The Poet Creek Express - Foamie Hybrid

[KCStudly]

During the day today I was able to get the loft up in temp enough to be comfortable doing the next stage of assembly gluing. I used PL between the foam battery compartment bulkhead and the wood (the TB floor, the biscuits and the ledge), and TB2 for where the wood vent blocking joined with the corner upright. I’m sure that the biscuits in the wood side of the foam joints would have preferred a water based glue (they are intended to swell), but since I have had spotty results with the TB2 and foam, the PL seemed to be a better choice. You can also see where I touched up a few dents in the foam with spackle.



The cans were used as gravity clamps and the little blocks of wood wrapped in butcher’s paper were clamped in place as temporary alignment blocks.


There was a slight void where the back of the battery bulkhead should have butted in the bottom of the dado (now an exposed rabbet), and my cans of GS went kaput after freezing, so I tried this stuff DAPtex Plus (DTP). I like it. It has a nice fine bubble structure, does not over expand hardly, and when I squeegeed the excess the exposed bubbles stayed tight; whereas the GS tends to open up into big voids. At least that is my first impression.


In the meantime I have continued work on the lantern case.

One of the reasons I have slowed down on the cabin proper, beside the weather, is because I didn’t like how the front foam was wrapping in my dry fits. It seemed like the clamp up method was getting overly complex in order to make sure the foam conforms to the profile with no voids. Even with the kerfing it wanted to spring away in places, but I think I have an idea for another method I will try and see if that doesn’t work better. I also need to figure out the mounting provisions for my swap meet shovel and an axe. I already bought a locking hand knob/nut that I planned to use to secure them, but it is looking more like I will mount one on either side of the locker bump out, so I need to work out the blocking for those and decide if I need to buy another knob.

[dales133]

Looks good mate seems everyone's making good progress but me!
Couple of quick questions for you,
How high is your trailer off the road to the top of the chassis and what's your estimated finished hight to your roofline and your door sill?
Reason I ask is I'm not complaining about my ground clearance but it's like 6 10mm to the frame top and I wanted to put 200 mm or so of underfloor storage in witch would put me around 2 meters roof line.
If your like me on the high side what provisions have you made for steps or access.
Sony to semi hijack your thread but I thought you may be looking at similar issues.
Keep up the good work, Cheers Dale

[pchast]

An approach to the problem may be to use strap clamps. I did when using staves to
build my foamy's roof. One on each side and one in the middle. The middle one was
a little tricky. I needed to watch that I didn't pull the glued piece into a bow.

[KCStudly]

Thanks, Dale.

I'm not sure of the exact numbers off the top of my head at the moment, but the chassis is at a comfortable sitting height with room to spare for the floor. No step needed, I will be able to sit and spin.

I originally targeted my galley counter top at 36 inches, but I think that crept up to about 42 inches with room under the counter for my cooler (which is about 17 inches). Subtract that and a little for the sliding tray and the counter rail and that puts my floor at about 23 inches. My floor is 1-7/8 inch thk and the main frame is 2 inches, so maybe 19 inches ground clearance at the bottom of the frame(?). I may switch to a slightly longer spring shackle to get a little more up travel with how my shock mounts turned out, depending on what the final weight turns out to be, so it may come up 3/4 inch or so.

The bottoms of my door openings are just the 2x2 wall sill plus the 5/8 inch lip of the door seal flange. Call it 2-1/4 inches once the trim seal is in place.

Looking back at my plan, it looks like I targeted about 22.8 inches for ground clearance under the frame. So that would have put the floor height at about 24-3/8. The only things hanging down will be the rear stabilizer jacks. The center mount tongue jack will be removed and stowed in the TB when underway.

Pchast, I've found the straps don't pull sideways. For example, when hooking them under the front edge and wrapping them over the roof, they do an okay job on the curvy part, but don't suck the bottom of the vertical part in at all. You have to put a board or shims in to get any push and that moves the straps away from the foam above that point, so more boards. Now I get a few good points but nothing in between, and the boards are constantly trying to twist out or put creases in the foam when sucked down. The 3/4 inch foam is flexible enough that it still bows up in places away from the straps, and if you are not careful, they can dig in.

So what I am considering is making a stretcher; a piece of bed sheet wrapped around a board at each edge, then clamp the lower board across the bottom of the foam and stretch the top. If I do it right the load will be evenly distributed, maybe. For the flatter more narrow bays between roof spars I think I may even make a stretcher out of luan ply to help the foam make the arc. The easy thing to do would be to weight the foam down, but I don't know if I want to put that much weight up on the roof. Not that it would fail, just don't want any permanent bows.

I dunno, it seems like it should be easy. Just spread some glue and stick the foam down, but nothing is ever as easy as it sounds.

