As a woodturner, we are often in pursuit of swift gratification. We like to create details with pin-point accuracy. A good finish can give impressive definition to both worked detail and that of the wood grain. To achieve that beautiful end piece, using the right finish is a must.
Why cyanoacrylate?
In the search for fast and durable finishes, I’ve only been satisfied with two. One is spray lacquer. Not the fastest, but reasonably quick, good looking and durable. The fastest, most durable finish I know of is a cyanoacrylate finish.
Cyanoacrylate adhesive makes a wonderful finish for wood. There are many methods for application as a finish. Some methods I like – others I don’t. For the most part, cyanoacrylate finishes have been relegated to small items such as pens. With a good technique, it can be used on much larger items.
The method explained here will allow you to use cyanoacrylate finishes on bigger turnings. If you have a method that works for you and are satisfied, continue with it. Please don’t construe my methods as the right or the only way. What I’ll explain works for me, and I’m sure it will work for you. If you are in need of something better than what you currently have, give my suggested method a try.
After trying, you’ll be able to make a value judgment to continue with it, adapt it, return to your old way, or continue your search.
Safety
Cyanoacrylate adhesive releases fumes that some people find offensive. Plenty of ventilation is recommended.
There are vendors offering odourless versions of cyanoacrylate, but I haven’t found the need to use them. I can’t offer information in this regard, or the working characteristics of those versions.
Depending on your sensitivity and the amount of cyanoacrylate being used, you can certainly use a filtering mask. An activated charcoal filter mask may alleviate any difficulties you encounter with cyanoacrylate fumes.
The cyanoacrylate curing process, or more accurately, crosslinking, gives off heat. This can be very hot! Take care when performing a cyanoacrylate finish to avoid being burned. Do not dispose of any application rags until they have completely cured and cooled.
A common problem faced by those careless with cyanoacrylate adhesive is becoming attached to their equipment or themselves. Cyanoacrylate adhesive cares not what it bonds together. You can easily attach your fingers together, or your hand to your lathe. Debonding chemicals are effective, but also require care in handling, use and storage.
Read and heed the manufacturers’ instructions for your safety. Ventilation and eye and face protection is always in order at minimum. Regardless of the finishes you use, cyanoacrylate, lacquer, rub and buff, or other, be aware of the food safety concerns. Unless the finish has been tested per your local regulations and certified as ‘food safe’, use your finishes as decorative finishes only.
1. Preparation is everything
In our rush towards completion, the preparation for finish is usually where woodturners scrimp. Regardless of the finish you are applying, your final look will never be any better than the workmanship underneath. Any dust, oils or other contaminants will hinder your finish. Scratches or other flaws will not be hidden. They will be amplified with any see-through finish.
Woodworkers will spend on average a third of their project time building the project. Another third is spent prepping for the finish. The last third is spent applying and ‘finishing’ the finish – rubbing it out, buffing or other final touches.
I don’t intend to tell you to spend one third of your time sanding and prepping for finish, but I do recommend you spend sufficient time to remove all of the scratches, debris and contaminants. These will only show up underneath or hinder the proper application of your finish.
Sand through the grits. Use the intermediate grits as needed. Don’t be afraid to continue on with MicroMesh abrasives if appropriate. MicroMesh abrasives work very nicely on dense woods. In normal situations, getting to 400 or 600 grit abrasive will be adequate. Remove the dust and particles between each grit.
You shouldn’t need to degrease if you’ve been careful with your waxes and oil through the process of turning and sanding. I always use a complete wipe with a paper towel with denatured alcohol to clean up all of the dust and any finger oils just prior to applying finish. Depending on your location, nearly any of the petroleum distillates will work.
2. Practice
Learning to apply a cyanoacrylate finish isn’t difficult. That said, you’ll certainly improve your results with practice. Don’t do your learning on a valuable turning. Take some scrap pieces and prepare them as you would to apply your finish. Learn and master the techniques on those less valuable pieces.
Turn just the outside of a bowl. Finish that. If you wish, continue with the inside next by hollowing, sanding and finishing. Your practice will pay off and your success percentage will increase. If someone tells you they are always 100% successful, I’d beware of anything else they said. Over the years I’ve become pretty proficient, but on occasion there is a less than ideal application. When that happens, I need to go back to the sanding and prep to apply again.
