| Author |
Message |
    
Doug Young
Unregistered guest
Posted From: 203.102.85.147
| | Posted on Thursday, 29 April, 2004 - 09:49: |    |
I have a BC S1 PW, and the veneer has cracked, and lifted and curled in places. How should I deal with this? It is all there and if able to be softened will be able to be glued down again. I have not attempted to do this for fear of snapping the curled veneer off. (BC4FM) |
Bill Coburn
Grand Master
Username: bill_coburn
Post Number: 137
Registered: 4-2003
| | Posted on Thursday, 29 April, 2004 - 10:07: | |
Steve
At the risk of patronising you can I compliment you on the most comprehensive detail you have provided above. I have shamelessly extracted it and will put it in 'Topics' lest it be lost in the ether. Many thanks for your time and efforts.
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David Gore
Moderator
Username: david_gore
Post Number: 389
Registered: 4-2003
| | Posted on Thursday, 03 February, 2005 - 11:34: | |
The following link may be of assistance in providing more information - this material is subject to copyright as detailed at the end of the webpage.
www.jag-lovers.org/xk-lovers/library/wood_restoration.html |
david
| | Posted on Saturday, 17 March, 2001 - 23:47: | |
Hi guys,
I've decided to refinish the veneered woodwork in my 86 bentley. The wood is in good condition but the coating is
starting to crack because of sun damage and time I guess. I have researched how I should go about this but there is
so much conflicting information on the web. My desire is to acheive the same high gloss finish that is on it now.
1. to remove the existing gloss coat some say sand it back but as the walnut is so thin I am not in favour of this
method. Others say use stripper to remove it. But what stripper? I beleive the current gloss on it from crewe is a
polyurethene composite. I wonder is this is correct.
2. After removing the gloss I have been debating whether to lightly stain the burl as the sun would have undoubtedly
bleached it. can anyone recommend the most appropriate stain. I have heard oil based stains are NOT the way to
go.
3. Now comes the application of the new gloss. I have heard some glosses will turn yellow after time. I am
considering using a polyurethene finish. I was actually wondering if there is something out there with a UV
protectant. Perhaps marine varnish would be the best bet?
Any advice would be very much appreciated. If somebody has tackled this mammoth task I'd love to hear from you
and would like appreciate knowing what are the best products AVAILABLE IN AUSTRALIA for this project.
kind regards David |
Deborah Saville
| | Posted on Saturday, 17 March, 2001 - 23:48: | |
Dear David,
Can speak with some authority on this subject as not only have we redone the woodwork on our Silver Cloud and
our Mark V Jaguars but our business is in the Marine industry and we refurbish boats, inside and out. A lot of the
vessels we do, come from Hong Kong, and they use a lot of timber veneer paneling so you can imagine, with the
heat, humidity and acid rain, the condition that we get them in.
First of all do not use a stripper on the old varnish, this is much too harsh. We only sand very gently and lightly with a
fine sandpaper. Patience is your only virtue here.
There is really no need for a stain as you will find that the veneer colour has been retained by the protective coating
of the lacquer.
We position the wood in a relatively dust free area (hosed down first)on a very still day and preferably warm as this
will make the clear go off faster. We use a 2 pac polyurethane clear (we used 2K CIA, which is available from
Harts Automotive supplies), spraying one coat every 24 hours and lightly sanding between coats. We apply about
approx 7 coats(each coat filling up any cracks) with the final coat being the one that is as dust free as possible.
As you build up the coats you will find a magnificent depth to the walnut burr and if it has a very knotty grain, even
more so.
The satisfaction is very rewarding.
Good luck
Deborah
Gold Coast Australia |
Steve
| | Posted on Sunday, 18 March, 2001 - 03:03: | |
Most of the veneered wooden trim fitted to vehicles since the 60's has been of very poor quality, Rolls-Royce & Bentley however have continued to use the finest backing materials and adhesives and this in my experience makes it the easiest to restore of any manufacturer. The only exception is the Camargue fascia where the veneers are bonded to aluminium, which causes particular difficulties during stripping. In answer to your question the lacquer used on your car was polyester and if memory serves correctly 1985 saw the introduction of an improved coating with a flex additive. This was better able to resist cracking and subsequent shelling. Prior to polyester, melamine materials were used but these would date back to the 1960’s.