[Wobbly Wheels]

I didn’t like how the front foam was wrapping in my dry fits.

When doing up the canvas on a boat, one normally wets it a bit first to get it to stretch enough to do up the snaps.
With that in mind, I wonder if boiling the canvas first might soften it enough to make it easier to work ?
It would definitely have to be tested first, even if just to figure out how much it'll shrink.

[KCStudly]

I think you have me jumping the gun a bit, WW, or I should not have used the word "wrapping" to refer to the process of bending foam to the profile. It occurs to me that I may want to revisit the idea of the contact adhesive; at least for the tricky front where I have the flat section over the locker and it transitions to a tight radius. Sure would be nice to get a "press and seal" attachment there.

[Wobbly Wheels]

Sorry KC, my bad
You're talking about foam wrapping and I read it as though you were thinking ahead to canvas.
I don't usually post well after I should have gone to bed...

[KCStudly]

WW, no biggie.

I only spent about 3-1/2 hrs on the build today, but I still don’t know where that time went. Just poking away at some details, made progress on the lantern case, and got the rear panel glued onto the tongue box.

While I still had easy access I faired the battery bulkhead to the ledge (the foam wanders around some despite the biscuits). It’s not obvious in the pic but I also rounded the corner of the miter, too. Just some hand work with the small block and 100 grit.


The Kregg screws that come up from the inside of the two corner posts (in the corners of the battery compartment) into the bottom of the ledge pulled the ledge back slightly when cinching up the screws during the glue up. Here you can see the vent hole in the back of the box (on the left), the rear corner post in the middle and how I faired the top of the corner post back flush to the ledge. Used the small matchbox plane and finished with the sanding block.


Not sure if I showed this before. At the top of the front corner post I had a false cut when cutting the rabbet for the ledge. I spaced out on the parallel vs. perpendicular side. The fix was to glue a little wedge shaped block back in. The photo also shows how I faired the top of the corner post back to the ledge.


With those details settled I could get back to work cutting the rest of the biscuit slots that would help keep the foam joints aligned. I prefer to use the bench top as a reference plane; it is easier to push down and forward on the jointer than it is to try and use a clamped board or other arrangement as a guide fence. So to cut the slots along the back top edge of the ledge where the back panel will join I laid the box on its back, but the jointer handle wouldn’t fit under the block for the shore power connections to get to where I had already cut the slots in the foam.


The solution presented itself in short order. Take the handle off of the jointer.


And finally, the rear panel of the TB glued and clamped on. You can see that I used boards under the clamps to spread the clamp load and prevent crushing the foam.


Along the top I used the wedge shaped strip, the drop that I had previously ripped off, to level the beveled edge for the clamp board.


Scraped the excess adhesive with a card and stick, then sat and stared at glue drying while making some mental and written notes.

Now I’m off to research battery tenders.

[KCStudly]

End of day at work; to follow up on Dales questions:
1) According to the plans, from the bottom of my floor to the top of the highest point on the roof (excluding the vent fan) is 52-9/16 inches. Because I was not limited by available widths of hard sheet goods (canvas is 72 inches wide) I was able to use almost the full 48 inch width of the foam for my side walls (47-1/2 inch after cutting the ceiling profile). This sits on top of the 2x2 sill (1-1/2 inch), that sits on top of the 1-7/8 thk floor (3/16 skin + 1-1/2 core frame + 3/16 skin). Add another 3/16 for the ceiling which sits on top of the walls, and the roof foam (1-1/2 thk).

2) I'm a lot less confident in my floor height now. I measured the actual trailer height as it sits right now with no load. To the bottom of the side rails are about 20 inches above ground. This is with the temporary roll around tires and wheels, so I expect this to go up about 2 inches when I switch to the 31 inch tires. So now, with the additional height from the longer shackles, it looks like we might be getting just a little higher than what is comfortable without having legs dangling a little. Call it 22-3/4 to the underside of the frame (assumes no spring compression from cabin weight), add 2 inches for the frame, add 1-7/8 for the floor; so that's 26-5/8 to the floor. Add 3/4 for the door seal flange with seal. That's 27-3/8 inch. My desk (counter top work station) at work is set low at 28 inches for a comfortable key board height and I can sit up on that without assistance, but my feet don't touch the floor... so neither will my 5'-2" wife's. My solution will be to bring along a little wooden step (that I made previously to help a feeble pet cat get up on our bed), or make some sort of folding/easily stowable steps. Perhaps ones that double as shoe boxes when deployed.

3) That puts my galley counter about 46 inches high. A bit higher than I would prefer, but I plan to have the two side wing tables lower, and they will add significantly to the available counter space.

If none of that works out to my liking, I can go back to shorter tires.

[KCStudly]

Just a short 1-1/2 hrs in the shop tonight; almost not worth the commute, but progress is progress.

