Frequently Asked Questions

Can’t find the answer you are looking for?  Ask us a question.

Simply complete the form here.

Interior Wood Finishing

Why is PPE so important when spraying waterbased products?

Eighty percent of the human body is made up of water. So as waterbased lacquers and paints are sprayed and become airborne the user inhales them, these particles can then be absorbed into the lung tissue with very little resistance. However when solvents are inhaled the body is unable to absorb them in the same way due to their foreign nature and complexity meaning the user will cough to remove the fumes/vapours.

Meaning that over time waterbased lacquers could be used daily without PPE and there would be no immediate side effects, however, water would start to build up in the lungs creating a lining which can then lead onto serious health issues like pneumonia.

Why do waterbased paints take longer to dry than solvent?

Water has a higher flash point than solvent, meaning that the temperature needs to be higher for the water to evaporate out of the paint mix leaving behind the paint finish. This explains why in colder weather waterbased paint takes longer to dry than usual as the water is struggling to leave the surface due to the ambient temperature. Read more about how you can improve drying conditions here.

What is IMO certification and how is it different from other fire certifications?

IMO (International Maritime Organisation, a specialised agency of the UN) Certification sets the global standards for fire safety. It involves a comprehensive fire safety assessment, where the product’s layers must be tested individually. When all the individual layers of the superstructure pass the IMO test, it means the whole structure is IMO certified.

Other fire certifications, including the newer European Standards like EN13501-1 go through testing on a finished surface, so when using the products to achieve a certificate the exact procedure and substrate must be used. The EN13501-1 aims to provide a common standard across the EU for fire safety, but changing any component or layer could invalidate the certification, as the entire assembly’s fire performance may differ.

It’s essential to understand these differences when selecting materials or designs for your next project, especially when compliance with specific fire safety standards is required.

Why do certain metallic colours look more sparkly than others?

Within the Hesse Creative Metallic range there are 5 different sub sections, within three of these sub sections, there are different particle sizes.

Certain metallic colours appear more sparkly than others due to variations in the size, shape, and orientation of the metallic particles within the coating.

The coarser selection (MC), creates a more sparkly effect as the particle size is bigger, meaning a larger surface area to reflect light creating the sparkling effect.

As the particle sizes reduce, the finish becomes more matte giving a similar effect to that of a paint finish but as a metallic colour.

Additionally, the base colour of the wood and the transparency of the coating can influence how light interacts with the metallic particles, further contributing to the varying levels of sparkle among different metallic colours.

Hesse Creative Metallic range has 112 colours to choose from. Find out more about this range here

Why does a stain colour significantly vary on different timber types?

Every timber type has a different density and grain pattern, meaning that liquids are absorbed at different rates. Once a stain has been applied the colour will vary as grain depth and timber hardness will impact the distribution of the colour. Find out more here.

Is there a quick way of doing the traditional liming method?

Yes, you will be glad to hear that there is a much simpler way of creating a limed effect without hours of applying and resanding of the timber. With a quick wipe on and a quick wipe off the TEP liming stain creates the finish in a fraction of the time. Watch the video following on how this is achieved: watch now

When it comes to fire retardant lacquers, what is the difference between an uprating wood coating and a maintaining wood coating?

There are a number of factors to consider when selecting an appropriate wood coating for your project. Firstly, it’s important to understand what certification is required on the project that you’re working on and secondly, you must understand if you are wanting to either uprate or maintain a wood coating.

To uprate, this involves operating the timber substrate to the required level of fire retardancy. Whilst maintaining refers to retaining the substrate at its existing level of fire retardancy.

It is possible to upgrade timber and achieve a level of fire retardancy by using an intumescent coating which encases the timber giving it the required certification.

To maintain a substrate, you need to choose a coating that has the same fire certification.

When applying fire retardant coatings, it is extremely important to understand the certification that the coating already has and how it was applied in order to achieve that certification. Key points to pay attention to are:

· The coat weight

· The substrate and veneer used in testing

· The conditions which the finish was applied

All of this information can be found on the fire certificate that is issued by the fire testing body. We always recommend looking at the final coating at a very early stage in the project to ensure that the specification is met and the best finish is achieved.

If you have any questions when it comes to fire retardant lacquers, please don’t hesitate to get in touch.

What’s the difference between water-based and solvent-based?

Solvent-based finishes are produced with chemicals that react with the oxygen, which can mean a quicker drying time. They are also less susceptible to environmental conditions such as temperature and humidity during the curing phase. 

Water-based finishes produce the same outstanding results, but are more environmentally-friendly than solvent-based finishes.  

More information on water and solvent-based finishes can be found here. 

What’s the benefit of water-based finishes?

Water-based finishes are less toxic, kinder to the environment and add less to your carbon footprint than solvent-based finishes. 

More information on the benefits of water-based finishes can be found here.

I’m struggling to get a good finish on my products, what should I do?

To get a good finish on your products, we suggest a ‘one-two’ approach, where the piece is first painted or varnished and then sanded down. This process can be repeated to improve the finish.  

We recommend selecting abrasives, such as sanding discs, to ensure you sand down efficiently after every coat, as well as using stains, lacquers and varnishes with excellent levelling properties to get a good finish. 

More information on how to get a good finish can be found here.

Which products should I use to get the best possible finish?

We advise investing in high quality finishes with excellent levelling properties and recommend Hesse Lignal stains and lacquers for this purpose. They can be used by lone practitioners or for use on a full-scale production line. 

We also recommend using Sia Abrasives, as their sanding discs are long lasting and are easily replaceable. 

More information on products to get the can best finish be found here.

How do I prevent wood surfaces greying?

Although greying is a natural process which occurs over time, the right coating and finishing products can go a long way to help overcome the issue.  

More information on how to prevent wood surfaces greying can be found here.

What makes wood surfaces turn grey?

Wood surfaces lose their natural golden colour, due to chemical changes after being exposed to the elements. Wood surfaces contain tannins, which give the wood its colour and lignins act as the glue holding the wood fibres together. When exposed to UV light, the lignins break down into simple sugars and the tannins can slowly oxidise, causing dead wood fibres to grey and discolour. 

More information on what makes wood surfaces turn grey can be found here.

How do I choose the right coating and finishing products to prevent wood surfaces greying?

There are a several market-leading Hesse Lignal products that have been designed specifically to protect surfaces against UV damage. We recommend the Hesse multicoat lacquer, base coat and natural solid oil to protect against greying wood. Our technical experts will be able to advise on the right coating and finishing products for your needs. 

More information on how to choose the right coating and finishing products to prevent wood surfaces greying can be found here.

Why has my paint bubbled or look like orange peel?

When your paint looks bubbled or has an uneven texture like orange peel, it is often the result of it drying too quickly. To get the desired smooth finish, you can add more thinner, or a slow thinner. Making sure you select a high quality paint, fit for purpose and prep the surface sufficiently before applying, will also help. 

For more information on why paint bubbles or looks like orange peel, contact our expert technical support on 023 9223 3310. 

Why is my paint not drying?

There are several reasons why your paint may not be drying and it depends on whether you are using water or solvent-based paint. 

If you are using water-based paint, it is likely that the spray room is not warm enough. A warm room will help to speed up the drying process. 

If you are using solvent-based paint, you could be using too much, or the wrong mix of hardener. Fixing this will lead to a quicker dry time. 

For more information on why paint isn’t drying, email our knowledgeable team on sales@redwood-uk.com. 

Can I spray wood finishings on plastic?

It is possible to spray wood finishings on plastic, but care must be taken to prepare the surface first. Sanding down the plastic will remove the gloss and create a texture for the wood finishings to stick to. There are also paints that are specifically formulated to adhere to plastics. 

For more information on spraying wood finishings on plastic, email our knowledgeable team on sales@redwood-uk.com. 

How can I make my project fire retardant?

Flame retardant paints and coatings are crucial for protecting wood from heat and fire. In the event of a fire, the fire retardant insulates the wood, resulting in a slower ignition time and less smoke production.  

All of our Hesse FANTASTIC range meet the testing standards of EN 13501-1 (The European standard: Reaction to Fire) which tests the materials response to fire, the emission of smoke and production of flaming droplets or particles whilst burning. With the highest rating, B-S1 D0:, no burning droplets or particles and very limited contribution to fire and smoke development. 

For more information on how to make your project fire retardant, email our knowledgeable team on sales@redwood-uk.com. 

Exterior Wood Finishing

Why does the primer on my exterior window frame have a yellow tinge?

Primers yellowing can occur for several reasons, one being the oxidation of the alkyds or oils which form the basis of traditional primers. Organic substances of any kind tend to discolour when exposed to sunlight, so oil-based primers tend to yellow over time.

However, yellowing can also occur because of the tannins in the wood leaking through. Read more about how we helped one of our clients to overcome this issue, right here.

What’s the best finish for aluminium clad timber windows and doors?

We recommend ZowoTec 433, created by German specialist supplier, Zobel Coating Systems, as it’s specially formulated for alu-framed windows and doors. Its ultra-matt finish is designed to give a natural wood effect, whilst being hard wearing, fast drying, with excellent dirt and wood repellent properties. Plus, it’s fully water based, so there’s no nasty solvents!  

More information on how to finish aluminum clad timber windows and doors can be found here.

How do I get rid of blue fungus staining on my external timbers?

Blue fungus staining is a common problem on external timbers, but it can be controlled with effective drying processes and virtually eliminated when the wood is sanded and planed. The application of a varnish or seal will also prevent future germination of fungal spores that may remain dormant in cut wood. We recommend using Zobel’s specialised exterior woodwork treatments. 

More information on getting rid of blue fungus staining from external timbers can be found here.

How do I prevent wood surfaces from cracking?

Making sure you choose your wood carefully in the first place will help prevent cracks. Choosing teak over oak for its dimensional stability, or going for a higher-grade batch of the same variety because it has been dried better, will help to prevent cracks. 

Wood stain or sealer will help to prevent cracking, as it allows more time for the water to be absorbed and lessens differential stresses across the piece. Reapplying a new coat, when necessary, will keep your wood in good condition. 

Paint also provides extra protection, as it’s impervious to moisture and does a great job of reflecting heat and sunlight away from the surface.  

More information on preventing wood surfaces from cracking can be found here.

Why do wood surfaces crack?

Wood surfaces crack when wood responds to changes in its environment, such as expanding or shrinking with humidity levels or an increase in temperature. Those changes will eventually cause the entire piece to grow or shrink, but in the short term, the outside of the wooden object may be affected more than its inside. It’s these different stresses on the wood that results in a crack. 

Also, rapid drying processes involved in kiln dried timbers will leave timbers with an uneven moisture content, rendering them more likely to warpage and cracking than air-dried wood. 

More information on wood surface cracks can be found here.

Should I choose an oil- or water-based wood coating?

Oil and water-based wood coatings both have their benefits, so which one you choose will be dependent on your requirements. The DIY section in general has shifted towards water-based wood coatings, as it is convenient, effective, fade resistant and more environmentally-friendly. But pros feel oil-based coatings give a better coverage of joints and fissures and improved overall finish. Oil-based coatings are less susceptible to temperature and humidity, plus have a faster drying time. 

More information on oil and water-based coatings can be found here.

Why are my wood veneers yellowing?

While yellowing is a natural process which occurs over time, the problem is often down to the type of lacquers professionals use.  

Many sprayers use pre-catalysed lacquers as they are excellent at protecting surfaces, but any finish with nitrocellulose in will oxidise the substrate when exposed to UV, resulting in yellowing.  

More information on yellowing wood veneers can be found here.

How do I ensure my wood veneers do not yellow over time?

Although a natural process, yellowing can be delayed by using suitable finishing products. We suggest using an appropriately formulated lacquer with a UV stabilising additive, as it’s proven to keep wood veneers a consistent colour for up to 5 years.  

More information on how to prevent wood veneers going yellow over time can be found here.

How can I increase the UV protection of my paint?

To increase the UV protection of your paint, we recommend applying a UV resistant primer and top coat. The tinted ZowoTec 203 is a water-based exterior primer that ensures maximum UV protection and the ZowoTec 421 water-based top coat is UV resistant with special UV absorbers. 

More information on how to increase the UV protection of paint can be found here. 


Why do sandpapers clog so quickly?

When sanding, wide belts have a tendency to clog due to excessive friction, which causes the surface to heat up and the paper to clog quickly. To prevent this, it is recommended to check the grit you are using. Using a grit that is too fine or too coarse can cause clogging, so it’s important to choose the right grit for the job. Additionally, it could be down to the sandpaper being too smooth, machine being set too quickly or the substrate itself being too wet.

As a commonly occurring issue amongst clients we offer onsite reviews with some of the market leading abrasive experts to ensure you get the best out of your sanding processes. Read here how you can book one for your workshop.

Is sanding down important to get a good finish?

Sanding down is vital to getting a good finish. Many pros opt for a ‘one-two’ approach where the piece is first painted or varnished and then sanded down. Sometimes those two procedures are repeated several times over. A pro will sand down every coat, even if it was applied in a spray booth. This eliminates any irregularities in the finish.  

More information on sanding can be found here. 

Why is hand-sanding the most efficient way to sand?

Hand sanding delivers a better finish than using power tools, which can leave scratches and can’t always manage the kind of fine-tuning around knots or fine mouldings which come naturally to practitioners of hand sanding.  

More information on why hand sanding is the most efficient way to sand can be found here.

What is the best way to hand-sand?

The best way to hand sand is to go with the grain. This will help to minimise torn wood fibres and will get your surfaces smoother, faster. Don’t over-sand as you’ll be wasting time, wood and abrasives. Start off using a grit that will get rid of the worst defects, then go on to re-sand with progressively higher grits to work out all the scratches.  

We recommend using non-clogging papers and sanding blocks for a good result. Contour sanding grips will also prevent damage to your fingertips. 

More information on the best way to hand sand can be found here.

How do I avoid burning belts?

Overloading belts can cause them to burn. The grit of your belt will determine how much material you can remove, so make sure you aren’t trying to remove too much in one go. Make sure you use the whole breadth of your abrasive belt, rather than one certain area, as it will lead to the unnecessary wear and tear. It’s also beneficial to check for additional residue on the belt, left from the piece itself, as a result of the heat produced from the sanding action. 

More information on how to avoid burning belts can be found here.

What are the best ways to prevent chatter marks?

To prevent chatter marks, carefully select your contact roller to make sure it has the proper rubber hardness (durometer) for your application. Check to make sure that the hold down roller is adjusted correctly based on your application and surface thickness. Also make sure you’re using the correct belt joint for your application. 

More information on the best ways to prevent chatter marks can be found here.

Why are my discs ripping on the edges?

Uneven wear and a build-up of sanding dust on your discs can cause them to rip. Our Sia disc multi-hole sanding range has an optimised air flow that extracts dust more efficiently and increases the lifetime of the discs. This means minimal clogging and a lower abrasive consumption, without compromising on the very high abrasive performance or high quality finish. 

For more advice on why your discs are ripping on the edges, speak to our expert team on 023 9223 3310. 


What’s so good about one-shot powder resins?

One-shot resin is an ideal solution, particularly for complicated projects, as it’s slow to set, so you have more than an hour to fine-tune an assembly, and it’s very creep-resistant, so it’s unlikely to slide out of alignment while you’re making adjustments. The long cure times also mean it’s easy to clean-up.  

One-shot resins are also ideal for outdoor applications as it’s very water-resistant. It is also easy to mix. 

More information on the benefits of one-shot powder resins can be found here.

Should I still use one-shot powder resins?

One-shot resin is an ideal solution for outdoor applications and complicated projects, as it very water-resistant and has a long cure time, meaning there is plenty of time to make adjustments before the resin sets. 

More information on one-shot powder resins can be found here.

Is it better to use UF resin or a more modern synthetic glue?

UF (Urea Formaldehyde) resins and modern synthetic glues are both popular and have their benefits, so which one you choose will depend on your usage and requirements. UF resins provide a solid glue line that offers less bleed-through and creep, with waterproofing characteristics, whereas a modern synthetic glue offers a cheaper effective alternative. 

More information on UF resins and modern synthetic glues can be found here.

What are some benefits of using UF resin?

UF (Urea Formaldehyde) resins are popular with professional woodworkers, as they have good waterproofing characteristics, making them ideal for marine or outdoor projects. They also provide a solid glue line and exhibit less bleed-through and creep than other adhesives. 

More information on the benefits of UF resin can be found here.

How do I recycle my IBCs?

