Archive for August, 2010

Ok, I stopped the work on the Retirement Cabinet… For what? So I could play with stains?
I really hate staining wood. It never turns out the way I think it should. (Please note my trials/tribulations with the Computer Station from… “mixing oil & water“)

I’m making a pair of bookcases — relatively simple ones — for a customer and I want to come close to the color of his Brazilian Cherry floor. I’m using Lyptus; a GMO wood — at least I think that’s what it is — some kind of hybrid of the Eucalyptus. The solid wood has a nice grain pattern similar to Mahogany and to this Brazilian Cherry (which is probably not a Cherry at all). The color is light, like white oak or Beech, with a bit of pink cast.

I did a stain sample for the customer:

Lyptus stain samples

Assorted stain configurations on solid Lyptus

Click on the image to get better detail.  My customer chose the configuration in the lower right hand corner.  Note that I am using only two stains in this process. Both are waterbased stains from General Finishes: “Black Cherry” and “Rosewood” The “stainbase” mentioned in the top samples is like a conditioner that helps control penetration.

The important thing about stain samples is that you need to finish the sample exactly the same as you will finish the final work. So, if you plan to spray the stain on the real thing, then spray the stain on the sample. And follow through with all the finishing steps — including any sanding, seal coats, & top coats.

Another thing is that if you are using both solids and plywood you should make samples on both because they absorb finish differently.  But, of course, when I did these samples, I didn’t have any Lyptus plywood. Too bad! Because the Lyptus plywood I got wasn’t/isn’t nearly as bright and defined as the solid. So I started another sample: Spraying on the Rosewood stain over raw plywood.

Rosewood stain on Lyptus ply

Lyptus Ply with Sprayed Rosewood; Wiped Black Cherry

It came out much darker & muddier than the solid wood sample. This image has the rosewood sprayed over the whole section. After it dried, I taped and wiped on/wiped off the Black Cherry on the lower half. Then finished as normal. I can’t say it looks too good. So, what to do? Well, make more samples, of course.

Because the above sample was dark & muddy, I decided to spray on Stainbase first to lighten up the color and, perhaps, allow the stains to penetrate the pores more than the flats.
(One thing I didn’t mention about the stainbase: General Finishes doesn’t make an actual “stainbase” — a solution into which one adds his own colorants to make a stain — so what I use & call “stainbase” is their “Natural” stain; a stain with no color in it. [is that an oxymoron?])

Anyway, I masked off some plywood and sprayed 1/2 with a single pass of the Stainbase, and the other half with two passes. Now, I wish I had pictures of these intermediate steps but I don’t, so trust me on this. I then wiped on/wiped off the Rosewood stain. I could see a little lightening in the color. After that dried, I wiped on/off the Black Cherry. Things didn’t look too bad.  There was no difference between the areas that had one pass of Stainbase or two passes So my plan was to just spray one pass of stainbase — to save time.

Now, here’s why it’s very very important to follow through with the finishing process EXACTLY as you will finish the final product:  After sealing and topcoating the samples, I noticed a distinct difference between the side with one pass of stainbase and the two pass side.

double pass is on the right

Even looking at this picture in lo-rez, it’s obvious the color difference.

So, what do we walk away with? Let someone else do your finishing!! No, No, No. Just be sure to follow through with all the sanding/finishing steps you plan to use on the actual piece. AND, if you’re using solid & plywood, be sure to make samples of both.

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(Ya know, writing this in parts is kind of difficult…. I have to keep going back to my old posts to read where I left off.)

I may have said that the cabinet is  frame & panel construction on all four sides, with each side the same.

Elm Frames taped together

Elm frames taped together

So, this is kind of what it will look like — hopefully, I can find better material for the panels than cardboard.

Let’s see. First things first: I milled all the frame parts to thickness & width, then cut to length (straightening grain where possible as shown last time).

Construction is mortise & tenon. This time around, I used a Festool Domino* machine to cut the mortises. Clamping the frame pieces required a little different set up because they are rather narrow plus thinner than a typical 3/4″.

Mortising the stiles using the Domino machine

Mortising the Stiles

The frames are only 9/16″ thick so I had to use some Formica laminate to shim them into a position where the cutter would be centered on the edge. The clamping set-up helps keep the stile against the machine, but mostly, it presses the stile down to the table so the mortise is cut in the middle.  I have a scrap piece of frame against the Domino so the wood clamp mechanism doesn’t rack. Looking closely you can see the plywood spacer used to position the end of the stile in relation to the cutter. (There’s an indexing pin on either side of the cutter that can’t be seen here.)

Mortising stiles for center rail

Mortising stiles for center rail

Mortising for the center rail required some changes. First off, I used a thicker cutter — 6mm vs 5mm — and I added the extensions shown so I could index the cut further away from the end.  I prefer some kind of fixed stop like this or a block of wood rather than a pencil line because it removes any guess work or chance of error about where the cut should go.  Well, usually it does:

Mortising boo-boo

Mortising boo-boo

The Domino machine can cut three widths of mortise. After cutting for the bottom rail which is wider, I reset the width on the machine, but forgot to change the spacer block. Oops!

Next step is to cut the tenons.

Cutting shoulder on the rails

Cutting the shoulders on the rails

All the rails have been cut to a length that includes an extra 1-1/4″ to allow for 5/8″ long tenons on each side. (I use a Forrest 80 tooth blade for almost all my crosscutting because it gives a very clean edge.)  My blade height is set just slightly higher than half the thickness of the needed tenon. This way, I don’t have to do a lot of clean-up where the shoulder meets the tenon. (So, for example, if my tenon needs to be 5mm thick, I’ll try to set the blade to leave 4.8mm of thickness at the bottom of the tenon at the shoulder.)

