Valid from: June 2006
Last reviewed: August 2020
NOTE: UNLESS STATED OTHERWISE THE WORD POLYGLASS ALSO REFERS TO POLYGLASS VEF AND PPA ALSO REFERS TO PPV. FOR ECOFLAKE USE VINYL TOLUENE INSTEAD OF STYRENE TO FLUSH EQUIPMENT.
Polyglass and PPA are spray-applied pre-catalysed with normal airless spray equipment. However, care must be taken to ensure that equipment is correct, in first-class condition and procedures must be closely followed.
Pump unit. The pump should be an airless spray type having a minimum ratio of 45:1 and delivery of at least 4 litres per minute. The pump should preferably be fitted with leather seals although Teflon (PTFE) seals are acceptable for small jobs, the best option is a leather, Teflon attenuating stack. All fluid filters should be removed both at suction and discharge ends.
10mm (3/8″) nylon lined fluid hose is required. Hose of smaller size will restrict gun pressure and must not be used with the exception that it is permitted to have a whip end of 6mm (¼”) bore hose provided the length does not exceed 750mm. Hoses lined with other than nylon will not handle this product. The gun should offer free passage to the fluid and be easily dismantled for cleaning. It should be fitted with suitable swivel connector to allow free movement on the hose, although a lighter weight gun will also handle the product provided gun bores are not restricting.
Tip sizes between 0.75 and 1.5mm (30 – 60 thou) for Polyglass and 0.5 to 0.75 (20 – 30 thou) for PPA, can be used with the required fan angle. Reversible cleaning heads are ideally suited to this application.
A mechanical stirrer for mixing hardener to each drum capable of vigorous stirring action.
An open top drum containing appropriate solvent for flushing pump unit.
A selection of tools suitable for changing gun, hoses and removal of pump wet end.
Suitable protective clothing shall be worn at all times.
Set up spray equipment with hoses and spray gun using nozzle tip within recommended range. Prime pump using Styrene Monomer. Apply full pressure (3000 – 3500 psi) and spray a small amount of Styrene to prove pump and gun. Release pressure and remove gun nozzle.
Should be carried out in accordance with the relevant specification for metal or masonry substrates (User Data Sheets SP1 or SP5). Relative humidity is not important but surface temperature should be at least 3°C above dew point.
Each drum of material is supplied with 1 bottle of hardener, retarder is available for an additional charge.
Mix drums of material as follows taking care to mix only sufficient material that can be utilised within the pot life.
(1) FOR MATERIAL TEMPERATURES BELOW 20°C
Remove lid from drum of base material, taking care not to contaminate material with dirt from top of lid, and agitate with mechanical stirrer. Check the time then add approximately half of 1 bottle of the MEKP hardener supplied with each drum and continue to agitate for approximately 1 minute. Add the second half of the contents of the hardener bottle and continue to stir until contents are thoroughly mixed (approximately 2 minutes).
Remove pump suction pipe from Styrene solution and, after draining, place into drum of catalysed material. Pull gun trigger and pump Styrene into a suitable container until Polyglass appears at the gun head.
After ensuring that Styrene diluted material has been discharged, re-circulate material into the feed drum for a short period.
Replace spray tip and commence spraying Polyglass immediately (see spraying technique). This product has a limited shelf life which is reduced with heat and pressure. Avoid delays in spraying catalysed material.
Mix further drums of material only at the speed they are required to prevent pump suction being uncovered and drawing air. Each drum, when mixed with hardener, should be poured into the original drum under the pump suction and residues scraped out to avoid excessive wastage.
Spraying may continue until approximately ¾ of the pot life has expired, after this time no further drums of material should be mixed and as soon as the pump runs out of material, spraying should cease and equipment should be flushed out using Styrene then MEK. Where spraying is to continue, the secondary flush with MEK is not required.
NOTE: Spraying should stop before suction pipe is uncovered to avoid gun splutter on the work surface.
The pump should be stroked rapidly during flushing operations and care taken to ensure equipment is thoroughly cleaned.
Spraying may recommence after flushing operation using a newly catalysed drum of Polyglass and washing Styrene out of line by removing gun nozzle as previously described. Where MEK has been used for cleaning, a small amount of Styrene should be used to flush MEK from the unit and lines to ensure no contamination of the Polyglass occurs.
(2) FOR MATERIAL TEMPERATURES OF 20°C AND ABOVE FOR POLYGLASS, AND BETWEEN 20°C & 29°C FOR POLYGLASS VEF
Remove lid from can of base material, add 1 full bottle of retarder and mix thoroughly by mechanical agitation.
