Wednesday, 12 June 2013

counter veneering

These are the internal sides of the sides of the cabinet. This is the substrate glue face that the figured maple veneer would be going over. Now these dark brown sections will show up under the veneer if I veneer over them due to the figured maple being a little bit transparent.

What I'm going to need to do is counter veneer it. I will be placing a 2mm figured maple veneer over it so no dark sections will show up under the veneer.

Before placing the counter veneer over it I need to sand down the substrate panel. at the moment the panel is 20.4mm. It is this thickness because when the last veneer face is added it will bring the thickness to 21mm which is the final thickness. What I need to do is bring the panel down to 18.40mm.

I tried using my drum sander in my work shop but it wasn't big enough. The panel is 586mm wide. The actual drum and sanding belt is about 2mm below this. Although some of the belt doesn't get used due to the gear box from the tracking conveyor belt being in the way.

I can taper the actual drum and make two passes but I tend not to like doing this since its a lot of stuffing around both in set up and un set up. It might be worth while sanding it at work since the wide belt sander is a lot wider and will easily be able to do this. Also the wide belt at work is a lot stronger than this drum sander and will require less passes through it.

Drum sander in work shop.

Drum not wide enough to sand the panel. Could taper he drum alignment but this requires a bit of stuffing around. Not really worth it when its a quick job. Doing it a work will be a lot faster. For bigger jobs I tend to like using the wide belt at work.

I the mean time thought it would be good to do some of the machining for the counter veneer. I would also be cutting some maple to make counter veneers for the Ikebana base (inside face) and the top drawer base (inside face) as well since these panels do have some black sections as well. The black sections on these panels are not as bad as the sides but they will be having the 4 way veneer matching on them and I don't want to stuff this up. The internal section is going to have the most light displayed on it so its important to try to cover up these black sections as best as I can so they don't show up under the veneer.

It's quite cumbersome cutting large stock on my multi combination machine due to the size of my work shop and lack of support it has on the sliding bench saw. I decided to cut a large section than cut it in half. These sections would be for the counter veneer for the ikebana base and top drawer base.

I over sized everything so it could be cut down. When cutting stock you tend to loose a bit due to checks at the ends.

Running the maple over the jointer. I got the jointer set pretty good. There is really only about a .1-.2 difference between the 4 corners of the work pieces.

I choose the faces to run over the jointer that had the least amount of rock. I find that these push pads work very well. You get complete control and are able to place even pressure over the piece when running it over the jointer.

My jointer blades are only 260mm wide. These two smaller stock pieces were about 250mm in width so I could run them over the blades quite easily.

I ran the stock through the thicknesser after this. I did not have a specific set size for this I just wanted to try and keep them as thick as possible. So I just cleaned the faces and removed all rough saw sections.

I could only run these pieces through the thicknesser at .5mm passes. This is due to my blades getting a bit blunt but also its only a single phase motor so its not that powerful plus im using pretty much the whole length of the blade which will put a lot of strain on it.

Since there will be a bit of material left over from the counter veneer for the ikebana panel and the top drawer panel. I can use the 2mm off cut sections for the inlay work.

I had though about using probably a cheaper alternative for a counter veneer like an ash or pine. I decided to steer away from pine due to its dark knots it has plus it shifts more than maple. Ash could have been another alternative but than finding some stuff that is totally white in colour and has no gum vein was another thing that I had to think about.

The maple was here to use and thought this would be a good alternative since the veneer I'm using is maple. Pine also tends to have some dark spots in it and heavy darky cream grain patterns. Even though it is most unlikely it would show up under the maple veneer did not want to take any chances.

I didn't have time to do tests hence why I also went with the maple. I'm not using that much for the counter veneering any way. If I was planning on counter veneering everything than I would be looking for a different alternative that is slightly cheaper and would be doing tests.

I'm quite happy with the maple its a very whitish cream and has no dark spots or dark grain patterns at all. This will make a perfect mask to block off the dark sections from the plywood substrate.

Measured the corners of the stock with the calipers. Each corner was varying in .1-.2mm so the set up was pretty good. The stock pieces finished around the 27mm mark. I wont be using all the maple from these small stock sections for the counter veneer. Any material left over I will use for the lamination edging panels with the wenge if it is thick enough.

