The Steamboating Forum

what is it and how do i do it?

http://i1117.photobucket.com/albums/k59 ... 377102.jpg

Hi John

I understand that a variety of approaches have been used, but one mentioned in Funnel that stuck in my memory was plaster of paris bandage. If you have a full back run of Funnel you will probably find several tips. If not let me know and I will see if I can lay my hands on one or more.

Regards

Pete

I only have the last year of Funnel

Yes, cloth saturated with plaster of Paris.

A few details: You must use cotton, polyester fabrics will melt and cause all kinds of nasty problems.

Pre-formed pipe insulation, split lengthwise, in fiberglass is available from Home Depot, put that on the pipe first, held in place with some Nashua 325 heavy HVAC tape. If you do not get pre-formed insulation, then you can wrap your pipes with fiberglass, about 1/2 inch thick is adequate.

Recommend you wrap your pipe insulation with a few layers of ordinary heavy duty Aluminum foil before applying the cloth. This holds everything in place before applying the Plaster "Cast". As a matter of fact, just several layers of the foil makes reasonable insulation, although fiberglass is better.

Cloth strips about 2 inches x 18 inches seem to work well for me, you only have about a minute to saturate the cloth with wet Plaster of Paris, then another minute to wrap around the pipe. After that, the Plaster starts to set up, and if you continue to work it you will not have any strength in the final outer surface.



It is really easy to make a mess here, but the cloth and plaster is cheap, so you can practice on the home heating boiler in the basement (or your hot water pipes in the basement) to get familiar with the process. Stop the insulation at unions that you may want to disconnect, then wrap these later with some fiberglass or aluminum foil, held in place with a ring of the Nashua 325 hi temp tape.

One can also use the wrapping for plaster casts. It can be found quite cheaply on ebay and it is already impregnated with plaster, so one only has to get it wet and start wrapping.

Wessley, did you use this on your piping ? did it hold up well ?, was going to go the plain plster of paris route but seems so much eaier and probably less messy too.

I tried to use ready made cast stuff, but it was a polyester mix fabric, and that will not work with hot steam piping. Years ago this stuff was pure cotton, maybe you can find it in pure cotton somewhere.

This is the method I used to insulate the pipes:





I first wrapped an insulating rope (about 1/2") around the tubes. Then, the "patient" was treated with two layers of elastic bandage. A kind of acrylic paint did the rest.

If necessary, the whole insulation can be removed - and the rope reused - without messing around.

Albert

fredrosse wrote:I tried to use ready made cast stuff, but it was a polyester mix fabric, and that will not work with hot steam piping. Years ago this stuff was pure cotton, maybe you can find it in pure cotton somewhere.

I wouldn't have thought the poly fabric would be a problem, after all it'll be encased both sides in plaster, and that on top of the other insulation. Strictly it's only a method of applying the plaster and holding it in place whilst it hardens, from then on the plaster will hold itself, even if the carrier cloth melted. Thereafter an occasional brush with white emulsion paint should keep it looking smart.

In theory, the steam pipe is hot, and the outer surface of the insulation is only warm. That would be the case if the insulation job was done perfectly, always with the proper thickness of insulation between the steam pipe and outer covering.

In practice there are typically regions of insulation where fit-up is less than perfect, especially around the small and convoluted piping of our steam launches. Gaps in the insulation let the heat get to the surface sometimes, and can make something of a mess with the outer covering starting to melt. Based on my experience with this issue, staying with real cotton is recommended.

As far as rope wrapping for insulation, that is nice for several installations, but presently I can find none of the stuff that is pure cotton, everything in my purchasing area is a blend of cotton and plastic.