Aluminum/foam/wood sandwich construction.

[Flonker]

I guess their is something you dont understand about Sips. The first word is structural. They will hold way more than you think. If you are only fastening your windows and doors to the wood frame then you dont understand how to build a vehicle. The doors and windows have an outside frame and an inside frame, they are fastened to each other, creating a sandwich of the outside skin the foam core and the inside paneling. Very tight, strong and leak proof. The skin, core, and paneling are bonded to each other. My Winnebago, built this way would hold on the roof, an a/c unit and at least 6 people in lawn chairs. As for no place to fasten the spars, I don't intend on using any. If my plan works as designed then the roof will be self supporting. The galley will be a wholly self contained unit that slides in from the rear, like a piece of furniture. All systems will be contained in this section with only electical and propane coming up from conduit in the floor.

So what will you tack the cabinets to? I'm thinking of 'glassing in some wood spars to screw them onto...

[jay]

that's why the good lord made construction adhesive!

cut the strips and adhere them with a couple of pins to prevent sliding and cut some spring sticks to reach the opposite wall. when dry, screw & adhesive the cabinets in place.

PL400 is pretty good- i wouldn't count pennies here - a tube goes a long way.

[Flonker]

that's why the good lord made construction adhesive!

cut the strips and adhere them with a couple of pins to prevent sliding and cut some spring sticks to reach the opposite wall. when dry, screw & adhesive the cabinets in place.

PL400 is pretty good- i wouldn't count pennies here - a tube goes a long way.

I'd still feel better if the spars were embedded in the walls, glued to the panels & 'glassed over. Construction adhesive is ok, but I plan on taking the trailer on the road, and some of the roads around here are rough as a corncob. I don't want the cabinets falling off going over an Arizona backroad.

[madjack]

jay, this is just a personal opinion on my part not meant as an inditement or personal thing against anyone...I have worked on and rebuilt a couple of commercial units...2 trailers and one class"c" motorhome...the construction methods used are as you described and they are nothing but crap, that are designed to fall apart with any real serious usage(have ya ever seen one that's been in wreck)...as a long time builder, of all manner of things, my pride in my workmanship would not allow me to build a piece of crap like they are...and that is what will result in using commercial camper/motorhome construction techniques to build a tear. If someone wants that, well fine...the great thing about building yourself is the ability to do it any way you like...afterall it is yours. But if you want something that will last thru the years no matter what kind of usage you put it thru "overbuilding", as most of us do here, is the way of it...my appologies for being long winded and no offense was intended towards you, Jay
madjack

p.s. good constuction adhesive does not make or make up for shoddy technique

[toypusher]

.....p.s. good constuction adhesive does not make or make up for shoddy technique

For that you need Duct Tape!

[BrwBier]

If, by commercial building techniques, you mean 2X2s and foam with aluminum on the outside, you are correct, that is crap. But if you do not know about Sips, I think it's time you pulled your head out, stand up and go out into the real world. Bonded, structural panels are strong and light. Adhesives are used in more places than you might think, go to the body shop of your choice and ask them how your car is put together. Or even closer, go out to your car and open the door and look at the seams. Adhesive.
To hold the galley in my tear, yes I will put wood, bonded in the wall with the foam at strategic locations.

[Greg Downunder]

Just when you think this forum has a spirit between members the other forums don't along come the dummy spits - I really dont see any point in belittling other's ideas or comments - this is an exchange of ideas and thoughts - the one thing I have learnt from reading all the posts over the last weeks is that no-one is right and I for one appreciate all the different ideas on this forum - with respect madjack to describe something as "crap" only incites and deserves this kind of response regardless of any other comment made
Suggest a nappy change fellas and lets get on with this great interest of ours - this forum is far to valuable and appreciated by the rest of us

[madjack]

...The "Gage Theory" at work once again.....I am not responding to nuthin'...heck I am going to bed................................

[asianflava]

With posts like this:

I guess their is something you dont understand about Sips. The first word is structural.

