lightweight foam shelves/cabinets

[cgypsy]

I was looking at an RV forum and saw a technique to build cabinets from sheets of foam insulation.

You add a layer of fiberglass net to the outside and it is supposed to make a very strong product.

I am thinking about using this technique to make some shelves to organize the cupboard under the stove and sink in my 22' cruiser.

Has anyone tried this? Is there any reason it wouldn't work on a boat?

Here is a link to the video showing how it is done. https://www.youtube.com/watch?v=ucf2FVIdr1Q

 

[Marco Flamingo]

Check out my modifications photo folder under "cabinetry." I've used Azek plastic lumber for a few things, including a raised footrest. I haven't watched the entire Youtube video, but I'm guessing that you can't stand on their foam cabinetry. Not a problem when using Azek as a footrest, cabinetry holding a sixpack, as a fill in piece for my V berth storage hatch, or in the case of my batteries, holding 2 Group 24s side by side (shown in my heater install folder).

Azek glues easily (if your cuts are clean) and holds screws. It has a smooth side (easy to clean) and a wood grain side (which I used for texture on my footrest.) Available the same places as the foam insulation board.

Much less fussy than the the fiberglass coated foam insulation and looks nicer. Most of my stuff is jam fitted or held with dowel and bungee cord so that it can be easily removed for cleaning out the entire area.

Mark

 

[cgypsy]

I've used Azek plastic lumber

Thanks Mark

Yea, Azek makes sense. I think it is still quite light and I'm sure it is much stronger than the foam board. There are a few projects I think it will work better for.

However, I'm still curious about these foam cabinets and whether they are durable.

If spring ever arrives here on Vancouver Island, I will have to make a trip to the Building Supply store.

 

[hardee]

Gypsy, Cool video, and a great idea. Should be good for lots of places; anyplace you wouldn't need to stand on at least. Looks to be easy to do, and should be strong enough for under the sink, or v-birth shelving.

Best to you in your project.

Harvey
SleepyC :moon

 

[cgypsy]

should be strong enough for under the sink, or v-birth shelving

Sleepy C - That is what I was thinking. I would really like to put some better storage solutions under the sink/stove area.

I had never seen that done before, but one of the really nice benefits is that you don't need a lot of carpentry skills or tools and it is super light.

There are some amazingly talented people on this site who have done all kinds of modifications that I would love to have, but realistically I don't have the skills to make my project look like theirs.

Building something out of foam insulation does not seem nearly as intimidating, but I would really like to know how durable it really is.

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[Larry H]

The materials are cheap enough to build something and test it to destruction.

You could make something like a bench or box, and test it by standing on it, putting tools inside, or other abusive testing.

Here is a link to the foam project on the website:
http://intothemystery13.com/ultra-light-weight-foam-construction-technique/

A stronger laminate can be made of foam and fiberglass cloth with either epoxy or polyester resin. The foam has to be selected to resist the solvents in the resin, so big box foam might not work.

A possibility would be to build the cheaper version, try it, and if not durable enough, make a more expensive foam/epoxy version using the cheap foam part as a model.

 

[ssobol]

...A stronger laminate can be made of foam and fiberglass cloth with either epoxy or polyester resin. The foam has to be selected to resist the solvents in the resin, so big box foam might not work. ..

By painting the foam you could protect it from the FG resin. Most epoxies work fine with foam.

 

[rogerbum]

Check out my modifications photo folder under "cabinetry." I've used Azek plastic lumber for a few things, including a raised footrest. I haven't watched the entire Youtube video, but I'm guessing that you can't stand on their foam cabinetry. Not a problem when using Azek as a footrest, cabinetry holding a sixpack, as a fill in piece for my V berth storage hatch, or in the case of my batteries, holding 2 Group 24s side by side (shown in my heater install folder).

Azek glues easily (if your cuts are clean) and holds screws. It has a smooth side (easy to clean) and a wood grain side (which I used for texture on my footrest.) Available the same places as the foam insulation board.

Much less fussy than the the fiberglass coated foam insulation and looks nicer. Most of my stuff is jam fitted or held with dowel and bungee cord so that it can be easily removed for cleaning out the entire area.

Mark

Actually, I think you could stand on foam cabinetry IF it were made with fiber glass and epoxy as opposed to window screen and paint. That's basically how many boats are constructed these days - this was just a cheap (and probably much less strong) way of doing things.

Plastic lumbers are great for many applications but they do tend to droop over time when they span much distance. That's why you never see long runs of plastic lumber on decks - it's always run perpendicular to the joists. Also, plastic lumber tends to have a much higher coefficient of thermal expansion than other materials so tight fits into dissimilar materials can be problematic. If I were to use plastic lumber for a shelf that spanned more than about 12-16", I'd want to either support it with a vertical piece attached to the bottom.

 

[OffLeash]

I really am fascinated by this. I am a cat lover and am focused on the need to keep the weight off cats.

