How to Finish Without Streaks?
Article - August 24, 2009
This Viewer Question is from Matt and its a little different than what we usually do. Instead of a simple question and a simple answer, this is an example of a long exchange that eventually leads to an excellent result and a happy ending. As you’ll see, it never hurts to ask questions!
I’m hoping you can help me with a finishing problem I’m having. I have completed a bubinga veneer coffee table, which I’m sure you are familiar with, as it is a David Marks’ design. In the past, I have always had good success with the General Finishes Arm-R-Seal Satin product on much smaller projects/surfaces. However, the large surface (18″ x 44″) of the table top is giving me fits. I can’t seem to produce a finish with this product that is streak or haze free. My technique thus far included:
1. First coat the surface with Seal-A-Cell followed by a light sanding with 320 grit.
2. I apply the Arm-R-Seal with a foam brush, spreading as thin as possible then wiping with a cotton rag, as lightly as possible. All application and wiping is done with the grain. I’ll work an area approximately equal to 1/4 the table top at a time.
3. Inevitably, as I’m about to move to the next section of the top, the wet edges of the previously wiped area are already setting up, making it difficult to blend the wet section back into the previous section.
Some guesses I have are that maybe the Arm-R-Seal product is too thick to start with making it hard to spread on quickly over the entire tabletop? But the instructions on the can indicate “do not thin”. Per the instructions on the can, wiping off the finish with too heavy a stroke can cause friction streaking, but I can’t seem to wipe any lighter than I already am? I’ve even tried not wiping the finish off at all, but the appearance after drying was too thick and heavy looking, not to mention the ridges from not being able to blend into the edges that are already tacking up. I’m in the process of attempting covering only a quarter of the surface at a time, not wiping with a rag, and letting this completely dry before proceeding on the the next section, but I’m afraid I won’t be able to blend the edges properly between coats. I’m working in a basement shop, approx 70 degrees with relative humidity in the “normal” zone of my humidity gauge. I’d guess by now I’ve already put about 10+ coats of finish on this project, sanding at 320 grit or 0000 steel wool between coats but still can’t get rid of the streaks/haze. I don’t have a lot of finish built up though, as I think somewhere during this process I sanded quite heavily in between to try to remove as much of the finish as possible.
Sorry for such a long winded question, but as you can probably tell, I’m a bit desperate at this point as far as what to do next. Hoping to hear from you, and thanks for all you do.
And this was my reply:
Hey Matt. You’ll be happy to know that this seemingly simple process baffled me for quite some time as well. Over the years though, I’ve developed a simple system of application that results in a perfect finish every time. The streaking you are describing seems to be the result of the finish being applied too thin. But you don’t want to go quite as thick as a brushed-on coat. The way I get a coat that is “just right”, is by using the wipe on/no wipe off method. And I would abandon the sponge applicator in favor of a simple folded rag.
Honestly, this process could take a while to explain in an email. And I hate to point to something you would have to buy as a solution, but this is the exact reason I created my DVD, A Simple Varnish Finish. In the video, I show each and every step of the process that I use. The DVD would essentially be a direct answer to your question here. If you are not able to pick up the DVD, I would be more than happy to help you along over email. But obviously, this is something that is much easier to show than it is to explain. Good luck my friend.
Thanks so much replying, and especially the same day! I thought if I heard from you at all it would take weeks! I will be placing an order for the DVD in the coming days. Meanwhile, it may be hard to answer this question without seeing the project, but are you able to comment on whether I need to strip all the old finish off as recommended by the guys at my Woodcraft store? My last sanding and buffing with 0000 steel wool seemed to clean up the imperfections pretty well. Perhaps watching the DVD, trying your technique first, then as a last resort strip if necessary? Thanks again.
If you keep applying thin layers, you’ll never get rid of the streaking. So what I would recommend is giving it one more shot before deciding to strip. This stuff is outlined in the video but I will give you a quick synopsis. You want to get a couple of cotton rags and fold them over several times to create a good sized square applicator. No wrinkles or seams if you can avoid them. Put your Arm-R-Seal in a shallow dish or bowl. Pre-wet your applicator with a little mineral spirits. This has two benefits: it helps the pad glide along the surface and it stops the pad from sucking up and wasting a bunch of varnish. Now dip the applicator in the finish and start applying it in long smooth strokes. Move quickly, deliberately, but not frantically. Each pass overlaps the previous by about half. Reload the pad whenever it stops laying down a good even coat. If you proceed all the way across the table like this, you should end up with the perfect film thickness that will essentially “reset” the surface and cover any flaws. It might take two coats to get it done completely, but it should do the trick. Since you’ve already applied a number of coats, the question is whether the finish will now be too thick. If so, you’ll have to strip. Oh and just an FYI, you never want to apply finish on only part of a surface, especially when using a varnish product. It will create unsightly borders and lines that you’ll never get rid of.