If, by commercial building techniques, you mean 2X2s and foam with aluminum on the outside, you are correct, that is crap. But if you do not know about Sips, I think it's time you pulled your head out, stand up and go out into the real world.

It makes you sound defensive from the get-go. People are just making suggestions and giving you their thoughts. We know what SIPs are, they have been discussed several times. That is why several of us, me included, made their own homebrewed SIPs. So, relax, we all need to catch our breath after last weeks drama.

[mikeschn]

At this time I'd like to remind everyone of the primary rule. No fighting.

Thanks for listening!

Mike...

[angib]

BrwBier,

Having worked on sandwich composite structures up to carbon-epoxy prepreg over honeycomb, I know that it's the joints and design details that matter, as overall panel strength will always be enough. So:
- Are you using only flat panels?
- How are you joining (structurally) and finishing (cosmetically) the major panels?
- How are you going to build the hatch?
- How are you going to add the wood inserts that you mentioned?

The simple answers you've given so far don't explain much. For example, glueing joints requires suitable bonding surfaces - how do you provide those where panels meet at right angles? Or do you think that glueing to the core material is good enough?

Andrew

[Arne]

Mike, my side was constructed like your picture..... Now, I think each frame member could be half the width, just a bit wider than the brad length used to hold the end walls and roof on.

I'm still thinking this out.... with full foam insul, the ply will be what creates the rigidity, just like those panels they build houses out of with ply inside and outside and just 4 inches of foam in the middle (no framing at all).

Framing placement is critical for mounting bulkheads, etc., as you mentioned, so pre-planning is very important.

[BrwBier]

To get the shape of the tear I plan to laminate multipel thin strips of wood, twice the thickness of the walls. Then bandsaw them in half so I have two exact matching ribs. These are then laid on the outer skin, filled in with foam, with attachment blocks set in appropriate places, then covered with interior skin and vacuum formed into one solid wall. The roof will be formed in the same way. As for the hatch, I am wondering if anyone has tried automotive style trunk hinges and a perimeter seal? The success to the whole plan is the laminated ribs. I have made these for an arched alcove in my house and cannot bend or break them no matter what.

[madjack]

BB, that sounds like a pretty good setup and would be stucturally sound, discussion have been had on using automotive hinges but no has tried to tackle the engineering issues that I know of. If you solve those issues...mainly stong enough mounting points for the hinges, it would give a really sleek outer appearance. I know you will keep us advised of your progress and there are probably several members interested in following such a concept thru to completion.
madjack

[Guy]

Dear BB,

Here is a link to the best SIP Forum and Knowledge Base on the internet.
http://www.sipweb.com/Forum/default.asp?FORUM_ID=1&CAT_ID=1&Forum_Title=SIP+Talk

There are a lot of homemade SIP and IP makers on that forum, including technical advice for easy solutions to problems that traditional builders consider difficult, impossible, or not feasible solutions with SIPs. However, do remember that not all Insulated Panels are Structural Insulated Panels, even though in each case the same outside and core materials may be used. A tremendous amount of the differrence is in the type of adhesive used, and the methodolopgy of production.

Also if you search, using the search function on THIS forum, you will find some great suggestions for attachments to SIP walls for windows, doors, and cabinetry. Look for a post by ANDREW (membername: ANGIB) where he described some attachment tecchniques used on boats that had been built with SIP technology.

As for Mark's first post in this thread speaking about happytrails. I actually went to visit Jamie in El Paso last November. He had even made his own roof and hatches out of curved SIPs. He made all his own SIPs, but his technique on the attachment of cabinetry and other items I would not recommend.

Also one of the boatbuilding sites that someone on this board linked to,
has a tremendous technical discussion of the strength of materials of both plywood and SIP construction techniques.


THIS IS AN EDIT:

Dear BB, Here is a link to a tread from last year that includes some sip info as well as Andrew's post which I referred to above.
http://www.tnttt.com/viewtopic.php?t=1926&postdays=0&postorder=asc&highlight=guy+sips&start=0
and here is the link to the kayak building site.
http://www.oneoceankayaks.com/Sandcore.htm