13-02-2013, 12:41 PM
Hi,
Whilst waiting for the linseed oil to dry I thought I'd add a few notes on how I achieved the new moulding profile around the two openings to the front panel.
Had the panel been solid then veneering would have been greatly simplified allowing the quartered Burr Walnut veneers to be laid in perfect alignment whilst allowing the joints to be cut as they were laid. However in this instance with two openings already in the panel and the edges being merely rounded over created a great deal of extra work and frustration.
The centre of the quartered pattern fell within one of the openings so preventing perfect matching of grain and preventing the cutting of joints this was made much worse by the curved section between front and top panels. In all it proved to be a nightmare of a job.
Taking the above into account add the problem of this Burr veneer expanding a great deal due to the wetting and hot ironing whilst attempting to render it flat.
Templates were made and used to initially cut the four veneers but with plenty of allowance this being a generous 1/4" all around. Due to the veneers expanding the outer edges were not a great problem as excess could be trimmed away but had not the extra been allowed around the opening then suddenly the veneer shrank in this area; it gained on the outside but shrank on the inside forcing a new joint to be cut vertically in order to bring the veneer to cover the panel. It was a real problem and unfortunately due to my inexperience not anticipated; it was a low point for me whilst trying to re-adjust the veneer without completely losing the pattern alignment. Cutting a joint on a flat section is very easy but boy it was difficult around the curve ending up with a gap which would require filling and colouring in later but by now I was trying to salvage this job which was going so badly.
With the veneers finally laid there was a lot of waste veneer overhanging the edges of the openings and again it proved difficult dealing with these; trying to cut wet veneer whilst it is hanging in space in an opening isn't my idea of fun and I removed as much as I dare because I was worried about disturbing the glue bond?
As previously stated more trouble followed when the veneer dried out as it badly buckled and curled tearing a section. This was successfully re-glued but again it was a very low point for me with my confidence taking a battering.
That's most of the bad news now here is how I went about trimming the veneer around the openings once it had dried. Oh yes this looks so easy; just run around with the craft knife and job done? Well not exactly; the edge of the panel fell away under the veneer due to the rounded moulding and the problem was now compounded by hard hide glue which could not be removed whilst it remained wet because of lack of access. The dried veneer was extremely brittle and trying to cut it with the craft knife was only partially successful; as the knife broke through in places the veneer closed and grabbed the blade with a high risk of damaging the veneer at the glue bond so little by little the bulk of the excess veneer was cut away but the moulding was still buried.
At this point I decided to try using the router and installed a straight cutting bearing guided cutter. The depth of cutter was very carefully adjusted to allow the bearing to run around the bottom edges of the opening without the cutter removing any material from the moulding. Taking a deep breath the cut was engaged and wonderful; it worked; taking a slow cut the veneer was reduced to the size of the opening on the inside of the panel leaving about 1/4" veneer still to remove but now with the excess glue?
The two cutters used.
Having a couple of rounding over cutters with bearings I selected the cutter which had the same profile as the moulding; I had to trim veneer away to expose the moulding in order to select the correct cutter. This cutter was then installed in the router.
I had already anticipated some problems at this stage in trimming the veneer and it was a bit of a gamble but I took the opportunity to cut two router bearing guides out of 18mm thick MDF before starting veneering as the MDF could be offered up and a pencil run around the openings. These two guides were cut out using the big Startrite band-saw just in case they would prove useful.
Using double sided self adhesive tape both router guides were attached inside the cabinet taking care to align as accurately as possible. With the cabinet clamped to the bench the profiled router cutter was adjusted to just skim the edge of the veneer; better on the safe side rather than to be sorry. The router was carefully run around with the bearing engaging the MDF guide and all was well. Rather than be silly and try to remove the excess veneer and glue in one pass I decided to remove it in increments. The engineers steel rule was thick enough to use as a gauge so using the rule the router turret stop was adjusted just nipping the rule then the rule was removed and the router plunged onto the turret stop dropping the cut each time. This worked a treat and what had been such an headache of a job suddenly turned out to be easy much to my relief.
The original moulding profile was simply rounded over (quadrant) including the veneer but this didn't give a true cut off between veneer and moulding and as I want to make a good job of applying paint to the moulding I decided to drop the router cutter just enough to remove the thickness of the new veneer; this isn't a deep cut but it gives a nice shadow line and a clean edge.
Hopefully the drawings will explain the difficulties better; the first drawing shows the original veneer simply being rounded over. The second drawing shows the new veneer overhanging obscuring the view of the moulding as viewed from the outer side of the panel. The third drawing shows the new veneer trimmed but now with a shoulder. The fourth drawing shows how the new moulding profile was eventually achieved.
New moulding profile.
