Looking for lightweight composite panel product

[glassice]

can you get old beer signs from beer stores
Bruce did packing tape hold the seams that be the 2 best tip i have ever got thank you

[eamarquardt]

Duane; the concept about vacuum bagging is that you remove most of the air from the surface. That allows normal atmospheric pressure; about 7 lbs per sq.inch. to apply even pressure.

Not to quibble but atmospheric pressure is about 14.7 psi. A typical shop vacuum can pull 60" of water column or about 2.2 psi. 2.2 psi over a 4X8 sheet of plywood is over 20,000 pounds or ten tons. As the pressure is between the two sides of the plastic bag the vacuum pressure will not flatten out the sandwhich but gravity should do a reasonable job (or you could put some additional weight to flatten out the sandwich during the bagging process) of keeping the sandwich flat. The pressure generated by the vacuum bag (again about ten tons for a typical 4X8 sheet and shop vacuum) will do a good job of keeping the sandwich together as the glue sets up.

Cheers,

Gus

[bdosborn]

I like the homemade panels that Bruce did with the plastic sheeting and the shop vac. Pretty neat. What kind of glue did you use to laminate everything together, Bruce? Did the shop vac really keep everything flat while the glue dried?

I used titebond II an it worked great. The instructions said it has a 30 minute clamp time so I left it under vacuum for 60 minutes. I had internal wood framing so I didn't care so much about the bond to the insulation. I'd do a test piece to check how well it adheres to foam. The shop vac worked very well, you just need to make sure there's a path under the plastic for air to get back to the vacuum. I used rope. The 1/8" plywood was really wavy but it came out flat as could be, without using any nails. I did shoot a couple of 27# pins into the plywood just to keep it from sliding around while we were putting the bag on.

It's definitely a 2 person job to get the bag on. We laid the wall on the plastic, glued the plywood, folded the plastic over and taped it shut. The clock is running on the glue at that point so we did a practice run on the first wall. We just taped the vacuum hose into a corner. Then we ran a laminate roller over the tape to make sure there weren't any leaks.

I was worried about the motor on the shop vac burning out from overheating but someone on the list pointed out that the motor is unloaded since its not pulling any air. I ran it for hours without any issues.

Bruce

[eamarquardt]

I was worried about the motor on the shop vac burning out from overheating but someone on the list pointed out that the motor is unloaded since its not pulling any air. I ran it for hours without any issues.

Bruce

If you noticed, as the vacuum built up, the vacuum motor sped up as the motor was under less of a load than normal. Overloading/overheating the vacuum motor shouldn't be a problem.

Cheers,

Gus

[xrover]

Duane; the concept about vacuum bagging is that you remove most of the air from the surface. That allows normal atmospheric pressure; about 7 lbs per sq.inch. to apply even pressure.

Not to quibble but atmospheric pressure is about 14.7 psi. A typical shop vacuum can pull 60" of water column or about 2.2 psi. 2.2 psi over a 4X8 sheet of plywood is over 20,000 pounds or ten tons. As the pressure is between the two sides of the plastic bag the vacuum pressure will not flatten out the sandwhich but gravity should do a reasonable job (or you could put some additional weight to flatten out the sandwich during the bagging process) of keeping the sandwich flat. The pressure generated by the vacuum bag (again about ten tons for a typical 4X8 sheet and shop vacuum) will do a good job of keeping the sandwich together as the glue sets up.

Cheers,

Gus

Gus, if you're going to QUIBBLE, at least you backed it up with facts. Well done and well beyond my comprehension. Damn, there are people smarter than me.

[Corwin C]

As far as holding things flat goes ... if you can get a good seal to the floor and only cover the top with plastic ...

[Papi]

For your application, how about the plastic corregated sheets that I've seen real estate people make signs out of? Strong, light weight, and waterproof.

http://www.coroplast.com/

I've been thinking about this since you mentioned it. I built a bird house out of the stuff and it held up wonderfully. Hmmm... I guess price and availability will be the biggest determining factor in the end.

[Cliffmeister2000]

$16.49 a sheet here

http://corrugatedtwine.com/3mmCorrugate ... heets.html

[jimqpublic]

Since this subject is still going...

To the original request- if 3/4" is the goal due to use of 3/4" edging material, it seems that 1/8" luan on both sides of 1/2" XPS (extruded polystyrene) would be the ticket.

If you want a whole bunch without having to make them yourself, check into one of the building panel makers. They typically use OSB and EPS, but the process is the same. They use a big multi-nozzle sprayer for the glue and then usually have a press to hold pressure on a stack of panels while the glue sets up. The price might be reasonable if their plant is working under capacity.

I think the problem with pre-fab panels for trailer construction is that you would either need to build without internal reinforcement at edges and openings, or else route out and insert splines.

Jim

[Archam]

There used to be a company on Kent Island, Stevensville, MD. That made refrigeration units from a product that was Aluminum skin on one side, foam core and a plastic knobby wall board on the other all laminated together.
This may be a standard product of the refrigeration industry.

[DIY-Stu]

$16.49 a sheet here

http://corrugatedtwine.com/3mmCorrugate ... heets.html

Free today and tonight! Election Signs!

[steve smoot]

You are so right, DIY-Stu. I saw two fellows in a pickup truck yesterday that were taking up all the election signs...That was really nice to see, I hate all that sh** stuck every dang where...screws up the view....Make a teardrop outta the stuff...

[DIY-Stu]

To bond them together simply use 40 - 80 grit sandpaper to lightly scuff, Run a roller/Perforator over the joint areas wipe with Rubbing alcohol then skim with epoxy. Contact cement also works, as well as CA glue. Could even help you figure out your design to make templates etc. etc. etc.

Think about it. make some ply's to make the thicknesses you want. Then cut using jig saw, razor knife hot wire, router table saw etc. Use glue sparringly to make your connections then when you finish your design pop the pieces apart and you have all of your templates.

A lot of the signs you will see on the roads are 4 x 8. hmmm that sounds familiar.

In the world of R/C Airplanes we call these SPADs Simple Plastic Airplane Designs.

I think I now know what I'm going to do first when I begin my custom project.

[Archam]

We are in Maine on business and noticed a guy going around stapleing a big yellow tag on one of the winning candidates poster which said "Thankyou". First time I ever say that done. I hope they come back in a week or two and remove them altogether; but I thought that was a classy touch.

[Tadlan]

I haven't done my walls yet, but I did a little 3'x4' test piece that has promise. I took 3/4 foam insulation and poked little holes in it on both sides using a board I had put a bunch of brads through. I rolled on epoxy with a foam roller and then sandwiched it with 1/8 luan. I don't have a vacuum bag, so I just put it on a flat surface and stacked stuff on top.

When it cured, I was left with a very strong, flat, rigid, lightweight panel. It can be cut like regular ply, better actually because it is rigid like thick plywood, but light and easy to maneuver. I cut it easily with a skillsaw and a jigsaw. I had no seperation between foam and ply. In fact, I couldn't pull them apart with all the force in my little hands. Epoxy is a little expensive. You could try a test with less expensive glues, but I'm not sure how well they will hold. Titebond probably won't cut it without an internal wooden structure. Some contact adhesive might do the trick for what you need it for though. I'm planning on doing something similar for some haunted house designs in the coming years. Let us know. It will be interesting to get other's results.