I did the same processes for the counter veneer stock for the sides. The only thing I had to do differently was to rip down one of the boards since it was 280mm wide which would not fit over my jointer blades. It was ok to loose this amount as the board I was cutting had a really bad edge and required me to remove this off.

These boards finished at about the 27mm mark as well. Again any material left over I will use for the lamination edging panels with the wenge.

Depending on the neck height from the band saw at tafe I may need to rip these boards in half. I still need to square the edges of the boards on the jointer as well. I did not do it on my jointer since I am not happy with my jointer fence. The bad thing about the multi combination machine is that the fence is shared with everything. I have tried to get it 100 percent square but still have issues with it. I figured it would be better to just wait and use the jointer at tafe.

 It may be quicker and less strain on the blade if I do rip the boards in half than rip down into the counter veneer strips. Even though I'm going to have to do more passes I will probably get a better finish. The counter veneer strips will have to be ripped out 3-3.5mm than sent through the jointer for further clean up. The counter veneer strips need to finish at 2mm.

There could be a chance that sections might chip out. So the chip out face I will lay down on the substrate glue face. What I will do since the thicknesser at tafe is a digital one I will be taking off .3-.5mm in each pass to limit break out. Normally you would use a wide belt sand or a drum sander but I don't have any of them at tafe. I can not afford to take it back to my work shop and use my drum sander there as I would like to try and press the jobs up at tafe that day. If I'm getting too much break out and really need to sand it than I will do it at work or my own work shop and wait another day to press them.

I plan on getting a magnetic feather board set up for when ripping these counter veneer pieces. I mentioned in one of my earlier posts about a video on ripping your own veneers on the band saw. Although depending on the size of the stock that I'm ripping depending on whether its the full height for the board or its ripped in half height I may just make up a really thick feather board block, pretty much like the one in the video.

This is the website I was talking about. It's from the wood whisper pod cast. The other post that has these videos in them is from the video research post section. 

While cutting material for counter veneers I decided to go over my other sections that required me to lay down the figured maple veneer. I noticed on the backs of the front door flaps were these ugly bow tie ply pieces added, which im not quite sure why they added them in. At the time I was not fust by it since the veneer could cover it. Although I'm having second thoughts about them.

The section on the edge should not mater much since most of it will be cut out. Its more the one below that I'm worried about. It should be ok since these sections don't show off really dark sections like the other panels which I know defiantly show up under the figured maple veneer. I might take a gamble with this and push on with it. I will veneer the top section one first before doing the bottom one to see what its going to be like. I will also note where they are to avoid extra sanding there if I can.

If it does show up under it which I don't think it will since it is pretty light in colour and not dark I will have to veneer over it.

This bow tie section that was on two pieces of one of the front door flaps. The other door flap was totally fine.

I decided to check the back doors as well. This was the only section that concerned me this black vein bit in the plywood. I think this maybe k. I will need to mark this section out to make sure not to sand that much near it. The other back door was totally fine.

Needed to sand down the top drawer panel as well through the wide belt at work. This panel needed to finish at 16mm when all veneers have been added. At the moment the panel only had one veneer face on it and the panel measured at 15.4mm. What I need to do is sand the panel down to 13.4mm. These panels will have the 2mm counter veneer as well as the sides. I only have the top drawer base panel the Ikebana base panel is still in the veneer press at tafe.

Needed to sand down the inside substrate faces for the sides of the cabinet. The panels were measuring at 21mm. I measured all four corners of the panel with the calipers. I needed to get the panel down to 18.4mm. The sander says 18mm because it is out by about .4mm.

Each pass was taking of .5mm.

As for the top drawer panel I needed to take that down to 13.4mm. The panel was measuring at 15mm. This panel I also measured at all four corners.

Finished the panel at 13.4mm. Again sander being out a bit so had to go past 13.4mm on the digital gauge.

To make sure that the parts went through the sander smoothly I needed to use a push stick. If the part got stuck in the sander it would cause ripple marks. I had to use a different push stick to the sides since the standard push stick we use was too thick. 

Making counter veneer laminates 

Double checked everything to make sure that the panels were measuring up right.

