ALEX FAST DRY vs ALEX PLUS: which one for the job
Both are DAP acrylic latex caulks with silicone, both paintable, both interior and exterior. Cranco carries both.
DAP's two sheets agree on almost everything. They differ on how fast the bead goes tack-free and on how wide a joint each one will fill.
Which to take
Take ALEX FAST DRY when the painter is behind you. It is tack-free in 15 minutes against ALEX PLUS's 30.
Take ALEX PLUS for the wider gap. DAP caps ALEX PLUS at a joint half an inch wide by half an inch deep, and caps ALEX FAST DRY at three eighths by three eighths. Past those, both sheets say to pack the joint with backer rod first.
Everything else matches: the same substrate list, the same uses, the same 24-hour return to service, the same 40 to 100 degree Fahrenheit application range, white only, and both exceed ASTM C834.
What the data sheets say
| ALEX FAST DRY | ALEX PLUS | |
|---|---|---|
| Chemistry | Acrylic latex with silicone | Acrylic latex with silicone |
| Tack-free time | 15 minutes | 30 minutes |
| Cure time | 24 hours (Full Dry Through; Return to Service Time 24 hours) | 24 hours (Full Dry Through; Return to Service Time 24 hours) |
| Application temperature | 40 to 100 °F | 40 to 100 °F |
| Service temperature | -20 to 180 °F | -20 to 180 °F |
| Indoor or outdoor | interior and exterior | interior and exterior |
| Substrates | wood (painted & unpainted), aluminum, most metals, vinyl, most plastics, glass, drywall, plaster, brick, stone, concrete, mortar, fiber cement, stucco, most common building materials | wood (painted & unpainted), aluminum, most metals, vinyl, most plastics, glass, drywall, plaster, brick, stone, concrete, mortar, fiber cement, stucco, most common building materials |
| Uses | window frames, door frames, baseboards, molding, trim, corner joints, pipes, vents, siding, other gaps & cracks especially prior to painting | window frames, door frames, baseboards, molding, trim, corner joints, pipes, vents, siding, other gaps & cracks especially prior to painting |
| Paintable | Yes | Yes |
| Package sizes | 10.1 fl oz (300 mL) cartridge; 5.5 fl oz (162 mL) tube | 10.1 fl oz (300 mL) cartridge; 5.5 fl oz (162 mL) tube |
| Standards | Exceeds ASTM C834 | Exceeds ASTM C834 |
What is the difference between ALEX FAST DRY and ALEX PLUS?
ALEX FAST DRY is tack-free in 15 minutes and ALEX PLUS takes 30. Both are ready to return to service after 24 hours, so what you gain is the wait before painting.
What the manufacturers warn about
DAP: application temperature range is between 40 °F and 100 °F.
DAP: joint size should not exceed 3/8 inch wide by 3/8 inch deep. If joint depth exceeds 3/8 inch, use backer rod material.
DAP: not recommended for use on copper or copper alloys. Will not adhere well to low surface energy plastics such as PP, PC, PMMA, PTFE.
DAP: apply in temperatures between 40 °F and 100 °F. Joint size should not exceed 1/2 inch wide by 1/2 inch deep. If joint depth exceeds 1/2 inch, use backer rod material.
Product pages and related comparisons
- ALEX FAST DRY Product details
- ALEX PLUS Product details
- DAP at Cranco Every DAP product Cranco carries
- Caulking against sealant