preparing mouldng for hand finishing

[Trinity]

does anyone use aerosol primer to give a smooth key for top coats please

[prospero]

Only on already-finished moulding that won't take water-based paint directly. The standard car body primer will stick well to certain finishes (not all....) and after it's completely dry it will accept water-based paint. It's a waste of time and paint spraying this type of primer onto bare wood.
To prepare bare wood to a smooth finish you either have to apply mulitple coats of gesso or fill the grain with brushed on and scrubbed in fine polyfilla and a few coats of a paint with plenty of 'body', sanded down after each coat. I use the ubiquitous smooth ripple paint from Wickes. It sands smooth, dries fast and is very economical in 5lt tubs. Pity it only comes in white.....

[Not your average framer]

I agree with Prosperro.

However, you can make things easier for yourself by carefully choosing the type of wood you use, because some wood types require more coats to hide the grain of the wood. Also some wood types are more prone to raising the grain when using waterbased paints and primers.

In my experience, tulipwood, beech and lime are some of the best wood types for handfinishing with the minimum degree of effort, but unfortunately the limited range of profiles in these woods automatically mean that we still have to use pine and obeche as well from time to time

Pine on the other hand can be more problematic, depending upon the type of finish you are trying to produce and the quality of the wood. It is a fact that not all pine moulding are the same in this respect. I prefer pine to be as knot free as possible, relatively uniform in grain and as close to white as possible, because I find that this gives the best results when hand finishing.

I'm not that much of a fan of obeche, because of the significant degree of variations in quality, which I encounter far too often these days, particularly the snotwood issue when you cut into an apparently perfect looking piece of obeche, only to find that it's all crumbly it the middle.

[prospero]

I agree with Mark.

Obeche plain mouldings are the most widely available and usually the most consistent. But you do get manky bits here and there. It depends on how it's cut, but sometimes you can get rough parts that swell up when wetted. But the grain filling process wets the wood and causes these parts to become more apparent. When it wood dries these swollen bits will not shrink back so you can sand them smooth and subsequent wetting won't cause further swelling.

Pine is a different animal altogether. Botanically speaking, it is a 'Softwood'. And the term 'Pine' covers a wide variety of species. Some trees grow fast and will have coarse grain. Some old trees have very close grain. Some have a lot of knots, some have very few. But unlike Hardwoods (Obeche is a hardwood. So is Balsa), It doesn't have pronounced pores. So if you get a nice piece of close-grained, un-knotty pine it needs minimal prep. The other thing is the moisture content. Newly sawn stuff is often quite damp and it can affect paint adhesion. I like to give the whole thing a coat of shellac on new cut wood. This also seals the knots, if any. Old boards, such as you might get at a get from a recovery yard are generally much better to work with - once you clean them up a bit. Recycled timber like this can be a lot more expensive though.
Although pine is free of pores it is often a major job covering the grain pattern on coarse-grained wood. The 'rays' - which are the tree rings if you look at a cross-section, are very hard and the wood inbetween is relatively soft. So no matter how much you sand it you can never get it perfectly smooth.
On the whole, pine is great if you want a finish that accentuates the grain - knots, splits and all. In this case a good going-over with a wire brush does wonders. If you are aiming for a dead smooth surface, for gilding or whatever, pine is not the best option unless you are resigned to putting on endless coats of gesso and endless sandpapering.

[vintage frames]

These are my own experiences with using bare-wood. As a base wood for gilding, I actually prefer pine. This is simply because of it's weight. I find a gilded frame cut from pine feels much more solid than one made of say, obeche. Having said that, I first wet the pine with water, let it dry and then sand smooth with 180grit wet and dry'. Otherwise the grain of pine will "print through" the gesso. Then size the wood with RSG, dry and apply gesso. OK, I spray my gesso but 2 or 3 coats with a brush is usually enough.
If I need a wood effect frame I first consider using obeche. This is obviously the most common wood for pre-cut mouldings and the cheapest. All it needs is a good water-stain, coloured up with some earth pigments, two coats of shellac sanding sealer, sanded smooth with 600 grit paper ( careful!) and a few coats of wax. Obeche is also a good base wood for veneers and paint effects.
If I use a quality wood such as oak, walnut or cherry, it is for the character of that wood alone and each species has it's own particular finishing program.

[Not your average framer]

Recently, I've been discovering that the cheaper profiles in obeche are ideal for spirit staining and then sealing / finishing with Polyvine dead flat (matt) wax finish varnish. It's a pity that Lion only stocks it in the satin finish, as the matt finish is not completely matt, but has a nice sheen to it and in my opinion it produces a visually much more pleasing finish.

Also the dead flat finish is the toughest and most durable of the three available finishes, due to the amount of finely ground silica in the formulation. Finely ground silica is the usual matting additive added to water based acylic varnishes and it's useful to know about this when you are looking for a more durable top coat finish.

For me, finishes on these cheaper obeche profile are all about speed and cheapness, but the resulting quality and appearance need not be compromised at all. For speed, I apply both the spirit stain and then the wax finish varnish with pieces of sponge with a fine cellular structure. This saves an enormous amount of time and in particular enables me to get an even, smooth application of the wax finish varnish, without creating an unneccessarily thick coat, thereby reducing the time required for the varnish to set.

BTW, the wax finish varnish tends to produce a self levelling effect as it dries and for this reason I have considered whether it might have any advantages as a grain filling / levelling primer, but to date I've not tried this, so it still remains only an idea!

[prospero]

When it comes to 'woody' type finishes using Obeche as a base, I have long since given up on staining it. I always seemed to get a 'niggly bit'. Small defect of tiny knot that spoils the whole look. I use a two stage paint finish - solid light basecoat with diluted darker wash dragged over. That way you have complete control. Any flaws in the wood are covered over.

[StevenG]

Hi Prospero

You done a few little demos a while back of a few handy techniques, have you any plans for more? I thought they were just great

Cheers
Steven

[prospero]

Well thank you for those kind words.

Anything in particular?

[vintage frames]

Hi Prospero - Why the difficulty with staining obeche? Granted it is a boring wood but would you not find the small knots and imperfections add some character to the wood? One reason I prefer obeche is the cheap base price, from where the cost of the work is in all the applied labour. Which wood would you recommend as an alternative?

[prospero]

No difficulty as such, just don't like the result. I agree that knots and suchlike can add to the character of a frame, but one little flaw on an otherwise 'clean' frame is just annoying. I love doing knotty pine frames, in fact just had a batch collected. But you do have to pay some mind to balancing the knots. I don't like to see all the knots on one side.
If I ever do stain/polish wood I use ash or oak. These woods have an attractive grain pattern that benefit from being accentuated. Obeche is a little bland in this respect, but is great for painted finishes.

[Not your average framer]

One on the advantages of the cheaper obeche profiles is that it doesn't cost very much to cut the lengths that you need from the wood in between any knots, or undesireable blemishes. I always allow for this in my pricing, so it's not a big deal to do this.

I find that staining a fairly featureless wood such as obeche can make knots look extremely obvious, so my policy is that any knots get excluded if it is realistic and practical to do so. My experience is that knot free wood can be a big selling point and that even cheapskate customers can be quite fussy about things like this.

Although we choose paticular mouldings to control our costs, there is no reason why our product should lack in quality, or appearance. Staining need not be only a one step process, but can be enhanced with wash effects before, or after staining to create a more claasy look and feel, without much extra cost, or effort.

[StevenG]

Well thank you for those kind words.

Anything in particular?

You're very welcome Nothing in particular really, maybe some little basic ones, (if you have time)

Thanks again

[prospero]

I'll keep my camera on hand.