I believed when I started this project the veneering would be the hardest part especially trying to apply Burr Walnut around the curve using the hammer method; I was to be proved wrong because it was both openings and the mouldings which caused me so much grief; I might sound to be exaggerating the problems encountered but believe me they were very real and hopefully by adding this information it will prevent others from falling into the same traps I found myself in.
I learnt a great deal about veneering from this project and although the job has been so highly frustrating it is the problems I learnt from and now I have a number of very useful solutions; not only can I now apply Burr Walnut around a curve I can retrieve the job when it goes horribly wrong. With my new found knowledge I can also prevent many of the problems encountered arising in the first place. Should I ever do a similar project I will do a lot differently.
A larger preparation area would be arranged on the bench allowing veneers to be arranged as they would be laid. The paper templates would be replaced by clear flexible Perspex or acrylic and a lot of care would be taken to ensure these were perfectly to size. The cabinet would be tested with a true straightedge to determine if there was any bowing to the panels to be veneered because a slight bow in the top panel would throw the joint completely out; in such a case it would be possible to align the joint perfectly on top of the cabinet but as soon as the veneer was formed around the curve the bottom section of the joint would be sure to open up leaving an unsightly gap. If the top was bowed then this would need taking into account whilst making the templates.
Taking this cabinet as an example where quartered veneer was to be applied; the veneers would be completely wetted then hot ironed and only now would they be cut to finished size using the new templates as a cutting guide. Whilst still on the bench the pattern of the veneers could be arranged and seen through the clear Perspex and the joints very carefully cut knowing that each veneer would in fact fit perfectly then in turn each would be laid using the hammer and iron etc.
David mentioned veneer shrinking in a previous post and this is a fact; wetted veneer expands a great deal hence when veneer dries it shrinks. To try to offset this shrinkage preventing joints opening up gummed paper veneer tape is quickly applied over all joints; correct veneer tape actually shrinks as it dries thus pulling the joint together. A number of other options are also available to ensure tight joints; some use fine panel pins to mechanically secure the joint during drying whilst others lay the first veneer normally but very slightly over-lap the abutting veneer; this second veneer is then laid from the outside towards the joint then the loose end is carefully lifted and tucked in to abut the first veneer causing pressure on the joint. I'm pleased David raised this matter because it is very important to take into account veneer movement during wetting and drying. I must add that I'm only considering hammer veneering using hot hide glue here; other methods and types of glue used behave differently.
I'm still on a steep learning curve and any suggestions or observations are always most welcome even the ones expressing caution or to possibly explain there is a better method or technique I could have used to my benefit in order to make the job easier or to save time. As with a number of forum members I exchange many emails in the background and in these emails we also exchange ideas and information. In a recent email Gary and I were discussing my intention of adding the inlay fan motif to the top of the cabinet which I intended to do right from the start because after all I was only using this cabinet as an exercise in order to gain more experience of veneering and to learn new techniques. I was pleased when Gary echoed my thoughts regarding adding the fan motif having now brought the cabinet to this late stage; we both are in full agreement that such a motif could be classed as well over the top? The motif would fall right in the centre of fanciest part of the veneer and rather than add to the beauty of the job it could possibly do the reverse and spoil the job; thanks for being so open Gary I really do appreciate your input so the fan motif will not be added. I'll still have a go at making one of these fan motifs and perhaps other pattern motifs as I feel they will be a very interesting challenge for me and of use for future projects. Another interesting point Gary mentioned concerned how such a motif would be added because after all the cabinet is now fully veneered and wouldn't such motifs be included during lay up as in marquetry?
To answer this valid question Gary it is possible to "let in" virtually any pattern by firstly making or buying the inlay then using this as a template to very carefully cut around before removing the veneer patch where the inlay will be bedded. This is very tricky for someone like me to achieve with no prior experience because a slip with the cutting knife would leave a cut that would show once the item was fully finished; I'm silly enough to have a go at doing such a job but in my favour I possess lots of patience and determination. In order to remove the unwanted patch; the outline would be cut to full veneer depth then a "scratch stock" could be used to manually route out the waste alternatively a router could be used either freehand or with a guide bush to run inside a suitable template. To install the new motif the area must be cleaned then glue added to the panel and never to the underside of the motif; the motif is then very quickly pressed home and excess glue immediately removed it is beneficial to apply pressure either by adding weight or clamping but a piece of non stick material must be placed between motif and whatever is used to apply pressure otherwise the job will be ruined. Here's a long but interesting video showing basic techniques.
http://www.youtube.com/watch?feature=endscreen&v=U3Q58SKDAEA&NR=1
I'm trying to add a much information as I possibly can and it's possible to miss some important point so thanks to Gary I've now included more useful information. I'll add details of my progress once I begin making a fan motif which I'm looking forward to. Thanks everyone for your support and encouragement which helps to drive me on to better and more difficult projects. At times I despair and could scream but then again what fun I'm having.
Kind regards, Col.
