Rose uses Aileen's Tacky Glue for gluing shells. She tried two popular products, Beacon's 527 and Eclectic's E-6000 when she first started making sailors valentines, but the fumes from both gave her headaches. Both these glues use ingredients that are hazardous to health. Both 527 and 6000 are used by many professional shell artists and you can use them safely as long as you protect yourself. Avoid skin contact and don't breath the fumes! If you can smell them, then you're breathing the fumes. Put a box fan in an open window and suck the fumes out of your house. You can read about the serious health hazards associated with these products in their Material Safety Data Sheets (click here for 527 and here for 6000).
Aileen's Tacky Glue is a water-based product that contains no hazardous ingredients. That's why we recommend it instead of 527 and 6000. HOWEVER, the safety of tacky glue brings with it the potential for warping your mat board or even your sailors valentine box if you apply too much of it too quickly. The reason is that some of the water in the glue can be absorbed into the fibers on the top side of the mat board, causing the mat board to warp.
Rose has always used the Tacky Glue very sparingly as she works (it has a tenacious grip, so it only takes a tiny dot of glue to fix a shell tot he mat board), so she's never had a problem with warping. Our experiment shows that sealing the mat board with lacquer and using glue sparingly is very helpful in reducing warping.
If you are planning to start your design with a background of sand, crushed shell or mineral chips, and you are going to use a water based glue, then this tip is for you. Covering the entire surface of a mat board, in one step with a water based glue can cause warping. We found that spraying the top side of the mat board with a sealer that is not water based will help seal the surface and reduce the tendency of the mat board to absorb water from the glue, thus reducing the potential for warping. We used Deft brand lacquer for our experiment as that is the product we use to clear coat our Sailors Valentine boxes. Coupled with taking care to avoid using too much glue at any one time, a sealed mat board should provide a better experience.
Pictures shown above are for the mat board that was sprayed on the top side with three light coats of Deft brand Clear Satin Lacquer. More coats of lacquer may improve the final result.
The mat board on the right (above) was not sprayed with lacquer.
Final result: the day after we applied the glue and sand to the mat boards, the mat board that had the lacquer seal coat (left) warped to a much lesser degree than the mat board that was not sealed.