Ned’s Shop Tips - Just some tips I’ve found to make laser making easier. Feel free to add your own. Imported and continued from the old G+ group.
Shop Tip - Touching up Cut Edges
Here’s a handy tip from my toolbox. You know how sometimes your piece of plywood doesn’t cut all the way through at one spot and you have to finish it off with a sharp knife? You then end up with an area of the cut that is clean wood compared to the brown lasered edge. You could sand off all the edges to make it match or, if you want to keep the dark edge, just use a brown sharpie marker to quickly color and blend the area. A black marker can work as well but the brown generally gives a better match. Also good for touching up engraved areas.
Shop Tip - Darkening Engravings (Note this product has been discontinued)
I had engraved and cut out a pair of Masonic emblems from a sheet of 1/4" Birch ply I had gotten from the local big box hardware store. The coloration of engraved area came out kind of blotchy and uneven. Really didn’t like it so I just set them to the side leaving the masking on. Since the masking was still on I decided to try a polyshade spray technique that I had learned, from an Laser group on facebook, to darken and even out the engraved area. It worked like a charm. I used two moderate coats as it doesn’t really build up that fast compared to something like spray paint. I prefer to always seal the surface before engraving so I don’t get any bleed for any type of infill, but if you are careful to do light coats this stuff isn’t really prone to bleed.
The only problem I have found with the minwax polyshade is that the valve on the can is very prone to leaking. Went through a number of cans without even using half the cans before they ran out of pressure. Solved this by using a small spring clamp with pivoting ends and a small piece of thin craft foam as a gasket to seal the end of the valve. I grind a flat spot on the back of the valve so the clamp doesn’t slip off. Always get through a whole can now.
Shop Tip - Engraving Infill with Calligraphy Inks
When you need a metallic color engraving infill try metallic calligraphy inks. Especially for gold this is my go to infill color. I’ve tried a wide range of gold paints/paint pens/gold leaf material but this brass ink pictured gives a very vibrant and iridescent yellow gold color that I love. Not perfect in all cases but for small details it usually makes the pieces pop.
Shop Tip - Stabilizing Small Details
When you are cutting out pieces with details that have narrow connection points you generally try to have at least 2 connection points, like the ball on the right in the picture, to give better stability. This is especially true for small details in thin stock. Where this isn’t reasonably possible you can add or expand an engraved edge, like the ball on the left, while keeping the unengraved area the same. This adds width to the connection point while having the illusion of a narrow one.
Shop Tip - Wood Grain Direction
In this edition of K40 Shop Tips let’s consider the impact of wood grain direction on your creations. In my experience there are two ways direction of the wood grain impacts projects created with wood, structural and visual.
The structural aspect is typically related to how much a piece of wood will bend when a load is applied, in that a piece of wood is stiffer when bent perpendicular to the grain then parallel to the grain.
This becomes more important as the wood becomes thinner and the pieces cut become narrower. In general, you usually like to have the long direction of you piece parallel to the grain for the best stability, but it will depend on your application. Plywood typically is less affected than solid wood and pieces >= ¼” thickness are also less affected.
Next up is the visual aspect. When holding a piece of wood up, with the face of the board facing you, the wood appears brighter when the grain is parallel (horizontal) to the floor then when the grain is perpendicular (vertical) to the floor (note that the wood shown does have a coat of lacquer which enhances the effect). This is caused by way the grain reflects light. When the grain is horizontal it is reflecting more light up into your eyes and reflects it away to the side when it is viewed vertically.
So, when making pieces that are to be viewed facing out, like for a plaque, I usually like to have the grain oriented horizontally when possible. However If the wood is painted so that the grain doesn’t show then it doesn’t matter.
The Following are some replies to my original G+ post that are worth mentioning:
Another point to remember is that wood will expand and contract. It is more noticeable across the grain vs. the grain running end to end. Plywood is also less affected by this, however hardwood and softwood with a large grain pattern, such as oak can expand and contract as much as 1/4" over a 4’ length. When assembling a large cabinet this becomes important, you do not want to continuously glue the joints when dealing with large widths, you need to leave free areas for the expansion and contraction to occur. Do not put too many fasteners close together to allow the expansion/contraction as well.
