Steel-reinforced putty solves repair problems

A recurring quality problem during the baking of powder coated refurbished aluminium alloy wheels led a resourceful surface coating specialist to discover a steel-reinforced epoxy putty.

A costly and recurring quality problem encountered during the baking of powder coated, refurbished aluminium alloy car wheels has led one resourceful surface coating specialist to discover that a steel-reinforced epoxy putty, QuikSteel, eliminates the issue, improves quality and saves costs.

Two years ago Peter Rubery encountered the problem in a company with which he worked.

Alloy wheels look perfect until the effects of scrapes with kerbs, neglect of maintenance and corrosion begin to degrade the high quality surfaces.

Fortunately, if the structure is sound and the damage is superficial, the wheels may be refurbished.

Minor dents and scratches are often filled with an epoxy resin, the wheel is resprayed and the finish restored.

However, the best and most durable finish, as applied by the original equipment manufacturer (OEM), is a plastic powder coating.

This is deposited electrostatically onto the alloy casting and baked to fuse and cure the coating.

Baking may take 10min at a temperature of around 190C.

The trouble is, as Peter Rubery and many others in the industry have found to their cost, that if a standard epoxy resin is used as a filler, the resin emits small air bubbles during the baking process.

This disrupts the surface in the area of the fillings and spoils the otherwise perfect finish.

Rectifying a small area is not possible, and so the whole coating has to be stripped off, and the problem may occur again the next time around.

The use of a plastic filler is preferable because the alternative is to fill the defects by welding, and this requires a lot of care.

It also involves much preparation before and fettling afterwards, grinding down the weld and finishing it to a high standard.

Many dents and scratches make the job impractical and uneconomical.

There is also the risk of heat from the welding process distorting the wheel locally and possibly weakening the structure.

When he first met the problem, Rubery set about finding a practical solution.

He tested every suitable filler he could find on the market and finally, through Partco, an official stockist, came across one that performed to requirements.

The product was QuikSteel from Kalimex, an importer of high quality repair, maintenance and antifriction compounds.

Described as a single-pack two-part epoxy putty and reinforced with fine steel particles, QuikSteel features an "industrial strength" specification, including an exceptionally high tolerance of heat.

More importantly, it did the job without creating the bubbles or gassing found in other epoxy or polyester fillers.

The QuikSteel epoxy putty performs so well and without any reactions because it resists continuous exposure to temperatures up to 260C and intermittent exposure up to 300C.

The material also possesses an exceptionally high shear strength of 4.9MPa (measured using the ASTM D905 test standard).

Peter Rubery brought his experience of the Kalimex product to his own company, Paragon Paint Finishers, an enterprise he started one and a half years ago, where he is Managing Director.

"In the many years of being in this business nothing I have come across compares with QuikSteel", said Rubery.

"We use it for a great many filling tasks on a variety of jobs, with different surface coatings, and it never causes us any problems".

"It is great value because the alternative would cost us a lot of money, plus the risk of losing business through quality issues".

Rubery has built up a strong portfolio of customers and in the first year of trading Paragon Paint Finishers turned over GBP 250,000.

The company now employs four people and deals with customers throughout the UK.

It is housed in a 560m2 industrial building in Milton Keynes, Buckinghamshire.

Offering a range of finishes, the company specialises in powder coating and will deal with any metal item including sheet, castings and fabrications.

Preparation processes include chemical treatment and stripping, and shotblasting.

Besides advanced resin powders, other surface coating processes include "wet" spray painting and stove enamelling.

The plant list includes two ovens for baking coated parts, one measuring 7.4 x 2.5m, the other 8.5 x 3m.

The powder coating equipment is from Gemar.

A high quality colour coding service completes the comprehensive range of capabilities Paragon offers its customers.

Parts and products processed include, at one extreme, a variety of industrial items including signage, street lighting components and office furniture.

At the other, Paragon has built up a thriving and specialist service refurbishing and finishing one-off items such as vintage motorcycle frames, and of course the refurbishment of aluminium alloy car and motorcycle wheels.

As a high performance and general-purpose epoxy putty, QuikSteel has a great many uses besides the application described here.

Its exceptional strength, hardness, heat tolerance, adhesion and quick-setting properties are exploited innovatively in industry and the home, for construction and repairs, or simply fixing parts and surfaces together.

A well known, national service provider offering emergency services to stranded motorists has officially adopted the product.

It is available in several other versions containing, instead of steel particles, either aluminium or copper, including a plain white version.

QuikSteel bonds to almost any solid, sound surfaces.

It is safe and easy to apply; users simply cut a piece of the right size from a stick of the two-part material and knead it.

This starts a chemical reaction that changes the previously and uniquely separated resin and activator components from a soft state into a homogeneous material hard enough to be drilled, sawn, ground, filed or milled, and finished with a variety of protective or decorative surface coatings.

Before hardening it may be moulded to any required shape or pushed into holes, leaks, breaks or cracks that need repair.

It can even be used to fill damaged screw threads for retapping.

The material sets in 5min and reaches full strength within an hour.

It will set underwater and is resistant to solvents such as petrol and diesel fuel as well as acids and other common chemicals.

Once set, it retains its strength at temperatures from -70 to +260C.

When kept in its tube, it has a normal shelf life of three years.

Back to top