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91% alcohol or 70%

SteveCuster
in Working with Wood
I realized I needed to make a fresh batch of A&I solution for the next kit I'm building. I mix my A&I in 32oz quart size bottles so it generally lasts me a long time. I made a batch using non-waterproof Higgins india ink like I usually do (5 tsps per 32oz). I used 91% rubbing alcohol, in the past I've always used 70%. I made an interesting discovery, the color was very splotchy. I had the same problem when I was coloring the wood on my O'Neills using rubbing alcohol and chalk, I thought it was normal because it was a new technique to me. I used 91% for that as well.

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I made a batch of A&I using 70% instead, I noticed no splotchy effect. The board on the left 70% the one on the right is 91%

2016-08-31 004
The one on the left is 91% in this photo, the right is 70%.

I've always heard it didn't matter which type and 91% would minimize warpage due to less water content. I did another experiment and found that the same was true with chalk techniques. I got significantly less splotchy coloring when using 70% over 91%. I'll be sticking with 70% from now on.

-Steve




Comments

  • Mike EnglerMike Engler
    Interesting. I'll test some and see what results I get. I sometimes have gotten splotchy results using Rembrandt chalks. Lately I have been using 99% isopropyl alcohol that the pharmacist orders for me, with the idea that it would virtually eliminate warping. We'll see- I plan to test all three with the same batch of basswood and also some white pine, which Mt. Albert is using for their tie stock.
  • adminadmin
    That's an interest discovery. In my experiments I have found that if I use a dull blade or am not careful and scrape coarser chalk pieces on the wood the resulting splotches form. Now we must see if we can reproduce Steve's findings...
  • vinceg
    I just stumbled onto this thread. It's very interesting. Did anyone come up with any new insights?
  • Jerry
    Your sure the wood didn't have the speckles in it before???

    Jerry
  • MuddyCreekRRMuddyCreekRR
    There's a lot less surface tension in pure alcohol.....the water content may help in dispursing the india ink or chalk.......now I need to do some testing too......
  • JayNSmithJayNSmith
    Has anyone tried denatured alcohol? Is that a bad idea? As I understand, it doesn't have any water so theoretically it wouldn't warp the wood at all and wouldn't raise the grain. Just curious.
  • Mike EnglerMike Engler
    I haven't done testing of Steve's theory. I do know that there is a short supply of isopropyl alcohol in many places because it is the primary ingredient in hand sanitizers.
  • JayNSmithJayNSmith
    I am waiting on my Rembrandt chalk to arrive from Blick, but perhaps I can do an experiment comparing isopropyl alcohol vs denatured alcohol with chalk after it comes.
  • brownbr
    Just checked my supply and it is 91%. Down to my last bottle at this point.
  • Jerry
    brownbr said:

    Just checked my supply and it is 91%. Down to my last bottle at this point.

    Better stock up summer's coming and you'll need something to go with Tonic & Lime!!

    Jerry

  • kebmokebmo
    a little while back i got an amazon delivery and it wasn't what i was expecting. i had bought my wife an irish jewelery box. just a 6 or 7 inch long by a bout 3 inch table top legged piano shaped etched pewter jewelry box for her birthday and that's what i thought it was (even though the box wa way too big) but when i brought it in and opened it, there were sox pints of 91% i/a in it so i contacted amazon immediately to see wtf happened. she calmly said i see your order, it'll arrive tomorrow. ok thanks, what do you need me to do with this box of alcohol. oh it was our mistsake sir, you can keep it if you want....
    perfect. i still have three left.
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