I would strongly suggest you do not sand the existing coatings. Apart from being time consuming the risk of breaking through the veneers is too high. The best method is to use a chemical paint remover however as the original coating is a flexible polyester and polyesters do not break down easily, go for a brand that has a reputation for being aggressive. If you plan on doing the entire wood set buy at least a 2.5 litre can.
Before you do anything make notes or take photographs showing the location and colour of the painted in areas on the ends of the waist rails etc. You should also try and obtain at this stage a small amount of brown cellulose paint matched to the instrument apertures.
Paint removers contain some pretty nasty chemicals so work in a well ventilated area and at the very least wear rubber gloves and use eye protection. Don't work in direct sunlight though as the stripper will dry out too quickly. To limit the amount of clearing up later lay down several thicknesses of a good quality paper, sufficient to do at least several pieces at a time. Tape up any joins and fold up the edges and corners to limit the flow of the paint remover. Upon completion the paper can be rolled up and placed in plastic bags.
Pour the paint remover over the pieces and leave it to react. Unless the wood has been refinished using a non-polyester material nothing will happen very quickly so don't expect instant results. It helps to keep the pieces wetted either by tipping on more paint remover or by scooping the excess off the paper and putting it back on the wood but don't scrape or otherwise disturb the coating. Eventually the polyester will fragment and take on, for want of a better description, a sugary appearance. At this stage scrape the coating away with a soft scraper, the spreaders used for polyester body fillers are ideal. Ideally the coating will lift away easily and the paint remover will not even have penetrated through to the veneer. Too soon and either the coating will remain intact or only small areas will lift away and then with some effort. If this is the case just pour on more paint remover and wait.
When the coating has been removed wash the pieces down with cellulose paint thinner to remove all traces of the paint remover. Any small fragments of lacquer can be picked off easily. Do this several times and do not be afraid to really wet the surface then leave everything to dry out.
As an alternative you can use a hot air gun and a scraper but be warned that fragments of polyester will fly off and eye protection is essential. There is also a very significant risk of scorching the surface with the resultant discolouration. In many thousands of pieces I have never encountered a problem using paint removers so I suggest sticking with this method. Try this with any Jaguar or Aston Martin wood trim from the same period however and the veneers will lift off, assuming this has not already happened.
At this stage the surface will be rough, slightly shiny and fairly dark in colour. After picking off any small fragments with a small craft knife begin sanding the surface. I wouldn’t bother using glass paper as a conventional woodworker might but suggest instead using 3M fre-cut, or similar, abrasive paper, which you can buy from any supplier of vehicle, paints. European and American grading systems differ slightly and as I have no idea what system is used in Australia it would be a good idea to cross-reference the European grades I will quote. While you are at the paint supplier buy some spirit wipe, sometimes called pre cleaner. Painters use this to wipe down prior to spraying to remove any residual contaminants from fingerprints etc. A litre will be sufficient.
When sanding it is essential to use a hard backing for the paper. If the backing has any give it will apply greater pressure on the edges and will have a tendency to wear through the veneer but even if this extreme is not reached any unevenness created will still have to levelled out by the clear coat later. I suggest starting with P120 used very lightly just to skim over the surface and break the slight glaze it will have at this stage before switching to P180. Make sure the paper is kept tightly against the backing. The paper will clog initially so wire brush it frequently or change to a new piece. Electrically operated orbital sanders can be used but care must be taken to avoid damage to edges as they are usually supplied with a soft sponge backing. When working around the instrument openings use a piece of 1” dowel or similar to back up the paper. Be very careful when working on the edges of the cross banding on the waist rails and companion sets, this will already have been well sanded during production. There are techniques to repair it but the best solution is not to cause any damage in the first place. After blowing off any dust you will find the surface is smooth to the touch and free of any scratch marks. Final finishing with P240 will improve the finish still further. Ideally using a compressor and blowgun, remove all traces of dust.
