Gasket

Blooming

Whitish and powdery looking stain that is caused by the poor mixture of the gasket material composition.

Cracks (leading to water ingress)

• Incompatibility with other glazing material
• UV sensitive (the UV resistance test is available for some gasket material)
• Brittleness (lost of flexibility)
• Stress cracking

Staining

Caused by plasticizer which migrate out to the façades and when dirt stick on it results on staining on the façades material.

Streaking

Caused by plasticizer which migrate out to the façades and when the rain wash it down and together with dirt results in streaking stain.

Debonding

1. Mismatch of gasket design vs. system design. As a result gasket cannot fit (probably too loose) and conform into the channel groove and hence drop out over time.

2. Insufficient supervision. Many sub-con or sub-sub-con has a desire to select gasket base of ease of installation. So they select gasket that is easy to install at the expense of seal performance, i.e. soaking the gasket into diesel (deteriorate gasket properties) to “slime” the gasket for easier insertion. Stretching the gasket but pulling the gasket beyond the elastic limits to “miniaturize” the gasket size is another way to help them.

3. Poor workmanship. The aluminium groove size varies out of tolerance i.e. some portion of the groove may have standard width of 5mm but this has increased to 8 mm at other portion and hence gasket fits well at 5mm portion but fits loosely at 8 mm portion.

4. Poor selection of gasket material. When exposed to heat, UV, acid rain and so on some gasket may loose their sealing properties and start to hardened, cracked, or shrink.