And a few days later Matt writes:
Thanks for your continued support in my efforts! I really appreciate your time. I received your video yesterday and have watched it through to completion twice. Very nicely done, and of course you make it look so easy. And, I’m convinced that it really should be that easy. BUT, something is still going wrong for me. I decided to attempt to strip first, just to try to make sure I was starting with the best possible surface. I wiped down the surface with who knows how many applications of mineral spirits, I’d say about an hour and a half worth of wiping on mineral spirits and wiping off”¦I can’t tell if I’m getting any of the old varnish off though”¦for one, my applicator (white cotton rag) is staying clean, and not taking on the “color” of the wet varnish as it appears right out of the can. Also, I assumed this process would result in a somewhat “gummy, tacky” surface as the mineral spirits are dissolving the varnish, but I found this not to be the case. It was actually “easy on and easy off”. So I’m wondering if once the varnish has had a couple of weeks to cure, will mineral spirits dissolve it? Assuming I have 10+ coats of varnish on already, any idea how long or how many wipings with mineral spirits it will take to remove all the varnish?
Well, anyway, after said numerous wipings with mineral spirits and after arming myself with the techniques in your video, I went down to the shop and proceeded making a nice thick triple folded applicator from three cotton rags (I had been using one third of one folded rag). I decided to attempt to build the finish with gloss Arm-R-Seal, reserving Satin for the final coat in an attempt to reduce the potential streaking from the flatteners in the varnish. I poured some varnish into a plastic food storage container (I had been dipping straight from the can of Satin Arm-R-Seal), wetted my nice thick applicator with mineral spirits, loaded the applicator with varnish and began wiping on in one continuous stroke. Here’s where I notice an immediate deviation from what I see in your video. Now I know you say that I’ll never get rid of the streaking by applying thin coats, but, your varnish in the video appears to be very thin and “watery” as it’s going on the surface. Mine however seems MUCH thicker and heavier. So much so that the applicator has a noticeable “drag” as I’m attempting to wipe the surface. Also, despite the fact that I think I have the applicator very saturated with varnish, I’m not getting a continuous covering on my first application stroke. Then, once the entire surface is at least partially covered and I’m attempting to go over it that one last time to make sure I have continuous coverage, which I know I don’t yet have (by way of a raking light), even with a re-wetted applicator, the varnish feels SO thick and seems like it’s already setting up. This final attempt at smoothing over the varnish just completely ruins the application. I either get too much “puddling” in areas or still not complete coverage in other areas. Total elapsed time for wiping at this point couldn’t have been more than 2-3 minutes. So, out came the mineral spirits and I wiped the varnish completely off and I’m back to square one. This behavior leads me to several possible conclusions: 1) maybe my varnish, being at least 6 months on the shelf, has already started curing in the can, although I do not notice any solidified material around the inside of the can or any “skin” on the surface when I open the can. Or, 2), maybe I already have so much varnish built up, despite my attempts at stripping, that the new varnish is no longer absorbing into the wood, but instead sitting on the surface and is just drying too quickly?
So, one no-brainer would be to purchase a brand new can of Arm-R-Seal, or I am so tempted to thin it out a bit with mineral spirits, despite the can’s instructions not to. Truthfully, I’m tired of buying that Arm-R-Seal, because it seems once I open the can, its shelf life leaves a lot to be desired. Admittedly, I have not tried that gas in a spray can that’s supposed to displace the oxygen in the opened can. Have you ever thinned Arm-R-Seal from the can, and if so, how many parts mineral spirits to how many parts Arm-R-Seal? Would you thin or just buy a new can? Does it sound like I have to be more diligent at stripping?
Well Marc, once again any continued help you can provide would be greatly appreciated. And again congratulations on an excellent video and continued success with it. I’m anxious to try the techniques on my next project, but I must find a way to complete this one first. Take care and hope to hear back from you.
Hey Matt. I hate to say it my friend but you can wipe that surface for 100 years and you’ll never get the varnish off. Cured varnish doesn’t redissolve in mineral spirits. We only use the mineral spirits to dilute uncured varnish in liquid form. To actually remove the finish, you will need a chemical stripper.
