Permatex Ultra Copper Vs. Red: What’s The Difference?
I compared them on max heat resistance, flexibility, strength, and how they stand up to oil and gas. When the rubber met the road, here’s how they stacked up: Permatex Ultra Red’s got better strength thanks to its higher tensile strength. But Permatex Ultra Copper really brings the heat – its max temp is 700°F vs Ultra Red’s 650°F.
- Permatex Ultra Copper Vs. Red: Specs & Uses
- My Hands-on Test of Permatex Ultra Copper
- My Hands-on Test of Permatex Ultra Red
Permatex Ultra Copper Vs. Red: Specs & Uses
⏰Drying Time
Permatex Ultra Copper: Tack free in 2 hours, fully cures in 24 hours
Red: Tack free in 1 hour, fully cures in 24 hours
🆚Benefits
Permatex Ultra Copper: High temperature resistance, sensor safe, superior adhesion and flexibility, replaces most cut gaskets, improved fluid resistance, low odor
Red: High temperature resistance, sensor safe, superior adhesion and flexibility, replaces most cut gaskets, improved oil resistance, low odor
🛠️Common Uses
Permatex Ultra Copper is compatible with differential fluids and housings; can potentially seal exhaust components like manifolds; and bonds well to aluminum at high temps.
Red can be used to seal valve covers; seal wood stove parts; High-temperature silicone withstands exhaust pressure; create casting molds
Technical Info
My Hands-on Test of Permatex Ultra Copper
✅Pros
I’ve used it on my BBQ/Smoker, automotive projects, and even on my wood stove in my enclosed utility trailer. Let me tell you, this stuff is amazing.
This is the way I’ve been doing my 2T exhaust connections with Permatex Ultra Copper silicone. It’s always been my go-to method, and it always will be. So here’s the deal, gotta make sure you clean those joints real good with Brakekleen or something like that, you know? That’s the key to keeping those pipes sounding tight, no annoying rattles. And let me tell you, it also saves you from dealing with that dreaded 2T oily mess all over your sweet bike!
Versatility
What I love about this sealant is its versatility. I used it for a do-it-yourself stove pipe installation, and it worked wonders in sealing up the pipe flashing through the roof. It’s slightly flexible yet firm, with a silicone-like touch. I put it to the test by firing up my wood stove to high temperatures, and to my surprise, it didn’t even change color or show any signs of wear and tear.
RecTeq RT-700
One of my favorite uses for this sealant has been on my RecTeq RT-700. After more than 300 hours of use, it has remained flawless, with no cracking whatsoever. The sealant spreads smoothly and efficiently, so you won’t waste it through overuse. Plus, for under $10, I still have plenty left for future projects that require a high-heat sealant. I initially bought two tubes, and I’ll definitely be purchasing more when I run out.
SBC headers
Now, let’s talk about its performance on my SBC headers. I wanted to ensure a perfect fit, and this sealant did the job exceptionally well. Following the directions, I let it sit for 24 hours before exposing it to heat, and the results were outstanding. I couldn’t be more pleased with the outcome.
Whether I’m creating a gasket from scratch or ensuring a factory gasket seals perfectly, this sealant is my go-to choice for all hot exhaust-related surfaces. Its adhesive properties and temperature resistance are truly remarkable. However, I must mention that the packaging could be improved. The bottle has a weak back stitch, and I faced an unfortunate incident where all the contents exploded out the back end due to a little too much pressure. Nevertheless, the product itself is fantastic.
Here’s the finished gasket. The orange color is the Permatex Ultra Copper. It’s a bit messy. It takes 24 hours to cure so I can’t cook on the large tonight.
❌Cons
Some users have reported issues with the opening getting plugged up when not frequently used, but I haven’t encountered this problem personally. It’s always a good idea to keep the opening clean to ensure smooth application.
FAQ of Permatex Ultra Copper
Q: Is Permatex Ultra Copper suitable for sealing stationary parts on my wood stove, rather than using standard gasket material?
A: Permatex Ultra Copper is extremely effective for sealing wood stove parts, with the exception of the firebox. It can seal moving parts at high temps and lasts for years.
Q: Could I use Permatex Ultra Copper in place of an unavailable gasket to seal radiator tubes to the heat exchanger on my gas furnace?
