Here are a few highlights of a great article by John A. Koski that was published in Concrete Construction Magazine
Enhance the quality and economy of precast products by using the right release agent
Almost every precaster has had a double tee or an architectural precast panel crack as it was being removed from a form. In some cases, an ineffective or improperly applied release agent may have been the culprit. At other times, the wrong type of release agent may have been used.
Knowing how to properly use form release agents and which agent should be used for a particular application can go a long way toward preventing costly mistakes. In addition, following proper procedures and using the right agent can enhance the quality and economy of a finished precast piece.
When examining prices of comparable release agents, compare them based on their cost per square foot of coverage, not by the cost of a 5-gallon pail or 55-gallon drum. For example, two release agents may sell for the same price for a 55-gallon drum. However, one may have an estimated coverage rate of 800 square feet per gallon while the other can cover an estimated 1,100 square feet per gallon. If they are equal in performance and other attributes, than the one with the greater coverage rate is a better value.
Make sure that spray equipment is working properly. For example, a partially clogged spray nozzle can deliver a release agent in spits and spurts, allowing a too-heavy application in some areas and none in other places. Also, make sure that the spray tip is the right size for the product being applied. A tip that provides spray that is too fine or too heavy can create problems.
Do not over-apply a release agent, especially when using a release agent that is chemically reactive. These release agents chemically react with the alkali in concrete to form a thin release film. Applying too much of the release agent can cause excessive surface dusting on the finished concrete.
Although these suggestions may help solve some of the problems pre-casters experience, if you continue to have problems with a release agent, call the manufacturer. Reputable manufacturers maintain technical-assistance departments designed to help solve problems and improve product quality. If a manufacturer can’t or won’t provide you with the answers or information you need in a timely fashion, consider switching to one who will.
Precast Concrete News from Concrete Construction Magazine
Hill and Griffith Customer Service
We're known for our hands-on approach. Let us visit your plant and recommend concrete release agents, packerhead concrete form releases, concrete form seasoning, potable water and non-petroleum concrete form release, biodegradable releases, rust inhibitors and concrete dissolver products that suit your needs.
We are pleased to provide samples in quantities large enough to allow you to "try before you buy."
Contact Us »
Technical Services & Support
On-site casting defect investigations, product testing, machine start-ups and much more. Also, lab facilities are available to provide testing upon request.
Contact Us »