Blacktop at 80 degrees

[micky]

I learned in the past couple weeks that blacktop at 80 degrees iirc is soft enough that the wheels of a floor jack, or the bottom outline of jack stands will sink into the blacktop. This is an especial problem with a floor jack because it's meant to roll backwards as the car is lifted, but if the wheels are stuck in the blacktop, the support plate of the jack will move underneath and wrt the car, making scarey noises at the very least.

Not only that but when I'm jacking up the right side, after I had jacked up the left and rested it on a jack stand, the jack did NOT move wrt to car. Instead it made the whole car move and that made the jackstand on the left side tip partly over.

And going down it makes even scarier noises.

I should have laid down plywood, just a little bigger than the jack, so it would roll.

However the weather was about 70 degrees in the past few days, and nothing sank into the blacktop, and the floor jack rolled as it's supposed to.

For 14 dollars, they sell a ~10 pound plastic bucket of stuff to fix the blacktop, but it's too cold at night to use it now. Next summer I'll patch the parking lot I've been using. I hope no one notices before then. ;-)

[Steve W.]

Yep, toss down as large a hunk of GOOD plywood as possible if you're trying to use a jack on anything other than solid concrete.

[Tegger]

"Steve W." wrote in news:m1a5lt$736$ [e-mail]:

Hardwood plywood is best. That's what I use. I also put squares of it under my jack stands.

Specifically, 15mm Baltic Birch, and 5/8" Maple, seem to be the easiest to find.

Any carpentry shop or furniture shop should be able to give you scrap pieces. There is also a small industry called "steel rule dies" that uses a huge amount of hardwood plywood. Check your local phone listings.

[clare]

Weld plates on the bottom of the jackstands to keep them from "cutting in" and get a floor jack with full width rollers instead of wheels/casters. A 2X8' hunk of 3/8" plywood for the jack works too.

[makolber]

Whenever i jack up the car intending to get under it, i think about sinkhol es. I know its a freak thing, but there could be a sinkhole under the asph alt where i happen to put the jack. That is why i use a least two supports for the car before i get under it. Mark

[EXT]

Much of the problem with asphalt black top is a combination of age and grade. You will note that the roads are made with a much harder grade of asphalt than most driveways. In fact many driveways are made with a grade of asphalt that contains a high percentage of sand compared to stone. This type will be soft and weak for years, while it is easier for the installer to place and roll. Commercial car parks and roads use a grade with much more stone and larger stones. This makes a firmer base that is less likely to deform under pressure. Many people do not like the look because the stone will start showing through when to top coating of tar wears off and the color of the stone starts to show through. If it is made with limestone, it will have a light gray appearance, I have seen green, red and other stone colors in local roads, including sparkles from crushed glass. If I was to pave my driveway, I would insist on a commercial grade of asphalt, to avoid the soft and easily damaged surface.

[Geoff Welsh]

unless you own the concrete (like my house's driveway), then please use plywood there too.

:-)

GW

[micky]

I remember when the next-door neighbors, the Lewises, put blacktop on their driveway in 1953. I was told that they were told that they had to be careful with it or it would be damaged. Maybe we little kids were told that too, but there was nothing we little kids or the big kids did to other people's driveways. And I don't think t here was anything the Lewises did to any driveway. I guess they were just repeating the contractor's warning. I suppose on occasion Mr. Lewis might hammer on something there, and that's what he wasn't supposed to do.

[clare]

NEVER get under a car supported only by a jack - or worse yet, 2 jacks!!

[micky]

I don't think we've had sinkholes in Maryland yet. So I'll try not to think about them.

I had a jack stand collapse once, and the weight on it was 1/3 its rating.

This last time, I had two jacks and two jackstands under the front side I was working on, and one jack and one jackstand under the other front side. And I tried to shake the car before I started working.

But I still had fantasies of the wheel hub backing plate cutting into my chest, even though I wasn't under that part.

[noname]

Damn! What failed? The pin? A weld?

[Ed Pawlowski]

I use the jack, a stand or two, and an 8 x 8 length of a wood beam that I stand upright.

[micky]

Neither of those. IIRC the metal bent, but I can't remember which piece of metal.

It wasn't one that seems like sheet metal, with a round tube and a tube a little smaller than goes inside, and a pin to set the height.

It had a little beam in the middle with teeth and a heavy cog that caught one of the teeth and that decided how tall it was. And a heavy L-shaped piece of round stock that woudl lift the cog if there were no weight on the stand.

It had four legs made of angle iron, and flat iron pieces about 1 1/2" wide welded on from leg 1 to 2, 2 to 3, 3 to 4, and 4 to 1. It's been

10 years but iirc one of the legs crumbled.

I thnk it was rated 3000 pounds when the whole car was only 3000 pounds, and 3 of its wheels were on the ground. We were doing the front brakes. It was the plymouth version of a LeBaron,a K-car, and a friend who weighed less than 160 sat on the drivers seat with his feet on the ground.

It didn't go down much because of the jack, but still scarey.

[WW]

Yep, toss down as large a hunk of GOOD plywood as possible if you're trying to use a jack on anything other than solid concrete.

[Steve W.]

Yep, toss down as large a hunk of GOOD plywood as possible if you're trying to use a jack on anything other than solid concrete.

-- Steve W.

Steve..Would MDF be better than plywood? No voids in MDF. WW

Not really any of it I have used doesn't like to flex. Unless the ground is very flat it will need to bend a bit. That usually means it breaks.

Plywood on the other hand will flex a bit without breaking. I have some here that I wish I had a LOT more of. It's stuff they used to build vegetable crates from for a baby food plant. It's about 3/4" thick, 12 plies, exterior adhesive with NO voids and beautiful fine grained wood.

[clare]

Baltic Birch

[Tony Hwang]

Hi, I use a piece of 2x10

[Tony Hwang]

Hi, I have a piece of 2x10 to support the jack.