links here
wickes
homebase
brewers


Varnish Finishes for your Front Door
By Ray Lewhite.

There are two principal reasons for using varnish on exterior work - either to further protect and enhance strong coloured painted surfaces and colours which are likely to fade unless varnished, or for the protection of wood surfaces which for reasons of appearance are left in their natural state.

Varnishing needs care to be taken over it if a satisfactory result is to be obtained. The better the gloss the more the blemishes show, and as the paint gloss will be much improved by a coat of varnish, the defects will tend to be further magnified. Some fine surface dust cannot however be avoided, and in time, with polishing, will tend to disappear. Large pieces of dusty or gritty material will show up badly, and preliminary work prior to varnishing is designed to ensure that only clean materials and brushes are used.
In describing the procedure for varnishing over paintwork, I will assume that the front door has been painted on the lines suggested in my last article. If possible at least a week should elapse before the job is continued, for this time will prove invaluable as a hardening period for the paint. Although it is possible to apply a modern varnish over gloss paint without rubbing down the gloss finish, it would be impracticable to attempt to get a really good varnish finish without a little wet flatting work.
If it were possible to take off the door for painting, then it can then be removed, otherwise the varnishing will have to be done with the door in place. The wet flatting need only remove settled dust and a trace of the gloss. There should be no brush marks to flat out. Use either worn 320 wet or dry paper or 400 grade if obtainable, or alternatively fine flour grade paper. If paper is used, after wetting rub a little soap on it first. Care should be taken to see that grit is not picked up and allowed to scratch the paint during flatting. A thorough wash off and a dry with chamois leather will make the door ready for varnish.

USING PUMICE POWDER

Varnish front door
Pumice flatting calls for a different technique. The pumice powder should be stored in a shallow wooden box and kept damp at all times. Wet a piece of felt (from an old hat would be admirable) dip it in the pumice powder and use it to rub the paint. Rub as you would for flatting with paper. Try not to be too fierce with the flatting, especially at edges for varnishing will draw attention to heavily rubbed places. It is possible to touch up with paint placers which have been rubbed through, but you will lose a day while the paint dries.
Careful washing off is important with all wet flatting work but even more so when using pumice powder. If any of this powder is left on and allowed to dry, it will result in a terribly disappointing bitty surface. In pumice flatting work, at the washing off stage, use a pastry brush or an old tooth brush to work out the pumice from quirks and mouldings, thus making sure the door is absolutely clean. Then wipe over again with a special "tacky" rag.
We are now ready for the varnishing, if the weather conditions are suitable. Clearly high winds, driving rain and really hot direct sunshine are unsuitable conditions in which to apply varnish and the work should be left until things improve. Take care to purchase a good varnish brush; you will be repaid by the quality of the final finish. Avoid Copal Oak, Church Oak and similar varnishes and choose one described as a synthetic varnish, or clear 2-4 hour lacquer. Many makers of such quick drying finishes use names similar to these, but be sure that any varnish purchased is suitable for exterior work. Extra pale quality and clarity hardly matter, as in this instance we may accept a slight colour change as the paint being varnished will be a good strong colour and not a pastel shade. Speed of drying does matter however, and the quicker the varnish sets the better the chances of a clean dust-free finish.

CHOOSING BRUSHES

Varnish front door
The most important factor in applying a successful varnish finish is the brush. Carefully wash out a good, well used one, two and a half, and a three inch paint brushes first in white spirit, then in soap and water and hang to dry at least overnight, but wherever possible for a few days, before varnishing is done. When dry, twirl them between the hands. This expels all lose matter which may have remained in the bristles. Pour the varnish into a clean wide mouthed container and if need be thin with a little genuine American turpentine. It is not often varnish requires thinning, but in cold weather the varnish may be a little too stiff for easy application. As we want to get a nice full gloss, the varnish needs to be applied generously but with due regard to the possibility of runs and sags.

APPLYING VARNISH

Varnish front door
The method of varnishing a front door is the same as for the application of gloss paint. With the inch brush lay on the varnish around the edges of each section, then fill in with the larger brush in bands, according to the size of the area being worked. After carefully scraping out the brush against the side of the container, lay off the varnish once in each direction. Do not over brush varnish, and having applied a nice full coat, leave it alone. When the varnishing is complete leave the door until dry, then replace the handles and other fittings. A brush found to be successful in the achieving of a really clean varnish finish is a tool well worth keeping as a varnish brush, against the time when further work of this nature will be done. Such a brush (or brushes) may be kept in raw linseed oil. Drill a hole in the brush stock, pass wire through and suspend it in the oil poured in a clean container. When needed again for varnish the oil is scraped out against the back edge of a knife. Where brushes will not be used again for varnish, they must be washed out in white spirit, then with soap and water, and allowed to dry before using them in paint. Now we come to natural or clear finishes, and it should be noted that French polishing, polishing varnish finish, or any other speedy and reliable means of getting a good clear finish must be further protected by a coat or two of exterior grade varnish. This may seem pointless but it is absolutely necessary, as none of the finishes capable of producing fine results remain durable unless one is prepared to go to the trouble of re-finishing at fairly frequent intervals.

