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How Do You FIX Blotching?

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Forum topic by HorizontalMike posted 02-09-2012 10:02 PM 3885 views 0 times favorited 8 replies Add to Favorites Watch
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HorizontalMike

7149 posts in 2378 days


02-09-2012 10:02 PM

Topic tags/keywords: blotch blotching fix fixing blotched sanding

Got ahead of myself on my latest project and stained three pieces BEFORE applying a wood-conditioner.

QUESTION: Can I sand off the current stain and start over with a wood conditioner? I am thinking of just sanding the faces that show (just three 2in-wide window frames).

I have only stained three bookcase window frames (the insides and edges won’t show).

WOOD: White Ash
STAIN: Minwax Golden Oak
CONDITIONER: Minwax Pre-Stain Wood Condtioner
FINAL FINISH: Minwax Tung Oil Finish

-- HorizontalMike -- "Woodpeckers understand..."


8 replies so far

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HorizontalMike

7149 posts in 2378 days


#1 posted 02-10-2012 12:15 AM

Ping… Would appreciate those who have had this challenge.

-- HorizontalMike -- "Woodpeckers understand..."

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CharlesNeil

1610 posts in 3335 days


#2 posted 02-10-2012 12:37 AM

Mike is it possible to get a pic, either here or email me one, Charles@charlesneilwoodworking.com. that helps alot, also tell me exactly what you have done and plan to do ( topcoats ), pretty sure I can help, but seeing it would be great,

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a1Jim

115202 posts in 3041 days


#3 posted 02-10-2012 12:42 AM

I guess the main man beat me to it ,I was going to recommend https://charlesneilwoodworking.3dcartstores.com/Finishing-Nightmares_p_200.html

-- http://artisticwoodstudio.com Custom furniture

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HorizontalMike

7149 posts in 2378 days


#4 posted 02-10-2012 01:14 AM

Thanks for the help Charles. Here are a couple images. The first is my blotching on the window frames, the second is my Barrister’s bookcase. The side panels (re-sawed White Ash) and the back-panels/floor-panels (White Ash Plywood) were pre-finished PRIOR to glue-up of the carcases/units.

Recognized issues:
1. Very hard to get plywood to match hardwood pieces. The combo of ‘Golden’ and ‘Provincial’ on the ply seemed to come close to matching test pieces of hardwood.

2. Blotching came up when I forgot to apply Minwax Pre-Stain Wood Conditioner when starting staining. FYI, end pieces never got pre-stain wood conditioner. I was going to start with the conditioner and had a brain fart and forgot in my rush to get going.

GOAL:
Trying to match up the pre-finished panel inserts with the remaining framing of the bookcase.

Window frames—2-coats (within 10min) of Minwax ‘Golden Oak’ stain. Blotching commenced.

End Panels—2-coats Minwax ‘Golden Oak’ plus 4 coats Minwax ‘Ting Oil Finish’

Plywood back/flooring—2-coats 2-coats Minwax ‘Golden Oak’ plus 1-coat Minwax ‘Provincial’ THEN 3-coats Minwax ‘Tung Oil Finish’. This actually helped to match up with test pieces of Ash hardwood.

-- HorizontalMike -- "Woodpeckers understand..."

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Rick Dennington

5179 posts in 2659 days


#5 posted 02-10-2012 02:36 AM

I would take a rag soaked in mineral spirits, and do a ‘wash” on the parts that you already put stain on….try to remove as much of the old stain as you can, and get it back to bare wood as best you can..let the mineral sprits dry real good, sand it w/ some 320 back to bare wood (?), apply the wood conditioner, and then once it’s dry, apply the satin….that’s what I would do…....The project is looking very good, too…..

-- At my age, an "all--nighter" is not having to get up and pee...!!!

