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Thread: Sprayed dye - spots around pores

  1. #1
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    Sprayed dye - spots around pores

    I'm so close to finishing this table...

    Sprayed the die lightly on the table and now it looks "speckled". The bottom of the table had it in one spot and I figured it was due to the fact that it had pooled in that one area. I paid careful attention and sprayed the top very lightly and it looks even worse! I'm using DNA + transtint dye which was recommended on the transtint docs and other forum posts.

    Is there a way to remedy this? Or fix it? Not really sure what to do next, or prevent it for future.




  2. #2
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    Before anything, replicate your technique on an off cut sanded to the same standard, then apply a coat of finish to it. This effect sometimes disappears but it depends on the product. Otherwise the solution is to stain again and wipe it as you go. You can use a weaker version of the same colour and it won't impact the final result too much. Again, test on a scrap to see what you can get away with colour wise.
    When spraying dye, it's best to use the gun to apply it and wipe it evenly with a rag to finish off. You do this section by section and work quickly so that you can wipe it with the stain still wet. This ensures the colour stays even rather than pulling back from each pore like is happening with your job. Cheers

  3. #3
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    Wayne, what solvent do you use? In spraying it with DNA, there's no way I could wipe it as it is flashing off within a matter of a second or two. I'll try applying the finish on an offcut to see what it looks like.

    If I did re-apply, are you saying to apply this over the existing dye? Or do I have to soak this thing in DNA to remove the existing dye? I did some wiping on the bottom trying to remove or blend the spots and it looked awful as you can visibly see where I wiped.

    EDIT: Tried repeating my method on an offcut which yielded the spots as well. When putting the finish on top, the spots actually become even more pronounced. So at this point I need to remove the existing spots. What's the best way to do this? Is there a way to blend what I've got currently, or do I need to take a ton of DNA and keep wiping till it's all removed?

    EDIT2: Ended up sanding it all back with 150 and working my way back up. Went and got lacquer thinner and tried spraying a mixture of 50/50 lacquer thinner and DNA in accordance with transtint's documentation and am still getting spots around the pores. Turned the air pressure to barely on, as I didn't want the air to cause it to flash off quickly. It even dried slowly but is still leaving circles around the pores. I'm at a loss here, I guess I can try wiping it but was really wanting to spray it for the uniformity and the surface area.
    Last edited by Ian Scofield; 11-03-2017 at 11:39 PM.

  4. #4
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    Purely spray staining is not great for pored timber like this. The spotting is caused by wet edge effect where liquid rolls away from an edge. Pored woods have this on steroids. However, there are two things to do.

    It sounds like you need to slow the stain further. Can you get retarder thinner? If not, mineral turpentine will also work. You need to add enough of either one to your stain to give yourself a couple of minutes drying time. This will weaken the colour but it's better to do a couple of coats to get the colour rather than risking going too dark. That's a decision for you on the spot.

    Assuming you have slowed the stain down, the application technique is to spray a manageable area with a wet coat then wipe off. You need a good cotton rag. Worn cotton winter sheets are good for this if available. Avoid any synthetic fibre. Those don't absorb well enough. Spray about half your table top with a full wet coat of stain working with the grain. Immediately put the gun aside and wipe it down with with rag using full length straight strokes with the grain. You have to work reasonably quickly get it uniform before it dries. Make sure you don't leave a hard line down the centre by wiping accurately to a glue joint. Leave enough time to wipe what appears to be a breadboard end with the grain as well making sure you fade/blend into the unstained area. Repeat the process for the other half. Spray and wipe accurately so that there is no hard line in the centre. When you've the whole area done, you can lightly fog in pale areas with the sprayer for colour matching. Keep this as a dry spray. Don't go overboard as stain greys off as soon as it is dry and you don't see true colour. Do the rest of the colour matching before the final clear coat.

    Spraying dye is not too bad on non pored timber. It is quick and cheap and therefore favoured by industry. However, as you have found out, it causes problems when you want something a bit better. My stains are a mix of dye and pigment. The speed of the dye is modified by the slower pigments. One of the base colours of the dye bleeds into the clear coats and replicates the colour of shellac. The pigment ever so slightly fills the grain. The result has the appearance of French polishing with the durability of a modern coating.

    Apologies for the wordiness. Cheers

  5. #5
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    I would either go with 50/50 DNA/water or an all water mix with your Transtint. That will give you enough open time to wipe it in/off after you spray it on, but only if you spray it heavy enough so it won't dry before you can wipe and that could lead to blotching. Nothing is easy or w/o risk. Or go with a more dilute dye and flood it on with a sponge, then wipe off the excess to drive it into the pores.

    Another way around your problem is to seal what you've already done with a dilute coat of dewaxed shellac, such as Sealcoat cut 50% with DNA, and then apply a pigment stain after that has dried. The pigment will fill those open pores with whatever color you choose. Or just use stain from the get-go.

    Or put your Transtint in shellac and spray toner coats instead of dye.

    Lots of options. Stick with scraps until you have it figured out.

    John

  6. #6
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    To the OP:

    If the surface tension of the dye mixture is high, it may not get pulled down into pores. I generally put a drop of dish soap in my dye mix (I use water instead of DNA, but DNA would have a lower surface tension I think) to help the problem. And you can also pre-wet the wood with water to help. Pre-wetting with DNA probably wouldn't help as it would flash off to quickly. This however may give you grain raising issues.

    I've only sprayed dye a few times, worked fine. But that was cherry and poplar. On oak where I've experienced the above problem, I flood on with a stain-applicator sponge and wipe off quickly. Best done in cooler weather and with plenty of hustle.
    Don't sweat the petty things and don't pet the sweaty things.

  7. #7
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    Thanks for the help. Based on the guidance here it seemed wiping was the only sure way to keep it from flashing off quickly and leaving the circles around the pores. I went ahead and wiped it on and it looked much better. Significantly more time consuming, but I think it turned out alright. I think I willl try for future going the water route and dealing with the raised grain or trying a sponge which can help accelerate the process and given a slightly more even coloring.

  8. #8
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    Quote Originally Posted by Ian Scofield View Post
    Thanks for the help. Based on the guidance here it seemed wiping was the only sure way to keep it from flashing off quickly and leaving the circles around the pores. I went ahead and wiped it on and it looked much better. Significantly more time consuming, but I think it turned out alright. I think I willl try for future going the water route and dealing with the raised grain or trying a sponge which can help accelerate the process and given a slightly more even coloring.
    Pre-wetting and sanding back generally keeps things undercontrol. And if you get a smidge of grain raising, leave it alone and get a few coats of shellac down to seal. Then a scuff sand is less "dangerous" for removing color.
    Don't sweat the petty things and don't pet the sweaty things.

  9. #9
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    increase your liquid flow and wipe immediately after spray. Like others stated, test test and test.

    I get this when spraying oak if I don't have my air/material mix set just right. I spray a lacquer based product that flashes pretty fast.
    -Lud

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