A: Permatex Ultra Copper is great for sealing coolant systems in auto/truck repairs. It can withstand temps up to 800°F and pressure over 15 psi. It remains flexible, unlike epoxy. For flat, secured surfaces it should create an excellent seal. It does not contain acetic acid.
Q: Is Permatex Ultra Copper effective if applied directly to the outside of an exhaust manifold leak, similar to caulking? It is for a Ford F150 2004 V8.
A: Permatex Ultra Copper cannot withstand the extreme pressure and heat directly on an exhaust manifold. Even high-temperature cements fail here. Exhaust bolt corrosion is common. Use proper tools to remove stuck bolts. Copper exhaust gaskets work well for sealing.
Q: Can I use Permatex Ultra Copper to create molds for casting, instead of standard mold-making materials? How difficult is it to clean off once cured?
A: Test first on a small area. Fresh silicone has solvents that may attack the existing mold material. For best results, use a mold release agent like vaseline or oil. Silicone caulk or latex rubber may also work for mold making. Apply in thin layers. It should clean up fairly easily when cured.
Q: If I apply this to temporarily extend my generator’s exhaust, will it clean off easily afterwards?
A: While it handles up to 700°F, exhaust temps are much higher. It should clean easily afterwards as a pliable silicone.
Q: Can I use this as a thread sealer on bolts, like for a thermistor on my motorcycle?
A: Permatex Ultra Copper bonds surfaces, it does not lock threads like Loctite thread sealers (loctite retaining compound vs threadlocker). Use red or green Loctite (loctite red vs blue) for securing bolts.
Q: Can I pour molten pewter into a mold made with Permatex Ultra Copper?
A: I would not recommend it. This is designed as a gasket sealer for engines/vehicles, not as a mold material.
Q: Is Permatex Ultra Copper waterproof once cured?
A: Yes, silicones are waterproof.
Q: Can I use Permatex Ultra Copper between the cylinder head and engine block if I have an antifreeze leak?
A: Unlikely to work. The head likely needs removal, repair, or replacement if warped from overheating. Retorquing may temporarily fix the leak. Permatex Ultra Copper cannot fix this type of mechanical issue.
Q: Can this be used with an exhaust manifold gasket on an older vehicle to improve the seal?
A: This high-temperature silicone sealant could be used to supplement the gasket seal. Test first in an inconspicuous area.
Q: Is Permatex Ultra Copper electrically conductive due to the copper content?
A: No, it is designed as a non-conductive high-temperature gasket sealer. You might be interested in conductive epoxy vs solder for that purpose.
Q: Would Permatex Ultra Copper work for my boat’s turbo and wet exhaust elbow join that currently has no gasket?
A: Possibly, but high exhaust pressure could overwhelm the sealant bead and push it out. This could lead to sealant debris in the engine, so test carefully first.
Q: What color is Permatex Ultra Copper?
A: The sealant I received was a metallic copper color, wet and dried.
Q: Can I use this to improve the seal on my exhaust manifold which has two broken bolts, with or without the gasket?
A: Yes, this high temp sealant could supplement the gasket seal even with broken bolts, but repairing them would be best.
Q: Can I use this to seal gaps and holes in my BBQ grill or smoker?
A: Sure, like I did.
Q: How long does the sealant take to fully cure?
A: Allow at least a couple of hours to fully cure before pressure testing.
Q: Would this work as a seal for the donut gasket on the downpipe of my WRX?
A: Yes, this should work well for that application.
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My Hands-on Test of Permatex Ultra Red
In 2 years of using this product, it has proven that there is no other product to use as resistant to water, heat, and it makes a gasket that can be cleaned like rubber when components are open and re-applied again. The downside is that it is hard to use. It dries out all the time when used and mainly breaks the tube when pressing it after a while, the tube pops open from other parts.
✅Pros of Permatex Ultra Red
Since this exhaust pipe is a “push-in” design it is always best to use a sealant to stop exhaust leaks. I personally like to use Permatex Ultra Red.
Decent Gasket-Type Seal
The first thing to be aware of is that this silicone is a bit thicker than colorless RTV silicone. I’d describe its consistency as being more paste-like than gel-like. It’s also nearly odorless compared to general-purpose colorless RTV silicones. It does what it should – creating a decent gasket-type seal.
