My lawn is full of so much thatch that I can bend down and pull up handfuls. I used a steel rake to pull up some today but it is still full of thatch. I feel like I could continue raking for days and never get it all. Will a rake meant specifically for dethatching be any easier to use, and more importantly will it pull up more thatch than a standard steel rake?
Where in California (according to your SE profile) are you?
Am asking, as from my limited research (knowledge) on grass types used in California, I discovered:
If you do have a warm season lawn (grass type), for the overall health of your lawn you should only dethatch in Spring, once the grass has woken from dormancy & is actively growing.
Dethatching at any other time of year greatly increases the chance of causing real damage to a warm season lawn.
On the other hand, if you have a cool season lawn (grass type), without a shadow of a doubt the best time of year to treat, perform maintenance, on your lawn is late Summer, early Autumn (Fall). Around "Labor Day" in the USA is generally considered about ideal.
Now adding onto "Mancuniensis" answer, I recommend paying a visit to your local tool hire shop (store) and rent yourself a mechanically powered Dethatcher (a machine you walk behind, just like a lawnmower) for a ½ or full day.
Additionally, as you paint a picture of a bad thatch problem, I would also be very tempted to get hold of a mechanically powered Aerator and aerate your lawn after dethatching. Doing so will open up the soil, get some much needed air in there.
Then after doing that, I would give your lawn a "natural" feed with a allover covering of ½ to 1inch (12.5 to 25mm) thick layer of screened compost (preferably STA-certified or similar).
A standard garden rake doesn't remove thatch well at all. Either of the following tools would do the job much better: