bathtub repair

[MoopMeep]

Looking for info on repairing my bathtub acne.

My house was built in 2002. It has a single piece bathtub with wall surrounding it. I think the tub and surrounding walls are fiberglass but I am not sure.

We have a young daughter, so to entertain her while bathing we bought some 8x11 sheets of plastic that have pictures of animals and shapes. These sheets are the kind that stick to the wall when they are moist. The sheets have been on the bathtub walls for a few months. We noticed that when we removed them yesterday that there are a bunch of 1/4 inch bubbles that have formed in the fiberglass wall. In total there are about 50 bubbles that have formed behind the plastic sheet that we had hanging.

I am trying to figure out the best way to repair. I see that there are repair kits to fix cracks and holes but I don't see mention of bubbles. Can I sand these out and then use a kit to repair the tub?

[Frank]

I would guess the tub is polyester resin which does tend to degrade when wet, particularly when acidic or basic. I would think that sanding would wear through any gel coat making it worse. Maybe someone sells a kit to fix your problem. Try to contact manufacturer. Google got many hits.

[Oren]

We bought our last house new. I went in during construction and found

6-8 framing nails that were shot through the fiberglass surround from the back side. The builders brought a guy in to fix it. After the work, I could not detect where the original holes were. Excellent work by the repair guy.

[Joe]

Back up a bit here, sport, and let's gather up a few solid facts. First, try to determine the manufacturer of your tub assembly. Reason being that their customer service will be the best source of ways and means to make a reasonable repair. They likely even have repair kits to help the luckless installer or contractor who has had a mishap with the product. In describing to customer service what happened to the tub, consider this scenario: the applique you cemented to the tub had an adhesive that was formulated with some resin or another. To keep it gooey, the resin is blended with a plasticizer. Plasticizers are often very high molecular weight relatives of solvents like lacquer thinners. But they have extremely low vapor pressure and tend to evaporate at rates measured in decades. However, they can migrate into other plastic substrates, which is what has happened in your case, causing delamination of the plastic surface and hence, a bubble. If this is the case, there is a chance the process could be reversed by gentle and prolonged heating of the tub plastic, logically a temperature below the boiling point of water. The slow evaporation of the plasticizer might allow the bubble to shrink. If the manufacurer custimer service engineer has no better idea, then it might work for you.

Joe