Editor's note: This week, two similar questions are answered.Question: My fiberglass pool is 15 years old. Recently, I have noticed lumps appearing on the inside wall in one 6-foot area. These lumps are perfectly round and range in size from 1 to 3 inches in diameter. After one or two days, they disappear gradually. This has happened three times, and they are not visible at this time. I have contacted the manufacturer, but the company says it has no idea what causes this and offered no advice. I need to renovate the pool deck and will not do this until I find out what is causing this problem, which seems to originate on the exterior shell of the pool.Do you have any ideas what is causing these lumps?Q: I have a 17-year-old fiberglass swimming pool. On the steps and the side of the pool are a few raised spots that look like half a bubble about 3 to 4 inches in diameter. You can step on them and they do not crack. Also, on the side of the pool, there are a few black spots, and when you touch them, the tips come off.

I have put stain remover in the pool as suggested, but it does not remove the spots. Any suggestions as to how to get rid of the stains on the pool surface?Answer: Fiberglass pools are constructed like this: A cloth mat saturated with resin is applied to the pool structure. These materials bond with a catalyst to form a hard, solid surface that is protected by a gel coat. This gel coat layer of the fiberglass pool is the interior finish, which is in direct contact with the pool water. The gel coat protects the fiberglass mat and resin from the chemicals in the pool water."About 20 years ago, several fiberglass pool manufacturers started adding vinylester resin between the gel coat interior finish and the pool structure," says Joe Fleming, national sales manager for Blue Hawaiian Fiberglass Pools in Largo.This resin in a pure form creates a watertight barrier to seal fiberglass pools and spas. This adds about $300 to $500 to the cost of each pool of water, Fleming says.Though some companies used this industry advance, others chose not to or diluted the vinylester resin.

One possible consequence is osmotic blistering, in which microscopic pores allow water to become trapped between the fiberglass mat and the gel coat. Mvp Weight Loss SurgeryThis blistering can appear in varying sizes from a pinhead- to a grapefruit-size, moisture-filled pocket.Moen Kitchen Faucets Wall MountThe repair procedure is to drain the pool, sandblast the interior, grind out the blisters and add putty to the affected area. Licorice Root To Loss WeightA new mat of fiberglass is applied, and a vinylester resin reseals that mat before a new gel coat is put on."This process can cost $3,000 to $4,800 for an average 15-by-30-foot pool, depending upon the amount of osmotic blistering and preparation time needed," says Bill Boyles, vice-president of B & L Pool Resurfacing in Lakeland.Most often, the job can be completed in three to six days depending upon the amount of preparation and weather conditions, Boyles says.

This repair can be a spot treatment, but it is not aesthetically pleasing and might cost as much as redoing the entire pool.The second problem might be what commonly is referred to as "black plague." This occurs when a pore between the gel coat and the pool structure contains chlorine and/or acid that reacts with an ingredient in the resin, resulting in a dark spot if the pH in the pool water is out of balance. If the pH is maintained, often dark spots will not appear.To eliminate the black spots, apply powdered ascorbic acid to the black or gray stains. This treatment will consume large amounts of the water's chlorine, so it is advisable to shock your pool the day before adding the ascorbic acid, and test your water chemistry every two hours to maintain proper water balance.We suggest you hire a licensed, trained and insured pool professional to evaluate your pool. If you contract with a company, be sure it has a separate pool-popping insurance policy to protect you from unexpected expenses should the empty pool shift or lift out of the ground.

Lottery results for Powerball, Florida LottoLottery results for Powerball, Florida LottoDo your homework before painting or sealing cool deckPuerto Rico birth certificates: How to get a new oneLottery results for Powerball, Florida LottoLottery results for Powerball, Florida LottoBubbles that show up on the working surface of a cured rubber mold can ruin detail and result in a mold that is unusable. Bubbles can come from different sources and there are different variables (most controllable) that will affect the size and quantity of bubbles generated. FAQ: I made a mold using urethane rubber. I mixed the rubber as directed, but when I demolded next day, my mold had a lot of air bubbles throughout including (worst of all) on the working surface . . . ruined all of my detail and the mold is unusable. Answer: Urethane mold rubbers are moisture sensitive, and often bubbles found in cured urethane rubber are a result of a reaction between the rubber in its liquid state and moisture coming from somewhere.

A moisture reaction can be severe (cured rubber will look like foam), depending on the amount moisture introduced to the urethane rubber mix.. Common sources of moisture that might react with liquid urethane rubber; 1. Humidity – urethane rubbers generally have a long pot life, which gives plenty of time for a moisture reaction in a humid environment. Remedy: work in a humidity-controlled environment (air conditioning) with as low a relative humidity as possible. 2. Wet Model – If liquid urethane rubber is applied over a model that contains moisture (such as newly cast plaster/gypsum or concrete), you will experience a moisture reaction. Remedy: when using urethane rubber to make your mold, seal a model containing moisture with high quality spray shellac followed by a release agent before applying mold rubber. 3. Mixing containers and mixing sticks – mixing containers made of wood or paper as well as wooden mixing utensils (paint stirrers) stored in a humid environment may absorb moisture that will react with urethane rubber.

