Saturday, 11 May 2013

Front Door Flap Fold Line Edging

Wasn't able to use the smaller offcuts to get the length of veneer edging that I wanted. So I had to cut off a 470mm length piece from one of the 2400mm veneer leafs.

The front door flap parts are 15mm in thickness. I cut the veneer strips into 20mm width pieces. I wanted a bit of over hang just encase the veneer slips when gluing. I just cut these strips with a pair of scissors.

There are a few changes that I will be making to the fold edge design. On the figured maple face side. There will be wenge edging added to the fold line. 8mm in depth. When the veneer is laid down a 7mm wide rebate trenching will be made on the inside fold edge line. The wenge edging will be glued here. I wanted to add this so when the doors are folded down it would complete the black edging shape.

This means that even though I am gluing an entire maple veneer strip across the fold line edge only 7mm of it in width will be seen. This will also blend in with the other orientation of edgings around the doors. The edgings on the doors ( if looking from side on) will consist of 8mm of wenge and 8mm of hard rock maple.

Top fold section ( which is really the bottom fold section of the front door) the top part of the fold line will be the 8mm wenge strip than the 8mm maple veneer edge. The bottom fold section ( which is really the top fold section of the front door) will be in reverse 8mm maple veneer strip than 8mm wenge timber strip.

Now that the veneer strips are cut I have to figure of a way of attaching them to the doors.

At first I was thinking of doing a clamping system like this but when clamping up with the sache clamps the clamping parts move along with the door section. 

Now I had thought of using masking tape or painters tape which would act as mini clamps. Now this would work for the timber edging since there is no flex in the material. For the veneer this would not work. Since there is over hang on each side of the door faces when placing a tape strip over it the over hang edges flex down putting pressure on the edges. This in turn makes the middle bulge up which doesn't create an effect clamp mechanism and would result in a poor glue joint. Also the strain of the masking tape on the veneer edges could cause cracking. 

To stop this I needed to screw timber strips to the top clamp board this would lock in place the bottom door section and prevent it from moving when being clamped up. You just need to make sure that you don't over tighten the sache clamps since it will put heaps of pressure on the timber strips where the diagonal edging is.

Now there are a few things to remember with this kind of clamp set up.To ensure that the top sache clamp does not damage the over hang section of the veneer strip in the fold line you need to add packers to raise the sache clamp up slightly so it doesn't sit on the veneer.

Also to ensure that the veneer strip over hangs on the other side you also need to add the same sort of packers for the bottom that create a gaping from the sache clamp edge and substrate face.

For this clamp job I would use polyurethane. Any gaps that are not closed the glue would expand and cover them up. This is not so much of an issue since the face veneers will cover the gaps up any way. To ensure that no glue gets on the faces I would place painters tape strips down so when the glue goes over it, it will be pulled off when the tape gets pulled off.

This clamp job would only work for the bottom flap section not the top. A different system would need to be created for this.

I did not really want to make a clamp jig for such a small job. So I decided on making a jig that could be used for another purpose in the final piece. Later on I needed to make a jig to drill the hinge holes. Since the door flaps were a weird shape If I build the shape on a square plate it would mean that I could use the straight edge of the plate to rest up against the horizontal borer fence.

This is not the best picture but what is shown here is the top flap section the jig framing around it that has clamp pockets built into them and the bottom plate.

After getting most of the drawing done for the jig I remembered in my veneer book about animal gluing where you don't need to use clamps/ presses you press on with heat and a veneer hammer. I thought this would be a good idea since due to the difficult shape it makes it hard to clamp up.

This jig drawing will be expanded on when coming up to boring the holes for the ZYSA hinges.

I needed to mask the veneer faces near the fold line to ensure that no glue would get on them.
I don't have a veneer hammer but thought about using some other tools that will do the same principal. Using blue painters tape will allow me to remove the tape with ease.

