Rainbow Roller

Contest Win: Grand Prize in Rainbow Contest

A roller that paints rainbows!!!

Instead of painting a single color, the rainbow roller blends 10 colors placed in the VIBGYOR order into a beautifully blended rainbow to help make everything a part of fantasy-land themed world.
Now to find that unicorn...

This idea came to me when looking at the Rainbow Contest on instructables. The publishing date this project coincided near about with the legalization of LGBT marriages in US which brought a lot of attention to this project. This instructable's comment section became a raging war zone and soon instructables staff had to step in and remove most of the comments to maintain their 'be nice' policy. A few blogs and social sites ran posts on it, notably the post by bored panda..

The body is made up of a paint-roller and an acrylic box for feeding paint. I used 2mm acrylic for it, but suggest 3mm or thicker in hindsight. The pieces were cut on a table saw and glued together with super-glue. As cyanoacrylates leave white marks on acrylic, using acetone or acrylic glue is preferable.

This uses 2 different types of sponges for transferring paint from acrylic cells to the roller. Selection of sponges is very important and took a bit of research.

The top sponge is a non-absorptive type and seals the bottom to keep the paint from leaking while providing space and proper pressure to keep the second sponge in contact with the paint and allowing it to soak paint. The second sponge is flap-like and transfers paint to the rollers.

Paint selection is also very important. Watercolors didn't work well as they did not transfer from roller to wall well. Acrylic colors work beautifully, especially if diluted with water. The ratio of paint to water is also important as too thin and it all drains out while too thick paint does to get absorbed properly by sponges and roller. Loading paint and rolling over single piece of paper gets the paint flowing properly and we're ready to paint anything in rainbow hues.