OAK AND MAHOGANY

Varnish front door
Let us assume that an oak or mahogany front door has been stripped of old paint in readiness for a clear finish, or you have a new door "in the white." The procedure is similar to that used for many other woods but I mention oak and mahogany as they are very popular. Woods similar to them in character and which may be finished in the same way are elm, teak, sapele, parana pine and gaboon. If timber is to be left unstained, glasspapering will be essential to ensure the wood is smooth and that hand mark stains and other surface stains are removed, then proceed with the coating work. Because of the action of strong sunlight, some stains tend to fade, so care is needed to select those which are known to have better resistance to fading. Oil stains, wood dyes of the Naptha type and water stains are better than spirit soluble stains. I prefer water stains which take time to dry out - an obvious advantage.

Some people object to water stains on the ground that they raise the grain; this is true and when the glasspaper is used to cut back the raised fibres there is a certain loss of stain. This effect can be minimised by first thoroughly wetting the wood with clean water and allowing it to dry out. Then glasspaper down the raised fibres and start staining. The water stain will not now raise the grain to the same extent.
There are two ways of doing the job, irrespective of whether you finish the wood in its natural state or use a stain to alter the colour. The coating system is the same but the preparatory work differs slightly. The first method is to build up the timber to a reasonable finish with a recognised wood finishing, then to continue with a coat of synthetic or other exterior grade varnish. Two coats will, of course, give better protection. The second method is to make a well build-up finish using exterior varnish throughout. The durability of both methods is about the same, so the choice rests with the individual.

Varnish front door
The first method can be a finish of either French polish, cellulose wood finish (which calls for spray equipment) or a quick drying varnish of the polishing varnish class. Briefly French polishing consists of building up the wood surface with shellac dissolved in methylated spirit and applied with a "rubber"; cellulose wood finishing call for the spray application of several coats of a specially formulated clear cellulose lacquer, and the polishing varnish finish involves the use of a quick drying hard varnish which may be flatted and polished but which, if used under an exterior grade varnish, would merely be flatted in readiness for the varnish.
It is the second method which I think will appeal most to readers, as the process can be carried through with one class of material using a brush throughout. After staining or glasspapering, the first step is to apply a thin coat of varnish to the door, rubbing well in with the brush. This takes the place of primer in a paint system so it needs some care in application. Overnight drying is essential at all stages of this work, and when the work is picked up again, the first task is to cut back the raised wood fibres with fine worn glasspaper. Varnish tends to make the fibres stand up in a similar way to wetting prior to staining, and at this stage the work will look very rough and unpromising.

Varnish front door
The next coat will improve things, for as the wood will now be sealed there will be no raised grain to cut back. If possible call a halt for a few days to allow the varnish to harden off before proceeding with the next stage. This involves a light wet flatting operation using worn 320 grade paper and a little soap to ease the rubbing. Now follows the first full coat of varnish and by this stage the wood will be showing the full beauty of its grain formation. In some instances, for example with close grained woods, the finish might be considered good enough. If not, a hardening period and another full coat of varnish should produce the desired result.
Varnish coatings, whether on natural wood or over painted surfaces are prone to certain defects due to climatic conditions at the time of application. Damp atmosphere in the vicinity of the varnish work may lead to a defect called blooming, in which a whitish may be seen on the surface of the varnish. If not severe this may be polished away when the varnish is hard enough to withstand a polishing cloth. Severe cases sometimes have to be stripped off, so you should try to avoid such defects by not varnishing in really humid conditions.
Another defect, common to varnish and painted work, but which shows up more on varnish, is called rivelling or wrinkling, caused by the formation of a top-skin while the under layer is still soft. The prime cause is the application of too heavy a coat, and this defect is often seen at quirks and mouldings where the coat is often thicker even though there may be no runs. Nothing can be done, and I mention this defect in the hope that readers who are aware of it may be able to avoid this happening.

LINSEED OIL

Varnish front door
Not everyone likes to see a full gloss finish on natural woods, and there is a strong case for treatment of exterior oak with linseed oil. This apparently simple operation is quiet frequently very badly carried out so the following hints may be useful.
In my opinion either raw or boiled linseed oil will provide the protection required. Boiled oil is darker and may be expected to give a darker appearance to the wood in time, and where there is no objection I should prefer its use because it dries very much better. Raw linseed oil when spread on a non-absorbent surface will take a fortnight at least to form a skin whereas boiled oil will dry very much quicker than that. No matter which oil is used, the secret is to leave none on the surface of the wood in the early stages, but to rub it well in. Later a thin film will be left on the surface of the wood by the continued application of the mixture.

OIL MIXTURE

Varnish front door
The oil is not used alone, but is mixed with genuine American turpentine at a ratio of 2 oil to 1 turps. This dilution will help the oil penetrate the wood. A rag should be used to remove surplus oil from the surface. When raw linseed oil is used, several days should elapse before repeating the operation so as to allow the oil in the wood pores to oxidise. If oil is left on the surface of the wood in an endeavour to get maximum protection it will form a sticky, non-hardening film, which will collect dust and be a constant source of annoyance.


See Fig.1
See Fig.2
See Fig.3
See Fig.4
Back to Home Page


Special Paint Finishes.