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CharlesNeil

1610 posts in 3335 days


#6 posted 02-10-2012 04:13 PM

Mike, Rick is prettymuch on point, I prefer naphtha over minerals spirits, it seems to pull the stain more so and also dries faster, back in the refinish days, sometimes when we applied a finish or stain, due to some unseen contamination in the wood, the stain or finish would not dry , we could gently wipe it down with nahptha, and it would pull out the contamination and allow the finish to dry. usually ash, like oaks do not blotch, what i am seeing here is definately blotching, and showing because you have the straight grain , ( as you should , for the frames, ) I would give it a good wash down as Rick has denoted, with some naphtha, and when dry give it a good resand, if the surface still feels a bit gummy, clean it again before sanding. Oil stains are more prone to blotch because they are designed to penetrate, as well as dyes, often even the oil prestains will blotch, because they have a tint of color, as well its often more a case of them not being dry in certain areas, because blotching is caused by softer grains with in the wood, and it simply soaks up more, and since Minwax is a linseed oil base, and it dries super slow, it will remain wet within the wood, so you sort of get a wet VS Dry , that appears like blotching, but once its dry it looks alot better. Oil base prestians, are designed to basically prevent penetration, meaning, they are made as clear as possible, when applied, they fill the soft grains and thus prevent the stain from being able to be absorbed as much , and usually cause the color to be much lighter as a result , but any prestian, will cause any oil stain to be lighter, because it has to seal the wood, to be effective, the other issue with oil base stains, is simply the oil, you will note that the can says it stains and seals, and it does, thus we have a catch 22, meaning the prestain is sealing the wood , and so is the stain, so color retention is going to suffer, this is why when using these stains, you can let the first coat dry, and apply a second and not get alot of difference, this is why am such a fan of water base stains, we just don’t have these issues, but that is another topic for another day. So again, lets wash this down and let it dry well, and wash it asecond time if need be, wet it well, and let it soak, so as to soften and redissolve the stain, in the event the stain has “set”, we may need to use some lacquer thinner, which is much stronger, and due to the deep grain of the ash, a good stiff brush may help get into the grains, if you use the lacquer thinner, be careful with the brush, as it can dissolve it, in which case I would use one of the soft brass, “toothbrush” brushes, and finally once its clean, if there remains color still, we can bleach it, with some Clorox, this will help to kill the color, but with any of the solvents or bleach please wear gloves, mask and go out side if possible, and be aware the solvents are flammable, if you have to bleach it, after its dry, be sure to neutralize the bleach with a table spoon of baking soda in a cup of water,( you will have to light sand as the bleach and water will raise the grain some ) I realize i have given you more than you wanted, but sometimes if plan A doesnt work, we have to have a plan B, ( lacquer thinner), or a plan C ( bleach) , the big key will be to get the oil out, and in a deep grain wood like ash or oak, its alot easier said than done, so please keep us posted as to how it goes,

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HorizontalMike

7149 posts in 2378 days


#7 posted 02-10-2012 04:48 PM

Charles,
Thank you so much for the detailed response. Once I have used up all of my oil-based supplies (already purchased), I will seriously look into water-based finishing.

I think I will try only to strip the outside/visible side of the window frames for now.

QUESTION:
• Since all of my inserts were NOT pre-conditioned prior to staining, do you think I will be able to match to them very closely?

• Or do you think I should just purposely have a contrasting difference in color between all of the bookcase frame and inserts? And if so, with what? Straight Minwax Tung Oil Finish appears to be too tanish with NO goldish/yellow tones at all and looks like it clashes with my pre-finished stained inserts (I had finished my Ash workbench with straight Minwax TOF and used this for comparison.

-- HorizontalMike -- "Woodpeckers understand..."

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Rick Dennington

5179 posts in 2659 days


#8 posted 02-10-2012 05:16 PM

Charles:

Good call on the naptha…..I didn’t include that, but I knew about it….I figured you’d cover him on the other steps…. I didn’t know if he would have to get that far or not, and just figured the m.s. would take care of the problem…..I think you’ve got him covered…....:). I like using naptha when necessary, and like you said, it dries so much quicker, thus cutting the down-time on a project…...Spot-on, as usual, Charles…....!!!!

-- At my age, an "all--nighter" is not having to get up and pee...!!!

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