Need input on design for upper cabinets

[Johnny M]

My Boler cabinet design and build of face frames are 1x2 select pine attached at the bottom to more 1x2s with right angle brackets as the bottom shelf support and attached with more angle brackets to a 1x2 tab glassed to the shell. The upper face frame is attached in a similar manner with angle bracekts. I am not happy with the design of the bottom part of the cabinet that supports the shelf and how it attaches to the shell/tab as it seems weak. Also there is no shelf support in the rounded upper corners of the Boler. This was my first attempt at building any cabinet ever but I want to make it better...

I have been pondering over this for several months, scouring the net of every cabinet tutorial I can find including here, and other Scamp, Casita and even Airstream sites to no avail.

About an hour ago I think I came up with the perfect yet simple solution. First I will built the cabinet frame like a normal residential cabinet using a 1x2 bottom frame for shelf support, an innergroove routed for the shelf and assembled with dowels and glue. For the rounded part of the cabinet I plan to use 1/2" wide aluminum flat stock to follow the curve from where the box frame stops to the face frame so the self can sit on the aluminum in the rounded corners and the whole cabinet can be secured to the wood tab glassed to the shell using wood screws through the back of the wood frame and the aluminum. Anyone have any thoughts on my idea?

[Johnny M]

I am hoping Ian G. or Robert Johans will chime in on this one...I am not an Autocad person but I do use graphic software for my print shop so I will see if I can draw this up and post as a pdf

[Donna D.]

Originally Posted by Johnny M

I am hoping Ian G. or Robert Johans will chime in on this one...I am not an Autocad person but I do use graphic software for my print shop so I will see if I can draw this up and post as a pdf

I'm watching and waiting. Not that I can offer any real solution or acceptance to your issue, but because I think your "solution" is interesting.

I wish you well and much success!

[Johnny M]

Thanks Donna!

[k corbin]

Hopefully the image above will make what I am telling your clearer than mud. As far as support for the cabinet frame it is essentially a variation of a bowstring truss. The roof itself forms the upper chord of the cabinet structure, which is what you are failing to account for in your engineering of the cabinet structure. The lower edge is of course the lower chord, and the upright verticals that divide it into sections are the web. So you just need to support those verticals by attaching them to the roof and the lower chord. Of course the verticals do help suspend the lower chord but the lower chord is also supported at the two ends. The roof is already supported by the walls and by its own arched shape but the upright dividers do help keep the roof from sagging under the load. The roof and walls are self supporting parts of your cabinet that give it strength and the loads from the frame are transferred to them.

The bottom of the cabinet is of course attached to the front face and the wall of the shell. It does help to add to the stability and also helps to distribute the load along the length of the webbed truss and the shell walls. You won't have the diagonals shown in this image but that is accounted for because you have a solid wall at the back and that solid wall is providing the diagonal stability.

Upper cabinets are bridges with bridge decking

[Johnny M]

This is what I had in mind, this only illustrates the bottom or base frame of the cabinet.

[k corbin]

Originally Posted by Johnny M

This is what I had in mind, this only illustrates the bottom or base frame of the cabinet.

Do you know what a stress skin panel is? A hollow core door is an example of a light weight stress skin panel. The sum of the strength of the whole is much greater than the small, lightweight individual pieces add up to because you completely bond the surfaces together with adhesive.

Build the lower base frame on your workbench. Use cardboard as a template for the curved area and a jig saw to cut those curves. Then glue 1/8" or 1/4" light weight plywood to one side of that wood frame and use a flush trimming bit in a router to trim it to the same size as your wood frame. If you wish to you can also put a layer of plywood on the underside and even have recessed LED lights shining down from under the cabinet. The front face frame is built in much the same way and assembled on your work bench.you can attach it to the base before you install the cabinet. You can attach your cabinet in place by adhering some wood blocking directly to the shell. You don't need a ton of blocking, just place it strategically. You won't need any fiberglass tabs, an appropriate construction adhesive or thickened epoxy will be sufficient to adhere the blocking to the shell.

The way you are planning to do it is a lot more messy and time consuming and more difficult to get all the pieces to line up perfectly. Factories pre fabricate everything they can outside of the trailers and then install the pieces in place. They do not stick build piece by piece inside of the trailer. While I did not build trailers in a factory I was a professional assembler and fabricator of large commercial aircraft for many years and among the various jobs I did during those years I did interior installations including overhead cabinets as well as some cabinet fabrication work. So 95 % of the work should occur on your workbench and the other 5% is actually installing the cabinet.

