– Existing Finish: If the wood has an existing finish that needs to be removed, stripping is typically the preferred method. – Surface Imperfections: If the wood has surface imperfections, scratches, or uneven areas, sanding is more appropriate.
Sanding will not be a lot less work, only sanding it will take longer and be a very dusty mess. Chemical stripping isn't that bad, just have to take a few more precautions with the process and the mess, but it's a lot faster/more effective than sanding.
Sanding the varnish with progressively finer grit sandpaper can help remove the finish and smooth the wood surface. Alternatively, use a scraper or putty knife to gently scrape away the varnish layer, taking care not to damage the wood underneath.
It's generally recommended to sand down the varnish before painting over it with gloss paint. Sanding will help the primer or undercoat to adhere better to the surface, creating a better bond for the topcoat.
It's generally recommended to sand down the varnish before painting over it with gloss paint. Sanding will help the primer or undercoat to adhere better to the surface, creating a better bond for the topcoat.
The allure of a fresh coat of paint is undeniable, but when it comes to varnished wood, skipping the sanding step can be a tempting shortcut with disastrous consequences. It's like trying to build a sandcastle on ice – the paint may cling precariously for a while, but eventually, it's all going to come crashing down.
– Existing Finish: If the wood has an existing finish that needs to be removed, stripping is typically the preferred method. – Surface Imperfections: If the wood has surface imperfections, scratches, or uneven areas, sanding is more appropriate.
If you are getting a rough finish after several coats of varnish, you may want to wet-sand the surface with 220 grit to level it out. Here I have leveled out the finish prior to the final coat and sanded it to 320 grit. I vacuumed the surface, wiped it down with a ragged wetted with mineral spirits.
Removing Paint or Varnish: For removing paint or varnish, use a coarse grit sandpaper, such as 40 or 60 grit, to quickly remove the old finish. Aluminum oxide sandpaper is a good choice for this task. Shaping and Rough Sanding: For shaping or rough sanding, use a coarse grit sandpaper, such as 40 or 60 grit.
This often results in an unsightly and uneven finish. However, with adequate preparation, such as cleaning, sanding, and priming, you can effectively paint over varnished wood. Proper prep ensures the new paint bonds well to the surface, giving you a smooth and long-lasting finish.
Paint stripping removes old paint or varnish with chemicals. This technique can be fast and efficient. If you're looking for a method with minimal effort, no sanding furniture might be ideal.
Many wood surfaces are treated with finishes like varnish, lacquer, or sealants to enhance durability and appearance. Vinegar can strip away these finishes, leaving the wood vulnerable. This not only affects the wood's aesthetic but also its ability to resist moisture and other damaging elements.
An orbital sander will make this job much easier and quicker if you're removing varnish from a flat surface. However, you will have to sand by hand for curved surfaces.
The Golden Rule of Sanding
The golden rule for choosing your sequence is to never skip more than 1 grit. For example, if you start with P80, and need to finish at P240, rather than using every grit from P80 – P220, you can do P80 – P120 – P180 – P240. This sequence cuts out P100, P150 and P220.
Start sanding with coarse-grit sandpaper. It will strip away the top layers of polyurethane. Work methodically in the direction of the wood grain to avoid scratches. Once the majority of the finish is removed, switch to medium-grit sandpaper.
Wet sanding is renowned for its ability to deliver a smoother finish on surfaces. The water acts as a lubricant that helps the abrasive material glide more smoothly over the surface, reducing the risk of leaving scratch marks that are often more apparent with dry sanding.
Re: removing varnish from furniture
There are two methods to remove the varnish on your table. Use an Orbital Sander in conjunction with 180 grit sandpaper. The other method is to use Bondall 1L Water-based Paint & Varnish Stripper.
Citristrip is a good alternative to Minwax If you're looking for a less toxic varnish stripper. Aside from Minwax, Citristrip was the best for removing finish. While the manufacturer recommends leaving it to soak in for at least 30 minutes, I noticed the finish bubbling up after only about 12 minutes.
Step 1: Sanding
Use 180-grit sandpaper and work the wood until the varnish is no longer glossy. For corners and other tight areas, use a sanding sponge or a bit of sandpaper. It is not necessary to remove all traces of the varnish, but it is critical to remove as much of the glossy finish as possible.
Sanding Tips (cont'd.): If you've applied 2-3 coats in one day, allow 48 hours drying time, then sand lightly, with the grain, using 320-grit sandpaper, before overcoating or applying the final coat. If 1 coat has been applied, the surface can be sanded within 24 hours.
Varnishing wood
Whenever water or any stain or finish that contains water comes into contact with wood, it causes the wood fibres to swell, which is called “grain raising” or “raised grain.” After the water has dried the wood feels rough to the touch, and thinly applied finishes also feel rough.
If the finish is very uneven, you will have to sand the finish flat and apply another coat of varnish. Then you will be able to buff the top coat of varnish to whatever sheen you like. If you try to buff a rough varnish surface, you will burn through the topcoat of varnish and you will see the coats in layers.
Marine Spar Varnish can be recoated in 10-12 hours at the recommended coverage rate. The varnish can be recoated without sanding up to 24 hours. Beyond 24 hours, sanding is required.