Spots after applying dye on red oak

[Clark Harbaugh]

As a previous post of mine stated, I don't use stain/dye very often, however an upcoming project is going to require it. I'm working through the learning process and doing a lot of testing on mixing colors, application process, etc, in hopes of ironing out all the kinks before the actual project. I've done several test pieces with no huge problems, or at least the issues I've had I was able to identify the cause and correct. However, on my last two tests, after applying the dye (using a Transtint dye mixed with water), I get these speckled dots that arise as it dries. I'm pretty sure I'm prepping (to 180 grit) and applying the same as I have been doing, so I'm not sure why I'm suddenly getting these dots. My application is simply applying a modest amount (not flooding the piece) with a rag then immediately wiping off the excess with a clean rag. Any pointers on preventing this?

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[Paul F Franklin]

Are you filtering the dye/water mix? A while ago I had issues with TT dye not dissolving/diluting easily/completely (in alcohol though, not water) and I had to filter it or I ended up with little specs, more or less like what you show.

The other thing that comes to mind with oak is a tannin reaction of some sort....you're not using steel wool as part of your prep are you? Or have lots of iron in your water? Could try distilled water.

[John TenEyck]

I think Paul's onto the potential issues. I would guess iron contamination somewhere, too, and steel wool residue or iron laden water would be the two most likely sources. Try DNA instead of water.

John

[Clark Harbaugh]

Thanks for the replies. I am not filtering the dye mix. I'm using distilled water, so iron shouldn't be an issue. No use of steel wool either. I just tried again on a fresh piece of wood - planed, sanded (Mirka Abranet), blew off the dust, and stained. Same results. I thought about using DNA, but my project will have a couple of very large pieces, and I worry about the reduced drying time.

[Frank Pratt]

If you're not filtering, then those spots are probably from tiny particles of undissolved dye. Try filtering a batch & I bet the specks go away.

[Clark Harbaugh]

Just tried filtering the dye and had the same results. For the filtering, I just used a funnel filter that I use for paint. Should I use something different? Would using some type of sanding sealer work? I know they are typically used before oil based stains, so not sure how well it would work before a water based finish.

[Frank Pratt]

Just tried filtering the dye and had the same results. For the filtering, I just used a funnel filter that I use for paint. Should I use something different? Would using some type of sanding sealer work? I know they are typically used before oil based stains, so not sure how well it would work before a water based finish.

Paint filters are quite coarse. You need something like a coffee filter. The dye is a very finely divided powder.

[mark mcfarlane]

FWIW, I had the same problem the one time I tried transient liquid dye in water. Anxiously awaiting your findings.

[Clark Harbaugh]

Still working through a lot of different tests on this. Filtering/straining didn't help. I'm mixing up a couple more batches, but instead of 100% distilled water, I'm going 50/50 distilled water/DNA. I'm hoping the reduced dryng time helps with what I assume is the capillary action of the red oak pores. I'm also trying different concentrations of the dye mixture. Maybe a couple of coats of a more diluted dye will return close to the same color but without the issue of the spots. I also noticed that using different rags gave me less of the issue, so maybe there is a contamination in the bag of rags I had (though that may be grasping at straws at this point). The last thing I'm trying is some water-based pre-stain conditioner. Trying to be as controlled as possible, I'm trying all the above in every combination and then will compare.

[John TenEyck]

Have you tried repeating this on some red oak from a different board, and also on another species like maple? Maybe it's in the wood itself. Also, instead of applying any excess, try it with a rag that's wrung out enough not to drip, and that the wood completely absorbs the dye from w/o having to wipe any off. I use a stain pad most of the time for applying dye and it works well for me.

John

[Clark Harbaugh]

I think the 50/50 mix of water & DNA is the answer to my issues. I ran a couple different tests using this as the diluting medium and applied to two different pieces, both of which had displayed the dots. Neither had the dots appear with the new mix. I'm going to re-plane, sand, and prep the original test piece just to verify.

[Frank Pratt]

Very interesting. I hope that's the solution.