I have used Azek quite a bit and really like some of it's characteristics but it is not exactly cheap and it is more flexible then regular wood so there are some limitations.. However, esthetically it is pretty nice.

This technique looks to be significantly lighter and a lot cheaper than Kevlar panels. Kevlar??? Yea...I am that focused on keeping cat's light and the price on Kevlar is truly just stupid!

After looking at the videos I think it could be fun to experiment with but it is going to be a bit rough on the surface and lack some esthetics.

So, I was wondering how you could improve the covering. Maybe Vinyl, or some kind of thick coat paint? Cost of material could end up costing more than Azek...but still lighter.

 

[Marco Flamingo]

However, I'm still curious about these foam cabinets and whether they are durable.

I've used that same insulation foam for other projects (check my folder on refrigeration), and if protected, it is semi-durable. It is available in a thickness that wouldn't require all the fussing to make a medium size shelf.

I mummified my foam cold box in duct tape and it has held up and looks okay. Painting glue over screen door mesh is going to result in a difficult surface to look nice and clean up easily. In a subsequent video, they show a paper mache covering technique over the screen. I haven't yet seen one of their finished cabinets, but I'm guessing that they would look a bit like a summer camp project. I know that Azek can be routed for a nice edge and can hold screws for a hinge.

Using insulation foam to save 4 pounds in weight? I don't have enough cabinetry on my 16 for the weight savings to pencil out. Of course, by the time you put on the screen, all the glue it will soak up, and cover with glue and paper, there might not be any weight savings.

Before I started using Azek on board, I glued up a couple pieces to test the strength of the glued connection. I hit the piece with small sledge hammer and finally broke the board. The glue line held. You can consider an Azek carpentry project as permanent. I first used the stuff when I installed windows on the third floor of my shop. After the install, I never wanted to climb a ladder to paint exterior trim on those windows, so I used Azek. It has UV protection and works great for exterior applications.

Mark

 

[drbridge]

I have worked with epoxy fiberglass quite a bit with the wood boats I have built. As an experiment I decided to build a fish box for one of them using 1" construction foam sheets. I sandwiched the foam in 10oz epoxy fiberglass, glued the pieces together with epoxy and then fiberglass taped all the seems. It turned out to be a very strong, lightweight insulated fish box. BUT, It was a ton of work and I had way to much time in to it by the time it was done. I still have it and I still like it. Would I do it over again? probably not. The epoxy fiberglass is expensive, messy and the sanding and dust is even more of a mess. If you have lots of time and a ton of patience you might like building like this. If you do, be sure to sand the foam with coarse grit before applying the epoxy so that it will adhere. What is wrong with building shelfs out of wood? if you want them light weight, Get some 1/2"x3/4" fir and make a frame. Skin that frame with some 6mm Okume ply and it will be plenty strong and quite light. Work will go way, way faster than foam/fiberglass construction and you won't have nearly the mess. I always have my jugs of epoxy and fiberglass on hand and I will break it out for the appropriate uses. Personally, shelfs are not something I would use it on.

 

[BTDT]

What glue did you use? I'm assuming Azek is the same stuff as Lowe's sells as white solid PVC boards. Flat white on one side and wood grained on the other?

 

[Marco Flamingo]

I paid the extra $1 and bought the Azek brand glue. It looks to be identical to the clear PVC glue, but who knows. It is usually near the Azek lumber. The Azek boards are smooth on one side and have a wood grain look to the other. A long piece does flex more than wood, but on my cabinets I glued a lip across the front to keep stuff from rolling out, and that stiffened up the shelf enough to stand on or hold batteries.

The only difficulty I had was with power tools. If you get off line with a circular saw and spend too much time trying to re-align with the blade running, it can melt the plastic and fill the kerf line. If you don't keep the router moving smoothly when rounding off an edge, you can get a similar melting. Power tool work just need to be zing zip and done.

For butt gluing two pieces together when I needed to make a wider piece, I always did it so that the factory perfect edges were being joined. Made for a nicer panel. The board had taken a slight curve from standing at the hardware store, so I had to bond the curves the same way, then add the edge to make it stay perfectly flat, although the curve was so slight that it really didn't make any difference.

I just remembered that I also used Azek for the shelves inside of the new cubby holes that I made during the heater install. Those might show in the heater install pictures. Those are just stuck in place with canned foam. That way, they can be torn out if needed (and I already needed to once). But the foam keeps them in place for all conditions required for boating.

Mark

 

[RichardM]

My father in law once built a foam-strip canoe encapsulated with fiberglass (epoxy resin, I think). Think of cedar strip canoes, but he used styrofoam. The finished canoe was incredibly light and plenty strong enough for normal paddling. There's no reason you couldn't build a cheap, light dinghy this way. At the chines, keel and stress points you could still add wood as needed. You've got me thinking!