View Full Version : Tips for wood inlays and finishes?

Linda Forte
02-10-2005, 10:53 PM
Greetings all,

I am interested in making small table tops that have wood inlay designs. Does anyone have helpful tips for using veneer vs. thin (1/8") wood, thickness of tabletop, finishes to protect wood before or after engraving, dealing with glues, seams, leveling, etc.?

I'm a bit surprised that I don't see a lot of posts on inlay from this prolific group.:rolleyes:

Thanks in advance!

Rodne Gold
02-11-2005, 12:03 AM
We do quite a bit of work for guys that do inlays and have found these tricks helpful.
We use a 1.5 inch lens for veneer cutting as its kerf width (the width of cut) is pretty narrow and we dont have to do male/female compensation (but the sheet has to be VERY flat to use this lens)
We dont use air assist as the air flow tends to blow small pieces around.
We often lam the veneers onto double sided mounting adhesive to make it self adhesive with a peel off back and we kiss cut thru the veneer and adhesive layer and leave the carrier paper intact , IE the same as one would cut vinyl. Firstly this makes it real easy to apply and stick and secondly it tends to flatten the veneer which is mostly not at all flat.
The other advantage of this is that you can weed the veneer of parts you dont want and then use vinly application tape to lift all the parts you want in one go with all the positioning intact and position it in one go over the part its inlayed into and apply it in one shot , very much the same way guys do vinyl lettering. Very helpful for small letters as you can inlay a tone of em in one go without tweezers etc.
We also have one of our small celled (small cells so that small vennered parts dont fall thru)honeycomb cutting tables converted to a vacuum table to hold down curled or warped veneers if not using the aforementioned method. If cutting on a table , be careful that parts dont fall into cells and one also has to order the cuts , like the inside of O's have to be cut first. You can just use an anodised ally sheet as a table , often with badly curled stuff that wont suck down , we just use a low tack adhesive spray on the table and shluck the veneer to it and then cut - the stuff is pretty thin (veneer) and one doesnt really have a problem with the back sides or have to have a table that allows material ejection thru the cut (like perspex wich needs to exple the molten pex out the back) as the laser vaporises the wood.
We often apply a layer of paper based vinyl application tape to the top side of the veneer as as not to get any smoke/resin damage and to protect the veneer surface if glueing etc - remove this right at the end.
We also try preserve both positive and negative when cutting a veneer , this allows for 2 images as you use the dark and light and the light and dark. (this is not alawys possible)
If the customer doesnt want positioning (ie the veneer cut in the same way as the graphic) we use a nesting program to fit the pieces in as closely as possible in the sheet and thus save money and time.There is a problem with this however in that cos the nesting program rotates things and juggles them to fit , the grain direction is all over the place.
We hardly ever laser engrave the bits the veneer has to fit into (I mean into the block of wood if you doing an inlay) as getting cosntant depth and a smooth bottom surface is almost impossible , we hog it out with cutters on our cnc overhead router (and here you got to compensate and be careful of sharp corners as you will alawys get a radius on a corner that is 1/2 the diameter of the bit)
We often use other materials for inlays , not just veneers.
We do a TON of wood grained formica rather than wood veneers as this is very cheap and durable material thats flat with no flaws , cracks etc , its not affected by moisture and it has a constant thickness and laser cuts AND laser engraves beautifully. We often use it as a cladding for stuff we do in supawood and engrave it and fill with gold or silver etc , it also comes in about a zillion finishes. As to finishing and glueing etc , Im not really a woodwork type guy so cant give specifics , most of my customers use some sort of spray finish which varies from matt to deep gloss. .
Hope this helps
Rodney Gold

Mike Mackenzie
02-11-2005, 12:15 PM

We have done a lot of Inlay work for both commercial and Music industries. I completely disagree with not using the laser to cut the pockets. If you use the laser for both tasks the parts match up perfectly. I also think that using 1/8 inch woods give you more flexibility and better fits without the problems of breaking. We do Inlays two ways the first is to laser the pocket about 1/16th inch deep. When we cut the mating pieces we will mirror image them and cut the material with the bad side down. What this does is to put the kerf of the cut toward the bottom so when you flip the piece over and place it into the pocket the angle is going down. The parts fit great without any compensation some of our inlays don't have any glue holding them together. I will post a pic for you to see this method. (method 1)

The second way of doing very intricate inlays is to use 1/8 woods and reverse cut the graphic in other words cut the entire background away and leave the graphic similar to a rubber stamp. Then flip it over glue and clamp it into the lasered pocket and sand off the remaining wood This is the Method 2 pic.

What this allows you to do is very small work without handling anything except one pc.

I recommend that any inlay work be done on unfinished wood then sanded and finished once completed.

We also use the bottom to top engraving mode when doing the pocket engraving what this does is to not allow the resin to build up into the pocket as it is lasering. If you don't have that method with your laser then once the pocket has been engraved you will need to take a toothbrush with some alcohol and clean the resin off of the edges so the parts fit. We also use a downdraft cutting table to hold the thin woods flat when cutting. I don't use the 1.5 inch focus Len's because when cutting 1/8 inch woods the ferf is actually more. The farther the focal distance the straighter the cut however you will have a larger spot size. We prefer the 2" focal Len's when doing this work.

