Maple Blotch

[Rick Johnston]

First time posting. Just a little better than average skills for a home wood worker.
Project is a coffee table, maple construction. Arm R seal oil/urethane top coat. The top is a glue up from a single board and it's much to light (blonde) to match my other componets and another similar table. One board in the apron had a similar problem. I used a preconditioner, then a combination of Watco oil in cherry and fruitwood. A little sanding the wet oil and I got the result I was looking for.

I did the same treatment with the top. First on the back side and all went well. However, the top blotched like crazy. I did apply a light coat of precondtioner with the back side trial. I sanded the blotch off and this time did a very heavy preconditioner coat. Same result!
I sand it off yet again pending another go at fixing it. With the random orbital I use, 120, 150 and 220. Plus finishing with a light hand sanding of 220. The end grain I used 320 grit. The end grain is so polished it really didn't take much of the stain.

Below are the Options. I'd welcome other thoughts. No. 1 seems the best approach. Whatever I try will be on the back side of the top, but wood already showed me that both sides react differently.

1. Use a water dye (Homestead) . Spray the product on and don't wipe. I did this this earlier today with a Homestead color that is just a little too brown on a test board and there was no blotching. The result looked okay other than the color needs just a hint of cherry added to it. I raised the grain first. Final coat is the Arm R Seal.

2. Do it all over again with the Watco, but this time do as Bob Flexner suggests of letting the conditioner dry overnight.

3. Use a washcoat of 1 to .5 lb dewaxed shellac. Then apply the Watco.

[Kent A Bathurst]

I always apply 2 coats of ~ 1# ultra pale dewaxed shellac as a sealer. Seems to work just fine.

[John TenEyck]

Spraying is your friend and the best (really only) way I know of to eliminate blotching. To assure no blotching you have to spray only enough to wet the wood, with no extra that could migrate. To get a dark color it's often better to spray several light coats to build the color, uniformly, rather than trying to do it all in one coat. You can use water or alcohol with Transtint dye; many prefer DNA for spray work because you can apply coats very quickly.

John

[glenn bradley]

I always apply 2 coats of ~ 1# ultra pale dewaxed shellac as a sealer. Seems to work just fine.

I do what Kent does on blotch-prone woods; a very light cut of dewaxed shellac

[Prashun Patel]

If you use shellac before the oil, you will reduce (how much?) the depth of color from the oil, so you may not match any more.

Given that you have access to spray equipment, I vote for that approach. There are two ways I've been able to exactly match a color:

1) Use a high-flashing solvent for the dye, such as ethanol or acetone. Spray it thin and let it dry and repeat to get the depth you need. Doing it this way - especially with acetone - creates a practically dry spray by the time it hits the surface. This prevents it from absorbing and blotching. CAVEAT: research the safety on spraying acetone. You shouldn't do this without understanding and addressing the safety.

2) Spray the color as a toner. First, shoot a thin cut of dewaxed shellac untinted. Then tint the shellac with an alcohol-based dye and and shoot successive coats. The upside of this that you are sealing and coloring on the top, so the color remains VERY even. You may need to tint a little heavier than in 1) because you want to avoid depositing too much shellac.

[Rick Johnston]

Thanks for the replies. I will post again with the fix and how it turned out.

[George Bokros]

Charles Neil Blotch Control worked great for me on a maple cabinet using TransTint dye for color, then ArmRseal fo top coat.

[Jerry Thompson]

Charles Neil Blotch Control worked great for me on a maple cabinet using TransTint dye for color, then ArmRseal fo top coat.

+1 on Neil's Blotch Control.

[Rick Johnston]

If I spray a water based dye and don't wipe but let it dry I believe that should be blotch free???

[John TenEyck]

Yes, as long as you don't spray so much that it pools on the surface and migrates to the more absorbent areas. Spray light coats, just enough to wet the wood. Spray multiple coats if needed.

John

[Rick Johnston]

I did spray the dye. It went well. Thanks to all.
John with a water based dye, I assume that's compatible with DNA? In that case you mix the powder directly into the alcohol?

