FoamStream...

[KCStudly]

Nice rendering.

Are there intended to be FS style plywood ribs (hull frames in submarine parlance) imbedded in the foam? If so, the extra arch ribs seem redundant to me. Even w/o imbedded ribs, with fabric skin in and out they may still be redundant (and kill head room).

Now just one question, where are you going to get a block of foam large enough, and how will you fish the hot wire thru the length in order to "core bore" the middle out?

[GPW]

KC, I guess we were thinking about FS style ply ribs , which would eliminate the need for the arches ... It was just an exploratory drawing , nothing chiseled in foam ...

In the Oil industry here , we’ve seen beaded foam blocks as big as pickup trucks (no idea what they’re used for ? ) ... Now if I could only get my hands on some ...

[Wolffarmer]

How would such a shape be in a side wind?

Randy

[ghcoe]

Now just one question, where are you going to get a block of foam large enough, and how will you fish the hot wire thru the length in order to "core bore" the middle out?

Maybe you can get these guys to help. They work with big hot wires and foam blocks. About 3 mins in.....

https://www.youtube.com/watch?v=6XoGn-N ... r_embedded

[GPW]

Randy , the rounded surfaces would likely allow the air to roll over the surfaces (less drag) ... Driving on the highway , the FS got passed by several big rigs that made me look like I was standing still ... Didn’t notice any reaction at all ... But we do need to observe sound design practices , like not making it too tall for the width ... and keeping the weight as low as possible (easy with foam ) ...

Gh, Big blocks of foam .... what FUN !!! The RC plane guys tried the Styro Spray , turned out expensive and a bit heavy for intended purpose ... and it didn'’t do well in a crash (what does? )

[Ned B]

GPW it was a slow night at the new job last evening & I was re-reading this project. I didn't realize how much the FS design influenced my own plan. The foam over skeleton approach for my trailer is the only way I can see to get the strength I need.

[GPW]

Ned , we were just following old aircraft fuselage building techniques... formers and stringers .. Having a solid framework made putting the foam on easy , and all the lightening holes in the rib-formers made wire running and hook attaching various things so very easy to many places ... Handy in ways yet undiscovered. Without the framework , i’d have had to glue the foam blocks carefully , and glue in “hard points" for various attachments, lanterns, nets , etc. The frame by itself was easy for me to pick up and move around (once balanced) so didn’t contribute much weight to the cabin. Guessing ~ 40 lbs.
Your frame looks Great !!! Can’t wait to see it go together!!! I know you’re going to like the results , especially towing....

I might suggest before final assembly of the framework , you give all the wood a good soaking of ... “the Mix” ... I should have done that , but didn’t .. and wish I had ...

[dales133]

Hey GPW sorry for the hijack but could you share some of your expertise in relation to wires coming into contact with extruded polystyrene.the point was raised that special coated wires might be needed (12v).
Thanks in advance

[GPW]

I , like the building inspector believes all wiring should be run in conduit ... But in a Foamie , running permanent wires is like wiring a tent ... It’s a CAMPER , not Better Homes and Gardens .. Not a tiny decorated “dollhouse” like the RV industry likes to push off on us ... all the stuff that makes it NOT like Camping ... The FS was designed without wiring , figuring any extra wiring needed can be run thorough the lightning’ holes when (if) needed ..

Besides in 12v systems , likely the copper wire will succumb to “black wire disease” long before the plastic degrades... common in DC systems ...

Unless you’re 20 years old and building this , I really wouldn’t worry about dissimilar plastics causing problems with the wiring ... Nothing to lose sleep over ..

[Ned B]

GPW, re the mix. I can see the sill plate getting that treatment, but the rest? Id rather use cypress for the bottom 1/3, then poplar or ash above. For that matter I could just use ash throughout. Cheap, easy to get up here & really strong for the weight.

[GPW]

Ned, excuse my caution , but it rains a lot here and I think why take a chance ... ? Easy enough to really protect all the wood , just in case... Having seen how one little leak can spread all over the place , I'd sleep better knowing I'd treated the wood ... We've seen so many things (especially RV's ) just totally ruined by one little leak and no waterproofing...

[Ned B]

GPW, yeah, you're in the tropics, I forget that. We get our fair share of moisture as well, though ours is a lot colder than yours most of the time. I guess the mix isn't that costly, but it might affect the look of the wood. As you say, I'm a woodworker. If I weren't going for ultra light weight, I'd be building a woodie in a heartbeat just for the aesthetics.

That being said, I may still find a way to have a decent amount of wood 'features'... frame, a couple of small cabinets, face frames around the doors, and the galley.

[dales133]

Thanks very much GPW was pretty sure you'd have a straight forward answer

[GPW]

Just a little reminder about the mix ... Buy the CHEAPEST polyurethane varnish you can find (not water based) ,and buy Paint thinner not Mineral spirits .... For some reason the "paint thinner" is ~$4 a gal. (ingredients marked on the label as 100% Mineral spirits) ... The container marked "Mineral Spirits" is $9 a gal ... I don’t know why , but the cheap stuff is the same thing and works fine for the Mix.. And once you mix a batch , you can use it on anything wood . We’ve used it on many projects now (including campers) and with great results .. best thing is , it really doesn’t discolor the wood that much ... OR you can add an oil pigment to it for various staining shades of color ... if wanted . It stores well too , and won’t go bad in the can ... lasts for years and years , when sealed ...

The way to tell if you’ve applied enough is when it no longer sinks into the wood and becomes shiny on the surface... all wood is different , some soaks it up , harder woods just get shiny quickly. Best pay special attention to the End grains... The open end of the “tubes" in wood. That’s where most of the water gets in . Capillary action then takes over and the water migrates down the tubes and into the wood. Block those ends and water absorption (and subsequent ROT) slows waaaay down ...

[tac422]

Doc,
What's the percentage of varnish to paint thinner ?