3. The correct materials
When I apply a cyanoacrylate adhesive as a finish, I use only thin viscosity cyanoacrylate. Some say that medium viscosity is the answer, and often will dictate the brand of cyanoacrylate. Some will even insist that the brand of paper towel impacts your success.
Not to offend those folks, but I’ve found that fresh thin cyanoacrylate from any manufacturer, applied correctly to a properly prepared surface, will be successful – regardless of the maker of the paper towel. I suggest you use your favourite cyanoacrylate adhesive and any roll of decent quality paper towel.
The glue should be fresh. Its viscosity should not have changed due to its age. You’d like it to be like water. I won’t quote the viscosity values in centipoise (cP), but if you look at various spec sheets, it will have a wide range and still be called thin cyanoacrylate. Water has a cP of 1, so get lower value rather than higher if you have a choice.That said, I’ve never seen a non-time degraded thin cyanoacrylate that I couldn’t get to work.
Skip the boiled linseed oil addition of the adhesive. For those who use the boiled linseed oil/ cyanoacrylate technique and are happy with it, by all means continue. Those who haven’t started, I recommend skipping its use. The chemical wizards that I’ve checked with say it adds no value to the process from their perspective. It adds cost and complexity for little or no apparent gain. You’ll also be using cyanoacrylate accelerator. The version using acetone as the carrier is preferred, but not critical.
4. Use proper PPE
As noted in the safety section, be certain you have sufficient ventilation so the cyanoacrylate fumes don’t cause you problems. The moisture of your eyes and nasal cavities will be affected.Once you’ve gotten proficient with applying cyanoacrylate finishes, you may wish to skip some of the hand protection. For starters, I recommend using gloves to prevent you becoming stuck to things.
As you apply the finish, too much glue or poor application technique can get you bonded to your work, your lathe, your clothes or yourself. With disposable gloves or the equivalent, you can simply peel off the glove and extract yourself. Gloves, especially the thicker nitrile, help protect from the heat a bit.
5. Be prepared for problems
Whether you work barehanded or with gloves, it is wise to have the cyanoacrylate release chemical at hand. You can buy the cyanoacrylate release chemical from your local woodturning supplier in small quantities.
The active chemical ingredient is acetone. If you wish to buy acetone in larger and cheaper quantities, nail polish remover is usually 100%, or contains very high concentrations of acetone. You can also buy acetone from your local home supply retailer in larger industrial sizes.
Using cyanoacrylate de-bonder
To separate things that have been bonded together with cyanoacrylate adhesive, soak the interface generously with acetone and wait. Slowly try to work the pieces apart, repeating the soaking process.
Be patient. Have your acetone source nearby and open. Should you get bonded to your lathe, your bottle of acetone halfway across the shop will not be convenient. Nor will opening it one handed. I use an old cyanoacrylate bottle that was cleaned well with acetone as my dispenser bottle. I open it and have within easy reach whenever I am working with cyanoacrylate adhesive. Always label any transfer container with the contents.
6. Take your time
When in the throes of working, the temptation to hurry and put on finish is typical.I recommend that you don’t begin until all is ready and in place. The work to be finished, whether one piece or many, should be sanded and cleaned to the best of your ability.
Your selected cyanoacrylate adhesive should be fresh and in sufficient quantity to complete your task at hand. Running to the store to buy more, or even going to your supply cabinet and opening a new bottle is disruptive.
When you get going, you want to work to completion without interruption. Have your PPE at hand, including extra gloves, towels and accelerator. Don’t forget to have your cyanoacrylate release agent open and at hand. A small dispenser of acetone will work nicely. Dragging your 900 pound lathe across the shop to get to the acetone ruins your day.
Summary
In this article I have shown you how to prepare for applying cyanoacrylate as a finish to your woodwork piece. To summarise – ensure that your piece is ready with a good sanding, and that your workplace is safe, with all the necessary tools and products to hand. Remember – there is no substitute for practice.
In the second article, I will be showing you how to apply multiple coatings of cyanoacrylate; how to achieve different thicknesses; and how to use sanding to achieve the finish you want.