PPG SigmaWeld 199 is a two-component, moisture-curing low zinc (ethyl) silicate prefabrication primer that is suitable for automatic application on shot blasted steel plates. Good cutting and excellent welding properties, including MIG/MAG welding in various positions (either automatic or manual welding), fast-drying and low fume release are some of the top features of PPG SigmaWeld 199.

Features & Benefits

• Provides regular, smooth weld seams
• Low fume release during welding and cutting
• No adherence of weld spatter at surrounding primed surface
• Excellent thermal stability minimizes heat damage during hot work procedures
• Can be used as a first coat in various paint systems
• Suitable for sea water immersion in combination with controlled cathodic protection systems
• Approved by major classification societies like Lloyd's Register and DNV-GL for use as a prefabrication primer

Product Data

Two-component, moisture-curing low zinc (ethyl) silicate prefabrication primer.

Notes:

• Refer below for more details on spreading rate and film thickness, overcoating intervals and curing times
• Longer overcoating intervals can be permitted when the primer is still in sound condition
• Full cure time for Relative Humidity (RH) of > 50 %
• Processing of coated steel plates (bending, welding, etc.) and overcoating is only recommended when the shopprimer is fully cured
• More detailed information on application, handling and storage of steel plates is presented in the SIGMAWELD 199 Working Procedure

Surface Preparation

Recommended Substrate Conditions and Temperatures

Substrate conditions

• Steel; shot blast cleaned to ISO-Sa2½, blasting profile 30 – 75 µm (1.2 – 3 mils)
• On steel blasted to above profile, the recommended DFT of 18 µm (0.7 mil), corresponds to 22 µm (0.9 mil) as measured on a smooth test panel
• Minimum thickness for a closed film is 15 µm (0.6 mil) measured on a smooth test panel
• Dust quantity on the surface to be coated must not exceed rating "1" for dust size class "3", "4" or "5" (ISO 8502-3-2017)
• Lower dust size classes (“1” and/or “2”) to be removed if visible without magnification

Substrate Temperature

• Substrate temperature during automatic application should be between 25°C (77°F) and 35°C (95°F)
• Substrate temperature during application and curing should be at least 3°C (5°F) above dew point
• Ambient temperature during application should be at least 5°C (41°F)

Note:

• Substrate temperatures of > 35°C (95 °F) during application increases the risk of dry spray, and is therefore not recommended

Secondary Surface Preparation

• During storage and construction, contamination of the prefabrication primer should be limited
• After fabrication, surface defects should be treated according to the scheme hereafter
• Where two possible surface treatments are indicated, the choice of treatment is dependent on the location and on the system to be applied (see table below)
• The preferred pre-treatment for optimal results is shown; other possibilities are indicated in brackets

Notes:

• Cleaning by silicon carbide impregnated abrasive pad - Dust quantity rating "1" for dust size class "3", "4" or "5", lower dust size classes to be removed if visible on the surface to be coated without magnification (ISO 8502-3)
• The back of welded plate may show discoloration (especially on plate where fillets have been welded on, this is not to be confused with burned areas and does not require special treatment
• Burned through areas may be present (this happens especially when welding thin steel) and these should then be treated as per 'burned areas' above

Application

Instructions for Use

Mixing ratio by volume: binder to paste 66.7:33.3 (2:1)

• The temperature of the mixed base and hardener should preferably be above 15°C (59°F)
• Stir the paste thoroughly before adding the binder
• Gradually add one-third of the binder to the pigment paste
• Stir thoroughly until homogeneous
• Add remaining binder and continue stirring until the mixture is homogeneous
• Strain the mixture through a 30–60 mesh screen
• Mixed paint is ready for use
• Some addition of thinner (THINNER 90-53) might be necessary depending on routing, line speed and steel temperature
• Agitate continuously during application

Air Spray

Recommended thinner

• Thinner 90-53

Volume of thinner

• 0 - 5%

Nozzle orifice

• 1.0 - 1.5 mm (approx. 0.040 - 0.060 in)

Nozzle pressure

• 0.3 MPa (approx. 3 Bar; 44 p.s.i.)

Airless Spray

Recommended thinner

• Thinner 90-53

Volume of thinner

• 0 - 5%

Nozzle orifice

• Approx. 0.43 – 0.53 mm (0.017 – 0.021 in)

Nozzle pressure

• 8.0 - 12.0 MPa (approx. 80 - 120 bar; 1161 - 1741 p.s.i.)

Cleaning Solvent

• Thinner 90-53

Curing Times

Curing time for DFT up to 18 µm (0.7 mil)

Notes:

• Curing times valid for a Relative Humidity (RH) of > 50 %
• Relative humidity of < 50 % will reduce curing speed and increase time to full cure
• At temperatures below 5°C (41 °F) curing will be limited and time to full cure will increase
• Longer drying times may be necessary at higher DFT and under unfavorable atmospheric conditions
• Processing (bending, welding, etc.) and overcoating of coated steel plates is only recommended when SIGMAWELD 199 is fully cured
• Degree of curing can be checked by MEK-rub test (ASTM 4752). Full cure is achieved when the coating surface is not affected by the solvent

Safety Precautions

• For paint and recommended thinners, see information sheets information sheet 1430, information sheet 1431 and the relevant Material Safety Data Sheets in the attachments section above
• This is a solvent-borne paint and care should be taken to avoid inhalation of spray mist or vapor, as well as contact between the wet paint and exposed skin or eyes

References

• Conversion Tables (information sheet 1410)
• Explanation to product data sheets (information sheet 1411)
• Safety Indicators (information sheet 1430)
• Safety in Confined Space and Health Safety, Explosion Hazard - Toxic Hazard (information sheet 1431)
• Cleaning of Steel and Removal of Rust (information sheet 1490)
• Specification for Mineral Abrasives (information sheet 1491)
• Relative humidity - Substrate Temperature - Air Temperature (information sheet 1650)