To assess the colour of the finished veneer apply the spirit wipe to its surface using a pad. Water will achieve the same thing but will raise the grain necessitating further sanding. Spirit wipe dries out fairly quickly but you will have quite a few seconds to judge whether the colour is acceptable. Rolls-Royce generally used stains or paints to darken the appearance but the natural colour is often quite acceptable for the veneered areas. The top of the waist rails however will be solid mahogany on your car and this will appear very light after lacquering so you will probably feel the need to darken these, often quite considerably, as did the factory. Staining and painting is done in stages with individual areas being masked off one at a time to avoid affecting adjacent areas. The instrument openings and end sections are painted in using a brush, ideally an airbrush, using cellulose paint over the bare wood. Spirit wiping will also highlight any defects such as areas filled during the original production. These too need painting in and once again an airbrush is the best way to do this. As a book match is used if any area is painted in on one leaf of veneer every other leaf should be similarly touched in. This would mean eight touch in’s across the early Spirit and Shadow dash or for a set or waist rails or a pair of picnic tables. After the touch in has dried re apply the spirit wipe and assess how good it looks. If you are not happy wash it off with thinner or lightly sand it before repeating the process. If you find areas that need filling, as is frequently the case, use a two part wood filler, which a specialist timber merchant should be able to supply in various colours. Mix it according to the directions, fill the defects and then sand them smooth. Finally paint them in.
Burr walnut naturally contains black so I would suggest using black to paint in any and all defects. Black will look 100% convincing if applied correctly and very little practice is actually required for small areas. Other veneers however do not have this advantage and some, like birds eye maple, are almost impossible to make convincing repairs over.
The ideal finish is flexible polyester for a variety of reasons but this is not really an option unless you can find a company to apply it for you. This gives the required thickness in one operation instead of requiring time spent building layers. Polyesters are used for finishing musical instruments like pianos and guitars and frequently used for decorative features in luxury yachts. You may get lucky finding such a specialist. There are a few excellent non-sand varieties that can give a very good finish almost to the standard of the original. The very finest finish however is only obtained using the varieties designed to be sanded and polished.
Polyurethane lacquer will give good results but it will take many coats and several sanding operations to build the required thickness to fill the grain and provide a flat surface for polishing, it can be brushed or sprayed. Avoid fact drying cellulose or acrylic lacquers as these will crack very quickly as they lack the necessary flexibility. They will also soften all the areas painted in which may streak if you brush over them. Two pack clear coats, particularly high solids varieties, used for painting cars are probably the next best alternative to polyester but there are very real health implications involved when spraying them. Any car paint shop can apply the lacquer for you and they may be willing to do this for a reasonable cost as they can easily combine small pieces with other work requiring clear coat spraying. Although they will probably not have any experience of wood finishing just tell them to apply three sets of coating with a light rub down with scotchbrite in between. You will then need to wet sand, using P600 or P800 wet or dry paper and a hard rubber block to level the surface. Take your time and wipe and dry the surface frequently to assess the progress. Polyester builds very well and rubbing through is never a problem but it is a very real danger with any other coating so take special care on edges. Now take the wood back to the paint shop and get them to apply another couple of sets of clear. You will then need to wet sand with P800 wet or dry paper to remove any “gun texture” and any residual sinkage into the grain. Follow up with P1200 and then polish using a suitable compound. Polyurethane requires longer drying times, more coats and more sanding operations. Whatever material you use seal the back with a couple of coats. Although the factory never did this it does give a number of advantages.
The final task is to refit the hardware and this can take some time, a lot of care and a good craft knife. Masking certain areas prior to lacquering helps but to lift the masking tape you will still have to cut through the lacquer.
Although time consuming you will find this task extremely rewarding and the results will last for many years. I wish you every success. |
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