Professional finish on bare timber using water-based paint only
Update from April 2011. To many in the decorating trade it is not possible to achieve a Professional finish on bare timber using water-based paint only. Discussions about painting bare timber using water-based paint only, still usually conclude with – you can’t beat oil for a base coat. True – usually.
Usually, for a good finish in water based paints ie acrylics, you need a sound oil-based surface to paint over. So if you are redecorating over previous oil paint, there is no reason why an all-acrylic system won’t work well, whereas from new, if you want a good base on new timber for topcoats of acrylic eggshell or gloss, there isn’t much out there to compete with 2 coats of oil based Coverstain primer or Tikkurila Otex. On new timber, filling is always a requirement.
5 star professional finish on bare timber using water-based paint only!
What do you do if you need a 5 star finish on new or scraggy, previously painted woodwork, and you can’t use any oil paint whatsoever?
Recent clients didn’t want the odours, or the pollution from off-gassing oil paint. Fine. But they still wanted a very classy traditional brush finish! Tricky. Just using 4 conventional coats of water based paints and conventional fillers, those demands are probably not viable. The first reaction is to manage expectations. My second reaction was, it is possible, surely, with a bit of effort? So I worked out how to deliver what they wanted.
Turn thinking on its head
I soon stopped going round and round in circles looking for the ultimate (but still sub standard) acrylic primer undercoat and eggshell. Going back to basics, I looked at the problem from the other end. The prep. A good finish is all in the filling!
The way I think is: if the surface is rock solid and well filled and prepared, the choice of top coat becomes less of an issue. In other words, with a good base, all your topcoats need to do, is lay on evenly. They don’t have to try filling any surface imperfections. Think about MDF, which tends to start “perfect”. With a good basecoat, most acrylic eggshell topcoats will look very smooth and solid on MDF.
So how do you get a really solid base for acrylic eggshell on dinged up or new woodwork? And quickly? The answer lies in the right choice of fillers.
Artists need to make their canvasses smooth before painting. The surface has to be flexible enough to cope with the canvas moving in different temperatures etc. Artists use liquid Acrylic gesso, as opposed to olde worlde gesso made from rabbit glue size.)
To achieve a professional finish on bare timber mouldings on tops of skirtings and architraves, I highly recommend adding a couple of coats of acrylic gesso to the filling process.
Step by step Professional finish on bare timber using water-based paint
1 – Prime bare/previously painted timber first with Classidur Universal Primer, or Mythic Universal Primer, or a water-based primer of your choice that will prime and seal knots.
2 – I tend to spot fill nail holes in the moulding and profile sections of architraves and skirting boards with a hard stopper filler. When dry I sand with 180 grade abranet using a delta sander for minimum damage. Jack Pauhl has a great list of options for filling nail holes and shows the materials and techniques.
3 – Acrylic gesso is smooth but gritty, runny but heavy bodied. I would liken it to Weathershield masonry paint in texture. As an idea of coverage on 5″ ogee/torus architrave or tops of skirtings, I found that 2 brush loads laid on evenly will cover a 10-12″ section of primed moulding. Leave one hour to dry, and repeat. Leave overnight, sand with 180 grade abranet. You have a really tough flexible base on which to apply subsequent coats of paint.
So in a couple of days, 2 painters can prepare and finish a lot of trim to the highest standard.
If you want to apply gesso really fast, spray. If the grain is really pronounced and requires several layers to make the grain disappear, you can succeed in a realistic timescale by spraying on the filler. I have had good success with a compressor driven Sata 100 B-P HVLP and a 2.5mm tip. Very little overspray. It was demoed for me by Alasdair of Flints Theatrical Chandlers before I bought all the kit. It worked as advertised.
The options are endless with a pressure pot attachment, enabling you to gesso larger areas too!
And this is a small scale gesso spray can option show cased by Megan of Megan Down the Rabbit Hole. It sounds a little thinner than the brush grade gesso that you can put through a powerful spray gun. But worth considering.
Surface filler for flat areas
I have covered how ot apply gesso on mouldings. Now you have to do some filling and sanding on the flat areas to ensure an overall solid, blemish free base for acrylic top coats. Rather than pick and choose what to fill, I skim over the “flats” on baseboard completely. I use something like Toupret 110 “polyfiller”. Zinsser Ready Patch would give good results. 2 skim coats are better than one. I use a flexible 2″ steel filling knife, and sand with 180 abranet. I would use an orbital sander or a rectangular abranet starter kit sanding block. Both attach to a vacuum for dustless sanding.
When I have filled and sanded all surfaces, I caulk joints. Paint at last. I apply 2 coats of top coat, sanding between coats. With darker colours I would suggest a tinted primer undercoat plus top coats.
I just took you through 7 or 8 stages to a finish! But each stage is straightforward and necessary. Ordinarily, if you use standard low VOC, low odour water-based paint systems on less than perfect woodwork, you need to down grade your expectations on the final finish. Compared to oil paints, even the best water-based primer/undercoats and top coats just don’t have enough body to fill surface imperfections. Generally, they look OK at first glance, but on grainy surfaces up close they tend to look a bit “skinny”.
But sometimes needs must, and you have to deliver 5 star finishes with water based products only. It is possible, and now you can suggest to your discerning clients, the options to go the extra mile with low odour low VOC products.
Change of chip
If you are one of the many decorators out there feeling bamboozled by what acrylic eggshell or gloss is “best”, why not change the chip a little. Try focussing on base coats not top coats. Let your preparation do the work, and just find an acrylic eggshell or gloss you like for the way it applies and lays off. And in worse case scenarios, with a drop of floetrol, flop it on and it will look great!
Water borne not water based
Please bear in mind that water-borne paints (hybrids with oil/water mix) will behave more like an oil paint. You still need a solid base to work from though, because flatter primers tend to suck the life out of topcoats. We have plenty of info to share on primers and topcoats on the forum. Primer options are not endless but they are specific.
Thanks for reading about how to achieve a Professional finish on bare timber using water-based paint only. All members of Traditional Painter are expert in filling and preparing wooden substrates. Painting kitchens day in day out will do that to a person!
Please share it on Twitter, Facebook, or print it out for reference. Thanks.
12 comments to “Professional finish on bare timber using water-based paint only”