As with ANY gasket-type application, you absolutely, positively need to be 100+% certain BOTH surfaces are clean. One thing I did take note of with this particular Parmatex Gasket sealant is that it seems to be thicker in consistency than other brands I’ve used in the past, which is good. It holds up well at high temperatures. I’ve used and abused this stuff at temperatures that I know were in excess of its rated continuous-duty temperature, and it held up regardless.
Good for One-time Projects
If you need this for a one-time project, get it. The sealant holds up well and works well. However, with little force, the bottle split, and the dispensing tip is flimsy. Seal and forget! Simple! It gets the job done, just a bit hard to get the silicone out. You have to push really hard. This worked great to fix a leaky airsoft gas magazine.
I have used this several times when installing diesel heaters in various camper van builds. I use it to seal the underside of the van to make sure NO carbon monoxide is able to get into the van from the exhaust opening, even when firmly screwed into the floor. This product is able to withstand the extreme exhaust heat of a diesel heater.
❌Cons of Permatex Ultra Red
Be forewarned that it is messy, and gloves and lots of clean-up material are needed, even when you are very careful. Do not let it touch your hands (per instructions), nor breathe it in while applying. This is used to seal the exhaust hole, not as an adhesive possessing much adhesive strength. Flares up my asthma like crazy if used indoors.
FAQ of Permatex Ultra Red
Q: Would Permatex Ultra Red work on roof shingles?
A: I would not recommend using this product on roof shingles. For roof shingles, you can read best adhesive for roof shingles. For shingles on your body, consult your doctor.
Q: Is Permatex Ultra Red approved for indirect food contact, like sealing an oven or grill?
A: After contacting the manufacturer, I learned this Permatex silicone sealant is not certified as food-grade or safe for food contact. For high temperature food applications, look for an NSF/FDA certified silicone made specifically for food use.
Q: Can Permatex Ultra Red be used with differential fluid?
A: Yes, Permatex Ultra Red can be applied to differential housings and covers.
Q: How will Permatex Ultra Red perform in a hot, sunny environment like Florida?
A: Permatex Ultra Red is rated for temperatures up to 650°F, so it should withstand a hot climate like Florida’s.
Q: Is this an appropriate sealant for a clothes dryer duct?
A: I would not recommend this product for a dryer duct. There may be other sealants better suited for that application.
Q: Can I use Permatex Ultra Red to install a cooktop over granite?
A: Yes, this high temperature silicone would work well to adhere a cooktop to granite counter tops. Consider matching the color.
Q: Is Permatex Ultra Red resistant to gases?
A: No, Permatex Ultra Red will eventually leak if exposed to gases.
Q: Can I use this as a gasket on a pellet stove?
A: This remains flexible but the high temperature silicone would be better for pellet stoves.
Q: Does this replace pre-cut gaskets?
A: No, this is intended to be used with, not instead of, pre-cut gaskets.
Q: Can I seal an exhaust manifold with this?
A: This high temperature silicone could potentially work for sealing exhaust components like manifolds.
Q: Can this seal a stripped differential drain plug?
A: It might work if the surfaces are clean and dry. Also consider a drain plug designed for stripped threads.
Q: Is Permatex Ultra Red electrically conductive?
A: No, this product should not conduct electricity.
Q: Is this compatible with PVC?
A: For PVC, a PVC-specific glue (dap kwik seal ultra vs silicone) may be better.
Q: Can this withstand a hot Florida sun on a metal roof?
A: Yes, it’s rated for temperatures up to 650°F so should withstand hot sun exposure.
Q: Can I seal a smoker with this?
A: I would not recommend Permatex Ultra Red for use around food preparation.
Q: Will this adhere to aluminum?
A: Yes, it bonds well to aluminum and withstands high heat.
Q: Is this paintable silicone?
A: No, silicones are not paintable.
I’m Ronald Stevens, a Mechanical Engineer obsessed with adhesives, glue, and all things sticky! My passion began in childhood when I’d always be the one playing with glue during arts and crafts. And I’d spend hours researching and experimenting. Happy reading, and remember: stick with the best, and you’ll never be stuck in a mess!
Feel free to contact me and join our discussion:
Would Permatex Ultra Copper be effective at preventing leaks on an engine valve cover that may have some imperfections?
Absolutely, Permatex Ultra Copper is superior to OEM gaskets for sealing valve covers. It conforms to any flaws in the metal like warping, whereas OEM gaskets require perfectly flat surfaces. It can withstand temperatures up to 700°F.