Structural Spray Foam

I haven't tried it, but it seems to me, that any significant reinforcement would require that the foam be stronger than the PVC itself, which is unlikely.

Won't work, unless you are making panels with two rigid sides and foam in the middle. Then it's fine.

OP, pls give us a link of what "structural spray foam" you would use?

I've been Googling however no applicable "structural spray foam" link found yet.

There's a reason you won't find "structural" spray foam.

It isn't.

While adhesion of foam to other materials is OK, it comes down to the amount of "holes" in the foam.

And the quality of surface preparation and "surface energy" of the materials the foam is sticking to.

There is no chemical reaction between the different materials. It comes down to surface roughness, or area, the foam is contacting and molecular attraction of the surfaces to each other. That's why sanding things, and good cleaning are the keys to good adhesive bonding.

Then, there's this guy: Van der Waals

Van der Waals force - Wikipedia, the free encyclopedia

There must be a material which can be used as a filler to PVC pipe to provide additional strength.

Electronics has potting material however not useful for this app.

Possibly a construction material of some type?

cement, kinda heavy though

Perhaps latex cement patch?

What about the floor leveling material also used to fill around in floor heating tubing?

If your objective is structural furniture, why not buy wood ?

The cost of the PVC + foam + time spent filling the furniture pipes will probably exceed the wood furniture cost.

Thanks for your suggestion . Currently my home remodelling is going on from denver renovations and I prefer purchasing wood for structural furniture . The furniture made of wood looks good and stay for a long time.

Furniture grade PVC is both strong, and UV resistant.

You can make a stronger chair by fitting cast iron pipe inside the tubing, but why?

Nobody will buy it.

I have successfully used Rebar inside 1/2 in PVC tubing. This was used for PVC structures in my orchard that support bird netting. The rebar was total encapsulated by the PVC so no resulting corrosion, rotting or other deterioration after many years of use. No sagging on long runs, and very inexpensive.

Your thoughts on this?

Dan

No but I've used cement before.....

http://www.homedepot.com/p/SAKRETE-2-3-cu-ft-Lightweight-Concrete-100033440/100598895#.UlBeFVCsiSo

Try pour foam, it will do the job. The higher the density the stronger your finished product will be.

This link tells you a bit about it - http://www.bertram31.com/proj/tips/foam.htm

My experience with foam for structural applications is pretty much the same answer given by those who posted above me.

I think it's great as a filler material or foam core, you can engineer furniture with very high strength to weight ratios. Compression and Torsional strength are the first two properties that come to mind with foam if you are looking to shave some weight yet meet structural load requirements. However, the use of the foam takes some consideration in placement and application.

With structural spray foam, I recall glass fiber is sprayed along with the foam as reinforcement for hot tubs. You may have a lattice or frame made of PVC in the shape of whatever you are spraying or spray into a mold. A man in Alaska built a home on the permafrost made of a composite of spray foam, aerated concrete, and some reinforcement (high R-value yet able to withstand 10+ on the Richter Scale). However, if you start to play with applications similar to these above, you need to pay close attention to size and quantity of reinforcement, it's dispersion in the media, and be wary of issues such as delamination, crack propagation, compatibility of materials, etc...

I recommend the Handbook of Composites by S.T. Peters for reference despite the $200 to $300 cost for the book and it has lots of valuable information on design, analysis and methods of construction, etc...

If you have a lot of math in your background then this book will be of great benefit for you. however, it's not necessary to have more than some algebra/precalculus to learn and benefit from what it teaches you. There is plenty of topics (over 1100 pages) covered in it that you can cherry pick from or read front to back to have a very comprehensive awareness of the entire industry.

Good Luck!

Fredski said:

"cement, kinda heavy though"

yeah, thats the best solution!

I f you contemplate using cement, don't forget steel the re-rod. That's where you will gain both strength and stiffness.

In place of steel re rod do you think a flexible cable pulled through the PVC furniture would add to the strength?

Disassembly of the PVC furniture to add rigid steel re rod is limited.

It depends on the direction you are trying to add strength. If you are considering crush strength, a steel flex cable might work. If you are looking for bending strength, a flex cable probably won't help. One thing that will help in all directions is to insert a piece of rigid tube into the PVC pipe. The tube ideally should be steel, but aluminum is not bad. The tube should be a close fit into the PVC pipe. If you provide more information on what you are trying to do, we may be able to be of more assistance.

The foam will stiffen the profile it all depends on what you need. I suggest taking a 4 foot section of tubing and support at each end and add some weight and measure the deflection then fill with foam and check same weight again. The pour foam is easy to use and fills without much cavities but even the spraycans will work within reason. Remember that the foams come in various densities so discuss this with a foam manufacturer and get a recommendation. Make sure the cure time is about the same for each test. Even though the foam does not stick well to PCV just filling the profile will show quite an improvement to the stiffness. Filling with sand and capping the ends will also stiffen.

It will not help. PVC (Poly Vinyle Chloride) has inherent wax (slip agent) in it, which reappears on the surface after it has been processed (extruded or molded). The sprayed foam will therefore start coming off very soon.

However, if you are determined to do it, use some surface treatment before foaming. A patern corona treater would be the best option, since surface treatment with flame will deform the molded surface due to intermolecular stress release of PVC surface when heated.

Millions of doors are being used today that owe they're structural integrity to polyurethane foam. Just saying.