Brush or roller for painting doors...

Thanks!.

I'm a little confused. I thought primer and undercoat where the same thing. However seems from your post that they are not? Could you elaborate a little about the difference?

One other thing. I've noticed that once I clean my brushes and they dry out they lose their "softness" so you get hard bristle marks the next time on. Anyone got any tips on how to maintain the brush in it's original state of softness?

Originally Posted by bob w

Hi Colin,
I agree, the best finish for doors is enamel applied by a good quality brush. However the modern acrylic multi purpose or (3in1) primer is easier to apply than oil based primers or undercoat and provide a very stable base for all top coats. This means only three coats instead of the four you advocate and reduces the risk of sag or build up which can spoil the appearance. Also the acrylics dry in 2 hours so greatly reduce the time it takes to complete the job.
Cheers
Bob W

I recently used an acrylic paint (self priming) and wasn't very impressed with it at all. I swore I would never touch acrylic again but perhaps it was just a one off bad choice. Will undercoat acrylic really produce a similar result to the oil based one? Drying time isn't an issue. I can let the door sit. I'm not in a hurry.

If you are taking the doors off anyway - I'd spray them up using one of those all in one paint sprayers from bunnings about $140. I would also use Aqua enamel becuase modern oil base enamels yellow fast.

For the architraves (assuming they are fixed) I'd use a paint pad if they are up to 150 mm wide - any wider then a very good quality 100mm soft filament finishing brush (about $60)

Originally Posted by Dirty Doogie

If you are taking the doors off anyway - I'd spray them up using one of those all in one paint sprayers from bunnings about $140. I would also use Aqua enamel becuase modern oil base enamels yellow fast.

For the architraves (assuming they are fixed) I'd use a paint pad if they are up to 150 mm wide - any wider then a very good quality 100mm soft filament finishing brush (about $60)

Sorry doogie, you were a few hours too late. I got back from bunnings around 9pm...

I went to bunnings and bought dulux oil enamel and dulux acrylic undercoat along with some Rota Cota brushes (100mm and 50mm). Also got some 180grit (finest I could find) for my 1/3 sheet sander and some wood filler should I need it. I'll start taking the door off tomorrow and progress through the weekend and see how it turns out..

I thought about the spray paint option but cash is getting tight unfortunately. I'll see how the brushes go. If the one door yeilds satisfactory results with brushes I'm fine. If not I'll think about the spray solution for the remaining doors.

Another way you can paint your doors is firstly by rolling quick dry oil undercoat on with a mo-hair roller. Allowing 16-24 hours to dry depending on the weather then sand back with 180 grit. Dust off or rag off the dust before applying the top coat/s. Cut/brush the sides of the doors and any area the roller will struggle to reach then roll the rest of the door. If you are going for a mirror finish I would lay the door off with the brush after rolling the door. You have to work quick when using oils and spread the paint evenly overwise you will get drag marks orange peel or runs.

The advice above is all good but a few extra points for you to ponder over.

First the answer to your question.

Primer is the first coat you apply. ( if it says primer it's meant to do a speciffic job.) First it is meant to give you the best adhesion to the new surface. Its also to provide a good key for the following coats of paint.

On wood adhesion is pretty easy, if its a hard wood thin it down so it soaks in to the timber, on softer woods you don't have to thin as much. but don't try and put on a thick coat its not meant to fill. On difficult surfaces, metal, aluminium, etc a even more specialised primer is often needed. These etch into the surface to get that adhesion for the following coats.

Undercoat is meant to provide a surface for the top coats. They are meant to level the surface. they contain fillers which allows them to fill the grain so you can then sand them down and produce a great surface which is smooth and blemish free. Depending on the timber you may need up to 3 coats, if you need any more you should be doing something else to get the surface flat first. Like better planing ,sanding or filling of the timber with a thicker material such as a putty.

The colour is designed to give you a flat smooth gloss/semi gloss etc surface. It is not meant to do the work of primer or undercoat. it doesn't stick as good as primer or fill as well as undercoat.

3 in 1 products are mentioned. They are primer/undercoat/sealers. a product for those in a hurry or who don't need a top finish. The sealer which can be also made to do its job well ( seal off underlying paint from being attacked by new paint or vica versa.) These combination paints do work well especially if you are only doing inside and don't have the problems of rain/sun etc that you get externally. Single type producs do do their job better than the combination ones if you are looking at best results but you have to buy 3 tins instead of one.

A few ideas. As you are taking the doors off, lay them down to paint them. Do your painting in an area where dust is not a problem in the air as the best job can be ruined by dust in the air falling into the finish after it is applied.

If you can put in two long nails or screws in the top and bottom edge of the doors. If you can support the doors on these nails with timber long enough to tip the doors over from one side to the other when they are supported by the nails you can brush all the edges and the surface of the door and then tip the door over and paint the reverse side. This can be done while the door is wet or when it is still soft and you won't hurt the paint. ( if dust is a problem it will stop it falling on the new paint also.)The enamel will take a few days to be hard enough to rest on something and not damage your paint job so this allows you to keep the paint away from being marked.

If done properly brushing comes out as good as spraying you just have to get the paint viscosity right so the brush marks flow out. Laying flat gives you a good chance of doing this as you don't have the worry of runs or sags.

Good Brushing enamel normally needs a bit of thinning from a new tin. The instructions will probably say add up to 10% of thinner (in this case turps) You may like to do a test piece. Take a little of the paint out of the big tin and experiment with it first. If you over thin you can add a bit more and you won't wreck the whole lot.

It was suggested you leave the paint in the sun, if you do it will only evaporate the solvent and make it thicker, what the idea is, is to heat the paint up so again take a small amount and place it in a container of hot water ( boil it and then dunk in the tin of paint. The temp will drop to at about 70degrees, the paint will be nice and thin to apply (without thinner added) and you should get a great result.

Once you have your undercoat flat (the finish will only be as good as this surface) do as was suggested roll on the top coat ( you can also flow the paint on with just your brush) and get the surface covered quickly make sure there is a good coat on, not anywhere where there is bald of thin areas. Then get your good brush dip it and wipe the excess paint out and proceed to wipe lightly with the tip of the brush to spread the paint out evenly and remove any excess off the surface.

Go along the door so the brush strokes are vertical if the door was standing up. If you have the viscosity of the paint right, use a good brush and apply it nicely you should get a brush mark free surface. Like everything else practice makes perfect. So do the backs of the doors first. If the doors have panels use a small brush to go around the edges of them first and always finish with the large most important areas last.


Let the paint dry for as long as you can, a week is good especially as the weather gets cool. if the first coat gets any faults in it rub them out with fine paper 240 320 (not 180) no need to ROS the whole panel only the faults if any.

Apply a second coat. ( you should have the knack by now)

If for some reason you make a huge blunder, when applying the undercoat/colour ( stick you hand in it etc) or even if the cat jumps up on it while its still not dry. It is normally better to wash off the paint with turps and rags and start again than it is to let the mess dry and then later try to sand out the problem. Just soak a rag in turps wash the paint and dissolve it (gloves help) . wipe with a clead dry rag while wet and soggy and when the rag becomes too soggy with paint throw the rag away and use the wipe rag to take its place and wipe off with another dry rag. You will be in a hell of a mess for a few minutes but you will be back to square one and ready to do it right in a few minutes not stuck with a disaster which may takes days to dry enough to them attack.

From my experience, a roller is much quicker than a brush on flat surfaces but it seems that a brush gives a better finish. Is it possible to put your base coats and possible one top coat on with the roller and then use the brush on the last coat, assuming the the appropriate sanding takes place between coats?