the other. The test strips are placed on the table in their holders and the instrument is then operated as indicated below.



The recorder body is robustly constructed from light alloy and the mechanism is mainly stainless steel and brass to avoid corrosion. A needle carrier holding six hemispherical ended needles travels the length of the test strip in 6, 12 or 24 hours. Other speeds are available to special order. The instrument accommodates six test strips 12" x 1". A time scale is mounted on the side cover and is graduated to suit the three different speeds.


Applicator and Casterguide


The Applicator - is a 25 mm stainless steel cube with a hole drilled centrally from one face through to the opposite face. From each end of this hole a gap 12 mm wide is ground from the hole to one side of the applicator, thus providing 2 gaps per applicator. The applicator is placed at one end of the glass strip with the ground gap facing the end. Paint is poured into the hole and the applicator steadily drawn down the glass strip and off the other end, the gap being the trailing end of the applicator. Paint will flow through the gap depositing a 12 mm wide film on the glass strip.

The standard applicator has a gap depth of 75 microns (3 mils) one end and 150 microns (6 mils) the other, which will apply a paint film thickness of approximately half the gap size. Any gap depth between 10 and 650 microns can be supplied to suit customer requirements.

The Casterguide - is a device for simplifying and “tidying-up” the process of applying the paint film to the glass strip. It consists of a cast aluminum trough with a ledge on each side to carry the glass strip and a step one end to allow the user to hold the strip in place. The applicator is then posotioned on the glass stirp at the step end and filled with paint as described above. When using the applicator the casterguide ensures that the film is applied centrally and, as the applicator is drawn off the end of the glass strip, the surplus paint is collected in the trough underneath.

This operation may be repeated several times before cleaning is necessary. For this purpose use only suitable solvents, do not use caustic alkali or caustic detergents since these will attack the aluminum metal.


6 Track Model (3 Pair Speed) & 10 Track Model (5 Pair Speed)



DT-BK10 Recorder DT-BK6 Recorder

These have independently paired operating tracks. Separate needle carriers are moved from parked positions by depressing individual plungers, sliding them along to zero positions and releasing plungers when operative. At end of travel, needle carriers are in parked positions. Unless otherwise specified, the tracks operate at a speed of 12 hours.

If required, provision can be made for some of the paired tracks to operate at speeds of 2, 3, 4, 6, 12, 24, or 48 hours. (Specify) The technique for preparing test strips and for reading the results is the same as for the standard BK Drying Recorder.



Prices subject to change    Prices listed in US dollars for domestic shipments within US, Canada, & Mexico only    Export orders require quotations - click here for a quote     For more info call us 1-800-762-2478 or 954-946-9454.
Item Number Item Prices

BK3 & BK6 Drying Recorders come complete with six needles, a set of clear glass test strips and steel applicator with 75mu and 150mu cuts (1.5 mil and 3 mil wet film)

BK10 Drying Recorder comes complete with ten needles and a set of clear glass test strips and steel applicator with 3 mil and 6 mil cuts (75 mu & 150 mu wet film)

DT-BK3 Standard 110 Volt 6-12-24 hrs, (Available in 3-6-12 hrs or 12-24-48 hrs) $2,467.00
Special 1/2-1-2 hrs / 1-2-4 hrs / 2-4-8 hrs / 24-48-96 hrs / 30-60-90 min (choose one) 2,621.00
Special Speeds 12-24-48 minute, Single Speeds and 240V / 50 Hz also available P.O.R
DT-BK6 Standard Speed 110 Volt all tracks 12 hrs, (Available in pair, all tracks 6, 24 or 48 hrs at no additional charge) 3,806.00
Special 1 to 96 hrs add - per pair of tracks add 155.00
DT-BK10 Standard Speed 110 Volt all tracks 12 hrs, (Available in pairs 6-24-48hrs) 4,733.00
Special 1 to 96 hrs add - per pair of tracks 155.00
Other speeds and 220 Volt models are available. Price & delivery dependent upon request.
DT-BK-A/S Stainless Steel Applicator Standard Cut 75mu and 150mu $257.00
DT-BK-A/SS SS Special Cut - Specify up to 650 microns 284.00
SS Special Cut - Specify up to 25 mils 394.00
DT-BK-N Needles (one dozen) 26.00
DT-BK-BW Brass Weights (5 gms) (pk of 6) 56.00
DT-BK-GS Clear Glass Strips (one dozen) 91.00
DT-BK-MC Casterguide 145.00


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