AFTER MIXING RETARDER WITH POLYGLASS IT IS ESSENTIAL THAT AT LEAST 5 MINUTES IS ALLOWED BEFORE COMMENCING THE ADDITION OF THE MEKP CATALYST.
Mix drums of material as follows taking care to mix only sufficient material that can be utilised within the pot life.
3) TEMPERATURES OVER 30°C
Where material temperatures for application are over 30°C pot life will be considerably shortened. This can be accommodated by refrigerating material in order to extend pot life. Should problems arise in application at high ambient temperatures the advice of Corrocoat’s Technical Department should be sought.
For application of Polyglass at ambient temperatures below 5°C or above 35°C, consult Corrocoat for recommendations.
Polyglass will cure well below freezing point and can be applied to hot surfaces, but special procedures may appertain.
Do not add more retarder than specified without specific instructions from Technical Service. If in doubt ask.
Pot life is based on product not ambient temperature, in any case pot life may be controlled by cooling the product prior to
application (this is not possible on Corrothane XT).
Catalysation temperatures referred to are material temperatures not air or surface temperatures. Check temperature of material properly before addition of inhibitor and catalyst. DO NOT GUESS.
Monitor material in the drum during application, pot lives are only approximate figures. Should obvious thickening, stringiness or lumps occur in the material this should be discarded, the equipment being flushed and cleaned immediately.
Never mix catalyst to base before adding and thoroughly mixing retarder to base. Never mix catalyst with retarder.
Attempts to thin Polyglass with Styrene for spray application will considerably affect the thixotropic properties. Only thin where absolutely necessary and never add more than 5% Styrene by volume. The addition of Styrene for thinning will extend the gel time; this may be considerable at low temperatures. Use only Styrene as a thinner, never use solvents or other thinning materials. The properties of Polyglass will be severely affected.
Overcoating with further coats of Polyglass may take place as soon as the previous coat has gelled sufficiently to bear weight of the next coat and whilst still tacky. Overcoating may be carried out as per the recommendations of the product data sheet after application of previous coat (see Data Sheet). However intercoat bonding is greatest with short overcoating times. In warm climates OR IN STRONG SUNLIGHT, independent of temperature, overcoating time will be significantly reduced. Special attention to overcoating on concrete surfaces is required (see separate Data Sheet on coating concrete). Care should be taken to avoid contamination between coats. There is no wax in these products therefore special treatment (such as wiping with Monomer) is not required for overcoating or repairs to freshly applied material.
Stripe coating should be carried out between coats, as with normal paint practice, to all weld seams, brackets, pipe joints, ridges etc. NB: In warm climates the maximum overcoating time will reduce significantly. It is recommended to work to a maximum of 2 days.
On completion of spray operations first flush with Styrene and then pump dry. Solvent should then be circulated through pump and spray lines for a period of at least 15 minutes taking care to flush drain and bleed-off ports. Styrene must not be used for the final flushing operation as this may polymerise within the system after some time.
Should for any reason pump failure occur whilst catalysed Polyglass is in the unit, the wet end should be quickly removed from the pump, dismantled and washed in solvent. Do not delay – Polyglass, under pressure, will harden very rapidly and it may not be possible to dismantle the wet end and remove Polyglass after a relatively short cure time. Spray lines may be saved by connecting to a second pump (if available) and flushing, guns should be dismantled and all passageways thoroughly cleaned. Tools should always be available for this work – REMEMBER – a compressor failure or burst air hose will stop the pump, but once catalyst is added to Polyglass, it will continue to cure.
With any spray applied coating it is essential that correct technique is used, but it is particularly important with Polyglass as the large nozzle requirement and dense flake structure may cause sag when Polyglass is incorrectly applied.
Polyglass should be applied by the wet on wet multi-pass technique as follows:
(1) Before spraying job surface, set pump pressure to give good spray pattern and atomisation at the LOWEST ACCEPT-
ABLE PUMP PRESSURE. Remember the higher the pressure, the shorter the pot life and the longer the thixotropic
recovery time on the surface.
(2) When a suitable pattern and atomisation have been achieved, start work by first spraying vertical passes (spraying from top to bottom/bottom to top). Do not try to achieve full wetting out of the surface at a single pass, but mist coat the area with several vertical passes until at least 90% coverage is achieved. Move to the adjacent area and carry out the same
procedure, then return to the previously vertically sprayed area and with horizontal passes, build up the coating thickness.