Another important fact all woods are not created equal always test a scrap pc to see how it reacts both cutting and engraving. The samples pictured here are using poplar, walnut, maple, mahogany, rosewood, basswood, and shell laminates.

Experiment and have some fun with this once you work with it. Its really not that difficult it does take time and patients which all of us have. ("right")

George M. Perzel
02-11-2005, 5:01 PM
Hi Linda;
Some great ideas and info from both Rodne and Mike. I have done inlays with veneers and thicker woods ala Mike's techniques. Mike's process is easier and more forgiving as the wood is thicker and tends to stay flat during the cutting process. However, that said, it's not that easy to find a variety of different woods in 1/8" thickness. When it is available it's pretty limited in width and expensive. If you have reasonable woodworking skills and are willing to invest in a good bandsaw and a drum sander, the supply problem goes away. I cut my own 1/8" veneers by resawing on a bandsaw and thicknessing them with the drum sander-really fairly easy.
I also use the 2" lens (on my 60 watt LaserPro Mercury) and often do not mirror image parts but cut all parts from 5 or 6 different woods and then mix and match them ( see head of lady below)- not too concerned about a small kerf as it adds character and doesn't look machine made.
I use the laser for both the male and female parts and have done a number of custom signs with contrasting woods-good to have a small brass wire brush to clean out pockets.
Mike's second method is a super idea-never thought of that for keeping very small parts perfectly aligned, such as lettering for signs and plaques.

QUESTION: Does anyone know of any software available which will take a vector image and separate it into individual parts, including duplicating the edges of ajoining parts? Inother words, if you had a triangle inside a circle which was inside a square, the result of separation would be the triagle, a circle with a triangle cut out, and a square with the circle cut out. I hope this makes sense.

Linda-good luck on inlaying and let us know if you need any help.

Ken Frisby
02-11-2005, 5:43 PM
Mike and George,

That is some outstanding work! Thanks for sharing it.

Jeff DeVore
02-11-2005, 7:03 PM
Beautiful work George and Mike. George I'm not sure if I understand your question but can't you do what you want in Corel? If they're grouped "ungroup" if the objects are welded "break apart". You can convert everthing to curves and select what nodes you want and break apart the line segments if you want. Hope this helps, Jeff.

Rodne Gold
02-12-2005, 12:08 AM
Yeh , I would maybe treat 1/8th inch thick (3mm) woods differently , the veneers we cut are ultra thin less than 1mm thick (25mm per inch) and our 1.5" lens has a smaller spot size and a lot more power density in that spot size (plus of course a lot less depth of field hence you cant cut thick stuff with it) and the speed of cutting is faster and the edges of the cuts have less heat affected zones. We fabricate most of the bits the veneers go into on our Cnc's and our customers are mainly production based so they want to do as least work as possible and they are incredibly fussy as to exact depth and bottom finish. So its no real hassle for us to mill the pockets whilst doing the other work. We have software with features specifically aimed at inlay work which automatically compensates for cutter width, male/female parts and uses corner sharpening techniques to combat radiuses. Most of the stuff we do is fairly large , like cupboard fronts and doesnt fit into our lasers whose working area is only 1m x 500mm so my application is somewhat different in this regard.
George , just ungroup the image, duplicate it and delete the sections you dont want in the duplications.

Linda Forte
02-12-2005, 12:45 AM
First a thank you and then a reply to George.

When I said prolific - I wasn't kidding. Wow - since my original post last night I got great techniques from Rodne, Mike and George - I can see myself trying all of the above for various conditions - but I don't have an overhead router so I'll have to stick with the laser for my pockets. I do have a good bandsaw and would love to get a drum or wide belt sander - I'll have to get into much more production first. I can't wait to try this stuff.

Mike - your method (#2) and sanding afterwards is a great idea for intricate inlays. One question though - what is the "bottom to top engraving mode"?

George - to answer your question about nested shapes - Adobe Illustrator can do what you asked. After you draw the shapes, make sure they have no fill and the same stroke. Select them together and on the Pathfinder panel, click "divide".

You must then select Object -> "ungroup" and you can pull apart the 3 objects. Illustrator won't vector cut though, unless you have the latest version, CS. You'd have to bring the shapes into Corel and give them a hairline stroke.

I'm a college graphic design instructor, so if you have any other software questions, let me know. You guys have already given me some great ideas!

Mike Mackenzie
02-12-2005, 2:01 PM

The bottom to top engraving mode just allows us to start from the bottom of the graphic and engrave to the top.

Most of the laser systems start from the top of the graphic and engrave down to the bottom. What this does is to get the resin from the wood into the already engraved pocket causing you to clean the resin out before inlaying the woods.

With the bottom to top mode the smoke or resin that is coming off of the wood is removed with the exhaust system thus no build up of resin.

This is strictly a driver controlled function it can not be done in any graphics program that I am aware of.