Newsletter Article - My Favorite and Only Finishes (Part 2)
I got my first crack at applying a spray finish in 1985 while helping Dale Nish finish a cabinet job. I made the mistake of standing a cabinet door on edge instead of laying it flat after he had sprayed it, this caused the finish to sag and run to which I got an ear full! It wasn’t that long before I was the one doing the spraying and that is when you realize how fast a top coat can be applied, especially if you have only ever wiped or brushed a finish. Over the next five years I must have sprayed hundreds of gallons of “Fullerplast" as a top-coat for furniture leaving Dale’s shop. Fullerplast, was a catalyzed urethane like product that dried to a very hard and water-resistant finish. I probably would have continued to use it once I returned home to Canada, but it was not available up here.
Regardless of the brand, most top coats are applied the same way. Learning to avoid drips is the first skill you must learn in spraying. You must keep the nozzle square to the work, about a foot from it, and spray with a side to side motion at the right speed to lay an even coat; heavy enough to allow the finish to level out but not so heavy to cause it to sag. It really isn’t difficult, but most beginner sprayers are very nervous spray finishing a project they just spent 100 hours building. Let me offer some tips that I have learned over the years that might make your venture into this arena a bit smoother.
1. Find one spray finish and stick to it. Most hobby woodworkers will not build enough projects to develop any sort of expertise with multiple finishes, so stick to one spray finish. This allows you to get to know your finish inside and out. How it dries in different weather conditions, how well it covers, does it require 2 coats or 4? And remember, the manufactures suggestions are just that – suggestions! They cannot account for all the environmental conditions in your shop so don’t be afraid to experiment and learn what works for you.
2. Dont worry about a sterile spray area. I spray finish in my dusty shop more than anywhere else. I prefer to do it first thing in the morning, dust has had all night to settle. I do clean the immediate area the night before, mostly so air from the spray gun won’t kick up the local dust and disperse it on to my work.3. Use a good respirator. I sprayed too many gallons without one and now I regret it. How many times have I thought, 'I will hold my breath for the few minutes this will take", bad idea - get and use a respirator! Spend the money and protect your lungs – you need them!
4. In-between coats always need to be sanded or scraped before applying a next coat. Sanding introduces its own problems, try scraping. On flat surfaces a sharp card scraper is hard to beat once mastered. It needs to be properly prepared and sharpened, any nicks or irregularities in the edge will show plain as day in the scraped finish. Use a light tough as you level the surface by removing the high spots in the finish; dont cut through to the wood. This method cleans up quickly and in open grained woods like Walnut and Mahogany, it doesn't fill the pores with finish dust like sanding will. You will need to sand any round surfaces but since the scraper will take care of the flats so fast the extra time sanding the rounds will be done in a flash!
5. Clean up when you are done. It is so easy to set the spray gun aside thinking you will do it later only to come back and find a solidified mess that will now take hours instead of the minutes had it been done immediately afterwards.
The spray finish I use is lacquer by AcromPro. The big advantage of lacquer that I like is that it dries quickly (actually it hardens). But once harden, when you spray another coat on top, the new coat will loosen up the previously hardened coat, bonding the two coats together as one. This is a huge advantage when spraying multiple coats. Instead of multiple layers of finish you get one thick coat of finish as each layer melts into the previous layer. Even dust from sanding between coats will melt into the next coat instead of showing as un-removed dust. This property also means the lacquer can be left in the gun for weeks and still be usable, just add more lacquer to melt any dried-up lacquer.
Lacquer does have a few down sides that you need to be aware of. It off gasses for a long time and if the cabinet is kept shut it will take even longer. My suggestion is to leave any close-able project open and with lots of air flow for a week or more. The chemical smell would surely bother anyone with sensitivities.
The other big downside of lacquer is its lack of resistance to water. The product I use is certified for use in kitchens, so my guess is it’s the best of the bunch when looking at lacquers. A quick spill is not a problem, but a wet glass or damp cloth is another story. You need to treat these surfaces like you would any piece of furniture, keep them dry!
For years I used the siphon cup style of spray equipment, high pressure and lots of over spray. If you are still using this archaic method of spraying, you are wasting a lot of your finish product. Switch to a HVLP (High Volume, Low Pressure) sprayer. HVLP is a very simple system with a small blower that is usually about a foot square and light making it very portable which for a small shop is a big deal. The lower pressure also reduces the amount of over spray.
Most professional lacquers will allow you to adjust the drying time to compensate for warm dry weather, this often causes the lacquer to dry before it levels, add retarder. You can also add flattening agent to adjust the sheen, I prefer a very low luster, so I always have flattener available to make the satin product even less shinny.
Warm dry conditions are usually better than cold and damp; room temperature is ideal. although since I live in a cold climate I am still able to spray in the winter. You will want to keep your finish warm and on days I need to spray outside, I keep the project warm and only move it out just before spraying.
Make sure the current coat has fully dried before you attempt to scrape or sand. A partially dry finish tends to roll into beads and will quickly clog sandpaper, preventing the abrasive from doing its job.
Remember if you use a satin for low luster finish, the flattening agent will settle to the bottom faster than you might think. Keep your finish lightly shaken or stirred while you are working the project. If it sits for more than a few hours between coats, I would stir it thoroughly before spraying another coat.
A big problem when spraying a large project is to get inside to adequately cover that area with finish. I try to break the project down to as many independent parts as possible, remove the drawers, the doors, keep the back off and spray it separately. Take shelves out and do them separately. The next challenge is where to put all the pieces and how to set them while drying. Dale would take a long strip of plywood and shoot hundreds of nails through to the opposite side. If they are left sticking out the opposite side by an inch or so, you can lay doors and shelves on them even on a wet side and you will be surprised how little you can notice the small contact spots. I always set the inside or the less visible side down on the nails. I use these racks to finish spray the edges and top side while it is resting on the wet inside.
I had a good friend in the wooden craft business, he made mostly Shaker oval boxes that were sold all over the world. Among his many outlets, we both sold through a small gallery not far from where I live in a town called St. Andrews, NB. I was visiting that gallery one day and while waiting for the owner to finish up with a customer, I was observing some folks looking at my friends display. His work was very exact, nice wood choice, great shape and well made. I watched as the customers admired from a distance, eventually went in closer to pick them up. The smiles that said "I want one of these" changed after the woman caressed the box top, bottom and sides. When they left, I went over to check the box she had picked up. The finish was a bit fuzzy, not smooth to the touch. I called my friend and shared my observations and offered a solution. I introduced him to the AcromaPro lacquer I had been using, he was quite accepting of my suggestion and I gave him my source. It was probably a year before we spoke again, I was pleasantly surprised to find his sales had near doubled! The finish can’t be over stated, it speaks volumes beyond the craftsmanship of the construction. I Hope some of this resonates with those of you looking to improve on your current methods. I wish you Good luck and be sure to enjoy your time in the shop.