Asphalt vs. Butyl Rubber
Asphalt vs. Butyl Rubber
Sound deadener products fall into two main categories based on the material used to dampen the sound. If you just need to know the what and not the why, a butyl-rubber based sound deadener is well worth the added expense. If you would like to know the why, here goes.
The original material that is still used in many of the lower-cost sound deadener products is asphalt (a.k.a. bitumen). Asphalt, a petroleum-based compound, does a fairly good job of sound dampening between freezing and normal room temps. As temperatures increase to 100 degrees, the acoustic loss factor of asphalt-based sound deadeners generally drops to about half of its room temperature values. For example, the acoustic loss factor for B-Quiet Extreme (an asphalt-based sound deadener) has a value of 0.29 at room temperature and 0.14 at 100 degrees. This means that asphalt-based deadeners are only working half as well at these higher temps. Exposure of asphalt-based sound deadeners to higher-temps can also create an undesirable smell. If you’ve ever used one of the asphalt-based products and had the car out in the sun on a hot day, a 140-degree interior temp can often make your interior smell rubbery or like roofers are pouring hot tar on your headliner. Since asphalt is a relatively inexpensive material, vehicle manufactures choose asphalt-based materials. The amount of product used by the OEM vehicle manufacture is extremely limited. This keeps cost low and has the smallest detriment to fuel economy (keeps the vehicle about 15 pounds lighter). The amount of asphalt-based sound deadener material used by most OEMs is only enough to keep the sheet metal from buzzing. Properly finishing the job that the OEM started by adding another 50 square feet of asphalt-based sound deadener to a vehicle interior will show some significant improvements. However, spending the additional $60-$100 it costs to use a butyl-rubber-based sound deadener, instead of the asphalt-based product, is well worth the added expense.
Butyl-rubber is a clear winner in the octagon versus asphalt. It has better standup, better takedown, better wrestling and better submission techniques. At room temperatures where all sound deadeners work their best, a comparable butyl-rubber product will be about 35 percent more effective at sound deadening compared to an asphalt-based product. B-Quiet offers both asphalt and butyl rubber based sound deadening products. In laboratory testing, butyl-rubber-based B-Quiet Ultimate recorded an acoustic loss factor of 0.39 versus only 0.29 for the asphalt-based B-Quiet Extreme. The performance improvement was on the order of 35 percent between room temps and freezing. At elevated temperatures, the performance difference was even more dramatic. At 86 degrees, the butyl-rubber B-Quiet ultimate had a 60-percent higher acoustic loss factor. At 104 degrees, B-Quiet ultimate delivers a 72-percent better acoustic loss factor over the asphalt-based B-Quiet Extreme. In addition to delivering improved sound deadening over asphalt, the butyl-rubber chemistry doesn’t emit the undesirable smells common with asphalt-based deadeners at elevate temps. As for durability, the butyl-rubber sound deadeners do not have the issues of hardening, cracking and have a reduced adhesion over time like the lower-cost asphalt-based products.
So, which is the best bet for you? It all comes down to budget and application. Both automotive sound deadeners are good choices, however butyl rubber tends to be the better bet.