I dunno maybe it's because time flies when it's multiflora rose and buckthorns that are getting whacked. It seems that these blades are needing retirement after 8 or so hours. Is this typical for this type of material. WIde range of material but much of it is 2". We are not hitting rocks or soil. Anyone out there care to share their experience? This is a 8" Renegade blade after about 4-6 hrs. We have since learned that using wd-40 would make a difference.
Eight hours seems short for a blade to be completely trashed. I have never used the circular saw blades, but did a lot of work using the three-blade brush knife, when I was cutting ski trails, last summer. I found that the blade would need sharpening after a single shift, but would last for a month or even two before it was too short to use, and I hit rocks all the time. Your blade mostly looks like it is caked in burnt-on sawdust. Maybe try cleaning and sharpening at the end of the day, and see if that has an effect? They also make carbide-tipped brush saw blades, but most of the guys I work with don't like them because they are shot after you hit one rock.
I'm not sure if you are still looking for solutions 6 months after your original post, but if you are not still looking, maybe it will help others.
I used a Husqvarna "Scarlet" blade on my brush saw for several years, since it was what came with my saw. It gave OK performance and was very easy to sharpen (use a 7/32" round file, same as what is used on a 3/8" pitch chainsaw chain). It would probably dull before the end of an 8-hour day of cutting buckthorn.
I did not know what I was missing until an acquaintance who does pre-commercial thinnings professionally suggested I try a Maxi blade.They are a better grade of steel than some of the others. The tooth pattern is a bit different from the Scarlet blade as well. It lasts much longer between sharpenings. It's just as easy to resharpen as the Scarlet blade, and uses the same 7/32" round file. One source is Oregon Maxi 8" Brush Blade (Oregon part number 41-935). Others sell the same thing. All seem to be made in Sweden. I suspect they are all made by the same factory, and just sold under multiple labels.
The 3-bladed brush blades last along time, but cutting even 1/2" buckthorn is pushing it with that type of blade. It's also very hard on the gearing in your brush cutter to try to "chew" your way through larger stems: buckthorn is really tough stuff.
We'll have to wait until next summer to test our current hypothesis but we think that it is important to keep the blade free of
resins. We think resins are building up on our blades and causing them to heat up. The expansion is causing checking and cracking. Next season we will be oiling the blades while we are using them.
Perhaps in the winter the resins would not be as bad.
I've never oiled my brush cutter blade. If your blade is overheating, there are two main causes of that: 1 - cutting with a dull blade, and 2 - the stems you are cutting are pinching the blade (try cutting from the side away from the lean. Trying to cut a tree too big for this tool could also be an issue.
As described in one other reply, Maxi blades work great! I just finished 25 acres of cutting saplings ranging in diameter from less than an inch to 6 inches. The Maxi blade will cut up to a 2-3 inch sapling with one smooth swipe. A 6" sapling requires cutting from both sides and takes 10-30 seconds. I only nicked a few rocks so could have done another 15-20 acres with the blade. Each time I fueled the saw I filed 3 strokes on each tooth taking only 3-4 minutes to sharpen the blade a keep it razor sharp. Must have cut "a million" saplings on the 25 acres, mostly hardwood.