Flextra vs Mulco Supra Expert: which one for the job
Both are Mulco thermoplastic sealants for exterior window, door and siding joints. Cranco carries both.
Mulco publishes the same substrate list for both. The split is joint size and the temperature you can work in.
Which to take
Take Supra Expert on a cold morning. Mulco rates its surface temperature from -30 to 40 degrees Celsius, where Flextra's sheet gives an application range of 5 to 30 degrees. Supra Expert's own product temperature still has to be above 5 degrees to gun easily.
Take Flextra where the joint is small. Mulco caps Supra Expert at 16 mm wide by 10 mm deep and sets a 6 mm floor on both width and depth.
Both are paintable, both are exterior only, both keep three years sealed, and both carry ASTM C920 Type S Grade NS Class 25. Supra Expert is flammable while it is being applied, with a flash point of 28 degrees Celsius.
What the data sheets say
| Flextra | Mulco Supra Expert | Source | |
|---|---|---|---|
| Chemistry | Thermoplastic | Thermoplastic | Cranco's catalogue |
| Application temperature | 5 to 30 °C (40 to 86 °F) | product 5 to 30 °C; surface -30 to 40 °C | Data sheet |
| Service temperature | -40 to 50 °C (-40 to 122 °F) | -40 to 50 °C | Data sheet |
| Indoor or outdoor | exterior | exterior only | Data sheet |
| Substrates | steel, galvanized steel, metal, painted/stained wood, natural/painted/anodised aluminum, concrete, masonry, glass, fibreglass, vinyl (PVC) | concrete, masonry, painted or stained wood, natural/painted/anodised aluminum, steel, galvanized steel, metal, glass, fibreglass, vinyl (PVC) | Data sheet |
| Uses | seal joints around door and window frames, sidings, glass in window frames | seals outdoor joints between two perpendicular surfaces exposed to thermal movement around door and window frames, sidings, glass in window frames | Data sheet |
| Paintable | Yes | Yes | Data sheet |
| Standards | ASTM C920 Type S Grade NS Class 25 Use NT; CAN/CGSB-19.13-M87 (cat 25); CGSB 19-GP-5M; 19-GP-14M; 19.17-M90; 19.24-M90 | ASTM C920 Type S Grade NS Class 25 Use NT; CAN/CGSB-19-GP-5M, 19-GP-14M, 19.13-M87 (cat 25), 19.17-M90, 19.24-M90 | Data sheet |
Every figure above comes from the manufacturer: Flextra from Mulco's published data sheet, and Mulco Supra Expert from Mulco's published data sheet. The chemistry row comes from Cranco's catalogue. "Not published" means the manufacturer gives no figure for that product.
Which Mulco sealant is for windows and siding?
Both. Mulco lists the same substrates for each, and both are exterior sealants rated to ASTM C920 Class 25 with a three-year shelf life. The joint size and the surface temperature at the time you gun it are what separate them.
What the manufacturers warn about
Before using the clear or the translucent product, test the resistance of the siding colour, the colour of some materials wash out by solvents and will yellow or colour the sealant. Does not adhere to polyethylene, polypropylene, recycled plastic, Teflon or other comparable materials. Make sure the joint variation does not exceed the "FLEXTRA" elasticity. When "FLEXTRA" is painted, the paint may crack if "FLEXTRA" supports a movement higher than the paint elasticity. The drying time of "FLEXTRA" depends on temperature, relative humidity and ventilation. The shelf life is diminished by warehousing over 25°C (77°F). Not for joints submerged in water for prolonged periods of time. Use outdoors only; do not use inside houses. When possible, the use of opaque colour is preferable to the use of clear or translucent product. Adhesion on material not specifically mentioned cannot be guaranteed. It is up to the customer to make his own performance tests or to consult our technical department.
Mulco: for exterior use only, on outdoor vertical or horizontal joints. Maximum joint size 16 mm (5/8 in) wide by 10 mm (3/8 in) deep; minimum width and depth 6 mm (1/4 in).
Mulco: at application the product is flammable and its flash point is 28 °C (82 °F); dry, it is combustible. The product's temperature must be above 5 °C (40 °F) to be applied easily.
Mulco: does not require painting; however it can be painted over 24 hours after application with latex paint.
Product pages and related comparisons
- Flextra Full specifications
- Mulco Supra Expert Full specifications
- Mulco Supra Elite The hybrid in the same range
- Mulco at Cranco Every Mulco product Cranco carries
Cranco's three counters
Call the counter nearest the job to check a product before you drive over.
Concord
255 Spinnaker Way, Unit #2, Concord, ON L4K 4J1
- Mon–Fri 7:00 am–5:00 pm
- Sat mornings, call for the closing time
- Sun closed
Mississauga
1122 Lorimar Drive, Unit B, Mississauga, ON L5S 1R8
- Mon–Fri 7:00 am–4:00 pm
- Sat–Sun closed