Walnut ink with PVA test - Caulking

[modeller_masa]

Hello, 

I got some walnut ink to use for caulking after I read some interesting topics about it.

 

Hot tab water was enough, and the amount of water can control the color from black to sepia tone brown.

 

At first, I mixed the prepared walnut ink with a fast drying Titebond PVA bond. It hardened quickly, and became a solid rubber. (Left picture) I used regular PVA glue, and it worked perfectly. (Right picture) I guess the walnut ink particles accelerate the PVA's hardening speed.

 

I've tested dyed PVA bonds in the past. I used black acrylic paint, but it decreased adhesion strength critically. The walnut ink that is mixed with regular PVA bond works like white PVA bond.

 

However, the thickness wasn't for me. The thickness of the PVA bond layer between basswood planks is 0.02~0.03mm.

 

In general, the width of caulking in reality is between 3.0mm (1/8") and 13.0mm (1/2"). I'm making 1/60 HMS Bounty, so I need at least 0.05mm of black layer between planks for realistic caulking. The 0.02mm may be good for 1/144 or smaller scale ships. 

 

The thickness of regular black paper, which has 90 gsm, is about 0.90mm, and black rice paper, which is 26 gsm, is about half that thickness. Therefore, the black rice paper is the best for me. 

 

 

 

Don't forget to wear gloves when you use walnut ink.  

Quote

An ancient use of walnut ink was to stain the hands of criminals in Romani communities. Once stained, it is impossible to wash off and remains in the skin for a long period of time. ( https://en.wikipedia.org/wiki/Walnut_ink )

[Roger Pellett]

Regular old fashioned poster paint powder (the kind used in grade school art classes) can be used to color glues.  I have used it for both PVA and Epoxy glues.  It does not seem to react chemically with the. Glue.

 

Roger

[Jaager]

On 11/2/2022 at 12:41 PM, modeller_masa said:

In general, the width of caulking in reality is between 3.0mm (1/8") and 13.0mm (1/2").

For aspects that are essentially a color effect such as caulking, it is worth considering scale effect.  If strict adherence to actual scale is followed, those color - especially dark color - parts may present as being much larger than they actually are. 

The Walnut dyed PVA  may be as wide as is needed.  Slamming the viewer with wide stripes may be a distraction.  Going wider may want the color of the caulking to be dialed back in darkness, a lot.