Preventing a Dull or Flat Look with Waterborne Poly
If you don't want a waterborne poly finish to look lifeless and drab, take a look at these tips on finish choice and application technique. July 8, 2014
Question (WOODWEB Member) :
I have been using oil based poly to finish off slab pieces and have recently decided to try using water based poly for these three reasons:
1. Easier and less messy to spray.
2. Faster drying time.
3. Less VOC's.
However we just tried it on a large walnut slab that was sanded to 220 using General Finishes Water based poly in Satin finish. Instead of bringing out the natural beauty of the slab it ended up looking grey and washed out. Is this blushing effect due to the weather here is Seattle (humidity between 80-90% and temp around 50 F)? I ended up using Restore a Finish over the poly and it seemed to bring out the character of the wood nicely. Any tips for how to avoid the blushing effect or any tips on other products that are relatively easy to apply and can be applied in a garage (non-climate controlled) setting?
Forum Responses
(Finishing Forum)
From contributor N:
Waterbase finish can be lifeless on natural wood. Some people mix dye with it to make it look more like a solvent finish. When I was using WB I would first spray a light coat of shellac mixed from flakes to give it some life then spray the WB.
From contributor V:
Seal the wood with dewaxed Shellac - it will make a world of difference.
From contributor C:
You might try sanding to 180 in addition to the shellac. It will help the wood absorb the finish a bit deeper and thus add to the chatoyance and overall look of the wood. As far as smoothing goes I sand after the sealer coat and a scuff sand between layers so the finish is just as smooth.
From contributor J:
No need for the extra steps. You just used the wrong GF product. The poly is meant to be a very neutral clear coat. You need to use their Endurovar or their exterior 450 varnish, they have much more life to them. Use gloss to build your coats as this will give the most clarity and depth. Thin your first two or three coats by 20% or so to get it down into the wood. Lastly you need to be patient and let the finish fully cure/mature. All WB’s look a little blue right after they are finished. After a week or two depending on the weather they lose that and look more normal.
From the original questioner:
What I guess I really need is a durable finish that dries quickly. As a small business we can’t wait a week to apply finish. Would conversion varnish be a better solution? Should we consider a wax product? Lastly, given that we are going for a contemporary look, we want a satin or matte finish.
From Contributor B:
In a high humidity environment, you just need to apply thinner coats. The WB dries quickly, but a heavy coat traps some moisture. Try four or five lighter coats instead of two-three heavy coats. This will reduce the blush, and the overall time for four-five coats to set up is about the same as two-three heavier coats.
From contributor J:
Use the Endurovar satin or flat for your last two coats. The only reason to build with gloss is to add life and clarity to the finish. They also make an accelerator you can add to the finish if you are dealing with high humidity.
From contributor A:
I’ve been using GF products for years. I always add touch of orange dye to pre-cat urethane (which is their tightest finish similar to nitro lac, that's the reason I haven't switched to the poly) and sanding sealer. It gives it a nice warm look. Also as others have mentioned you don’t want to build the coats with a satin/flat by the time you’re done. The finish will look dead so use GF's sanding sealer or gloss for your build coats and only one coat of whatever desired sheen you like. Also WB's like air circulation, so in your case of a garage a small 20" box fan will suffice to make the WB kick quicker and take care of the blushing. If you’re looking for a tougher finish you could add their Crosslinker for the final coat.
Also when it gets cold instead of thinning with water I warm up my finish by putting it in bucket of hot water for a bit. Even in cold weather you should be able to do three-five coats a day using the fan and heated finish.
From Contributor F:
Separate the products for discussion. Contributor J and Contributor A are talking two different products than the one the original questioner used. All three seem to handle differently for me. The Pre-Cat sprays the easiest and Endurovar takes time to learn. The Endurovar ambers but the poly and the Pre-Cat do not. A call to General Finishes has always brought me excellent assistance. I've used these and the older Pro Acrylic for more than ten years and only had blushing with Endurovar when I put it on too heavy.