Pulled the clamps off of the TB back panel. Not really any issues to correct there, so nice. Remembered to bring the wood filler, so filled the holes from the temporary screws where I attached the strong backs. The pic was more to remind me what I had done, than anything interesting.


Next up I thought it would be a good idea to fillet the acute corner between the TB back and the battery bulkhead with spray foam. That way the fabric skin (that will come eventually) will have an easier time conforming. I trimmed a fake credit card into a scrapper with a nice big radius. By closing the angle of the scrapper down a little from the actual angle, when the card was dragged with a trailing angle it would scrap both the back panel and bulkhead evenly. Here you can see the result with the scrapper shown sitting on top of the ledge.


You can’t really tell from this pic, but I had to make a slight adjustment to the end of the battery bulkhead so that the front panel dado would fit correctly again. The bulkhead ended up a tad forward and was keeping the bottom of the front panel from lying flush at the front. Just a little hand sanding with the coarse board took care of it.


While cleaning the foam nozzle, and inadvertently squirting some more foam out, I decided that it would be “bad” if the can were to go off in the tote bag that I have been using to haul stuff. There was a thin slot in the nozzle shroud right behind the trigger, so I fashioned a trigger lock (the red strip of credit card plastic) to help mitigate that chance.


Plus, I ordered a BatteryMINDer yesterday.

And the train kept a rollin’.

[tony.latham]

Pchast, I've found the straps don't pull sideways. For example, when hooking them under the front edge and wrapping them over the roof, they do an okay job on the curvy part, but don't suck the bottom of the vertical part in at all. You have to put a board or shims in to get any push and that moves the straps away from the foam above that point, so more boards. Now I get a few good points but nothing in between, and the boards are constantly trying to twist out or put creases in the foam when sucked down. The 3/4 inch foam is flexible enough that it still bows up in places away from the straps, and if you are not careful, they can dig in.

KC:

Can you get ropes under your cabin? You might try making up some 8' (or so) ropes with loops on both ends and attaching each cargo strap to the loops -front and back. I think they will also pull the foam on the bottom in.

That box is looking great,

T

[KCStudly]

Can you get ropes under your cabin?

It's not so much an issue of having a place to attach the straps; I can hook those to my build cradle if need be. It's more an issue of parallel lines of force. Tension in the straps runs vertical while the foam wants to be pushed against the front wall perpendicular to the straps. Also, there is the space above the locker bump out where straps would tend to bridge.

That box is looking great

Thanks. I figured I'd just slap it together in a day or so... Silly me.

[KCStudly]

A little follow up on the DAP spray foam; don’t bother. The stuff has absolutely no structural integrity. I went to touch it gently to see how it had cured and it pushed in so easily I thought that it had not cured. I fished into the garbage where I had wiped the excess, so that I could assess that more aggressively, and the dried chunks there just disintegrated to dust when handled; not at all as firm or robust as GS.

I probably should have gone with my gut and used filled epoxy, but the ease of just squirting stuff out of a can was just too tempting. I may be able to toughen that fillet up by gluing down some FG tape, but to be honest, I am worried that the DAP won’t even stand up to epoxy on a brush. May have to dig it all back out. … but it is so weak that should be relatively easy.

I contemplated taking care of that now before boxing things in any further, but being leery about opening Pandora’s box, decided to keep going for tonight.

Used PL to install the front and street side panels as an assembly. After squeezing the PL out along the edges and base of the TB, I realized that I still hadn’t cut the last biscuit slots in the inside rear edge of the narrow side slat at the corner joint with the rear panel. Fortunately the PL has a nice long working time, so I did not spread it out yet, quickly measured for the slots (too gooey to match mark), got the tool out and set up, cut the slots and proceeded. From there I used the coarse notches in my little credit card spreader and stuffed the biscuits. With the three part panel ‘tape hinged’ and laid open on the bench, I ran a bead down the valley of each of the miter joints, closed the joints and locked the panel in place.


By taping from the side to the back while pulling tension into the tape, that joint closed up well, then I used a stack of wedge shims and a block to foot the pipe clamp to pull the bottom edge tight.



The curb side of the front panel is beveled where it tucks behind the corner post, so that end was fairly well captured, but I ran a couple of temporary drywall screws thru the dado into the edge of the ledge to make sure that that part of the joint pulled up tight. Used a couple of the wooden washers from before to spread the load out.


Since the angle was the same, that same wedge of foam was used along the top of the front panel to square up the strongback used to clamp the panel to the base.


Rollin’ along.

[GPW]

KC, Thanks for being guinea pig on the DAP .... scratch that off the list ..

[KCStudly]

.
Yup.

Made progress on the lantern case and got the last of the foam panels glued on to the tongue box.





(Probably my shortest progress post?)