Jack stand under scissor jack?

Old-Biscuit wrote:

If this block would have been turned on it's end, instead of it's side, and a board placed on top and bottom, this would have never happened. If cinder blocks are so fragile, then we've got millions and millions of building around the world that are subject to crumbling, so we all better get out of wherever we're sitting right now, because most likely your house is sitting on a cinder block foundation, if not on a concrete slab.

If salt deteriorates cinder block, then the building industry is also in serious trouble. How many embankments along the highways are made of cinder blocks too? Hum? Salt is not the damaging factor in cinder blocks. It's the little pours and holes and dimples that hold water, freeze, and cause cracking that makes them crumble.

The strength of the cinder block is when it's turned on end, not it's side. And it can have no movement, has to be on something solid, to be solid. On dirt or grass, there's to much give without a proper foundation UNDER the block.

What I'm saying is, if used correct and for the right reason, cinder block are very strong and will last a multitude of events, including salt. But, as this photo clearly shows, this is absolutely the wrong way to use one, especially for a camper.

About the bottle neck jacks: They are very strong too. I have a set of them, and the are capable of supporting my entire camper (with wheels off the ground). By themselves, they are very strong and restrict trailer movement to some degree, better than than the factory installed scissor jacks.

These jacks have been around for a long, long time. My parents used them on their 1963 Phoenix travel trailer in 1963, as back then, jacks did not come factory installed. When I got my own pop-up camper, some 30 (plus) years later, one of the first things I got was a set of these exact same type of jacks, and have been using them ever since in addition to the factory installed jacks. But I don't put them under the existing jacks. I end up having 8 jacks supporting (4 factory installed and 4 bottle jacks). (Makes for great support for winter storage, but too much work when actively camping.

Placing the bottle jack under a scissor jack would provide stability for the camper, only as strong as the collapsed position scissor jack will allow (this doesn't make sense to me).

Old-Biscuit wrote:

This is because cement block was used the wrong way. It should be placed directly under the frame, not under small base of a trailer jack. Fine tune-up of the height should be done with a piece of lumber or plywood, not with the jack. Each layer should be more than one block, ex. 2 blocks 1st layer, then another 2 blocks crosswise (if you need another layer).

Are you sure somebody in this photo didn't try to move the truck, forgetting about cement blocks? ;)

They are brittle, I agree.

Back to the OP's point of having jack stands under a stabilizer/scissor jack - I have had a scissor jack collapse on me in two situations while jacking up automobiles, In both cases the car tried to roll backward (on a slightly sloped gravel drive) and the jack failed to take the side stress. I have never had a jack stand collapse like that. FYI - I also got rid of that gravel driveway.

Almost all "cement" blocks aren't really cement blocks. They are haydite blocks and no where near as strong as actual cement blocks. And also nowhere near as heavy which is why they are used so much. Cement/concrete blocks are strong and very heavy.

Old-Biscuit wrote:

And solid "patio stones" aren't much better. Sprinkle a little road salt on them and they will disintegrate into fine gravel.

Just to make it clear - removing wheels was not what puzzled me. Rot, UV effects, theft etc. I've been only wondering about jack stands under the collapsed scissor jacks.

Step stones under the jacks is also clear - more stability and less sinking into ground.

Old Bisquit - I'm curious why cement blocks should not be used on extended stay. Nobody seems to have problems with them.

With the scissors jacks completely collapsed, it seems to me they would be acting as nothing more than frame pads sitting on the jack stands. The collapsed jacks shouldn't cause any stability issues in that situation. The jack stands themselves are likely used to add stability in all directions, versus the extended scissors jacks, that tend to be the most stable in only two directions.

I would think that the jack stand would be less wobbly than the scissor jack if there is a side to side load applied.

It would be difficult to locate the jack stand directly under the trailer frame, and level the trailer, without using a floor jack or something. Perhaps another reason is to lower the overall height of the RV, so there is one less step to get into the RV.

Removing the tires prevents trailer theft, and in a site where the owner might only show up once every 60 - 90 days, it would increase security, and also not 'rot' the tires on the trailer, as they can be used on another trailer that is being moved more frequently, and a newer set installed should this trailer need to ever be moved - say in case of floodwaters coming closer.

Fred.

Not too sure WHY anyone would use them directly under existing scissor jacks......doesn't sound very stable BUT set up under frame as supports can be useful. They are rated for 6000# each so stronger then scissor jacks (stabilizers)

And when folks go using cinder blocks obviously they are fools so nothing surprises me.

Have seen all kinds of set ups in CGs and I just walk quickly by shaking my head.

Scary :S