Remedy – use mixing containers made of plastic, metal or glass. Also, use mixing utensils made of plastic or metal. 4. Repeated opening and closing of parts A and B can introduce moisture from the air to the unused material. Remedy: After dispensing place the lids back on the containers as soon as possible and store in a dry cool place. Also, try using Smooth-On’s Xtend-it, a dry gas blanket designed to extend the shelf life of moisture sensitive polyurethane products by displacing the air in the container. If using larger quantities of urethane rubber or plastic, you might want to consider buying dririte tubes to attach to your 5 gallon or 55 gallon containers, or a tank of nitrogen to cap your container after dispensing material. Urethane Rubber Mold – Over Applying Release Agent FAQ: I’ve noticed tiny “champagne” bubbles on the working surface of my finished mold, which are now being reflected in my castings. What causes these bubbles? Answer: The description of bubbles as “pinholes” or “champagne” is an indicator that too much mold release was applied to the rubber mold prior to casting resin.

People tend to get carried away, thinking that more release agent is better. This is not only a waste of release agent; it will cause “pinhole bubbling” to occur in the plastic. Remedy: use the “Spray-Brush-Spray” technique for applying mold release agent. 1. Spray a light mist coating to the mold surface, 2. Use a soft bristle brush to spread release agent over all surfaces including deep detail and undercuts and 3. Apply another light mist coating and let dry for 15 minutes before mixing and applying mold rubber. FAQ: After demolding a one piece block mold (poured), I noticed a single large air bubble on the working surface of the mold. What caused it, how do I avoid it in the future and can I repair the bubble? Answer: As noted before, air bubbles can come from different sources. In this case, the air could be coming from a few places: 1. When you poured rubber over the model, Liquid Rubber Found Its Way Underneath The Model, thereby displacing air that ended up as one or more large bubbles in your cured rubber.

Remedy: the model must be tightly secured to a platform or base and a bead of hot melt glue or modeling clay material should be applied at the interface between the model and the platform, providing an airtight seal. Remedy: The goal is to prevent the liquid rubber from going underneath the model. Most liquid rubbers (even high viscosity silicones) will find there way into the smallest holes (even pin holes) 2. Highly Porous Models - Models that are highly porous (made from such materials as dry plaster, concrete or limestone) contain a lot of air. When liquid rubber is poured over these models, the air contained in these models has to go somewhere. If nothing is done, the only place the air can go is up through the liquid mold rubber and occasionally; the air becomes trapped in the mold rubber as it is curing. This air is reflected in the cured mold as air bubbles of different sizes located in different areas in the mold. Remedy: Drill an air vent up the back of the base or platform on which the model will be mounted.

Elevate the base slightly in all four corners with modeling clay or wood pieces – make sure the base is level. Then, secure the model to the base as usual. When the liquid rubber is mixed and poured over the model, the air will escape through the vent hole underneath the model rather than go up through the liquid rubber and possibly be trapped. Silicone Rubber Mold - Bubbles In Silicone rubbers are thick and most have a high viscosity. Silicones do not de-air themselves as readily as urethane rubbers and need to be vacuumed. Consequently, if you mix and pour silicone rubber that has not been vacuumed over a model, air may be trapped in the mixture as it turns from liquid to solid and these bubbles may show up on the working surface of the mold. For More Information, Consult FAQ – Vacuuming Silicone Rubber Bubbles In A Brush-On Mold? It’s all in how you apply the rubber . . . FAQ: “My mold rubber dripped off my model when I applied it and when it cured, I had tiny bubbles on the working surface of my mold that are reflected in my casting.

What am I doing wrong?” Answer: You are probably trying to apply too much mold rubber to the model surface. When making a Brush-On Rubber Mold, Do Not Over Apply Rubber – Especially The First Coat. More Is Not Better – People assume that brush-on mold rubber needs to be applied in “quantity.” Applying globs of rubber to your model surface entraps air and wastes your valuable material. Generally, it is better to apply 4 thin layers than 3 heavy layers. Thin layers work best – especially for the first layer or “detail coat.”A thin initial coat will minimize entrapped air and capture the best detail from the model surface. The secret is to apply the first layer thinly with dabbing strokes that will get rubber over and into all of the surface detail. Over applying rubber entraps air that is then reflected in the finished mold and castings – air bubble city! Applying rubber in this manner also lets bubbles move away from the model surface and up through the rubber where they can pop on the surface.