Out in the elements a protective coating is needed to prevent the brass from oxidizing or tarnishing. This is the process that happens when oxygen and atmospheric gasses comes into contact with the surface of the brass.

Most manufacturers use a high quality clear lacquer to coat the brass and thus protect it.

When a brass door knocker is engraved the engraving process cuts into the surface of the metal. If it is lacquer coated the engraving will also cut through the coating exposing the metal behind it. The exposed metal in the engraved area will oxidize and tarnish in a short time.

An engraved door knocker should be lacquer coated after the engraving process. This seals the entire door knocker and prevents your investment from deteriorating prematurely.

At our Your Door Knocker studio we dip our products in high quality UV resistant clear lacquer as one of the last steps in the production process. This completely seals the door knocker and ensures a long life.

In our foundry we produce small parts and door knocker components in this manner. We describe this operation at these pages of our site. At The Foundry

This ancient technology is used in many industries producing a large variety of items. Everything from high precision machined parts to plumbing components to ornamental items such as our brass door knockers.

Casting of brass using the sand casting method is an important element in the manufacturing industry. I doubt that any one of us has not had need or use for a cast brass item at some time or another.

Not all of our door knockers are produced in our foundry. It is small and designed for prototyping and very small production runs. Our larger quantities are produced in production foundries that are set up for this type of production.

The foundry operation can be quite dangerous if not done properly. The handling of 1800F to 2000F molten brass is not for the meek of heart. A foundry operation either large or small must be an extremely safety conscience work place.

With proper planning and careful manufacturing methods the foundry like most manufacturing processes can be done by skilled personnel using good equipment.

There are other methods used today to produce some brass door knocker styles but the good old sand casting method is still one of the best.

Brass is a nonferrous metal with good electrical and thermal properties. It also has excellent strength and corrosion resistance. Being an alloy it is available in many varieties. Not all brasses can make good brass door knockers though.

Brass is not a natural element, it is an alloy of copper (Cu) and zinc (Zn). Other elements such as lead, nickel and tin may be added to the mix to achieve certain properties. Depending on the final product to be made the mixture making up the brass can vary. Some brass parts need to be strong while some may need to be resistant to salt water and still others may simply need to look good. The recipe can be changed to accommodate each of theses requirements.

Sometimes the changes cannot be detected just by looking and other times differences are quite apparent. Some of the changes affect the color of the brass which can vary from silver to gold to red depending on the mixture.

A door knocker needs to be made from a bright yellow brass that casts and polishes well. It must also be machinable and engraveable.

The desired properties are achieved by keeping the copper content around 67%-72%, the zinc content around 24%-29% with 1%-3% each of tin and lead. As a general rule the higher the copper and lower the zinc contents, the softer and easier to machine the brass is.

The addition of a small amount of lead makes the brass easier to machine. Tin is added to increase strength and corrosion resistance. Tin will also help prevent the zinc from leaching out of the brass over time.

A quality finished product requires a quality “recipe” for the brass. There are many specifications written for brass that may apply to different industries. Standards are written by such organizations as ASTM, SAE, CDA and MILITARY to name a few.

The elements that make up the brass are mixed in a foundry. They are melted together at temperatures that vary around 1800F – 1950F. When molten the liquid mixture can be poured into a mold to form the product or poured into an ingot for storage for later use. Most product foundries purchase the brass already mixed in ingot form. The ingot is then remelted and poured into a mold to make a product.

After the brass is molded into a shape it is called a casting. The casting is then polished, finished and machined into the completed brass door knocker.

When it comes to engraved door knockers, some fonts will be better than others.

Most engravers would use the diamond drag method of engraving for a brass door knocker. This method works by dragging a precision sharpened diamond tipped stylus across the surface of the door knocker to scratch in a pattern . Brass is a relatively soft metal so this method works extremely well. It creates crisp lines with which to form letters.

Some fonts use a single line to make the letter while others use 3 or more side by side to make the letter bolder.

When engraving a door knocker you really want the engraving to show up from a short distance. For this reason the bolder the letter is the easier it is to read. Boldness is achieved by using more lines to form the letter. A one line font uses just one scratch per thickness of the letter. This is great for small letters on jewelry and such but not so good for larger items like door knockers. Here we need at least a two line font.

Most two line fonts form outlines of the letters. The letter is hollow, that is there is no fill. For many door knockers this works very well.

Three or more line fonts use the additional lines to fill in the letters thus making the letters stand out more.

Font choices usually include the standard Helvetica, Roman, English and Script fonts as well as a selection of ornamental fonts. You will want to make your choice based on the style of the door knocker and the effect you wish to create. You can see our Your-Door-Knocker font choices here.

Font choice has a big effect on engraved door knockers. Be sure to take a little time when picking our your font.

