Printable View
Can (or should) a sanding sealer dry before applying stain? Or, should the stain be applied before the sanding sealer has dried? When I look up this information I get conflicting answers. Some say wait for the sealer to dry, lightly sand, then stain. Others say you must stain before the sealer has dried or the wood won't take the stain.
The latter makes sense, but that would mean rushing larger or many pieces. Also, how does that affect multiple coats of stain?
I've never heard of applying stain over sanding sealer before it has dried, so that seems like a bad idea to me. Maybe you are confusing sanding sealer with the various blotch controllers or stain pre-conditioners being sold.
I don't use sanding sealer, period. I often use Sealcoat shellac as a sealer, however. But both can be used to give a more uniform staining job on blotch prone woods like maple, pine, etc. In any case, you allow the sealer to completely dry before applying the stain, and often it's best to lightly sand the wood with 320 or 400 grit before staining. Sanding it removes the sealer from the less porous areas while leaving it in the more porous areas which helps give a more uniform staining job.
But you can figure this all out on your own by making samples. Go try out a bunch of ideas and make up your own mind as to what works best. Never try something on your project before making samples from start to finish.
John
Sanding sealer or any other coating material goes on after the stain. Doing it the other way is incorrect which goes some way to explaining the conflicting advice. If you apply stain after sealing, you are effectively applying a toner, not a stain.
The difference between a stain and a toner is that a stain is colour dispersed in a solvent eg water, alcohol, aromatic hydrocarbon etc. A toner is a tinted/coloured translucent coating material eg, polyurethane, nitro lacquer etc. They all get called stains but behave quite differently. When you put stain over a clear coat, toner is what you end up with.
When applying stain directly to the timber, you can apply as many times as you want to get the depth of colour you want. You can also selectively apply to colour match. Cheers
Wow, this is interesting. Sanding sealers are used on bare wood for a variety of reasons before colorants are applied. I would look up a Jewitt, Gedrys, Flexner or Dresdner answer for sealer use in furniture making questions. They all have miles more finishing under their belt than most of us. You will find it as a first coat and as an intermediate coat depending on the use case.
Finishes that are "self sealing" like those containing shellac or oils often don't require a sealer or can be thinned and used as a light first coat. This acts as a sealer thereby eliminating an extra step and any compatibility issues. This use case can vary from preventing blotch to creating a consistent surface in things like tiger maple.
Sealers are also certainly used on top of finishes to block undesired interactions, lock in color and so forth. Maybe if you tell us what you are specifically trying to do you will get better answers for your particular situation.
I was actually referring to a Pre-Stain Wood Conditioner to prevent that blotching. The can I have says it seals. On the back it says "Do not let the pre-stain conditioner begin to dry or stain will not penetration surface." I'm in Arizona. I don't have time to apply anything on something without it beginning to dry before I reach the other side of a piece of wood.
Any recommendations as to a good blotch preventor that can dry prior to staining?
Yes, you apply stain with that pre-stain conditioner still wet...and you need to be using compatible products, too, preferably from the same manufacturer.
Michael,
You are getting confusing advice because there are two basic approaches to washcoating wood. Let's back up a bit and get to some basics. Firstly, wood blotches when it is stained because parts of the surface take up more stain than other parts. Some woods (pine, maple, cherry) are well known for this and may require washcoating (pre-stain) to avoid blotching. Other woods take up stain more evenly and do not usually require washcoating. You do not mention what species you are staining. You may not need to washcoat.
Wood that blotches does so because some parts have more open pores, and take up more stain, than other parts. A washcoat tends to prevent blotching by partially filling the porous parts of the wood. This tends to reduce the overall penetration of the stain, but reduces the penetration in the porous parts more than in the others.
So, the degree to which washcoating reduces stain penetration depends on the nature of the washcoat. If you put full-strength varnish, lacquer, sanding sealer, etc on the wood and let it dry it will prevent almost all stain penetration. That explains one part of what you have read. If you dilute the washcoat and let it dry it allows more stain to penetrate but may still reduce blotching. You can adjust the dilution to suit yourself. Finally, you can just apply a dilute oil in mineral spirit solution to temporarily block the pores. That's the approach where you have to apply the stain while the pre=wash is still wet, i.e., while the pores are temporarily filled with washcoat.
The easiest for you would be to try the product you have on a piece of scrap wood left over from your project. Apply it, let it dry and then stain it. I'll bet that the result will be satisfactory. If the wood does not take up enough stain, try diluting the washcoat. If the wood still blotches, you will need to follow John TenEyck's advice to experiment. Try a washcoat of dewaxed shellac in alcohol (Sealcoat diluted 1:1 or 1:2 with denatured alcohol) or varnish diluted (1:3) in MS or naphtha on a piece of scrap. Let it dry and stain it.
Doug
Ah, different product than that which I was speaking to :). Jim and Doug have got you covered.Quote:
Originally Posted by Michael Costa
Charles Neil's Product.Quote:
Originally Posted by Michael Costa
Thanks for the detailed responses.
