Spontaneous Combustion in your Gunsmithing Shop

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Spetember 15, 2021 


By Robert Dunn, GCA Community Manger and Gunsmith 


Having purchased a classic fire prevention can for oily rags today at a yard sale, I felt inspired to write about potential fires in your gunsmithing shop in the hope that I may prevent some accidents from happening out there by passing on a few simple tips and reminders. I’ve had quite a few run-ins with dangerous fires throughout my life and they can be scary and devastating. Many times throughout our gunsmithing careers we might become complacent about fire safety and in certain cases, it may cost us dearly. I wanted to briefly write about some of the fire dangers that you might face in your gunsmithing shop, as many times you will be using fire or flames to complete a repair. There many types of welding and if you are careless there is a chance that you can start a fire in your shop or even catch yourself on fire! We use heat and flames to build up material on a worn part or to join two broken pieces of a gun. Extreme heat is also used to both harden and anneal steel depending on what you are trying to accomplish with your gun repair. Fires can also occur from old or faulty wiring, but the most common fire in a machine shop is caused by the mismanagement of dust and metal chips.

The point that I wanted to drive home today is that oily or solvent-soaked rags do spontaneously combust. I have seen this occur several times in my travels. Spontaneous combustion can and will occur when a cloth, rag, or paper towel is slowly heated to its ignition point through oxidation! I have been witness to these exothermic combustions in as little as 1 hour after applying an oil-based stain or topcoat, but they can occur for up to a few days as the oily rags dry! This is the reason that I quickly scooped up my “oily rag can” at this morning’s yard sale!

I will share a story with you that involves Master Gunsmith Bob Dunlap and myself whilst filming the Pivot Barrel Shotgun Course! Bob and I truly multitasked through the entire production of this course. To make a long story short, an old English shotgun’s buttstock accidentally took a dive off of the workbench and demanded a repair that first involved gluing and then touching up with a boiled linseed oil finish. After Bob finished applying the last coat of boiled linseed oil and I finished an inertia block repair on my Dad’s Charles Daly Model 500, we headed out for lunch. When we returned to the gunsmithing studio after about an hour, the rags that Bob used for cleaning up the boiled linseed oil had combusted on the countertop and were burning next to the stock he had so diligently repaired! There was no damage to the gunstock or film set, but I guarantee that if we ordered dessert with our lunch, the Coquille Fire Department might have just beat us back to the studio/workshop!

On two occasions, I have had paper towels combust overnight after applying oil-based finishes to gunstocks. The towels ignited and burned at some point during the night in the tin coffee cans that I had placed them into! The coffee can was left in the middle of my large workbench just in case it caught on fire! My Dad taught me to do this at an early age when we used to restore antique furniture together. I don’t mess around these days and all rags go into my burn cans.

For more information about how to insure you and your gunsmithing shop’s safety and well-being take a look at my article in GunTech #174 that is entitled “Gunsmithing and Firearms Safety…a Reminder”.

I would really like to hear about any experiences that you may have had with spontaneously combusting materials in your shop! Please hit replay and let us know your thoughts!

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