Solid cement block under jack-safe?

[Camelfilter]

Howdy, I'm curious what folks think.

Is it safe putting a solid cement block under a jack? I use jack stands for safety, never just a jack.

I used to have a hardwood block to put there, but lost it in a move. I had been using 2x4 remnants, but used them for other projects.

Thanks!

[Towncivilian]

Since it's solid I might - if it were something like a cinder block with holes I'd be wary of it buckling or crumbling under the weight. I guess it's still possible for a solid cement block to crack, too. Wood can split. I suppose since you'll be supporting the vehicle with jack stands after lifting, it may be a moot point if the "jack booster" breaks, just make sure to be clear of the vehicle should it drop without warning during lifting!

[AllTheTimeInTheWorld]

Cinder blocks were jack stands when I was a kid. I didn't use anything else (of course leaving a little tension on the jack). Depending on how you use them (flat sides up and down with a bottle jack over the center webbing) they never failed me. That being said, a floor jack and jack stands is way safer and fairly cheap so why take a chance?

[Camelfilter]

My jack just lifts the tire-barely, hence I've used wood (block/2x4 remnant) to lift higher to place jack stands.

I no longer have the wood, but I do have a 4" thick cement block. I kinda go along with Town's thinking in that it should do allrite. If it fails it would likely fail catastrophically...

[Buzzman]

I've been around a while, and have heard and read about too many stories of cars and jacks collapsing and killing someone.
I just did the rear brakes on my wife's Altima yesterday.
I blocked the front wheels (to stop the car from rolling), and used two jack stands as well as leaving the actual car jack under the car (under light load). 3 jacks in total holding it up.
Even with all that, I still get nervous working underneath the car when it's in the air.
Personally, I wouldn't trust a cinder block to save my life, but maybe I'm just a little over cautious.

[Chuck Tribolet]

Cinder blocks are mostly air. No way I'd use one. Find some scrap 2x or 4x. I needed a couple of pieces of 2x12 to get
the nose of the 'vette high enough to get a floor jack under it. The local lumber yard dug in their scrap bin, no charge.

Chuck

[Camelfilter]

Yeah, I agree I wouldn't use a cinder block.

I'm asking about a solid cement block 4" thick to put under my jack, untill I get some proper wood blocks or a better jack.

This is to jack up the Pathfinder.

Then I place jack stands, then work on the Pathy.

Thanks.