[Chris Padilla]

I had great success spraying an NGR dye on maple (think making maple look like dark chocolate walnut) with no blotching. John convinced me to try sanding everything to 180 and then spraying. Bingo...success! Do layer it on to get the finish darker and darker. This method will also find EVERY defect or imperfection or foreign substance on your wood so make sure it is clear of such things (you know, like glue residue and such....)

[John TenEyck]

I did spray the dye. It went well. Thanks to all.
John with a water based dye, I assume that's compatible with DNA? In that case you mix the powder directly into the alcohol?

If you are using Transfast powdered dye, then no, it's only soluble in water, although it may be possible to add DNA to it after it's dissolved in water. Don't know for sure, but I imagine it would be OK. Read to directions, or call Jeff, if that's of interest. Anyway, Transtint, the liquid, is directly soluble in both water and DNA (and other alcohols).

Glad the spraying worked out well. I know others have had success with various blotch control strategies like shellac, glue sizing, etc., but I've just never found any of them fool proof. The only thing that has never failed for me is spraying. Guess I'm a one trick pony - but it's a good trick. The only problem is getting it on uniformly in 3 way inside corners.

John

[Rick Johnston]

John, as stated the dye worked well. Frankly So well that I wish I applied the fix to a problem board in the skirt that I tinted with Watco Danish oil.!! I'm sure a true professional would tint something to improve what I though was "okay" before I saw how well the water dyed worked.
IF I WANTED TO KEEP after treatment on this one skirt board what are my options? It's a board that is about half the end skirt on the table. I suppose there is an oil dye that I could use??? The dye was a Mosers - I need to look if there is the same color in oil.

[Rick Johnston]

John as I have an oil finish I suspect that an oil dye will not work.

[John TenEyck]

Yes, oil soluble dyes will work under an oil based finish. Lockwood makes oil soluble dyes and I think you can get them from Constantine's. But I really doubt they will make an exact color match to the WB dye you used and even if they do I doubt it would look the same anyway. I think you might be better off chemically stripping the piece of wood that doesn't match, sanding it, and then using your WB dye finishing process. I've stripped small sections of pieces several times w/o problems. You just tape off adjacent pieces, carefully apply the stripper, and carefully scrape it off after it's lifted up the finish. Sometimes you have to do it 2 or 3 times to get out as much color as possible. Neutralize and you're good to go. If you don't want to try stripping it, you might be able to just sand or scrape off the old finish.

John

[Andy Pratt]

Rick I realize you have solved your problem so this comment would just be for your general information or for people reading the thread in the future.

There are two ways to control blotching in wood: sealing it to allow your subsequent dye/pigment to affect the wood relatively uniformly, or using a toner.

If you a seal the wood the typical "can't go wrong" thing to use is a dewaxed shellac. Spray a light coat of this on and then apply your dye stronger than you would have without the sealer. An important thing to remember is that you will always get less color change per dye/pigment amount when you have sealed the wood vs when you have not. So, don't expect to turn maple into walnut with this method. You can do multiple coats but figure that the second gives you 50% of the impact of the first and so on.

If you are using a toner you have to understand that you are obscuring the grain of the wood and getting a more "fake" or paint-like look to your project wherever you apply it. This can be done really gracefully or can make your solid wood project look like a piece of cheap walmart furniture. You will have to spray finish to do a toner nicely and with each coat you will obscure the grain more, so it is important to get your finish tone right early on (make practice pieces etc).

If you make a mistake on a project and have a blotchy surface to work with you have two recourses:

1) If you cannot darken the finish based on your or your customers requirements then you have to sand it back down until the blotch is gone or almost gone and then reapply the finish correctly. I have noticed that sometimes the tiny remnants of blotch from an imperfect stain sanded 95% off make a really cool look once a good finish is applied over them. Unless you are in a time crunch, give the dye a full 12-24 hours to dry and you will save yourself considerable cost in sandpaper.

2) If you can darken the finish then just lightly sand your blotched finish, apply a sealer (dewaxed shellac) and apply your much darker finish. If you are going up a few darkness levels it is very unlikely you will be able to notice any blotching after you are done with this option.

Hope this helps,
Andy

[Rick Johnston]

Andy you mentioned sanding after the dye. Would that not alter the dye effect subject to how much wood removed?
The advantages of the shellac sealer vs just spraying the dye and letting it dry are?