Living Dangerously with Chemicals

There are several ways to create a PCB and one of those ways is called acid etching. This PCB fabrication method works by chemically removing unwanted copper from the board. Resistances are placed on the portions of the copper board that one wants to remain after the etching process.

One chemical of choice is ferric chloride. This acid is usually a cheaper option than other chemical compounds used for etching. There are two types of this acid and one type is called hex hydrate ferric chloride. This type comes in a light yellow colored powder and is usually dissolved in water with about a tablespoon of salt for a clearer, easier inspection of the PCB when it is submerged in it. The other type is called anhydrous ferric chloride which is a green-brown colored powder. This is a more dangerous chemical and it is highly discouraged to be used but if one decides to, observe extreme caution when dissolving this in water as it creates a lot of heat. Never add water to the powder, add it to the water instead.

pcbThere is a chance that this chemical may not successfully etch the board, making it far from ideal for PCB fabrication. If this happens, one can add a small amount of hydrochloric acid and leave the board submerged in it for about two days. When using any of these etching chemicals, use a ceramic or a plastic container, be sure to use gloves and safety glasses when handling such chemicals as they can be damaging to the eyes and skin; also, avoid splashing at all costs.

Another acid of choice in PCB fabrication is sodium per sulfate. This is a white-colored powder that is a good etching solution for copper printed circuit boards. This chemical has some advantages over ferric chloride and other similar copper-etching chemicals. Unlike ferric chloride, sodium per sulfate does not stain clothes, skin, or containers. It leaves no residue in plain water and rinses quite easily. Its etching speed is faster and it maintains a good etching rate throughout its mixing life.

As to be expected though, this chemical also comes with disadvantages when compared with other etching chemicals. Sodium per sulfate has a shorter mixing life (or, in a way, durability) when used in an etch tank; it has a maximum of three weeks regardless if it is being used or not. If ferric chloride triggers a potentially dangerous reaction with metals, sodium per sulfate reacts in the same way upon coming into contact with natural fibers such as linen, cotton and wool.

In addition to those already mentioned, other chemicals can be used as etching agents for the PCB – these include hydrogen peroxide and hydrochloric acid. Same with ferric chloride, a non-metallic container is needed for this as well. Mix two parts of hydrogen peroxide with one part hydrochloric acid; by doing that you’ll create a good etching agent. While etching with these chemicals, make sure that the area is well ventilated. In addition to this, acetone is needed to remove the resist from the PCB after etching. Compared to the other methods discussed, this may be the safest for etching the PCB with chemicals. However, extreme caution should still be observed.

When using any of these PCB fabrication methods, always remember to be safe. Be cautious when handling dangerous chemicals and be sure to prepare everything that is needed to keep the etching area secure. Also, follow the instructions very carefully, including those about the proper disposal of such chemicals. Keep in mind that any mistakes can cause serious damage not only to one’s surroundings but even to oneself.

Misters and Pressure

Misters have a wide range of variants to choose from. Whether you‘re running a business with an outdoor theme, or just want to bask in the sunlight without worrying about the heat, there’s an available mister for you. From personal variants to complete misting systems, a spectrum of this fun cooling system can be installed in your premises.

However, do you know the two main types of this item? Stay with us in this article and we’ll take you through the two types – the high pressure and the low pressure variant.

The most efficient form is the High Pressure Mister. This type of misters cover a wide range of area and is perfect for almost all types of establishments – houses, restaurants, bars, pools, even greenhouses.

Since it has high pressure, this kind can drop temperatures over 35 degrees Fahrenheit and can be amplified by misting fans to spread the cooling effect to wider areas. The high pressure also forms a finer jet of mist, speeding up the evaporation of the liquid. The instantaneous evaporation yielded from the high pressure variants gives it an edge of low pressure variants, since it produces a cooler effect. The flash evaporation

capabilities of the high pressure variant can also produce fogging effects in the surroundings.

This type is mostly used in commercial areas, commonly found in restaurants and resorts. This is due to the face that high pressure types are more costly, as compare to low pressure variants. High quality material is needed to ensure the capability of the hose and nozzle to withstand the high pressure brought about by the misting pump. Tubing is also made of stainless steel to make sure that the material does not break down due to the high pressure. High pressure variants usually contain multiple nozzles for wider coverage. Multiple nozzles also contribute largely to the cooling capabilities of the high pressure system.

commertiolLow pressure types, on the other hand, have this reputation of spewing large water droplets that can get you wet. Of course, this is entirely false, since misters have to pass a standard to be categorized as such, and not as a bathroom shower. However, the main difference of low pressure types with high pressure ones is indeed the authorization of the water droplets. Indeed, low pressure variants produce relatively bigger droplets. But their size is enough to evaporate quickly and promote cooling in the area. The moisture produced by low pressure misters is also very refreshing as it hits one’s skin on a warm summer day. Due to the lower pressure, you wouldn’t expect a fogging effect from this variant of mister.

Low pressure variants are perfect for households that run tight on the budget. It’s perfect for personal use and backyard installations – a nice way to cool down during a nice afternoon with friends. The absence of a high pressure misting pump can be attributed to its cheaper price. It can be installed using a typical household water system, and does not need additional force to create mist. The material used for the tubing is nylon. The misting process mostly happens in the nozzle installed in the hose. You can also opt for the multiple nozzle option to cool down the area faster.

The low pressure mister is also cost effective for households and establishments who don’t regularly have to use a misting system. It also does not consume a lot of water, as compared to the high pressure variants.

Now that you know the two basic types of misters, which one should you opt for? Always consider your lifestyle and budget when choosing to buy a mister.