I dressed up the maple in my work shop about a half a weekago and it has already shifted. The boards have bowed a bit. Before slicing the timber boards into thin laminates I had to dress one face again to make sure it was totally flat and square. I also squared up the edges as well.

This is the set up on the band saw. I clamped the jig to the 'T' fence on the band saw.

The pivit point on the jig allows you to realign the cut and keep on track. I marked out my cut lines with a marking guage than filled the line in with lead from a pencil to make it more visible. Using a marking gauge will allow you to have a starting point to reference from that is always right.

The line from the end face was 4mm. The counter veneer laminates need to finish at 2mm. I have given my self this much to play with as most of the time the whole laminate that your cutting wont be exactly 4mm. The wider the timber board is the hard it is to keep the laminate straight.

It so important to try and get the first cut of the job good. You really need to get the first 80mm right if it isn't you will start to go off track and by the time you get to the end the laminate will have tapered.

Its very important to try and get the board flush on the top of the pivot point and the bottom when making the cut. If it starts to move away from the pivot point section from the bottom you will find that the bottom of the board will not be cutting at the 4mm width mark even though the top shows it is.  Hence tapering.

The wider the board the hard it is to make a totally straight cut. Plus since the neck is opened up heaps it exposes more of the blade which causes it to move more. Usually older band saws that have had a lot of use you will tend to find it harder to get a totally straight laminate cut. This is another reason also to make sure that your wheel tension for the blades is correct as well. Make sure to have a very sharp blade. Wider and thicker bandsaw blades are better for this since they are designed to cut larger timber that mainly requires a straight cut.

Only have the band saw extended to just about 5mm above the job your cutting. This will prevent less flex in the blade but also is a safety factor. When a band saw blade snaps it comes out the side like a whip. Plus when finishing the end cut on the laminates use a push stick keeping your hands totally away from the job.

There is another set up you can do when cutting the laminates on the band saw. This tends to require building a large fence that connects to the 'T' fence and having a large feather board to prevent kick back and help you to keep the blade cutting true to the cut line. ( this is the set up shown in the video)

Beginning of cut laminates for the counter veneering. Most of them were cutting pretty straight. It is quite difficult to cut the laminates and keep them totally straight without the chance of the laminate tapering in the cutting process.

I measured the four corners of the laminates most of them were about .3-.5mm out in difference. There were some really bad ones but they still managed to stay above the 2mm mark. As long as the laminates stayed above the 2mm mark I wasn't that fust.

When running through the band saw its just best to go through it slowly without any force and let the band saw do the work. You want to try to keep the cut straight and prevent it from moving away from the reference line.

The laminates were buckling as soon as I cut them. This is due because of a couple of reasons. 1. The planks seem to look like they are more from the crown of the tree which is really prone to movement. 2. The planks are back saw which is a lot more prone to movement compared to quarter cut. 3. the thinner the laminate the more it will shift again this also depends on the type of wood.

Each new pass that I did on the band saw to make another laminate I had to dress the board on the jointer to get a new straight square reference point for the pivot bar to rest on from the rip jig on the band saw. Plus I needed 1 clean face so I could use this as a reference when running through the thicknesser.

Next time I dress maple on the jointer at tafe I may bring my pressure pads that I use in my work shop. I don't really like how you have to let go of the piece when moving over the guard you seem to loose pressure on the board when running over the blades. I will still be using the guard just will be using the pressure pads instead of my hands. I found when dressing really wide stock on this jointer there can be some movement with the board. The pressure pads prevent this movement and give you more control.

The laminates cleaned up pretty well when running them through the thicknesser. When running thinner parts using a melamine sled works better as it helps to move the pieces through easier. The sled measures 16.1mm so what ever your machining you need to add that to your stock thickness as well.

I also found if you angle the laminates slightly you get a better finish. I dropped the speed also of the thicknesser and only took off .4mm each pass to prevent blow out. There was some blow out in some sections but this was also due to grain directions that were going in different directions and also the blades were blunt and needed to be changed.

I left the laminates at 2.3mm. The last .3mm I would run through my drum sander on the best face. It will not mater if there is blow out on the glue face since you will not see it. If there is blow out on both faces than I will have to use a very blond bog. Using a blond bog will prevent it being seen from under the veneer. I need to cover up these sections since they can sink the veneer when being having veneer pressed to it.

