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Re: after a long pause, it's time to start building

PostPosted: Wed Aug 03, 2016 1:03 pm
by Bob Hammond
I'm tempted to change my plans. I found these 250ft rolls of 1/16" x 1.5" veneer for $10ea. One is white oak, and the other teak. There may be 2-3 rolls still available.

Now if a guy wanted to make a hooped vardo/ conestoga trailer, this would be very useful material for laminating hoops. (you might need to open the image in a separate tab/window to see both rolls.)

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Re: after a long pause, it's time to start building

PostPosted: Thu Aug 04, 2016 6:03 am
by GPW
Bending regular wood is a lot more practical ... and probably less expensive ... :thinking:

Re: after a long pause, it's time to start building

PostPosted: Thu Aug 04, 2016 6:42 am
by Bob Hammond
It is 'regular' clear wood with scarfed joints and fully sanded. And at $10/250ft, I think it may not be too expensive, especially considering the time and labor of cutting and dimensioning lumber. For simplifying calculations, I calculate that 6' semicircular hoop at 5/16" thick requires about linear 50ft.

Of course, it would be perfect for a canoe as well.

Re: after a long pause, it's time to start building

PostPosted: Sun Aug 07, 2016 4:19 pm
by Bob Hammond
As a research scientist doing experiments, I learned that working out techniques is sometimes difficult and disappointing, and also that explaining imperfect results is valuable, for oneself and others.

Here, I wanted to glue the plywood inner walls to the exterior foam walls. I thought that a vacuum clamp with plastic painters' sheets might be just the thing, and so I made a manifold from $10 worth of 1/2" PVC plumbing. I cut slots halfway through the pipe about every 6". I roughed up the foam with a wallpaper scorer (didn't like) and so scarified the surface with a handplane (did like, as shown in an earlier post). The I spread glue at 8:2 glue:water v/v ratio, then folded over the plastic sheet and turned on the Shopvac. Everything sucked right down and looked great at first, and then I realized that the shopvac would probably burn out because the air passing through it also cools the motor. So I tried cycling it on and off. Well, I ended up adding weights, but one corner still did not stick. So, I think there were several factors that resulted in a so-so outcome;

1. The choice of the >Shopvac brand< wasn't a good idea. It turns out that newer Shopvacs have a non-replaceable thermal fuselink that will blow and brick the unit if it gets too hot. (It can be replaced with other things, but it's a PITA.)

2. I think that I diluted the glue too much for this purpose. It was easy to roller on, but not thick enough to get a good bite on the foam and plywood quickly. 9:1 would be better, or less.

3. I thought that I had started early enough in the day, but by the time I got things organized the sun was full up in the sky and shining down hot on the scene. I should have done the glueup in the evening.

This is a good idea that doesn't work well enough, yet, and your suggestions will be appreciated. Next time, I think that I'll clamp the long edges first, and then turn on the vac.

Re: after a long pause, it's time to start building

PostPosted: Sun Aug 07, 2016 4:22 pm
by Bob Hammond
This the manifold, upside down. The side with the slots is placed down on the plywood, to facilitate the extraction of the air from under the plastic sheet.


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Re: after a long pause, it's time to start building

PostPosted: Sun Aug 07, 2016 4:23 pm
by Bob Hammond
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Re: after a long pause, it's time to start building

PostPosted: Mon Aug 08, 2016 9:44 am
by Bob Hammond
I think that I've got it beat. I thickened & applied the glue, then covered, and drew it down with the shopvac. Then I cauled and clamped down on the long edges, threw on some weight. After about 5 minutes with the shopvac, I switched quickly to the woodworking dust collector (w/o the bags). It doesn't pull as many inches of vacuum as the shopvac, but it can run all day and night long since the motor is cooled by its own fan.

Before I forget, I started a thread in the general discussion about building ultra-lightweight speaker cabinets for this foam from leftover XPS. I started the thread there so a wider audience than foamers might have useful comments.

viewtopic.php?f=2&t=66799

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Re: after a long pause, it's time to start building

PostPosted: Tue Aug 09, 2016 4:02 pm
by Bob Hammond
Here I'm gluing the front curve of the cabin. I cut a 7.5d bevel on both sides of the foam 'plank'. The width of the plank is 5.25 inches, which should result in a quarter circle with a 20" radius. It was taped in the usual fashion, and the long 2x4s are set parallel on the flat surface of the deck. The deck has stayed flat through hot humid days and occasional rainshowers.

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Re: after a long pause, it's time to start building

PostPosted: Tue Aug 09, 2016 7:58 pm
by ghcoe
Looking good. Sanding is a bit of a pain on those curves like that. I had to do a similar build on my hatch radius. I used GG in the construction and it dries a lot harder than the foam. I took a dremel tool and ground the glue below the sanding surface. I would then use light weight spackle to fill in the void and then sand smooth. Work well.

Re: after a long pause, it's time to start building

PostPosted: Tue Aug 09, 2016 8:04 pm
by Bob Hammond
Thanks for the tip. The glue squeezeout is minimal. I did a moderate application of glue, and then wiped the mating surface with a damp cloth - no spraying or misting. A lot of water seems to produce a lot of squeezeout.

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Re: after a long pause, it's time to start building

PostPosted: Wed Aug 10, 2016 3:17 pm
by KCStudly
Even a hair line joint of GG will sand harder than the surrounding foam. As you sand the seam/GG compresses, but doesn't remove at the same rate as the surrounding foam. When you stop sanding the GG/seam pops back up and sits proud from the surrounding foam. You try to sand it some more and the situation gets worse. Before you know it you have two low areas on either side of a high area. No bueno.

Just saying, been there, done that.

Re: after a long pause, it's time to start building

PostPosted: Wed Aug 10, 2016 10:14 pm
by pchast
"Fine Homebuilding'' had a recent video about insulation of a cellar. They used
spray foam and some Gorilla Glue. The excess foaming was removed with a
notched trowel as a saw run along the blue foam. I think it was a metal trowel.

Re: after a long pause, it's time to start building

PostPosted: Thu Aug 11, 2016 8:13 am
by Bob Hammond
I think I'll glue up a test joint with the 15d angle to try some of the methods. One thing that happened with the handplane was that occasionally it removed foam shavings just as if the foam was wood. At the time, that wasn't my intention. Maybe I'll hone and set the blade and see if I can smoothly plane the gg and the foam

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Re: after a long pause, it's time to start building

PostPosted: Thu Aug 11, 2016 10:12 am
by Bob Hammond
We did a test fit for the curve; it looks good. Now onward to the headboard shelves and rear bulkhead & galley frame.

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Re: after a long pause, it's time to start building

PostPosted: Fri Aug 12, 2016 5:58 am
by GPW
Bob ... “ Now if a guy wanted to make a hooped vardo/ conestoga trailer, this would be very useful material” ... Since you mentioned it , I now believe that PVC would make good hoops for a Connie’ ... We regularly heat bend PVC pipe to make Bows (archery) , and we’ve yet to have a bow failure ... Nice thing is you’re able to flatten out the ends for easier attachment to a base box ... :thinking:

... and it’s ridiculously cheap .... 8)