Introduction:

Viton® (fluoroelastomer) sealants are capable of withstanding exposure to extremely harsh chemicals (such as concentrated acids and organic solvents) that severely damage other elastomeric materials. For this reason, fluoroelastomer has become a very popular joint sealant in environments (such as secondary containment areas) where exposure to harsh chemicals is possible.

Pelseal joint sealants can be applied in manners consistent with other commonly used elastomeric joint sealants. The following guidelines will be useful to applicators who are not familiar with elastomeric sealants or need specific instruction on applying Pelseal products.

Each application is unique, and it may often be necessary to vary the application methods. If an applicator decides to deviate from the guidelines specified in this document, it should be done with a full knowledge and understanding of how this deviation may affect the nature of the cured sealant. It is always wise and sometimes necessary to test application methods and material compatibility with a small test sample before a costly application is initiated. For this reason, Pelseal® Technologies, LLC offers samples of all products and encourages the evaluation of these samples before any purchase.

Joint Design:

A qualified engineer should determine the appropriate spacing and size of expansion joints based on the coefficient of expansion of the substrate. Joints that are too narrow or spaced too far apart can cause excessive movement of the sealant.

When filling an expansion joint, the sealant should be applied approximately half as deep as it is wide. For example: sealant in a ½” wide joint should be ¼” deep. Fill deep cracks or expansion joints with backer rod. If this convention is not followed, the movement of the substrate will cause excessive deformation of the sealant that could lead to failure(Fig 1). Fig. 1-The joint in A is filled too deeply, and when it is stressed in B, a large amount of material is displaced, causing potential failure. The improved design of C incorporates a flexible backer rod.

In rectangular joints that are not deep enough to require backer rod or filler, bond- breaking tape should be used to prevent three-sided contact and excessive stress on the joint during expansion and contraction cycles (Fig. 2).

Fig. 2- In instances in which backer rod cannot be used, non-adhesive bond-breaking tape allows the sealant to stretch naturally during contraction.

Surface Preparation:

Prior to application, the joint must be clean, dry and free of debris, oil, chemicals or any other contamination. Remove any loose material.

Concrete surfaces (particularly freshly poured or sawcut concrete) contain high levels of reactive materials like calcium carbonate. These reactive materials can chemically react with the fluoroelastomer sealant to produce gases that cause large voids in the sealant. Using an epoxy primer can prevent this problem. If none is available, then neutralize all concrete surfaces prior to application of the sealant.

Primers can improve adhesion of the sealant to concrete, but the following considerations must be evaluated:

1. Does the primer bond well to the substrate?
2. Does the Pelseal bond to the primer?
3. Will the primer crack or become damaged during joint movement?
4. Will the primer be damaged by exposure to chemicals that are present or could be present in the application?

Application:

Pelseal products should be applied at, or as close to, 70° F as possible. Higher temperatures will promote faster release of solvent, quicker curing and shorter pot-lives. Lower temperatures can increase the viscosity of the material and make application difficult. Make sure the Pelseal product is at the same temperature as the substrate.

After the surface has been prepared, carefully plan the application and make sure all necessary tools are available before beginning. Different products and different jobs will require specific tools. Read application data sheets related to the specific Pelseal product, and become familiar with the consistency of the product before proceeding.

Do not apply the caulk thicker than 1/4”-3/8” in any one pass. Thick applications can pull away from the sides of the joint as the product dries. Thick applications are also more prone to trapping air pockets. Make two or three passes with at least 8 hours between passes for thick applications.

To further reduce voids, cover sealant with polyethylene sheet or tape immediately after application. This will prevent the surface from skinning too quickly and allow air to escape. Avoid direct contact between the polyethylene and sealant. Remove the polyethylene approximately four hours after application.

During application, keep the product covered whenever possible to prevent solvent release. In their liquid state, Pelseal products are extremely flammable and should never be exposed to any source of flame or spark. Keep area well ventilated, and use appropriate respirators. Carefully read and follow all instructions in the MSDS.

Final Points:

It is important to know and understand what to expect from an application before starting. Investigate and answer all questions as completely as possible before beginning a project. The guidelines of this document are very general and each application is unique. Pelseal® Technologies’ technical representatives are always willing to help answer specific application questions.

Viton® is a registered trademark of DuPont Performance Elastomers

Pelseal® is a registered trademark of Pelseal® Technologies, LLC

*The information printed herein is furnished free of charge and is based on technical data that Pelseal Technologies, LLC. believes to be reliable. It is intended for use by persons having technical skill, at their own discretion and risk. The handling precaution information contained herein is given with the understanding that those using it will satisfy themselves that their particular use conditions present no health or safety hazards. While the information contained herein is believed to be correct, Pelseal Technologies, LLC. makes no representation as to the accuracy of it. Since the conditions of product use are beyond our control, Pelseal Technologies, LLC. assumes no liability in connection with any use of this information. The evaluation of the product described herein under end-use conditions prior to specifications is essential. Nothing contained herein is to be taken as a license to operate under or as a recommendation to infringe any patents.

Warranty: Pelseal Technologies, LLC. warrants that at the time of shipment, its products are free of defects in material and workmanship. THERE IS NO OTHER EXPRESS WARRANTY. SELLER HEREBY DISCLAIMS ALL IMPLIED WARRANTIES INCLUDING THE IMPLIED WARRANTY OF MERCHANTABILITY AND FITNESS FOR ANY PARTICULAR PURPOSE INDICATED BY BUYER TO SELLER. Seller's sole obligation under this warranty shall be, upon prompt written notice by Buyer of any defect or defects, and inspection, if required by Seller, to replace FOB Seller's plant, or at Seller's option, to allow credit for any defective products expressly warranted herein against defects by Seller. UPON PURCHASE OF SELLER'S PRODUCT(S), IT IS EXPRESSLY AGREED UPON BY BUYER THAT THIS REMEDY OF REPLACEMENT OR CREDIT, AT SELLER'S OPTION, IS BUYER'S EXCLUSIVE REMEDY UNDER THIS WARRANTY. IN NO EVENT SHALL SELLER BE LIABLE FOR CONSEQUENTIAL DAMAGES.