Composite fiberglass/foam panel build question

[ScottReb]

Sounds like a wonderful trip! Enjoy

 

[stomperxj]

I am going to be laminating my own composite panels for my trailer build using 1" Dow foam and Filon. Hopefully going to get started on the walls by the end of January. Link in my signature

 

[ScottReb]

StomperXJ,

Be aware the panels that have printing on them, ie most XPS panels, have a film that interferes with adhesion. Dow and OC make panels that are planed at the factory for lamination. Not available in the US for less than 10K square feet. Just be aware.

 

[Victorian]

You are correct. Foam from home depot or other hardware stores are not suitable for Composite panels in vehicle body construction.

 

[rruff]

Be aware the panels that have printing on them, ie most XPS panels, have a film that interferes with adhesion. Dow and OC make panels that are planed at the factory for lamination. Not available in the US for less than 10K square feet. Just be aware.

What sort of film? The Foamular sheets I've used in 1" and 2" thickness don't have any perceptible film. The 1/2 inch sheets have a film that can be peeled off.

The planed panels have more precise and uniform thickness. That's certainly nice but not necessary. https://www.dow.com/en-us/products/PanelCoreXPSInsulation

I'm using a dog brush with sharp steel teeth to prep the foam.

 

[ScottReb]

Evidently the embossed lettering causes a "film." The planing not only makes it more uniform but removes that. if you look at EU or AU panels they offer planed no lettering without the large (truckload) volumes needed that we have here in the states.
If you play around with pulling the skins off you can take a thin layer of XPS off and see all the letter on the skin side. Adhesive dependent of course.

 

[stomperxj]

StomperXJ,

Be aware the panels that have printing on them, ie most XPS panels, have a film that interferes with adhesion. Dow and OC make panels that are planed at the factory for lamination. Not available in the US for less than 10K square feet. Just be aware.

Aware and have a plan to cure this. Thanks!

 

[stomperxj]

... are not suitable for Composite panels in vehicle body construction.

This isn't necessarily true from the testing I have done

 

[rruff]

This isn't necessarily true from the testing I have done

Nor mine. I'm still confused about the "film" ScottReb is referring to, unless it is the ink itself. At any rate a dog brush makes many fine grooves that penetrate the surface, and this greatly enhances adhesion.

 

[stomperxj]

Nor mine. I'm still confused about the "film" ScottReb is referring to, unless it is the ink itself. At any rate a dog brush makes many fine grooves that penetrate the surface, and this greatly enhances adhesion.

I bought a spiked carpet seam roller that seems to work well at putting nice divots in the foam for more surface area for the glue.

 

[rruff]

I bought a spiked carpet seam roller that seems to work well at putting nice divots in the foam for more surface area for the glue.

I tried one of those as well as a wallpaper perforate. The dog brush is the best. This type.

 

[stomperxj]

I tried one of those as well as a wallpaper perforate. The dog brush is the best. This type.

Cool thanks for the tip

 

[Victorian]

This isn't necessarily true from the testing I have done

I wanted to know more about that topic and called our plastics engineer in Germany. He told me that they do very expensive tests in a lab to simulate years of usage on the road. Standard hardware store foams failed! They simply fractured or turned into dust. After all they are designed to be used in buildings that don't move.
Same goes for fasteners, epoxies and other adhesives that are not designed for that application. Even though composite panels look very simple to make, there is a lot of engineering and expensive materials going into them.
Don't get me wrong, I don't want you to drop everything. But I thought it's important for people to know that there is a difference.

 

[stomperxj]

I wanted to know more about that topic and called our plastics engineer in Germany. He told me that they do very expensive tests in a lab to simulate years of usage on the road. Standard hardware store foams failed! They simply fractured or turned into dust. After all they are designed to be used in buildings that don't move.
Same goes for fasteners, epoxies and other adhesives that are not designed for that application. Even though composite panels look very simple to make, there is a lot of engineering and expensive materials going into them.
Don't get me wrong, I don't want you to drop everything. But I thought it's important for people to know that there is a difference.

I'm sure that RTM-X is the correct choice for refrigeration truck applications and other vehicles that see hundreds of thousands of miles per year over the road. Unfortunately that foam isn't available in small quantities in the US. I won't be using consumer grade adhesive either. If your panels came in big enough sizes and I could afford them I'd be going that route.

 

[ScottReb]

According to Dow and OC their planed, laminate designed version of panels are the same construction/make up as their building panel, densities being equal. Ive only spoken with the US reps for both, but the specs for RTM appears the same. Victorian is most certainly the authority and the Europeans have been doing this for longer than we have so they might have further developed the materials. The homebuilt airplane crowd has been using standard XPS for years, in similar densities, with great success.