Sherwin-Williams Macropoxy P300


We no longer stock this product, but can recommend Sikagard 62 as a great DWI approved coating alternative.

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This Product has been Discontinued


We no longer stock this product, but can recommend Sikagard 62 as a great DWI approved coating alternative.

Sherwin-Williams Macropoxy P300, formerly known is Waterline P300, is a solvent free two-pack epoxy water resistant finish for use on the internal surfaces of potable water pipes and tanks.


  • DWI approved as a site and factory applied coating for potable water retaining structures ref DWI 56.4.253
  • Water Industry Act 1991 : Section 69
  • Water Supply (Water Quality) Regulations : 1989
  • Water Supply (Water Quality) Regulations (Amendment) 1991 - Regulation 25(1)
  • Water Regulations Advisory Scheme Directory Reference 0512526

Recommended Topcoats

Macropoxy P300 is only recommended to be overcoated for touch up purposes.
Prior to overcoating, these areas must be thoroughly abraded, then solvent washed using Cleanser Thinners No. 13. Allow all solvent washings to dry, and thoroughly ventilate the area before applying touch up coat. 

Surface Preparation

For tank internals and for maintenance of existing tanks, blast clean to Sa21⁄2 BS EN ISO 8501-1:2007 using angular grit. Minimum surface profile 75 microns.
Ensure surfaces to be coated are clean, dry and free from all surface contamination. 

Application Conditions & Overcoating

Macropoxy P300 should preferably be applied at tempera- tures in excess of 10°C. Relative humidity should not exceed 85% and in these conditions good ventilation is essential. The use of dehumidifiers to maintain stable environmental condition is recommended during application and curing

of the coating. Substrate temperature shall be at least 3°C above the dew point and always above 0°C.

At application temperatures below 10°C, drying and curing times will be significantly extended.

Return to Service : Applied coating must be allowed to cure for 16 hours at 3°C or above before returning to service. Should ambient temperature fall below 3°C in this 16 hour period, a further 16 hours should be allowed, once the ambient temperature rises above 3°C.

If it is desired to overcoat outside the times stated on the data sheet, please seek advice of Technical Team. 

Product Details

Data sheet

Brush, Spray
2.00m² per litre
Touch Dry
1.5 Hours

Customer agrees that before placing an Order, Customer has read and understood the most up to date Product Data Sheet for the Product. Where we have access to the Product Data Sheet from the manufacturer, we will either provide a copy on request, or include a link to the Product Data Sheet available on the manufacturer’s website. Customer further agrees that we have no liability for any errors or omissions contained within the Product Data Sheets. For more information, please see our Terms & Conditions of Sale.

questions Tony Leyland on 2018-10-25 09:43:40

Hi, is a primer recommended forSherwin-Williams Macropoxy P300 on steel the has been blast cleaned to SA2.5?

Answer from Rawlins’ Technical Team: 

After recommended preparation, no primers are required or recommended, Sherwin-Williams Macropoxy P300 is used directly to the blasted steel.

questions Colin Spruce on 2017-09-14 11:02:15
Question: re Macropoxy P300 paint, is this suitable for a lime slurry of PH 12.5 value Regards
Answer from Rawlins’ Technical Team: 

Sherwin-Williams Macropoxy P300 would not be suitable. Lime slurry (calcium hydroxide) would require an epoxy phenolic at a minimum, Sherwin-Williams Epo-Phen FF can withstand up to 50% at 60°C.

Question about the product

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Sherwin-Williams Macropoxy P300 is only available with the shipping and delivery timescales listed below - please do not contact our Customer Support Team with enquiries about alternative or earlier shipping and delivery times.

Saturdays and Sundays, as well as Bank Holidays, are not classed as working days.

Orders placed after the cut-off for this product will not be processed for earliest dispatch until 9am the next working day.

All delivery costs below are excluding VAT