So, there is a piece of furniture I'd like to try making. It's a hutch. Since I know I'll screw up here and there I'm not about to spend $700 for mahogany. I decided I'll use baltic birch instead. I would like to stain it when finished. I know I'll have end grain issues etc, but would like side grain to look as good as possible.
I'm sure most have some experience with staining plywood.
Colour goes down on the surface before any other product is applied if you want to retain an appearance as close to natural as possible. Uniformity is not the goal - natural timber is not uniform. You may not want or need that however.
This approach has somewhat been lost due to the increasing number of heavily promoted premanufactured products on the market and the decreasing trend for makers to put the time into colouring. As I am sure I have said before, colouring and finishing is 3 dimensional. Colour is affected by texture and finishing method. It is necessary to manipulate all of these to get a good result. Cheers
Michael
Wayne Lomman has many years of experience as a professional. So, his last comment is correct, but IMO it is mainly esthetic. The fact is that birch is prone to blotch and, as natural as that may be, you may not like the look if you stain it without prewashing. Birch is sometimes called "Appalachian mahogany" because what you want to do is not uncommon. The problem is, getting from almost white birch to a reddish-brown mahogany color is difficult. The first guidance I would offer is to question whether you really want that mahogany color. If you do, the second guidance I would offer is that you are unlikely to get the color you want with one coat of oil stain over prewashed birch plywood. And two coats of oil stain are (IMO) out of the question. It will look muddy and tend to streak. The vehicle for oil stain does not dry hard and a second coat tends to bleed. You would have to seal it with dewaxed shellac or it will bleed into varnish topcoats.
That brings us to toning, which Wayne has already defined. You can use tinted shellac or tinted varnish, Minwax Polyshades is an example. Again, IMO polyshades has too much tint in it and is therefore very difficult to brush on evenly. You might have some success if you dilute Polyshades 1:1 with MS and use it as a wiping varnish over stained wood that has been sealed with a coat of dewaxed shellac. Then you could add thin even coats until you get the desired color. Work this out on a piece of scrap before you try it on your hutch.
That's how I would stain the piece. It's a lot of work. A smarter but slightly more expensive approach would be to use mahogany veneered plywood. That will get you back to what Wayne is speaking about -- a more natural looking finish. It will spare you the labor of the coloring process I described above.
Regarding the edges of plywood, the best way to finish those is to edge band with solid mahogany. The edge banding would only need to be an eighth of an inch thick so it would not require a lot of wood. The cheap and easy way is to buy iron-on mahogany veneer tape.
Best of luck
Doug
If you don't want to "screw it up" I would choose a wood more easily worked and finished than Baltic birch. I much prefer to work with solid wood, leaving plywood for such things as panels or backs. In addition, birch is difficult to finish well, unless you plan to use paint. It blotches easily, though dye is somewhat less prone to blotch. For example, oak stains easily and is not very expensive. Oak does have distinctive grain, but it can be filled after staining or coloring. Panels of plywood are also readily available.
I'll probably keep it light in color. It doesn't have to be mahogany. I'm only usino baltic birch because I know I can build the entire thing with 3 sheets which is much cheaper than using solid lumber. After my learning curve and oops etc, I would most likely remake it with nicer wood.
Actually, now that I'm thinking of it, I could probably tear down the Baltic birch one and salvage the hardware for the new one and then have plenty of plywood left for other projects.
Sometimes just talking something out puts ideas in your head that you didn't think to consider.
Thanks guys.
Ps... Doug posted about TenEycks method and also mentioned Wayne. What do you guys typical do to store/save the info for later use? I was just going to copy and paste it into a note program and try to keep it organized. I figure that would be easier than trying to hunt it down in here 3 months from now.
Michael, making the unit from ply is nothing to apologise for. In fact, the apologies are owed to you from those who have criticized your choice of materials. Go ahead and make it to the best of your ability. You have chosen perfectly acceptable materials that will make a piece of furniture that will last a lifetime, so don't think about demolishing it. Your time and efforts are worth more than that.
With regard to your colour, keeping it light will simplify the process. Stain and coat it with the back off. It makes the job much easier to access and you avoid the internal corners that are difficult to colour evenly. Dry fit the back and hold it in place temporarily while building the cabinet but take it off and polish it and the cabinet separately.
In general, when I referred earlier to a natural finish, what I am talking about is a finish the fools the average person into thinking they are looking at real timber. This means colouring in a way that retains the dark and light, the straight and figured, the end grain and long grain etc. Toners are just a weak colour on top that belts everything into an average colour, a bit like wearing sunglasses. Stain, on the other hand, works directly on and within the timber to change the colour at its source, allowing the clear coats on top to enhance and protect the colour.
By the way, copy and paste my notes any way that is within the rules of the forum. Mine are stored in my head and I use this forum to pass on the knowledge that was freely passed on to me, since I no longer have any apprentices to pass this onto. Book writing can wait. Cheers
Michael,
Thanks for following up. I think a lighter color will avoid many problems for you. I have been making notes for many years, from woodworking forums and other sources. I made them as I went along, as I learned this craft. I store them on my computer. It's distressing how easily I can forget somethig that was once clear to me. I am a writer by nature, if not by profession, so after about 15 years of that, I did turn them into a book. You can find it on my SMC profile.
Doug