After cutting shoulders, I cut the cheeks:

Cutting the tenon cheeks on the table saw

Cutting the tenon cheeks on the table saw

I have a Vega rip fence on my Rockwell table saw. The Vega has a nice micro adjust feature that allows me to fine-tune it’s distance from the blade so I get the tenon thickness exact. (Here I’m using the stock Combo blade that came with my Powermatic saw. It gives a smoother than expected rip cut.)  The fence also has a channel in the top for sliding various accessories along it. I built this simple Tenoning jig years ago out of scrap. It has served me very well.

After cutting the cheeks, I trim off the long edges of the tenons on the bandsaw. (No pic) Then I round the long edges with a Swedish single cut mill file.

Rounding the tenons

Rounding the tenons

I fit each tenon to a specific mortise. assemble the frames, and check for square.

Next I’ll mortise the leg blanks and cut tenons on the front & back leg rails (stretchers).

Domino Mortising leg

Mortising the legs for upper stretcher

Mortising for bottom stretcher

Mortising for bottom stretcher

Mortises in legs

Mortises in legs; jig still in place

The stand’s legs are still square & haven’t been sawn to shape. I made up a jig that references off the top & inside face of a pair of legs (back legs in this case). I’ve rotated the legs so the two surfaces that face each other (left to right vs front to back) are up & ready to receive the mortise. I’ve marked on the jig the center lines of each mortise. (If you were able to look closely at the lines, you would see that they are not equidistant from the inside edge of the leg. This is because the bit does not cut an equal distance from the scribed line on the machine. The lines are about 0.7mm off center and there appears to be no fix for it [see * below].)  For the second set of mortises, I add a spacer. I have two dowels in the edges to maintain alignment and I’ve extended the reference lines.  The last picture shows the mortises complete.

The work on the Stretchers’ tenons is similar to the frame tenons so I don’t have any pics.

The Retirement Cab has to sit idle for a while now so I can catch up on a couple of paying projects.

* I bought the Festool Domino machine the day it went on sale. I really like it for what it does. But it has two flaws that don’t seem to have any fix.
1) The cutting bit (looks kind of like a brad point drill bit) seems to “climb” in the mortise. This means that the mortise is not perfectly parallel to the referencing fence (be that the table as in the earlier pictures or the jig in the last pictures) In this project, it’s not so bad & I can sand out any problems. But if I were cutting facing mortises & using a loose tenon,to join them, the error would double.
2)  The second flaw is mentioned above: the center reference lines (of which there are three on three different surfaces) do not indicate the exact center of the cut. So in some cases, I have to adjust my cut to get it centered. Now if I’m using the indexing pins mentioned at the very beginning, one of the pins is excentric and can be rotated on it’s axis to correct for this error. But the “wings” I used for the center mortises don’t adjust so I again have to make corrections via trial & error.  For such an expensive machine, it’s a pain.

When I created the link to the Festool site, I found that they have come out with a new model that’s slightly different to mine. Maybe they’ve corrected these problems (but probably not).

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I’ve already mentioned how precious this wood is to me, so cutting it gives me the fits! (I had images of the two planks I’ll be using, but I seemed to have erased them from the camera before I uploaded to the computer…sigh.)

Here’s the Elm that will be used for the cabinet:

Cutting the Elm plank

Cutting the Elm plank

Cutting the Elm plank #2

Second view of the cut plank

These planks are “Flitch cut” meaning that they are the full width of the tree, so I have raw edges on each side. The Elm and Dosié also have boring insect holes in the sap wood. Fortunately, no insects!

Because the cabinet is basically made up of four frames with panels, I will work to cut the Elm to provide as much straight grained wood as possible. So I’ll work from the edges (just past the bugs) towards the center.

The first cut gets rid if the buggy raw edge. Then I ripped out the giant split in the middle of the plank.

Ripping the split out of the Elm plank

Ripping the split out of the Elm plank

I had hoped I could get all the frames out of just one side of  the plank, but I had to cut into the other side. The center of the plank had a lot of medular ray pattern that didn’t match the rest. It looks real nice — kind of like Sycamore — but won’t fit in. (If I can remember, I’ll take a picture & put it in the next post.)

Here’s the Elm cut in strips:

Elm plank ripped for cabinet's frames

Elm plank ripped for cabinet's frames

I have the pieces repositioned pretty much the way they came off the plank.

Next step is to mill the Elm to thickness (9/16″) and width (1-1/8″, 1-1/2″). Some of the wood’s grain doesn’t run parallel to the cut so I needed to “straighten” it out:

Straightening the grain

Straightening the grain for the rails

Before I cut the rails & stiles to length, I laid up a sample of the door to see how it worked with the stand:

Mockup with door

Mockup with sample door in place

I looked at this setup for an afternoon. It looked fine, but I slept on it. Next day, I made a modest change — 1/2″ off the length of the rails (BTW, rails are the horizontal pieces and stiles are the verticals. I was doing woodworking a couple of years before I learned the difference.)

Narrower door on mockup

slightly narrower door

It’s not much of a change, but I liked it better so I proceeded to cut the frames.

Ok, here’s the quartered Elm showing the ray pattern:

Medular ray pattern in the Elm

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