Whilst waiting for the linseed oil to dry I thought I'd add a few notes on how I achieved the new moulding profile around the two openings to the front panel.
Had the panel been solid then veneering would have been greatly simplified allowing the quartered Burr Walnut veneers to be laid in perfect alignment whilst allowing the joints to be cut as they were laid. However in this instance with two openings already in the panel and the edges being merely rounded over created a great deal of extra work and frustration.
The centre of the quartered pattern fell within one of the openings so preventing perfect matching of grain and preventing the cutting of joints this was made much worse by the curved section between front and top panels. In all it proved to be a nightmare of a job.
Taking the above into account add the problem of this Burr veneer expanding a great deal due to the wetting and hot ironing whilst attempting to render it flat.
Templates were made and used to initially cut the four veneers but with plenty of allowance this being a generous 1/4" all around. Due to the veneers expanding the outer edges were not a great problem as excess could be trimmed away but had not the extra been allowed around the opening then suddenly the veneer shrank in this area; it gained on the outside but shrank on the inside forcing a new joint to be cut vertically in order to bring the veneer to cover the panel. It was a real problem and unfortunately due to my inexperience not anticipated; it was a low point for me whilst trying to re-adjust the veneer without completely losing the pattern alignment. Cutting a joint on a flat section is very easy but boy it was difficult around the curve ending up with a gap which would require filling and colouring in later but by now I was trying to salvage this job which was going so badly.
With the veneers finally laid there was a lot of waste veneer overhanging the edges of the openings and again it proved difficult dealing with these; trying to cut wet veneer whilst it is hanging in space in an opening isn't my idea of fun and I removed as much as I dare because I was worried about disturbing the glue bond?
As previously stated more trouble followed when the veneer dried out as it badly buckled and curled tearing a section. This was successfully re-glued but again it was a very low point for me with my confidence taking a battering.
That's most of the bad news now here is how I went about trimming the veneer around the openings once it had dried. Oh yes this looks so easy; just run around with the craft knife and job done? Well not exactly; the edge of the panel fell away under the veneer due to the rounded moulding and the problem was now compounded by hard hide glue which could not be removed whilst it remained wet because of lack of access. The dried veneer was extremely brittle and trying to cut it with the craft knife was only partially successful; as the knife broke through in places the veneer closed and grabbed the blade with a high risk of damaging the veneer at the glue bond so little by little the bulk of the excess veneer was cut away but the moulding was still buried.
At this point I decided to try using the router and installed a straight cutting bearing guided cutter. The depth of cutter was very carefully adjusted to allow the bearing to run around the bottom edges of the opening without the cutter removing any material from the moulding. Taking a deep breath the cut was engaged and wonderful; it worked; taking a slow cut the veneer was reduced to the size of the opening on the inside of the panel leaving about 1/4" veneer still to remove but now with the excess glue?
The two cutters used.
Having a couple of rounding over cutters with bearings I selected the cutter which had the same profile as the moulding; I had to trim veneer away to expose the moulding in order to select the correct cutter. This cutter was then installed in the router.
I had already anticipated some problems at this stage in trimming the veneer and it was a bit of a gamble but I took the opportunity to cut two router bearing guides out of 18mm thick MDF before starting veneering as the MDF could be offered up and a pencil run around the openings. These two guides were cut out using the big Startrite band-saw just in case they would prove useful.
Using double sided self adhesive tape both router guides were attached inside the cabinet taking care to align as accurately as possible. With the cabinet clamped to the bench the profiled router cutter was adjusted to just skim the edge of the veneer; better on the safe side rather than to be sorry. The router was carefully run around with the bearing engaging the MDF guide and all was well. Rather than be silly and try to remove the excess veneer and glue in one pass I decided to remove it in increments. The engineers steel rule was thick enough to use as a gauge so using the rule the router turret stop was adjusted just nipping the rule then the rule was removed and the router plunged onto the turret stop dropping the cut each time. This worked a treat and what had been such an headache of a job suddenly turned out to be easy much to my relief.
The original moulding profile was simply rounded over (quadrant) including the veneer but this didn't give a true cut off between veneer and moulding and as I want to make a good job of applying paint to the moulding I decided to drop the router cutter just enough to remove the thickness of the new veneer; this isn't a deep cut but it gives a nice shadow line and a clean edge.
Hopefully the drawings will explain the difficulties better; the first drawing shows the original veneer simply being rounded over. The second drawing shows the new veneer overhanging obscuring the view of the moulding as viewed from the outer side of the panel. The third drawing shows the new veneer trimmed but now with a shoulder. The fourth drawing shows how the new moulding profile was eventually achieved.
New moulding profile.
I believed when I started this project the veneering would be the hardest part especially trying to apply Burr Walnut around the curve using the hammer method; I was to be proved wrong because it was both openings and the mouldings which caused me so much grief; I might sound to be exaggerating the problems encountered but believe me they were very real and hopefully by adding this information it will prevent others from falling into the same traps I found myself in.
