The Current Situation

In the glass and aluminum industry, as far as sealant application is concerned, many are familiar with the acetoxy cure of sealant. This type of sealant gives off the vinegar smell when applied. However, when we look at the substrates or the type of material where the sealant is adhered to, many installers are using the wrong type of sealant. This could be due to lack of awareness that is a proper sealant for each application and the absence of a one-type-fits-all sealant. Furthermore, many are pushing the boundaries to downgrade to a lower quality of sealant to be more cost-competitive. Nevertheless, we will discuss the different types of curing systems of sealants in this article.

The Most Common Curing Systems in the Market

Cure System pH Release Agent Benefit Disadvantage
1. Acetoxy Acidic Acetic Acid (Vinegar) Fast cure.

Short tack-free time

Cannot be used on concrete and corrodible substrates
2. Oxime Neutral MethylEthylKetoxime (MEK) Good adhesion to plastics

Fast Cure Neutral

Slower cure time than acetoxy

Poses health issues when used over the long term. Masks are recommended when caulking.

3. Alkoxy Neutral Alcohol Can be used on many substrates Slow cure

With reference from above,

1. Acetoxy cure sealant 

This is again the most common type of sealant as especially for most small scale glass and aluminum installers in the market. This product can be easily bought in some hardware stores also. A lot of glass installers love to use our Dow Corning Glass Sealant, which is an acetoxy cure sealant, because it cures really fast, allowing them to complete their projects on time. However, this product because of the acidic properties, could corrode the substrates it is trying to bond to, which can eventually lead to loss of adhesion. Hence, an acetoxy cure sealant has limited applications. Dow Corning Glass Sealant is recommended for glass to glass application mostly, as its name implies . It is not recommended for structural glazing wherein you bond the glass to the aluminum frame

2. Oxime Cure Sealant

This type of sealant cure is growing in popularity due to is odorless feature. There are relatively more substrates it can accomodate compared to the glass sealant because it is neutral cure. However, oxime cure sealant poses health issues and it is said to have carcinogenic properties. We strongly advise to use masks when applying oxime cure sealant.

3. Alkoxy Cure Sealant

The alkoxy cure sealant is also neutral cure and has the longest curing time among the 3 curing systems. It produces an alcohol smell as it cures. However, the odor is not too strong. One of the best benefit we can get from an alkoxy cure is the many substrates it can be applied on. For most of the high rise projects in the Philippines, most of the glass and aluminum fabricators are using alkoxy cure system. Hence, from structural glazing applications, this is the curing system to choose because it will not corrode the aluminum where the glass is bonded.

 

This table provides you with the list of Dow Corning / Xiameter products and its corresponding curing system.

Curing System Product
1. Acetoxy Dow Corning General Purpose , Dow Corning Glass Sealant
2. Oxime Dow Corning Neutral Plus, Dow Corning Sanitary and Tile, Dow Corning 688, Dow Corning 991
3. Alkoxy Dow Corning 790Dow Corning 791, Dow Corning 795, Dow Corning 995, Dow Corning 983, Dow Corning 896, Dow Corning 121

To differentiate which product will be used for which application, please see