Top Tips for Surface Preparation


Top Tips for Surface Preparation:
When you make a project preparing the surface is an important part of the process, we provide some do’s and don’ts to help it go smoothly.

When you make a project preparing the surface is an important part of the process, we provide some do’s and don’ts to help it go smoothly

The way you treat a surface to get a finish will depend on what it is you are working on and how you want it to end up. A precious antique needs a very careful sympathetic approach to restoration, while a recycled pallet project will take some harsh treatment with coarse abrasives. So you need a different approach that suits each job. 

There is a very wide range of abrasives available to suit different needs

Abranet is particularly efficient at sanding surfaces and it doesn’t clog like conventional abrasive paper

Here are some useful tips and guidance to help you
1. If an important surface is dented, often a highly visible top surface, you can use a steam iron and paper
or an iron with a damp cloth to lift the crushed fibres. Don’t try this on an antique though! Leave the wood to dry and if necessary use a fine grit paper to rub away any projecting fibres. Don’t expect a perfect result
but it will be much less visible.

If the wood is dented you can use a steam iron and a sheet of cloth to help remove the dent

 2. Stripping off an existing finish is justified if it doesn’t have a delicate patina or ‘acquired’ surface finish like antiques do. It becomes necessary if the finish is too thick and likely to clog a sander, paint or varnish for example. Use a safe type of stripper, follow the safety instructions and be patient as the process takes a little time. Neutralise the chemical action in accordance with the manufacturers instructions. 

3. Often, surfaces are just very dirty or clogged with wax. You can buy wax cleaning agents that, when used with medium or fine wirewool, can clean a surface nicely ready for a new finish. Wipe away all the dirty residue and allow the surface to dry before any further work. 

A wax cleaner and medium wire wool or a scouring pad will remove a lot of dirt from the wood grain

4. Sanding is the process of ‘roughing up’ the surface of wood to make it smoother. This is a bit perverse, scratching a surface with sharp pieces of abrasive material just to get a better finish – but it works. 

5. There is one golden rule, start with coarser abrasive and work through increasingly finer grits until you are satisfied with the result. This depends on the job, fine quality cabinet work demands a fine finish while joinery will take a coarser finish. 

6. Sanding a turned item is often done on the completed item or parts of it, on the lathe while it is turning. It can’t be done static as the results would be poor and it is harder work. Remember to remove the toolrest for safety and have an extraction hood close to the work to take the fine dust away. 

Sanding on turnings is normally done with the work rotating, which is easier and gives a more consistent finish than static sanding

7. With furniture it is always better to do most abrasive work before a job is fully assembled if you can. It is much easier to work on separate parts and sanding can reach into corners, etc. or before mouldings are applied so it gets sanded properly. 

8. One of the worst offences is ‘cross grain’ scratches caused where the abrasive goes over a join line between perpendicular components. This is hard to avoid but do the piece that butts to the other piece that runs through, so when you do the latter hopefully its scratch lines will obliterate the other ones. 

Where wood grain meets at different angles, great care is needed to avoid cross-grain scratches occuring

9. Prepare timber correctly first. If it isn’t beautifully flat and smooth to start with, don’t expect abrasives to somehow create a perfect result. Softwood can be bought fully prepared and some sections of hardwood also. Anything else will need a planer/thicknesser to flat it and square it. 

10. Choose the right starting grade of abrasive. For cabinetwork (as an example) no coarser than 120 grit and possibly finer. This obviates a lot of work and damage in sanding. Veneered surfaces need a finer starting grit still, 240 then running through to 320 grit and possibly 400, the bigger number indicating finer grit particle size. 

11. Although DIY stores and builders merchants stock standard aluminium oxide abrasive there are a much wider choice available if you search around. Specialist abrasives and woodworking suppliers can supply finishing papers and web type flexible material and Abranet with is a highly efficient non-clogging form of abrasive. 

12. To check whether a surface is really ready to have a finish applied you can put a thin coat of sanding sealer or water-based varnish on an area and check how it looks against the light once it has dried. Also, don’t ignore the power of touch as fingertips are a sensitive way of checking the quality of a surface. ν


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