Sanding Ikebana panels. 

I needed to sand down the ikebana panel like the top drawer panel because of the counter veneering. The panel needed to finish at 13.4mm.

Measured all four corners to make sure it measured to 13.4mm I was out a bit by .1-.2mm but this didn't bother me.

Began placing out the counter veneer pieces for the Ikebana and top drawer bases. To create more structural balance I wanted the end grains to alternate. Although this depended on what was the best surface. Hard rock maple tends to chip out a bit due to its alternating grains. There were some chip out sections on the faces of the maple counter veneer pieces. The worst sections I needed to make sure that they were located in the off cut areas or on the back that would be glued down. I had only about .3mm to clean off.

Once taken out of the press to clean the .3mm I would be running it through the wide belt sander at my work.

Before cleaning the edges on the jointer. I marked out the joints of the counter veneer panel with a triangle and number the pieces with chalk.

Since the counter veneer pieces were cupping I needed to secure them in a binding press jig. Even though this would bend and create a curve due to the thickness of the pieces the jig it still would be ran up against the fence. You would be running this over the jointer in the same way if you were wanting to square a edge of a curved door.

Edges clean. There were some chip out sections due to the alternating grain but I was not too fust due to it being covered over by veneer.

Transferring the panel shape to the counter veneer panel pieces.

Cutting off the off cut sections on the band saw.

Pieces are cut out and ready to be connected together. The off cut pieces I would still be using. I would be using these for the inlay sections on the wenge.

Both the glue faces on the substrate and counter veneer pieces needed to b scored and very lightly sanded.

Connected the pieces together with blue painters tape.

I wanted to press both the Ikebana panel and the top drawer panel up in one go. I did not have a middle caul so I had to cut one out of some scrap. I found an MDF board that I could use but it had a lot of dry glue on it. This needed to be removed so it would not damage the faces of the counter veneer.

I used the panel sander to clean the faces. It was a good exercise to use this since I had not used this before.

When using this its important to keep the pressure of the pad on the sander belt even when running across the panel. You want to keep moving the pressure bar to its not focusing on one place. Focusing on one place for too long will cause hallow points.

Also so your not having to stretch over the whole board its best to start in the middle and work your way down. When you have sanded the bottom section flip the panel over and sand the other side.

Transfered one of the caul shapes to the MDF panel than cut it out on the band saw. I just sanded to the edges after this so they were not sharp.

Needed to coat the press face of the caul with baking paper. This is so the panel would not stick to the panel due to the rising glue.

Before applying the glue sprayed down the surface with water to kick start the curing process. Spreaded out the polyurethane with a painters scraper.

With thicker veneers its best to also put glue down the veneer joint.

Taped the edges of the counter veneer down to the substrate.

Placed both panels in between the cauls and placed in the press. This needed to be left for over 4 hours.

Laying out the counter veneer pieces for the sides. I alternated the end grains to make the counter veneer sections more structurally stable. Marked joint sections with triangle than numbered.

Had to cut some of the counter veneer pieces down to suit the size of the sides

I had to dress some more stock to make pressure cauls to hold the counter veneer pieces in. The counter veneers pieces were kind of flimsy and having them in between the cauls made it easier to clean the joint edges.

Running the counter veneer over the jointer to clean the joint edges.

Scoring the substrate glue faces of the sides and the glue faces of the counter veneer.

Taped the counter veneer pieces together with blue painters tape. The joints were not 100 percent perfect but I wasn't bothered but this heaps since they will be covered over with the figured maple veneer. It's those joint lines that needed to be totally clean.

Spreading out the polyurethane glue to the substrate glue faces.

Knocked brads in near joint lines in offset section areas. Taped counter veneer down to substrate to prevent slipping.

Pressed up job in press between clamp cauls and will need to be left for 4 hours plus.

Removing painters tape from the counter veneer sections on the sides and the Ikebana base and top drawer base panel. I was told using a hot iron loosens off the tape from the counter veneer a lot quicker. I just heated the painters tape than scraped off with the card scraper.

I first knocked the brads in with a nail punch to prevent the nails from damaging the sander belts. I sanded off .3mm from the substrate panels on the counter veneer faces. I needed to have these totally clean and level before laying down the figured maple veneer.

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