What I would need to do is apply some yellow glue to the edge faces and leave for an hour. I also needed to spray water on the glue face of the veneer and apply glue to it as well. After the hour has passed the glue has cured enough where it is ready to be melted to create the bond of the veneer to the plywood. You want to apply heat with a hot iron and as you go along you want to press the veneer with the veneer hammer to get rid of any ripples/ air bubbles.

I would apply the glue with a paint roller to ensure that I get an even application across the whole glue face.

This will be an experiment for me since I have not done this before I have only seen this in books.

I decided to press one of the veneer edges up in the press that I made. This press could only be used for the bottom section of the front doors. I decided to use the polyurethane for this glue up job. Liked I stated before there needed to be packers place at the bottom and also the top.

To prevent the veneer from sticking to the jig I added baking paper to the edge.

I wanted the edge kept clean as possible so I added veneer tape on the faces near the edge encase of any expanding glue. Before applying the glue dampened the edge with water to speed up the curing process.

You don't want to use heaps of pressure on this jig, you only want enough pressure that is going to properly secured the veneer to the edge while the glue cures.

While waiting for the job to dry in the press. I decided to give the heated glue application a go for attaching veneer to substrates. For this application you needed to use distilled water so I decided to go out and buy some.

What you want to do is apply the glue over the surface than spread it out with a paint roller on both the edge and the glue face of the veneer. You want it to dry just enough so it is not sticky any more. This takes about an hour with most yellow glues.

Usually apply the another layer over the edge since the first layer tends to soak into the edge too much.

Now you want to spray distilled water over the show face of the veneer. This is because moisture is being applied to both sides. (distilled water to the front and moisture from the glue to the back) You need to do this to prevent the veneer from buckling due to un even moisture application.

Once you have sprayed water over the veneer apply glue the same way you did to the glue face edge.

After waiting for an hour it is time to heat the veneer and press it down. Normally you would use a veneer hammer but sadly I don't have one. I just used a large plasters scraper but applied about 5 layers of masking tape to the edge to prevent me from tearing the veneer when applying pressure across it to get any air bubbles out of it.

When using the hot iron I find using max heat works best and you want to apply light pressure while moving up and down the piece. If it was a large piece you would work at small sections at a time while pressing out the air bubbles from the veneer hammer.

I found that the hot iron left black marks on the edge. These marks would be removed with scrapers and sanding.

Now it is time to pair away the off cut veneer with a very sharp chisel. I usually use the edge of the chisel since this gives the best pairing result when removing the over hang of veneer.

You will remove most of it with the chisel and tiny bits left over will be sanded off.

There is going to be a slight gaping but this wont be highly noticeable on a dark brown back ground.

To remove the black marks on the veneer you want to use a cabinet scraper and sand paper. You want to do this very carefully so you don't get rounded edges. I found using my thinnest cabinet scraper was the best for this since it was light enough to use in taking off small amounts on delicate areas.

Its best to go slow with this and apply little pressure and making sure your going straight and level. I found continuously checking with a square made sure your course was going in the right direction. Its not overly bad if you have a small rounded edge on the inside its more the outside. The bigger the rounded edge the more it will be seen when the doors are closed. I want to try and hide the fold line as much as possible.

Same with the sanding you want to try and keep it as level as possible. I found using a 240 grit sand paper worked well. You don't want a high grit since you could have a chance of taking off too much.

I decided to give the hot iron work plate face a bit of a clean with a rag and some mentholated spirits. This should remove any gunk off the plate.

Since I knew this worked well I decided to do the rest of the edgings. After a few I got the hang of the right amount of glue to add.

Heating the veneer to the edge with the hot iron.

Some times ironing different textile materials you using baking paper over it to prevent gunk markings  from happening. I decided to do this on the veneer as well. It helped to some extent.

The edge that I clamped up the the jig did not work overly that well. There were some sections that I had to cram glue in and use painters tape to clamp down and leave to dry.

Once all veneer edging sections were dry and over hanged veneer was pared off. I sanded down any high spots with the orbital sander on the faces. But again remembering not to stay too long near the edge as well as applying too much pressure encase of getting rounded edges.

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