Holts Firegum – Product Review
February 11, 2023
Exhaust pipes. Most are made of mild steel and mild steel enjoys nothing more than to return to the earth from whence it came at every opportunity. Unless you’re fortunate enough to have picked up a classic with a stainless steel system, or you’ve upgraded it yourself, then the chances are you’ve had to deal with a rotten exhaust in the past. If you haven’t then strap in because the likelihood of having to replace one section or another is probably imminent. Rust is the biggest cause of exhaust issues but the upside of using mild steel is its inherent affordability, which makes replacing various sections relatively kind to your wallet. Having said that, you can’t just jam two pieces of pipe together and hope for the best. With a standard sleeve system, whereby one end slides into the other and is then held together by a clamp, it’s imperative to utilise some form of exhaust paste – like Holts Firegum – which will not only aid in lubricating the two sections, making it easier to fit them together, but also, and more importantly, it helps to provide an air-tight seal meaning all of the exhaust gases make it to the end of the system rather than leaking out all over the shop.
The Product
Costing less than a fiver for a single 150g tube of Holts Firegum exhaust assembly paste it should last you quite a while, unless you’re constantly repairing exhausts. We’ve had the same tube for years now and the product hasn’t deteriorated or hardened in that time. The paste is easy to apply and it creates a 100% gas tight pipe seal that hardens from the heat of the exhaust, securing the different sections of exhaust together and preventing them from rusting solid. It doesn’t contain Asbestos and is heat-resistant to 1000 °C.
The Test
The catalytic converter on our Volvo 940 Turbo recently made a bid for freedom after the clamps holding it to the exhaust downpipe finally rusted through and so we had to re-attach it to the car. This meant first removing it entirely then cleaning up the joins at either end and finally fitting new clamps. Where the rear of the cat attaches to the rest of the exhaust system is a sleeve connection and so we had to break out our trusty tube of Holts Firegum to make sure we had a good, airtight seal.
The Result
After prepping the two end sections of pipe, which in our case involved angle grinding some rusted metal off and then wire brushing the two end sections of pipe to remove any loose material, we then liberally applied the Firegum, smooshing it around the circumference of the exhaust with a gloved finger. The two sections slid together smoothly thanks to the lubricating effect of the exhaust paste and then we were able to fully tighten our new U-clamp in place. We left the car overnight, returning in the morning to run the engine and check for any leaks and we’re happy to report there were none. Exhaust fixed.
The Verdict – 5 out of 5
This isn’t the first time we’ve used Holts Firegum to repair an exhaust and it certainly won’t be the last because the fact of the matter is the stuff works and it works well. It’s been well over a week since this particular repair and the exhaust remains leak-free. If you can afford a full stainless system then that’s the route we would advise you take but for those of us stuck with a mild steel exhaust then this is a must have addition to your tool box because you will need it.
