Elliptical stains on white oak with Transtint/DNA

[mark mcfarlane]

Below is a pic of some white oak, sanded to 150 grit, then rigorously blown clean with compressed air. The transtint dye with DNA (1:200 mixture, ~half normal strength) shows elliptical artifacts around the open pores. The colors in the photo aren't accurate, but it shows the problem.

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Anyone have an idea what is causing this?


I have run a bunch of tests with other stains, oils, varnishes... on the same wood and no other product shows these elliptical artifacts.

My guesses that the DNA is interacting with something in the wood.

[Wayne Lomman]

Not all stains work with all timbers and techniques. If you can't get the effect you want with transtint, use one of your alternatives. Transtint may be good stain, but despite the hype they are no closer to perfect than any other stain brand.

The only way I can advise to get around the problem is to spray the stain. You would meed to practically dry spray it so that you avoid the separation that is happening. Cheers

[mark mcfarlane]

Thanks Wayne,

I am wondering if there is some 'impurity' in my sandpaper that is causing this problem. My first pass of sanding was with a Jet stationary belt/edge sander.

[Steve Swinehart]

It may be the wood itself. Here's a link to an illustration (http://hort.ifas.ufl.edu/woody/images/compartmentstyloses.gif) showing the tyloses in the wood cells of white oak. They make the wood impervious to water. It may simply be the wood rejecting the water based dye in those specific cell areas.

[mark mcfarlane]

It may be the wood itself. Here's a link to an illustration (http://hort.ifas.ufl.edu/woody/images/compartmentstyloses.gif) showing the tyloses in the wood cells of white oak. They make the wood impervious to water. It may simply be the wood rejecting the water based dye in those specific cell areas.

Thanks Steve. FYI, this was an alcohol-based stain, I didn't use a water base I used DNA.

[Wayne Lomman]

Mark, it's not a contamination issue. It is an effect that is not uncommon in pored timbers. What you have discovered is that some stains work better than others in a given situation. As I said above, you may get around it with a change of application technique, but another product will probably do what you want with less hassle.

In general, staining is a combination of science and art. Science has given us a range of pigments and stains that are satisfyingly consistent out of the can. Art takes those materials and adapts them to the task at hand, rejecting those that don't do what you want, not because they are rubbish but because they don't suit the task. Cheers

[mark mcfarlane]

Mark, it's not a contamination issue. It is an effect that is not uncommon in pored timbers. What you have discovered is that some stains work better than others in a given situation. As I said above, you may get around it with a change of application technique, but another product will probably do what you want with less hassle.

In general, staining is a combination of science and art. Science has given us a range of pigments and stains that are satisfyingly consistent out of the can. Art takes those materials and adapts them to the task at hand, rejecting those that don't do what you want, not because they are rubbish but because they don't suit the task. Cheers

Thanks Wayne. I am investing the time to learn more around the 'finishing process'. I appreciate your perspective. I've completed 20 test boards for this project, and picked up a bunch more 'dyes/gel stains/shellacs/...' tonight that will result in another 10-20 samples.

[John TenEyck]

Mark, how did you apply the dye? I've never had that problem with Transtint/DNA with white oak.

John

[mark mcfarlane]

Mark, how did you apply the dye? I've never had that problem with Transtint/DNA with white oak.

John

John, I used a paper towel, either a white or blue one. The same thing happened two me on two different test panels. I did a third Transtint test today using yellow dye and water, and didn't have the same problem.

[Robert Engel]

I'll be watching this one.....

[John TenEyck]

John, I used a paper towel, either a white or blue one. The same thing happened two me on two different test panels. I did a third Transtint test today using yellow dye and water, and didn't have the same problem.

Mark, I would change to a sponge or rag and really flood it on, let it sit a few seconds, and then use the same wrung out rag or sponge to wipe off the excess. You don't want to leave any excess behind because it will dry from the center out and leave a ring. I prefer spraying dye whenever possible, but putting it on manually works just fine, too, on many woods and WO is one of them.

The fact that you didn't have a problem with the yellow suggests to me it's your technique. It could be contamination, too, but I don't think so at this point.

John

Oh, I see now that the yellow dye was with water, not DNA like the other tests. Hmm, that's interesting. I actually prefer water because it seems to give better color but hate using it on WO because of the grain raising. Some folks use a 50/50 mix of DNA/water but I never have. Not sure where I'm going here, sorry.

[Prashun Patel]

I suspect those are 'lap marks' brought about by the dilute nature of your stain and the fast-drying DNA. If you wipe over the entire piece with a wet sponge, it can sometimes go away, but I find the best way is as John suggests: FLOOD the dye on with a sponge. Also, try water not DNA. This will give you more working time. The fears of grain raising are overblown. It's easy to deal with later. The only time I use DNA is if I am spraying (for efficiency, or because I want it very dark and even and fear blotch). You have neither situation here.

The nice thing about water too is that a household sponge deals with it better than it deals with DNA (DAMHIKT).

[mark mcfarlane]

I believe I understand the fundamental problem I was having.

The dye diluted with DNA is absorbing into the pores much better than the same dye diluted with water, i.e. larger residual volume of dye stuck in the pores in the DNA mix. After I wipe the DNA version 'dry' and set it aside, excess DNA based dye is weeping out of the pores, making the rings.

The pic below shows two samples, both mixed at 3:200.

The samples were made as follows:

1) Flood on dye with a blue shop towel
2) wait ~1 minute
3) Wipe off with same blue shop towel
4) wait 3-4 minutes
5) take the picture below

21 is water and transtint
22 is DNA and transtint

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FWIW, I've given up on using Transtint in DNA for this particular project. I'm having some good luck with different products.

[mark mcfarlane]

I ran additional test boards today using a MinWax oil stain and two Danish oil blends and watched them carefully.

All three finishes show the same problem of the stain/oil weeping out of the pores. Since the pores are arranged linearly with the grain, you get the elliptical weep spot.

None of these finishes showed as serious a problem as the Transtint dye, but the stain and oils are all still weeping a little bit 5 hours after the original flood-application.

So the problem is not unique to Transtint dyes and DNA, but they show the effect more than the other finishes I have tried.