Bloodwood (Brosimum Rubescens)

经典a片

Over the weekend I picked up some additional bloodwood at the Bloomington Woodcraft store.

Bloodwood has a grain similar to mahogany but with a rich red color. It machines very nicely. It has a sweet aroma. However, as we do with all exotics, we are very careful about dust control procedures. It sands into a glossy finish with 600 sandpaper.

More about our vacuum hold downs

We have been using the vacuum pods for pieces under 12"x30". These are described on Baycraft Design's web site. Scroll down until you see Vacuum Clamping. We use the same vacuum pump and pods. We bought our first pods and a manifold from Nappy Products. We are now building our own pods using plastic from a local supplier mostly for the convenience and speed in that we can build what we need when we need it. If you build your own pods make sure the plastic you use for the pods is not warped.

We get our gasket material from All Star Adhesive Products. These people are great to work with.

On our last sacrifice board we had cut grooves for a 2x4 area for holding sheet material. Typically we don't cut anything larger than 2x4. It worked quite well but the problem was that frequently we were cutting boards smaller than 2x4. We do glue-ups of exotic woods and cut boxes out of them. The glue-ups aren't always 2x4.

When we replaced the sacrifice board on our table we decided to try an experiment. We cut the hole for the shop vac, but then, rather than cutting the channels first, we tried just placing the gasket material directly on the table. For our materials it has worked very well. When we need a different size vacuum area we just cut out sections or scrape off the gasket material that we don't need and lay down a fresh strip for our new border.

A Word About Mechanical Hold-Downs
When vacuum works it is great. However, there are occasions where it does not work.

As mentioned in an earlier blog entry, when we cut veneer we use
3M 90 Spray Advesive.

If a piece of material cannot be held in place with vacuum then we will use mechanical methods. My preferred mechanical method is to place the material on the spoil board and then screw pieces of scrap boards down next to the material -- essentially to "frame" in the material. Sometimes our "frame" boards will have a 45 degree bevel so that it overlaps the edge of the material in order to apply some downward pressure.We have also used clamps.

We have also screwed material directly to the table. Screws are useful when you have an unruley piece of wood that you are trying to flatten. The down-side(s) of screws are:
1) you leave holes in the material
2) the material can split at the screw holes
3) you run the risk of hitting a screw with your nice new $75 carving bit.

Grenadilla Wood (Dalbergia Melanoxylon)

We have been working with grenadilla wood this week. This photo abive show Michael planing some of the boards prior to glue-up. Our specimen is rather light for this type of wood. To me it smells similar to rosewood. We have been working on our glue-up techniques. This will be used for a project that will be shipped out of state. We wanted a piece that would be unusual.

We also did some nice carvings today. Below you see one that I was just finishing up. the piece was carved in red oak. It carved surprisingly well. There was one section with a small amount of tear-out that was cleaned up with some hand carving tools.

Vacuum Hold-downs

We have been experimenting with various vacuum hold down methods. The latest method is take a piece of 1/2" plywood and lightly carve where the material will be cut through when we cut our hardwood sheets for boxes. We then lay gasket material inside the pattern carved on the board for each box piece. Next we cut a hole in the middle of the area for each piece. Finally we hog out some material on the underside of the board to create a plenum.

To use this contraption we place the "plenum board" we just created on our table which has a hole drilled in it that is connected to a shop vac. The hardwood sheet is placed on top and the vacuum is turned on. On our first prototype we had hogged out too much material and we had severe sagging in the center of the board. However, everything held in place during the cutting process.

This process certainly has possibilities.

Veneer, hardwood glue-ups, and line cards

Line Card
We have developed a line card which is shown to the left.

Veneer
We have been working with cutting veneer on the Shopbot and have that down fairly well now. We are using the 3M 90 spray adhesive mentioned in a previous entry for both hold down while cutting as well as on the final product.

We tried some paper backed walnut veneer today.

Pros and Cons of paper backing:
Pro: the paper helps hold the pieces together during removal after cutting
Con: since the veneer is 0.020 inches thick including the paper it means the wood itself is thinner and it is easier to sand through it.

Glue-Ups
Michael has become skilled at hardwood glue-ups. Our process is as follows:
1. start with 4/4 hardwood lumber
2. split the boards into 3" wide pieces
3. resaw the 3" boards to yield 2/4 lumber
4. plane the edges sending all boards through the planer together
5. use yellow glue or All-Wood Epoxy and Michael's special glue-up table
6. The finished boards can be planed on either the Shopbot or the planer if they aren't too wide.

Box Making
We have been using a 90 degree 3/4" V bit for making boxes. Masking tape seems to be the key to getting all pieces lined up.

Learning about marketing

We spent the last several days at a home builder show meeting with builders and cabinet shops. Our toughest challenge has been lack of demand due to the fact that people don't know our carving services exist. Also, it looks like our target customer base is the top 5% of the market. We met with a number of people who had recommendations about where to display our carvings in order to build demand.

The most interesting idea was to display some of our carvings at an art gallery. Michael stopped into the gallery and they were enthused about what we had.

We will be carving examples for a number of shops in the area in order to gain visibility with the key decision makers in the area.

We also have an order for material to display at a sign show.

Cutting veneer on a CNC

Today we did some work with cutting bubunga veneer on our Shopbot.

We have tried various hold down methods:
High vac/low volume - won't even hold the piece
Low Vac/high volume - doesnt hold the edges well enough
Spray adhesive - works pretty well.

We are using 3M type 77 stray adhesive and are about to experiment with type 90. There is little resedue left on the parts. We are still determining the proper amount to use. The first batch was too heavy which made for a longer process removing the parts. The second batch had a few gaps. Occasionally we would expereince the material moving so the cut was a bit off. In the worst case a piece broke of and went up the dust chute.

However, we are hopeful since the results were still very good.

We have also found an epoxy that works for ebony. The Smith All Wood Epoxy seems to do the trick. It is available from Luthiers Mercantile