The most aggravating part of many DIY projects is arriving at a point where you can't continue without a specific item. That means either stopping temporarily so you can drive to a local store (if they even have what you need) or stopping for several days while you place an online order. That can eat up hours (or days). By the time you finally get the part, your project has lost all momentum or you've overpaid to have something "in-hand" right now.
We can't eliminate that problem in all cases, but there is one instance in which we can keep the interruptions to a minimum -- finding the right gasket. In most cases, you can be set up to make your own gasket in a matter of minutes and continue your project without wasting your time or (too much) effort.
Non-Asbestos Gasket Material -- The Best Thing Since Sliced Bread
The single best investment for any DIY mechanic is a roll or sheet of non-asbestos gasket maker material. This modern composite sheet (usually made with aramid fibers, fillers, and binders) replaces the old asbestos versions and handles heat, oil, fuel, coolant, and moderate pressure without breaking down.
A single roll costs less than most store-bought gaskets but will last through dozens of repairs (I'm still working on a roll that I've had for over a year). Keep one around and you’ll never be stuck waiting again. It comes in various thicknesses, so you can match it to the job -thinner for carburetors, thicker for exhaust manifolds or water pumps.
I'm in the process of rebuilding an old Johnson 6hp outboard. It's always cheap insurance to swap out the thermostat, but when I opened the thermostat housing, the gasket stuck, peeled, and ripped to shreds (to be fair, it's likely 50+ years old). After cleaning the old gasket material off (never a fun job), I was able to cut a new gasket with no waiting, no fuss. The sheet I cut it from cost me $7 locally and the process took a few minutes.
I still have most of my sheet left. Meanwhile, a "genuine" OMC thermostat gasket is selling for almost $9. And it looks really similar to the one that I made...that's because it's functionally identical.
During testing of that motor, I pulled the nozzle from the front of the fuel pump. The ancient cork gasket beneath it was shot. I cut a new gasket from the same sheet and replaced it. It sealed perfectly and let me run the engine for testing. Would I go down the lake with this setup? Maybe not, since the current replacement is usually made out of fuel proof rubber.
But, that gasket only comes as part of a kit that costs $17. Too expensive to order one for testing, but my temporary gasket let me run the engine without waiting on a replacement.
It's surprising how many die-hard mechanics don't know this trick. But wait, there's more!
The Emergency Backup: Cardboard + Linseed Oil...Cap'n Crunch to the Rescue!
When you’re really in a pinch and don’t have sheet material ready, an old-school trick still works surprisingly well: cardboard (sometimes called chipboard) soaked in linseed oil.
Linseed oil can be kind of expensive, but the upside is that I've only ever bought one quart in my lifetime, and it's still over half full, even after making a bunch of gasket material and refinishing a couple of rifle stocks with it.
Take a piece of heavy cardboard (cereal box, backs of notepads, etc., or you can even order it at the link above.) and soak it thoroughly in boiled linseed oil. I usually apply with a rag or cloth, but if you can immerse the cardboard in it for a short time, that's even better. Then, let it set overnight. The oil polymerizes as it dries, turning the cardboard into a flexible, fuel-proof seal that holds up at low temperatures and low pressures. For an even better seal, add a second or third coat after it dries.
This works well for temporary fuel-line flanges, small carburetor repairs, or any spot where you just need to stop a drip until you can make a proper gasket. It’s not for high-heat or high-pressure applications, but for quick fixes it has saved many of my projects from grinding to a halt.
"What? I have to wait overnight?" Nope, Just keep some on-hand already pre-soaked, and it'll be ready to go when you need it. It's not like you have to work hard to find cardboard...any cereal box will work. I scavenge cardboard ahead of time so I'm not hunting.
Also, be sure to get boiled linseed oil, which is processed so the drying time is much faster. Don't get raw linseed oil because you'll be waiting days for your gaskets to cure. Also, it should go without saying that you don't want to use corrugated cardboard, like the boxes are made from. That kinda defeats the purpose of a gasket altogether.
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Linseed oil soaked cardboard (top)
and "raw" cardboard (bottom) |
SAFETY TIP: Never let the oily application rags lie in a bunch...linseed can give off excessive heat as it cures and it has been known to catch fire. Always lay anything soaked in linseed oil out to dry before use or disposal.
When I begin a project, I make sure I have a few sheets of cardboard already soaked and ready to go.
It paid off last summer, when I had to pull the head, exhaust cover and by-pass cover from my Johnson 9.9 due to a water jacket blockage, I wanted to put it back together and test the water flow through the engine before I did the final reassembly. I made some temporary gaskets using the cardboard/linseed oil trick. I re-assembled the whole power-head and pumped water through it, confirming good water flow. The gaskets really worked well, and saved me from having to wait and test everything after it was already back in one piece.
Although this is best for temporary use, I would trust this long-term in some low-temperature noncritical applications, such as sealing between a carburetor and air box, sealing low-pressure water fittings, etc. There's a Mariner outboard out there somewhere that probably still has an oil-soaked cardboard gasket between the air intake and the carburetor, and there's currently one between the airbox and carb on my homemade outboard motor. There are tons of stories out there of old-timers using cardboard gaskets long term with great success.
Other options - cheap and easy.
I've made carb gaskets out of Fel-Pro 3045 before. It's an even cheaper option than the non-asbestos material but it's more suited to low-temp applications. Once, I ordered a carb kit for the aforementioned Mariner outboard and I accidentally tore the carb-to-manifold gasket when I tore the bag open. I bought a roll of the Fel-Pro for a few bucks at the local parts store, cut it out and put it on the motor when I re-installed the carb. When I sold it, that gasket was still in place and working fine.
There are a variety of options out there for pre-made gasket material to match a variety of applications. Almost all are cheaper than buying pre-made gaskets. You can look up which types of gasket material are best suited for your application.
Of course, there are some applications where you just have to bite the bullet - such as metal ringed head gaskets and such. But for the rest, you can almost always find a suitable material to make your own.
Pro Tip - Often times, ready-made gaskets are just laser cut from specific types or brands of gasket material. When you see a product listing for them. you can sometimes get the identifying number of the appropriate material from the gasket itself. You can then order the material directly and make your own.
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| Gasket made from Interface Solutions TS-9003 material |
How to cut your own gaskets...it's easier than you think.
Here’s why this whole method is so awesome —you can make your custom gaskets fit precisely with little effort or skill.
- Clean the mating surfaces thoroughly (no old gasket bits or debris - really tough to remove gaskets can be loosened with a mix of diesel, ATF and pure acetone - be careful though, because it's nasty stuff).
- Lay your gasket material (non-asbestos sheet or prepared cardboard) flat over the surface you want to seal.
- Grab a rubber mallet (or a soft-faced hammer).
- Tap firmly but gently all the way around the outer perimeter and around every bolt hole. The sharp edges of the metal flange do the cutting for you—the material shears cleanly as you hammer.
That’s it. In under a minute you’ll peel away the excess and have a gasket that fits like it was factory-made. No tracing, no scissors, no guessing. The mallet method gives you a perfect contour every single time.
The Real Payoff: Time and Money Saved
Think about it: a typical OEM or aftermarket gasket can run $15–$50 and take days to arrive. With this method you’re looking at pennies per gasket and about five minutes of work. One roll of non-asbestos material pays for itself after just two or three uses. And the best part is, your project keeps moving forward...no waiting, no agonizing, no fuss.
As always, as an Amazon affiliate, I earn from qualifying purchases. All products that I have linked are products that I have purchased directly, or that I am familiar with through other means. I will never link to products of poor or unknown quality.
