Thermal Spray Metals and Metallizing -Northern Virginia

Northern Virginia- Metallizing is a process that can be used to replace worn corroded metals or provide a protective cathode layer using Zinc, aluminum or 85/15 alloy, or RF/ EMI shielding using dense metals such as Babbitt. Metalizing can also be used as a decorative coating when materials such as bronze or copper are applied. When a high temperature functional coating is required on steel surfaces aluminum can be applied with outstanding results.

ASCo applies thermal sprayed metals most often for corrosion protection. Pure zinc wire as an example is melted in a hand held pistol device and sprayed onto target surfaces. Resulting surfaces will have a uniform coating of zinc quickly and efficiently. In many instances when hot dip galvanizing cannot be performed because of fabrication limitations or rapid turnaround is require, thermal arc sprayed zinc can be used as a direct replacement for hot dip galvanizing.

Steel surfaces such as molds or dies wear quickly because of aggressive erosion can be improved using hard alloys such as Hastalloy or other hard metals.  These are also spray applied.

Metallizing can be used as a functional coating when applied to aluminum and steel when it is sputtered onto a surface to create a permanent metallic non-slip surface.

Artist and designers use thermal sprayed coatings and apply them to concrete surfaces, or to change the color and texture of fabricated metal sculptures. Copper or bronze for instance may be applied to steel or aluminum in a thin film that can be patina coated making the finished product look like copper.

Removing paint from fiberglass surfaces / stripping automobile fiberglass / Stripping corvettes

Blast cleaning and more specifically plastic media blasting is a common method to removing paint from fiberglass surfaces, fiberglass composite, polyester and epoxy , SMC plastics and molded rubber. Fiberglass stripping must be approached carefully and the project goals fully understood. Certain resin layups strip easily, others will have limitations including air bubble holes and others that have weather or may be polyester layup and water logged will have disappointing results.

Removing paint from an early 1960’s Corvette may have surprising results for the uninformed owner or body shop. Fiberglass lay ups were engineered to have specific characteristics. The early corvette for instance had production schedule requirements, price point, esthetic finish approved by the manufacturer and all of this required customer acceptance. Not on the list was stripping the car after 50 years. Stripping paint using any type blast media on a late 1950’s or early 60’s corvette that has been painted several times will result in a “rough” or “grainy” surface, this is not all bad however. The soft, poorly adhered or UV damaged polyester resins need to be removed until a sound base surface is found. These cleaned surfaces will also require more work to bring it back to showroom or better conditions. But ultimately the project will have better long term results, filler, primer and paint adhesion will be outstanding and the value of the automobile will be maximized.

Stripping any composite materials requires experience to select the correct blast media to be used. We here at ASCo have 35 + years’ experience and many standard stock medias/ abrasive to select from. We do not decide on what material to use until we have a full understanding of the project and project goals and have inspected the parts first hand. Even after careful consideration test samples are often done to prove the methodology.

Automobile Stripping/ Media Blasting / Metal cleaning/ Stripping cars

Automobile Stripping/ Media Blasting / Metal cleaning/ Stripping cars  and rust can be done most efficiently using one of three methods

  1. Hand / mechanical sanding/ chemical stripping and power tool cleaning
  2. Immersion dipping in a hot caustic solution/ chemical stripping
  3. Dry media blasting / soda blasting / sandblasting / plastic blasting / walnut shell Blasting / glass bead blasting

Before you select a stripping method, start with project goals. Goals may include budget constraints, completion time, expectations for longevity and quality of finish and the customer’s ability to handle large bare metal surfaces and process them at one time. Typically restoration and body shops can handle large parts and volumes as normal course of business but the hobbyist restorer may not because of space limitations.

We here at ASCo American Stripping Company Manassas strip paint, rust and corrosion using a dry blasting processes. The blast media used for a specific project is a function of the existing condition of painted or rusted metal and the type of metal. It is also important to understand if any of the parts are wood, aluminum or have lead or other types of fillers.

We start the media selection process after we understand the project goals and type of paint to be used. The most common request is that the aluminum or steel surfaces are clean and free of rust and corrosion. The second most important requirement is that the surfaces are not damaged or warped and third what is the cost.

Hard blast media’s includes garnet, aluminum oxide, silicone carbides and similar abrasives that are expensive but are also very uniform in size will always provide a “white metal” or clean surfaces if care is take. It is important to understand that certain coatings including tars and mastics, undercoating, multiple layers of paint are probably not good candidates for any blast cleaning because they cannot be removed easily or cost effectively. Attempting to remedy all problems with one cleaning method can create additional problems and should be avoided.