[honda03842]

I built a cabinet that runs the width of our Scamp 16. It is made of 1/4 " plywood and an 8' 1x2. It is supported in the rear by a rt angle piece of aluminum 1/2x1/2. It's been up for 6 years and has approaching 100,000 miles on it. The only other pieces of wood are the 3 doors, all 1/2 I checked pine. Can be seen in Preparing a 1991 Scamp under Modifications.

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[honda03842]

The discussion of our overhead cabinet begins at post 45. The vertical 1x2s are to strengthen the door openings.

http://www.fiberglassrv.com/forums/f...a-46387-4.html

[james kent]

Although the upper cabinets in our Boler are molded fiberglass, 1/4 to 5/16 plywood tabbed together and then directly to the body shell would be structurally very stable. The. Only added wood in ours is a 1/2 inch frame backing the openings for hinges and pulls. All of our cabinetry is tabbed using 6 inch fibreglass tape. This makes them part of the body construction and adds great strength to the shell.
No rivets required.
Jim


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[Johnny M]

Originally Posted by james kent

Attachment 98357
Although the upper cabinets in our Boler are molded fiberglass, 1/4 to 5/16 plywood tabbed together and then directly to the body shell would be structurally very stable. The. Only added wood in ours is a 1/2 inch frame backing the openings for hinges and pulls. All of our cabinetry is tabbed using 6 inch fibreglass tape. This makes them part of the body construction and adds great strength to the shell.
No rivets required.
Jim


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That is what I had in mind Jim using the wood tabs glassed to the shell so I have something to anchor the cabinets to. I thought the aluminum for the rounded part of the cabinet was a good solution to otherwise not having any support to the rear of the shelf in the rounded corner as it is easy to bend to follow the curve of the trailer and should be plenty strong enough to support the shelf in that area. The structural support to the shell was one of my reasons for wanting to build the cabinets in this fashion and I have already eliminated 90% of the rivets in my shell, just the windows, roof vent and hatches now have rivets.

k corbin you have some good ideas. I am willing to put in the extra work with the glassed wood tabs for the added strength to the shell. With this design of my cabinets I will built the lower frame with the aluminum on my bench and attached the pre curved aluminum to tie the ends of the lower frame then attach the shelf and face frame. Then place the cabinet in the trailer and screw the back of the bottom frame to the tabs and also the aluminum to the tabs as well, then finally screw the top inside of the face frames to a tab on the ceiling using an L bracket. Does that make more sense? My explanation may not be the best.

[Johnny M]

Norm thanks for the link, I looked at your picture of the cabinet over the rear window, can you post a picture of how it is attached to the shell?

[redbarron55]

Take a look at my remake of a 1985 16' Scamp.
I put in Oak cabinets (wall kitchen cabinets 12" X 30" ) along the sides.
I cut the cabinet backs and tops off and left the bottoms and cut the sides to match the curve of the wall/roof.
I cut the insulation away along the mating areas and screwed and glued them to each other and the fiberglass.
The overhead cabinets for a 12" deep beam along both sides of the trailer.
The bottoms bonded with front strip also stiffen the walls side to side.
Since I have bulkheads the cabinets are also attached to I don't have any iron curly supports to hold them up.
As for stiffening the roof you can stand on mine.
The roof basically has two quarter round 12" stiffeners the length of the trailer on each side.
Since each cabinet is glued and screwed to it's neighbor it's like a solid beam of 12 oak.


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[Johnny M]

Originally Posted by redbarron55

Take a look at my remake of a 1985 16' Scamp.
I put in Oak cabinets (wall kitchen cabinets 12" X 30" ) along the sides.
I cut the cabinet backs and tops off and left the bottoms and cut the sides to match the curve of the wall/roof.
I cut the insulation away along the mating areas and screwed and glued them to each other and the fiberglass.
The overhead cabinets for a 12" deep beam along both sides of the trailer.
The bottoms bonded with front strip also stiffen the walls side to side.
Since I have bulkheads the cabinets are also attached to I don't have any iron curly supports to hold them up.
As for stiffening the roof you can stand on mine.
The roof basically has two quarter round 12" stiffeners the length of the trailer on each side.
Since each cabinet is glued and screwed to it's neighbor it's like a solid beam of 12 oak.


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JD I like what you have done with your Scamp and have studied it often while renovation ours. I am sending you a PM with my number and would like to talk to you about your cabinets and bath.