Typically there are three variations of the name. One is to place just the last name on the door knocker. Another is the possessive version with a ‘s on the end. The last variation is a plural version with an s on the end of the name.

Before we go any further let me state that all three methods are correct on engraved door knockers. It just depends on what the you want to say.

The most common method is to place the last name alone in the engraving area of the door knocker. This method is simple and elegant.

The possessive version with the ‘s is also popular. This one is saying that this house belongs to this family. From an engravers standpoint there are a couple issues with this method. One is that the hyphen ‘ does not always stand out as well as the other letters on an engraving. This causes the engraving to be visually off a bit even though it is not. It also adds two characters to the line. This may be beneficial if the name is short. It will help fill the engraving space more efficiently. In the case of a long name it may take up to much space thus forcing the engraving to be smaller to fit into the space available. In the case of a last name ending with an s the plural would be a hyphen without an additional s. I recommend avoiding this. When engraving a name ending with an s with a hyphen following it the finished engraving looks off center. This again is due to the added hyphen not being as visible as the other letters.

The plural version is nice. It says more than one family member lives at this house. An s added to the end of the name only adds one character and will seldom cause a problem. In some instances it could cause confusion as to whether the s is part of the name or is a plural version of the name.

As I mentioned earlier the most common method is to put just the last name on the engraved door knocker. If you are in doubt this is usually the best choice.

Nothing personalizes a house like an engraved door knocker.

Depending on the size of the hardware being used these holes may be up to 3/8 inch in diameter. There are things to think about on both sides of the door before you drill.

Once their exact location is determined the holes must be drilled squarely through the door. The door knocker will lie flat on the outside surface of the door. The mounting lugs are machined into the back of the door knocker so that the hardware must enter at a perpendicular angle. If the holes through the door are not square the hardware will not screw into the door knocker casting.

It is a good practice to have the finished holes large enough so that the mounting hardware fits loosely into them. A very tight fit may do well on the day that the installation is made but if your climate is like ours, there is as much as a 100 degree temperature difference from summer to winter. Changes in temperature causes expansion and contraction. This could cause damage to your door or your door knocker over time if the fit is too tight.

The actual drilling of the holes can damage the door. It is a good practice to first drill holes at the precise mounting locations that are less than half to size of the finished hole. The smaller hole would be drilled all the way through the door. This smaller hole gives you the chance to check your work as well as provides a guide for the finished holes.

With the smaller holes drilled through the door at the exact mounting locations you can drill the finished larger holes. Do not drill the finished holes all the way through. This would have the potential of damaging the surface of the door where the drill exits.

Instead, drill the hole half way from one side and then drill the rest out from the other side of the door. This will provide clean entrance points on both sides of the door.

With a little planning and careful work your door knocker installation will be a pleasing addition to your home for years to come.

A replacement door knocker installation that is a through the door mounting method, the bolt center dimension has added meaning. You will probably want to use the same drilled holes that are already in the door. If so you will have to find a new door knocker with the same bolt center dimension as the previous one.

The bolt center dimension is the measurement from the center of one bolt hole to the center of the other bolt hole. We have shown this dimension on our door knocker comparison page.

The new door knocker must match the old door knocker at this dimension or your new door knocker will not fit the existing holes.

There are no industry standards regarding the bolt center dimension or the size hardware to be used. These are left to the manufacturers discretion. They are usually dependent on the shape and style of the door knocker itself.

At times it can be difficult to find an exact match. Sometimes you have to settle for getting your replacement door knocker as close as you can to the original. Then you may make an adjustment by enlarging the holes in the door or drilling an new hole and using one of the old ones. In these cases something needs to be done with the inside of the door to cover up the old  or enlarged holes.

If the holes are enlarged they may be covered by using larger washers on the inside to cover the larger hole. If a third hole was needed the old one will need to be filled in.

The best bet is to find a replacement door knocker with the same bolt center dimension as the original one if possible.

The phrase Bolt Center references the geometric center of the diameter of the hole that is drilled for a bolt to pass through. Theoretically the center of the bolt will pass through the center of the hole as it goes through the door. In the case of our door knockers this would be the mounting bolts for the through the door mounting.

We refer to this point as the bolt center because this is the exact point that the workman should drill the hole for the bolt so it matches the door knocker. Right in the center.

In the case of our door knockers the bolt center dimension is the same as the distance between the bolts. If you measured from the bottom of one bolt to the bottom of the other the distance would be equal the bolt center dimension. This is true because both holes being drilled are the same size.

Lets imagine for an example that the top hole does not use a bolt. Instead the top hole is an eye viewer that requires a hole 3/4 inch in diameter and the bottom hole is a standard mounting bolt that needs a 3/8 inch diameter hole. In this case you could not drill holes based on the bottom of each. You would need to know where the center of each hole is and drill there.

This is why we use the term bolt center for our through the door mounting instructions.