After building this area, return to the adjacent area with horizontal passes. Check wet film with suitable gauge and,
where necessary, build film thickness by alternate vertical and horizontal passes until desired wet film is achieved. On
completion, move to the next adjacent area to be coated, again starting with vertical passes.
REMEMBER GOOD INITIAL WETTING WITH VERTICAL PASSES IS ESSENTIAL FOR BUILDING THICK FILMS WITH THIS PRODUCT.
Correct spraying technique will enable substantial wet films to be applied in a single wet on wet application.
Primers such as PPA should be applied in a similar manner, but maximum WFT should not be exceeded (see Data Sheet).
On vertical surfaces such as tank side walls etc., Polyglass should preferably be applied in two coats to achieve the specified DFT. However, on horizontal surfaces such as decks, single coat applications up to 2mm WFT are acceptable.
Dry film thicknesses should be checked wherever possible between coats, so that the wet films of subsequent coats can be
adjusted accordingly, to avoid over-thickness, wastage or compensate for monomer evaporation and shrinkage.
It is essential that when applying these materials in enclosed spaces good ventilation is achieved, not only for safety reasons but also to achieve short cure times. However, Polyglass materials are 100% solids (no solvent) therefore over-thickness will not be detrimental to the cure, but monomer within the coating will evaporate to some degree dependent upon temperature and ventilation level. In theory apart from a small shrinkage allowance, all the WFT will convert to solid as a DFT, but in practice because of monomer evaporation much larger losses in DFT occur. It should be borne in mind that because polymerisation takes place more quickly at higher temperatures, with low level ventilation thicker DFT’s will be achieved from the same WFT than with low temperatures and high level ventilation. Greater losses will also occur when applying multiple thin coats rather than single thick coats. For good cure at low surface temperatures, Polyglass should always be applied at WFT’s of greater than 500 microns.
It is always preferable that testing is carried out after the application of these materials. This comprises three specific tests.
(1) Dry film thickness testing, to ensure that the specified DFT has been complied with using a good quality tester
preferably of the inductance type.
(2) Holiday detection to ensure that there are no pinholes within the coating. This should preferably be carried out using a
high frequency AC spark tester at a minimum voltage of as per Corrocoat data sheet 7/30.
Wet sponge testers are not effective with Polyglass coatings.
Polyglass has a very high dielectric strength and provided at least 24 hours cure (at 200C) has been allowed before testing,
damage to the coating will not result at these high voltages provided the probe is not kept stationary.
(3) Full cure (Acetone) test. In order to assess whether or not full cure has been attained the Acetone test should be carried out.
(a) A small patch should be well washed with clean Acetone to dissolve the surface inhibited film and remove
stickiness; the treated area should then be allowed to dry.
(b) Using a small amount of Acetone on a forefinger, gently rub the previously washed area. Should the surface
become tacky or should it have proved impossible to achieve a tack-free surface in the washing procedure, the
coating is not fully cured.
NOTE: On Polyglass 100 this test is only relevant to post cured product.
REPAIR OF DEFECTS
Thin areas should receive further coating application.
Where pinholes or holidays are detected these are best dealt with by using a 3mm flat bottomed drill to enlarge the pinhole down to the substrate then tamping Polyglass into the hole, before brushing a small amount of material over the top and immediate surrounding area.
Where extensive pinholing occurs this may have been caused by gassing due to surface contamination and the area should be re-blasted, the substrate examined and fresh coating applied. Because these materials are 100% solids, sags, runs and droops are not usually detrimental to the coating performance (except in severe instances with primers including PPA and PPV). However, where these defects are unsightly it may be preferable to treat them for cosmetic reasons. This should be done by allowing a reasonable hardness of the coating to be attained then grinding smooth. All dust should be vacuumed from the surface before overcoating.
The Health & Safety Data Sheets for these products should be read before use.
Observe usual safety precautions for using airless spray equipment, and in particular ensure that pump unit is earthed to avoid static discharges.
When working in confined spaces and tanks always ensure that a safety operative keeps watch externally. Full face air fed
breathing apparatus should be worn. Maintain auxiliary breathing aids for rescue externally, with suitable access equipment such as ropes and ladders where necessary. Discharge ventilated fumes to a safe area.
Always place ‘No Smoking’ signs. Mark areas with danger tape and keep suitable fire extinguisher to hand.
Use flame or explosion proof electric equipment.
Ensure adequate eyewash facilities are available; know the location of the nearest first aid facility and emergency telephone.
This list is not exhaustive and all aspects of safety should be considered before commencing work with these products.