Strengths
What it’s good at
Bonding unfaced foam insulation to porous wood, drywall, concrete, or brick without burning through the foam.
Limits
Where it falls short
One surface must be porous. It will not bond filmed-faced foam, polyethylene vapor barriers, PE, PP, PTFE, acrylic, or glazed surfaces; brace or fasten panels until cured.
Specifications
Manufacturer specifications
Every number below is quoted from the manufacturer’s own documentation, linked at the end of the row.
- Working time
- 20 min[2]
- Full cure
- 7 days — Temperature, humidity, substrate porosity, and adhesive amount affect cure time[2]
- Max service temperature
- 170 °F — Cured service range 0 °F to 170 °F[2]
- Min application temperature
- 40 °F — Apply and cure between 40 °F and 100 °F[2]
- Water resistance
- Water resistant after full cure; not for permanent immersion, damp surfaces, or rain within 24 h[2]
- Food contact
- No — not tested for direct or indirect food contact[2]
- Cured color
- Light blue[2]
How long it takes
Working time, clamp time, and full cure are different things — this is the order you experience them in.
- Working time20 min
- Full cure7 days
Sources
Where these facts come from
- [1]Loctite PL 300 Foamboard — product page — Henkel Corporation (Loctite) · Manufacturer page · Retrieved 2026-08-12
- [2]Loctite PL 300 Foamboard Construction Adhesive — technical data sheet, revision March 26 2018 — Henkel Corporation (Loctite) · Technical data sheet · Retrieved 2026-08-12
