Tips on Exterior Painting
Ron Taylor reveals all with his tips on exterior painting. He covers preparation, Repair Care, sanding v burning off…
Interior and exterior painting requirements are different!
The finish on exterior paintwork has different requirements to the finishes used for internal woodwork and kitchen cabinets.
Interior paint needs to level well and put up with the trials of everyday living, abrasion resistance, staining (chemicals, cleaners, food, etc). Exterior paint has to put up with the elements and withstand different types of staining (insects, plants, etc). That’s why every manufacturer usually has different products for interior and exterior work.
Get your priorities straight for painting exteriors
To me, the priority on an exterior job is that it needs to last. A few brushmarks or dent or two in the finish will soon be ignored by homeowners, if they don’t need to repaint for another six years, or more. I’m not saying skimp on the preparation or not care what the job looks like, but durability is the key.
You could spend ages sanding that window to achieve a glass like finish, only for a gust of wind to make it look like you hadn’t even bothered. Premature failure of the wrong (or even right) type of filler caused by the sun will soon have your perfect paint job looking poor, allowing water to seep under the paint film.
Dealing with rot
Only recently have I started using the Repair Care system for rotten wood and open joints. It isn’t cheap to get set up with, but once you have, you won’t look back. I used to spend ages chiselling out rotten wood, applying wood hardener, waiting for it to dry then building up coat after coat of 2-pack filler, only to find the repair didn’t last, because I either hadn’t removed all the rot or the filler just hadn’t adhered.
Repair Care 1-2-3
1 – Use the Repair Care Metabo router to remove rot. It is a breeze, as is opening up failed joints.
3 – Apply the finishing filler, Dry Flex, in 1 coat. This shapes easily and gives a tough, permanent repair that will never fail.
If you do a lot of exteriors it really is worth looking into this system. If you decided to go the Repair Care route, call in one of their area reps. They will give practical demonstrations onsite and explain all you need to get started.
It’s a great service and my rep, Gary Simmonds, sold this system to me in a very short space of time.
Also talk to people who use it, as their input in invaluable, thank you fellow Traditional Painter, Neil.
Sand or burn?
I’m not a big fan of burning off old paint. If it’s loose and needs it, then fine, but to remove vast areas of sound paint? No way for me. I find scraping off loose paint and sanding with a Festool RO90 or RTS 400 is all that’s needed on most jobs.
Different kind of primer/basecoat
Some finishes will require a primer and some are 2-coat systems formulated to go straight over the existing surface after preparation. I prime all bare and prepared areas with XIM Peel Bond.
Peel Bond is a high build, high adhesion, penetrating primer that will stick to anything. It is highly flexible and extremely thick. Applied as intended, and with multiple coats it will bond and level prepared areas, ready for water based topcoats.
The substrate still needs to be prepared, but using this product will greatly improve the final look of previously painted woodwork that is not in top class condition.
Please note that although Peel Bond can be applied over old oil based products, it is not formulated to be overcoated with oil based finishes.
Zinsser Peel Stop is another excellent product, if you want to prime and seal down old paint or problem surfaces. This doesn’t offer the high build qualities of the XIM product, but it’s worth having in the van, as it works and it is inexpensive for the benefits it offers.
Oil based or water-based paint on exteriors?
There are a lot of exterior paint systems out there now and it can be a bit of a minefield at times. Water based, oil based, hybrids, gloss, satin, eggshell… where do we start for the best finish and longevity?
In reality, there probably isn’t a product out there that is perfect for every job, and what is suitable for one job probably won’t be ideal for the next, especially if you are talking about sheen levels.
Eggshell and satin would have been virtually unheard of years ago for exterior trim, but more customers like the look of them now. But on a busy main road they can be problematic due to the dirt pick up of the lower sheen. If it’s a good product, the longevity of the film may not be a problem, but it will look aged quicker, if road dirt and vehicle exhaust fumes are settling on the duller sheens.
I personally prefer the lower sheens, as they have a tendency not to highlight surface imperfections, but they are not always the best product for certain applications.
Water-based For me water based topcoats are the way to go on exteriors. I find them much easier to work with and the best products will last as long, or longer, than oil based finishes. Their stain blocking isn’t the best and they can actually draw stains through them that weren’t apparent before. But spot priming with a product such as Zinsser Cover Stain will stop this.
Oil based finishes have changed dramatically over the last few years and for me have become harder to apply for most applications. Also the much slower drying times make them difficult to specify for exteriors, particularly casement windows. Windows need to be closed and the British weather can turn quickly, so a product that is still tacky after 8 hours isn’t for me. I know water based paints have their problems as well, but the positives outweigh the negatives in my view.
Acrylic finishes I’ve been a big fan of pure acrylic finishes on exteriors in recent years. Dulux Trade Aquatech Opaque and Mythic Exterior Semi-Gloss are my prefered choices.
The Aquatech will stick to existing oil based finishes with the right preparation but the Mythic really needs a primer for adhesion. I would go for Zinsser 123+ or Johnstone’s Ultra Primer rather than Mythic’s own primer, as they allow the finish to flow better.
Pure acrylic paint won’t stick to glass. If you intend to lap onto glass, and who doesn’t, its best to prime it first.
Hybrid finishes I am now warming to hybrid (eg oil and water) products for exterior paintwork. They adhere to existing oil paints with little effort. They leave a slicker, harder finish than pure acrylic paints, especially the satins, and I feel they will look better for longer, because of this.
Sadolin Superdec has been around for ages and has a proven record. But there are other great products on the market such as Johnstone’s Trade QD Opaque (which offers fantastic opacity), Sikkens Cetol BL Opaque, F & B Exterior Eggshell and lately, Mylands Wood & Metal Gloss, which are all hybrids and will offer good protection and lower maintenance cycles.
Beware brushes in hybrid paints
These products will take their toll on brushes though, as they don’t wash out with water completely. I now wash out the paint as well as I can, then suspend the brush in diluted 50/50 Krud Kutter Original or Krud Kutter Brush Wash using a Hildering Wash & Go brush storer. (Krudkutter has since been discontinued, Fluxaf Pro Clean is one to check out.) This keeps the brush soft and ready to go the next day or over lunch. (More options from Matt Evans for storing brushes for waterbased paint use)
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