PTFE FLUOROGOLD - Joining sheets

The Fluorogold is always bonded to a substrate in the Fluorogold shop. I don't know why yours has to be so big, 290KN is roughly 65k. Without neoprene backing, Fluorogold is good for about 2k depending on temperature, say 36 sq.ins, say 6"x6", 150mmx150mm. The top should always be a little bigger than the bottom, all round, including the movement. The bearing does not need to be as big as the support itself.

Split your bearing into two, each one having a single sheet on the bottom and a butted double sheet on top, the butt joint always being above the bottom sheet, whatever the movement.

Usually, I provided a sheet metal shroud in dirty configurations.

http://www.sepbearings.com/teflon-slide-bearings.html

http://www.sepbearings.com/media/fluorogold.pdf

Nothing to add, except, always enlist the help of the suppliers technical resources.

Thanks for the reply and website links. I agree the top should be bigger than the botton to keep the PTFE protected, however the pipes lateral movment is over +/- 600mm from the pipe centerline. These are large LNG pipes. It is not practical to make the top larger and there is no space to allow for a larger pipe shoe base.

The bearing area, stainless steel sitting on the PTFE is 580mm x 100mm and is to support a 290 KN load. The PTFE is exposed to sun light and as this is in northern Australia the design temperature is 75 degrees celcius.

I have recieved information form our supplier, although I would like to get other peoples opinions.

I guess the only option is to source a supplier than can produce PTFE more than 600mm square. Pitty we can't restrict the pipes movment with line stops.

I have a little difficulty in imagining a situation where you cannot have a wider shoe, but can accommodate +/-600mm of lateral; movement. Of course, there is a lot more that I don't know of the situation.

Years ago, I had a stainless steel version of a roller skate attached to a pipe shoe in lieu of a sliding bearing for reasons analogous to yours. As these are big pipes, they should be able to push small wheels through accumulated dust and sand.

Hi,

dovetailing is not a good idea.

There is no need to join bearing plates.

As you can support with the tips of your 5 fingers a dish - the same way you can support your thermally moving pipe by as many bearing pads as suitable.

Each pad has to be flexibly mounted so that the vertical load is distributed regardless of tolerances. Optimum pad size to be discussed.

And each pad has to be horizontally secured against friction forces.

Depending on dust conditions it may be highly advisably not only to follw above recommendations but may be to think about a dust- and sand-"tight" enclosure.

Put down on paper with signatures and dates your bosses needs and your objections, he will forget what he ordered you to do - if anything fails.

RHABE

You can cast your own sheet. If you can find a volatile organic solvent for PTFE You can cast youR own sheet by making viscus solution of PTFE and casting it in desired shape.

You will have to leave it for sometime at a warmer temp at which solvent can evaporate. more is the viscosity less will be shrinkage.

Never heard of such. I think the key is, "If you can find a volatile organic solvent for PTFE". I'm not aware of any such liquid, are you?

Fluorogold is manufactured by Saint-Gobain Performance Plastics and is available in continuous rolls etched or unetched for bonding in thicknesses up to 6.35mm (.25") and typical widths of 304.8mm (12"), which can be slit to 250mm (9.84"). What thickness are you using?

Thanks AppsGuy for the reply. We are thinking of using 3mm etched on one side. (not sure of the imperial conversion). Using 3mm eliminates the doformation under compressive load (my load conditions are mentioned above (hopefully I have done the calculations right). We are using araldite 2 pac mix to join the PTFE to carbon steel plate, compressed and then placed in an oven for a certain time.

If there is no deformation of the PTFE we probably could use pieces of PTFE. I will have a look at the company you have mentioned. The worry is Australia is so far away and you have to factor in transport costs. There is a company in Sydney that makes it called Dotmar, I am currently finding out if they can make a continuous sheet.