So, what makes your project different than mine in the video (aside from size), is the fact that you have so much varnish already on the surface. A well varnished surface will feel like it drags more than one that has raw wood or just a coat or two of finish. So if the finish is drying too fast and you aren’t getting the coverage you need, there is only one thing to do. As you mentioned, you should dilute it. You can usually ignore just about any can that tells you not to dilute. As long as you are diluting with the right material and in the right amounts, you can dilute all day long. Most times these warning are on there to protect the manufacturer, because it keeps the product working in a predictable fashion. You change the formula, you change the way it works and they can no longer help you if you have trouble. Also, by adding more of a thinner, you increase the VOC count. But I say dilute as needed and don’t look back. So given your description, I would dilute the material about 25% with mineral spirits. That should allow you the additional working time and will still leave a pretty good coat. But always move quickly. On larger surfaces, you get about 2-3 strokes to get it right before you need to move on. And don’t count on being able to go back, because it will already be tacky by the time you get there.
Also, even if your Arm-R-Seal is getting old, as long as you are not seeing solids in the can and the finish is curing, it is probably still good. And it shouldn’t have a reduced working time because of it. So I would stick with the same can and just do the dilution. Now remember that every second that can is open, the finish is curing. So if you had been dipping into the can, that means it was open the entire time you were finishing. If you just open the can, pour out what you need and close it back up, you have dramatically reduced the opportunity for oxidation. The finish will last much longer this way, assuming you seal the can up. And this is without products like Bloxygen.
OK so now you see what has to be done. If you decide to take a mulligan, you need to use a chemical stripper. This is messy business. The more environmentally friendly ones require it to sit for at least 30 min. You’ll see the varnish bubble up. Carefully scrape it off, let the surface dry, then give it a decent sanding to remove the residual varnish. You might need a second round of stripping in some areas, but the fresh varnish should come off relatively easily.
Keep the faith my friend. Its all one big learning curve. Think about how many things you’ve learned on this one project alone! Armed with all this information, the next project will be that much easier.
Matt’s final reply:
A month or so later, and I’m finally sending you some pictures of the finished product. I took your advice and thinned the varnish 25% and that made a world of difference. I chose not to strip the old varnish, but instead gave it a good sanding to the point where I “evened” the streaking as much as possible. In hindsight, the worst mistake I made on this project was with the sanding between coats of varnish”¦I think I was taking off too much of the finish with each intermediate sanding, to the point where I was cutting through the various layers to various degrees”¦that, I believe, is the streaking effect I was seeing. The finish is by no means perfect right now; to a discerning woodworker’s eye, it’s not something I’m really proud of, but to the average admirer’s eye, I can live with it. All the methods in your video are spot on, so I’m really looking forward to applying your techniques on my next project. For now though, I must again send you my thanks and appreciation for bailing me out of what at first was a complete ruination to a project I was otherwise extremely proud of. Of course, thanks to David Marks as well for coming up with an amazing design, and for making his designs available via Wood Works and his web site.
A few details about the table: Overall it measures 48” long, 18” wide, and 16” high. The legs and aprons are made from one piece of 8/4 maple for grain and color continuity, as well as providing the proper grain orientation for rift sawing the legs. The top is a bubinga veneer that I resawed from one 4/4 piece of “waterfall” bubinga that I purchased from Rockler. The underside of the top is a maple veneer resawn from the same piece of 8/4 maple. Substrate is a piece of Ã?Â3/4 ply. The inlay is ebony. This project was a “first” for me in many ways:
- resawing my own veneer and using a vacuum press for bonding the top panel
- mortise and loose tenon joinery, accomplished on the router table with the help of a shop made fixture for holding the 44” rails vertically on end
- bandsawing the rough shape of the leg and final shaping by hand with a block plane and sand paper
- inlaying the thin ebony strips and using scarf joints to hide the joints (which also gave me an excuse for purchasing a small, more maneuverable router!)
Funny how it wasn’t my first attempt at using a wipe-on varnish finish, and that’s what ended up giving me all the problems! Since my bubinga stock was neither wide enough nor long enough for the top, I had every intention of using a 2 way book matched pattern, however after laying out the book match, I decided against it due to the different way the light reflected off the top when the grain changed orientation. Instead, I chose a slip match to preserve a continuous reflective quality to the entire top.
If you deem it worthy, please consider sharing the photos with others on your web site. Or, feel free to indulge in a little self-promotion with my quotes of gratitude; you deserve it. You might be able to sell a couple extra copies of your DVD in doing so.