Recycling IBCs responsibly is important and you should adhere to hazard disposal regulations to avoid potential harm to humans or the environment. If your IBC contains hazardous waste, you should contact an authorised business to collect, recycle and dispose of your containers. 

If the contents aren’t hazardous you need to pre-treat the container and make sure it is completely empty, so it can be collected and recycled.  

Alternatively, our reusable Eco Crates are much more environmentally-friendly than single use alternatives. They minimise the hassle of disposing of your IBC containers and customers have also seen a reduction in adhesive waste. 

More information on recycling IBCs can be found here.

Why is resin bleeding through on my veneer?

The main cause for resin bleeding through on your veneer will be that the glue mix is too thin. To help prevent this issue, we recommend adding an extender to increase the viscosity. 

For more advice on products to prevent bleed through on your veneer, contact us on 023 9223 3310.  

Which adhesive is best for veneering?

When it comes to choosing the best adhesive for veneering, it comes down to your specific requirements. At Redwood, we take the time to understand your needs, so we can recommend the most suitable products for your project. 

UF resins are popular with many of our clients as they have good waterproofing qualities, making them ideal for outdoor or marine projects and they exhibit less bleed-through than other veneer glues.  

However, more modern synthetic glues are convenient, considerably cheaper and require less mixing and drying time. 

For more information on the best adhesive for your veneering project, contact our expert team on 023 9223 3310. 


How do I find the best eco-friendly products?

At Redwood, we only work with suppliers that have made commitments to become more sustainable. We have become the UK’s largest supplier of Hesse Lignal coatings – as Hesse is renowned for their continuing efforts to reduce emissions and bring awareness to occupational safety.  

We stock hundreds of low-VOC primers, base coats, finishing lacquers, sealants and more. Our technical department can advise you on the most appropriate products and manufacturing methods to reduce your workshop VOC emissions. 

We have also introduced a range of products designed to reduce our customers’ carbon footprint and impact on the planet. Our Eco Crates are the ideal eco-friendly alternative to traditional IBCs for PVA adhesives. Our fully reusable crates are better for the environment than single use alternatives, they minimise waste and will save your business money. You won’t have to dispose of leftover PVA, as the only waste produced is the inner liner bag itself which holds the glue. Plus, we’ll collect the crates free of charge, ready for your next delivery. 

More information on how to find the best eco-friendly products can be found here.

How can I tell what products are truly ‘low-VOC’?

Manufacturers should provide evidence of the ingredients they use, so check the packaging to see if a product is truly low VOC. Where possible, you should avoid toxic and polluting ingredients such as toluene and xylene, and carcinogens such as arsenic, beryllium and cadmium. Generally, water-based solutions are more environmentally-friendly. 

It’s also worth considering the manufacturing processes and company’s carbon footprint to see how eco-friendly they truly are. 

More information on low-VOC products can be found here.

Is Redwood an eco-conscious supplier?

Put simply, yes we are! At Redwood, we only work with suppliers that have made commitments to become more sustainable. We have become the UK’s largest supplier of Hesse Lignal coatings, who are a leading force in reducing emissions, as well as introducing a range of products to reduce our customers’ carbon footprint and impact on the planet. 

The products we stock are carefully selected, and we stock hundreds of low-VOC primers, base coats, finishing lacquers and sealants. Our technical department can also provide expert advice on how to reduce your workshop VOC emissions. 

We have also designed fully reusable Eco Crates, which are the ideal eco-friendly alternative to traditional IBCs for PVA adhesives and are better for the environment than single use alternatives. The Eco Crates minimise waste, you don’t need to dispose of leftover PVA and the only waste produced is the inner liner bag itself which holds the glue.  

Our vision is to assist every responsible manufacturer in wood to reduce their impact on the global environment. 

More information about our sustainability initiatives can be found here. 

What colour ranges do you match to?

We stock many standard colour ranges, but we also match any solvent or water-based colour, with our comprehensive colour and stain matching service.   

More information on the colour ranges we match to can be found here. 

How long will it take my order to arrive?

We are proud to offer a fast and reliable service, so next day delivery is available. 

Call us now to place an order on 023 9223 3310.  

If you couldn't find the answer you were looking for, please contact our team on 023 9223 3310 or sales@redwood-uk.com