I learnt a great deal about veneering from this project and although the job has been so highly frustrating it is the problems I learnt from and now I have a number of very useful solutions; not only can I now apply Burr Walnut around a curve I can retrieve the job when it goes horribly wrong. With my new found knowledge I can also prevent many of the problems encountered arising in the first place. Should I ever do a similar project I will do a lot differently.
A larger preparation area would be arranged on the bench allowing veneers to be arranged as they would be laid. The paper templates would be replaced by clear flexible Perspex or acrylic and a lot of care would be taken to ensure these were perfectly to size. The cabinet would be tested with a true straightedge to determine if there was any bowing to the panels to be veneered because a slight bow in the top panel would throw the joint completely out; in such a case it would be possible to align the joint perfectly on top of the cabinet but as soon as the veneer was formed around the curve the bottom section of the joint would be sure to open up leaving an unsightly gap. If the top was bowed then this would need taking into account whilst making the templates.
Taking this cabinet as an example where quartered veneer was to be applied; the veneers would be completely wetted then hot ironed and only now would they be cut to finished size using the new templates as a cutting guide. Whilst still on the bench the pattern of the veneers could be arranged and seen through the clear Perspex and the joints very carefully cut knowing that each veneer would in fact fit perfectly then in turn each would be laid using the hammer and iron etc.
David mentioned veneer shrinking in a previous post and this is a fact; wetted veneer expands a great deal hence when veneer dries it shrinks. To try to offset this shrinkage preventing joints opening up gummed paper veneer tape is quickly applied over all joints; correct veneer tape actually shrinks as it dries thus pulling the joint together. A number of other options are also available to ensure tight joints; some use fine panel pins to mechanically secure the joint during drying whilst others lay the first veneer normally but very slightly over-lap the abutting veneer; this second veneer is then laid from the outside towards the joint then the loose end is carefully lifted and tucked in to abut the first veneer causing pressure on the joint. I'm pleased David raised this matter because it is very important to take into account veneer movement during wetting and drying. I must add that I'm only considering hammer veneering using hot hide glue here; other methods and types of glue used behave differently.
I'm still on a steep learning curve and any suggestions or observations are always most welcome even the ones expressing caution or to possibly explain there is a better method or technique I could have used to my benefit in order to make the job easier or to save time. As with a number of forum members I exchange many emails in the background and in these emails we also exchange ideas and information. In a recent email Gary and I were discussing my intention of adding the inlay fan motif to the top of the cabinet which I intended to do right from the start because after all I was only using this cabinet as an exercise in order to gain more experience of veneering and to learn new techniques. I was pleased when Gary echoed my thoughts regarding adding the fan motif having now brought the cabinet to this late stage; we both are in full agreement that such a motif could be classed as well over the top? The motif would fall right in the centre of fanciest part of the veneer and rather than add to the beauty of the job it could possibly do the reverse and spoil the job; thanks for being so open Gary I really do appreciate your input so the fan motif will not be added. I'll still have a go at making one of these fan motifs and perhaps other pattern motifs as I feel they will be a very interesting challenge for me and of use for future projects. Another interesting point Gary mentioned concerned how such a motif would be added because after all the cabinet is now fully veneered and wouldn't such motifs be included during lay up as in marquetry?
To answer this valid question Gary it is possible to "let in" virtually any pattern by firstly making or buying the inlay then using this as a template to very carefully cut around before removing the veneer patch where the inlay will be bedded. This is very tricky for someone like me to achieve with no prior experience because a slip with the cutting knife would leave a cut that would show once the item was fully finished; I'm silly enough to have a go at doing such a job but in my favour I possess lots of patience and determination. In order to remove the unwanted patch; the outline would be cut to full veneer depth then a "scratch stock" could be used to manually route out the waste alternatively a router could be used either freehand or with a guide bush to run inside a suitable template. To install the new motif the area must be cleaned then glue added to the panel and never to the underside of the motif; the motif is then very quickly pressed home and excess glue immediately removed it is beneficial to apply pressure either by adding weight or clamping but a piece of non stick material must be placed between motif and whatever is used to apply pressure otherwise the job will be ruined. Here's a long but interesting video showing basic techniques.
http://www.youtube.com/watch?feature=endscreen&v=U3Q58SKDAEA&NR=1
I'm trying to add a much information as I possibly can and it's possible to miss some important point so thanks to Gary I've now included more useful information. I'll add details of my progress once I begin making a fan motif which I'm looking forward to. Thanks everyone for your support and encouragement which helps to drive me on to better and more difficult projects. At times I despair and could scream but then again what fun I'm having.
Kind regards, Col.
Happiness is a wreck of a cabinet to restore.
