91% alcohol or 70%

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.

2016-08-31 003
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.



  • 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.
  • 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...
  • You gentleman are like a hound on a scent. I want to wish everyone a wonderful Labor Day Weekend. Now don't work to hard. Modeling does not count as work, unless you are building a Sheepscot kit.
  • I just stumbled onto this thread. It's very interesting. Did anyone come up with any new insights?
  • Your sure the wood didn't have the speckles in it before???

  • There's a lot less surface tension in pure alcohol.....the water content may help in dispursing the india ink or I need to do some testing too......
Sign In or Register to comment.