Fire and Health Risks of Potassium Dichromate

Potassium Dichromate is a strong oxidizer and a carcinogen, so don't mess around. August 26, 2008

Can a 5% solution of potassium dichromate in distilled water be safely sprayed in a totally enclosed spray booth without the risk of fire (since it is an oxidizer)? The project is a 2'x3'x10' tansu console. My concern is the crystal residue that will settle in the spray booth and I do spray solvent type finishes. I have completed the final sprayed sample. What do you think?

Forum Responses
(Finishing Forum)
From contributor C:
Yes it is an oxidizer so oxidizers can and do react with cat finishes. If youíre spraying into filters that contain these finishes you may want to re-consider. I have seen one fire started during work hours where bleach was being sprayed in a similar situation, and it auto ignited - what a mess.

Anyway my advice to you is no! Even though you may get away with it, if it's a small project you also may not, and I would err to the safe side rather than the unsafe. Can you apply it by rag or brush? That is how I apply it most of the time on smaller jobs.

From contributor C:
Run a test. Take a small amount of the finish youíre using and set it outside and add 1/4 oz of the PD formula to it and stir, and then wait and see if there is a reaction or not then you'll know for sure if itís safe or not. That is if you use the same finish all the time.

From contributor J:
I have achieved any finish ever put in front of me without ever using any of these ridiculous chemicals and methods. There is always a way to achieves anything without killing yourself doing it.

From contributor C:
Contributor J is correct about it being carcinogenic. Use all due caution, wear a mask and protective clothing, gloves and etc. Spray with hardly any air and mostly material as close to the fan/filters as possible. Thatís why I said I mainly apply by rag or brush instead of spray Ė itís much safer.

Contributor J what do you us - oils and waxes? Everything else I know of has the potential for causing all kinds of health problems and that includes water base dispersions? Itís not what you use as much as how it's used. I have no cancer and Iíve used PD and other's since the 60's, though i know everyone has their own chemistry boundaries as to how there affected.

From the original questioner:
The test is a good idea. Spraying allows me to apply a minimal amount of chemicals to the wood surface and eliminates saturation. With this finish schedule, Ferrous sulfate is applied first and then the Potassium Dichromate and the color is magical. I seal and mist on a 50% NGR mahogany. I finish with brown wax polish and nothing compares. Maybe close but definitely not the same. It's all about chemical reaction that happens. Killing yourself is not good. Finishing materials can be used safely. Itís unfortunate health risks come with the job and our existence.