Rust and paint removal for automobile parts in recent years moved away from hard abrasives and into plastic media or other soft media materials. More recently that too has changed and more and more people are using baking soda or soda blasting as a method to remove paint and rust. Soda blasting is simple, easy and low risk, the down side is soda is not very aggressive and may not fully clean your surfaces to an acceptable standard, especially for removing rust. Soda is not without problems beyond marginal surface preparation. Portable mobile soda blasters that come to your house and advertise soda as being environmentally friendly are only partially correct. DEQ, Department of Environmental Quality and EPA has limitations on virtually everything that goes down the storm sewer or drain. Paint chips that are removed with any process may also contain hazards that are never allowed into storm sewers.

Warping sheet metal parts is a common concern and is often misunderstood. Warping is a result of peening or stretching the metal on one side and not the other and typically not caused by heat. Heat can however warp or distort metal but the temperatures have to be so great and so intense that if that is the case you are using the wrong vendor for you blasting needs. It is typical to get a 5 – 10 degree temperature rise on a sheet metal fender for instance. The temperature is measured on adjacent surfaces that have not been cleaned. Typical compressed blast air that has been through an after cooler may have a temperature of 15 – 25 degrees warmer than ambient so some temperature rise can be anticipated. Large size heavy abrasives accelerated at high velocity are more likely to peen, soft light weight media such as soda or plastic blast less likely to peen, but also do not clean the surface as well.

It is important to understand that each project has different goals, each car is different, and a 1968 car that has original paint and has been stored outdoors will be a much easier car to strip than a garage kept car that has been painted several times.

Before you start your project stop by our Manassas Virginia facility, let us show you our operations and method of handling parts then we can talk about your project.

Media Blasting

Media blast cleaning metal, fiberglass or aluminum surfaces is often used to remove  paint, rust removal or corrosion and to prepare the surfaces for a new protective coating.

Media Blasting can be virtually any type of pneumatically accelerated granular or powder material. Silica sands are rarely used anymore because they are not predictable in granular shape, hardness and can be expensive to remove salts that may be present. Additionally because of high silica that may cause respiratory hazards to unprotected workers or workers downwind if it is an open environment, this type of abrasive is not very popular anymore. Each type of media has benefits; sometimes it is a low price point per pound, sometimes it is the cleanliness of the raw virgin materials. No one blast media works for all applications, and many times the wrong media can create more problems than intended for a novice or untrained operator.

Many types of softer metals are blast prepared including, zinc, aluminum, copper, brass, bronze. Soft metals are often stripped using soft abrasive media such as plastic, walnut shell, soda blast. Soft abrasives do not however remove stubborn coatings or rust and corrosion without significant additional effort if at all.

Hard abrasive media may include manufactured materials such as aluminum oxide, silicone oxide, minded garnet, crushed glass, coal slag, silica sands, steel grit, stainless steel grit and many others. Hard abrasives are most often selected for rapid cleaning and cleaning to produce a specific profile and used on steel surfaces. Profile is used to insure protective coatings, thermal sprayed metals, epoxies or powder coated finishes adhere according to manufacturer’s specifications. Typically the higher the profile the better the adhesion.

Associations such as NACE or SSPC have identified ranges of grit size and weight to achieve predictable profiles and levels of cleanliness and guideline production rates. These guidelines use clean mild steel as the baseline for surface preparation.

VA Welding Expert at Asco American Stripping in Manassas Park, VA

While the media selected for a particular project is important so are other factors. Air pressure, volume of air and clean dry air to propel media. Clean media is important to be sure that it has not been contaminated with oils, chlorides or other contaminants. The type of blast nozzle will determined stand- off distance required, production rates, air volume required. Blast nozzle and pressure may be changed several times on each project based on complex shapes and coatings to be removed.

Safety is important when using certain media such as walnut shells that can produce large amounts of static electricity or CO2 dry ice can displace oxygen in unventilated spaces and create unsafe work conditions.

A byproduct of any blasting process, including soft media blasting is peening. Peening is the compression of a surface and can be measured using Almen strips. Low pressures and soft media peen less than heavy hard spherical media accelerated at high velocities. Peening can be a desirable and beneficial result of a blasting process or it can create warping of light and heavy gauge metals.