Another thing along those lines to consider is which side of the board to use. I’ve sometimes used a board that had a slight cup to it, after I’ve straightened it or planned it out. I would then like to keep the “bark side” up or out in case it wanted to cup a little more later on so it’s not as noticeable.
Another - always apply finish to both sides of wood to reduce stress and bowing.
Good rule of thumb is whatever you do to the top side should be done to the bottom, like if you glue laminate to the top, you should also laminate the bottom side.
Shop tip - Double Masking
When you want to brush color fill an engraved area with a light color paint (e.g. white) the dark engraving residue can be a problem in that it can contaminate the paint and cause it to darken. You can carefully wipe off the residue with a damp cloth, but a faster and better way is to apply 2 layers of masking to the piece before engraving. After engraving simply pull the top layer of masking off and the residue is gone. Very handy for large areas and you don’t have to worry with accidentally wiping residue into the the engraving. Works best with a medium to heavy tack masking first with a lighter tack mask on top. Keep in mind that masking is another layer of material that the laser has to remove, so the more masking thickness the more power you need to apply to remove it. Typically not a big issue, but something to keep in mind.
Shop tip - Aligning Objects for Engraving
When you need to precisely align a workpiece for engraving, especially for an odd shape or when engraving close to an edge, give this a try. First place multiple layers of painters/duct tape on the engraving surface and trim off the excess. Create a cut layer that is a little smaller than engraving surface and then run the cut fast with low power. The goal is to have the cut not penetrate the bottom tape layer and thereby leave a mark you can see for alignment checking without marking the actual surface.
Edit: I found after a tube upgrade that with the increased power just painters tape wasn’t sufficient, without many layers. Now use a layer of painters tape, then a layer of heavy duct tape, then a layer of painters tape. The thickness of the duct tape allows several checks with just replacing the top layer.
I have a jig for holding the object but my setup isn’t precise enough to allow an accurate alignment of the jig with no checks.
Object with double masking layer (number of layers required will depend on your min power/speed and on the thickness of your making tape.
Alignment need to be shifted to the right a little.
Shop-Tip - Edge Bleed
When I am planning to do a paint infill in an engraved area in wood I prefer to seal the wood first with a finish before masking the surface and engraving. This will typically help prevent paint bleed into the top layer of the wood along the newly exposed edge grain along the edge of the engraved area.
If you need to work with unfinished wood, or need extra protection from edge bleed, try this tip. After masking surface and engraving, take a can of clear finish/sealing spray and spray the engraving with the masking still on. Rotate the wood and repeat spraying from all four sides to ensure that all the engraving edges are covered and let dry. This will seal the edges of the engraving to prevent bleed and also “prime” the engraving to reduce paint uptake into the wood.
Shop Tip - Cardboard Prototyping
In the modern consumer economy, especially todays direct-to-consumer, cardboard packaging is very ubiquitous in every household and we are always stuffing it into our recycle bins.
In the hands of a maker, however, cardboard can serve lots of uses. One of the things I find cardboard useful for is prototyping laser cut projects.
It’s one thing to design something on a computer screen, and try and decide if it’s the right size or fit for something, and it’s another to actually hold something in your hand. Sometime it works out just like your initial design and other times you have to make several iterations to get it right.
So I will typically cut out prototypes of an object in cardboard before switching to wood. It’s cheap (free), cuts very easily and is commonly ~ 1/8" in thickness, which approximates 1/8" plywood.
I usually keep several large sections of cardboard stashed away that I hack pieces off of as I need them.
Here I am prototyping a stand I recently made.
Spot on. I’ve gone through mountains of cardboard checking fit, orientation, etc. Save yourself money and grief.
I’m forbidden to stash anymore cardboard until I find room for it!
If only you could find some boxes to put it in!
Shop Tip - Aligning Double Side Engravings
When engraving both sides of a round piece, it can be difficult to orient the piece the same after cutting and flipping to engrave the second side.
To make this easier here’s a little tip. Using a square, mark lines on both sides of the piece being engraved/cut. This is ideally done with masking on both sides. Then, when you flip the piece after cutting, it’s easy to see if the line on the back is parallel to the front line indicating that back orientation is the same as it was for the front.
Back after engraving and cutting the front.
Very clever. Nice and simple.