Marcy Solid-Core Butyl Tape — 5/16" × 10ft | Individually Boxed | ME825
✅ In Stock
Marcy ME825 solid-core butyl tape in a single-application box — the 5/16" round profile for mechanically-fastened glass and general automotive sealing where a medium-diameter bead is needed. Steps up from the standard 1/4" when the channel or gap requires a fuller butyl profile to seal completely. Works reliably in hot and cold weather. Individually boxed for the mobile installer — no cutting, no re-wrapping. Not intended for windshield installation — use foam-core butyl (ME612C or ME810B) for windshield applications.
Specifications
- Part Number: ME825
- Size: 5/16" (7.9mm) round × 10ft
- Core Type: Solid-core
- Format: Individually boxed (single-application)
- Application: Mechanically-fastened side and back glass, door vapor barriers, general automotive sealing
Application
Apply along the glass channel or frame opening before pressing the glass into position. The 5/16" profile fills wider channels than the standard 1/4" while remaining manageable for positioning the glass. For mechanically-fastened side, rear, and quarter glass and general body sealing. Do not use for urethane windshield installations — use foam-core butyl for those.
What is solid-core butyl used for?
Solid-core butyl is the correct sealant for mechanically-fastened glass — side windows, vent glass, sliding rear windows, and quarter glass on trucks and SUVs where fasteners hold the glass in position. It is also used for door poly vapor barrier re-adhesion and general body sealing where a flexible, weather-resistant bead is needed. It is not the correct product for urethane-bonded windshield installation — use foam-core butyl for those.
When should I use 5/16" instead of 1/4" or 3/8"?
Use 5/16" (ME825/ME815S) when the channel gap is too wide for the 1/4" bead to fill completely, but the 3/8" diameter would create too much resistance positioning the glass. The 5/16" is the middle profile — common on mid-size trucks, vans, and SUVs with moderately wider channels than standard passenger cars. When in doubt, match to the gap width in the seated position.
What is the difference between solid-core and foam-core butyl?
Solid-core butyl is an all-butyl bead that seals effectively for mechanically-fastened glass. Foam-core butyl has a foam center that provides rebound compression — this is required for urethane windshield installation where the foam fills voids as the glass cures. Do not substitute one for the other in windshield applications.
Does solid butyl work in both hot and cold weather?
Yes — Marcy solid butyl is formulated for all-weather use. In cold temperatures it stiffens slightly but remains workable with light warming. In hot weather it becomes softer and more pliable, which aids application but requires care not to stretch the bead during placement.
Should I use boxed or bulk solid butyl?
Individually boxed (ME625, ME825, ME925) is ideal for mobile installers — each box is a clean, single-application length. Bulk packs (ME615S, ME815S, ME915S) offer a longer roll at lower cost per foot, better value for shops doing high-volume work where material efficiency outweighs the per-job convenience of the boxed format.