Hybrid Foamie Benroy Build

[TimC]

I am going to start a Benroy Teardrop soon with my son. He's just ordered the NT aluminum flatbed and I hope to assemble that trailer in the same way I did my second build with the axle slung under the springs and moved back to a 60/40 position to distribute weight toward the tongue. That was on the steel NT 5x8 flatbed. The aluminum looks like the same design so I think it will work. We'll see when it arrives.

My first Benroy was and is a successful and fun build, but, I want to keep the weight down a bit on this build. I'm considering 2" foam walls with a solid plywood floor, plywood bulkhead (is 2" foam OK here?), and an "inside-out" roof technique with 1/8" lauan ceiling, 1-1/2x1-1/2 spars and 1/8" lauan double thickness on the exterior.

I'm not sure how foam is reinforced for doors (I'm hoping he springs for the commercial doors from V. technologies) and wall attachment to the floor. I'll also need to splice plywood to get the 54" wall height and just under 9' wall length. Then there is the hatch build. Foam or plywood?

Can someone steer me toward build journals that might have detailed descriptions and photos showing these techniques. I tried to look through GPW's build, but 400+ pages was a little overwhelming. I'm sure he has some good details to learn from as I think he was one of many who helped me through my first build. Thanks in advance. In the meantime I will be searching on my own for some ideas.

#1 build on custom made 5x8 flatbed


#2 build on steel NT 5x8 flatbed(which my brother bought from me at this stage, walls assembled and floor done, and is currently finishing up)



Thanks, Tim

[ghcoe]

You can read through my #1 build http://tnttt.com/viewtopic.php?f=55&t=54099 . It is only 52 pages long and mostly deals with the build without going off topic too much. It is similar to a Benroy.

[TimC]

You can read through my #1 build http://tnttt.com/viewtopic.php?f=55&t=54099 . It is only 52 pages long and mostly deals with the build without going off topic too much. It is similar to a Benroy.

Thanks George. I've read through ten pages and learned a lot. I'm going to look into the hot wire method even though I am not doing as many cuts as you have. It'll come in handy for adding wood frames inside the edges of the foam as well as mortises for my spars for the roof and "inside out" methods. I think I'll even cut dados in the foam at the floor seam area to allow for a flush attachment point.

Tim

[GPW]

Tim ,please understand that my lengthy postings were all EXPERIMENTAL and exploratory procedures over many years … Now that the experiment is over and Foamies are Proven … There’s no need to read it anymore … unless curious .
I do believe George has written a more concise and descriptive narrative (s) , and I highly recommend checking out all his new and updated pragmatic innovations …

Good Luck !!!

[TimC]

Tim ,please understand that my lengthy postings were all EXPERIMENTAL and exploratory procedures over many years … Now that the experiment is over and Foamies are Proven … There’s no need to read it anymore … unless curious .
I do believe George has written a more concise and descriptive narrative (s) , and I highly recommend checking out all his new and updated pragmatic innovations …

Good Luck !!!

I understand... no negative criticism intended, but, I can see that maybe my comment may be taken that way. I did read through many pages and there is very good info there. I'm definitely curious! I was just wanting to see how to do specific tasks. Still working on that effort. I'm going to experiment with a homemade hot knife for now as my son's trailer is on back order and we will not likely see it until late August.

I'm not really going for ultra light, just lighter than my first TD. That had an overbuilt custom trailer with heavy steel square tubing. Just the aluminum trailer will weigh considerably less to start. The walls will probably be the only foam construction for my son's camper. Maybe the bulkhead, but, probably not as I want something solid to attach cabinets on both sides with options to add items anchored to it later without pre-determining reinforcement spots in the foam.

Now I just have to figure out where folks use different adhesives and why. I used PLP extensivly in TD#1 and TD#2. I'm curious about the use of Gorilla Glue and Great Stuff...

Tim

[TimC]

I played around with several ghcoe inspired hot wire foam cutters and after several tries with 12v wall worts and 12v battery chargers I tried an old soldering gun I hadn't used in years. The wall worts, for whatever reason, shut off power to my cutter contraptions and the vehicle 12v charger (2a/6a) cycled on and off too often to make it work reliably (I didn't know these things cycled like that).

I found a youtube guy that showed how to replace the stock soldering gun tips with homemade 12g copper wire. It holds its shape well, heats quickly and I am able to turn it on and off conveniently with the trigger switch. I made a tip to cut a dado (3/4" x 4") in foam for a 3/4" plywood splice or to add reinforcement to doors, spars, bulkhead, etc.

A rough trial cut in 1 1/2" thick foam. It was easy to follow my sharpie line, but, I think I will rig up some kind of jig to guide the cut.




Even with the tip at almost 4" long it cut a nice 2 1/2" deep dado in my trial at a respectable speed.


Thanks to George and GPW for their help. Now on to designing my foam walls to floor attachment method...

[ghcoe]

Hot wire is fun

[TimC]

Hot wire is fun

It is! Can't wait to get started. Now I'm debating whether to go with spars and plywood for the ceiling/roof or have some fun with foam. Gonna research bending foam. You have a good kerfing tool to try to make using my soldering gun.

[TimC]

George, in a past post on G Gripper and TBII and primers it was mentioned that drip edges solved some problems with standing water degrading TBII. I can picture what you are talking about, but, just want to be sure. Are you talking the bottom edges of the walls holding water, dew or condensation for extended periods after a rain or early morning drying spell? It makes perfect sense, just want to be sure I understand.

Also, I'm experimenting with TBII on untreated pink foam. I know this has probably been done a bazillion times. Its just for my satisfaction and curiosity. It definitely grips well as long as I get a good wetting on the foam prior to canvas then add more TBII to the canvas to wet it completely. I'm using the TBII as a primer as well for my first coats of paint. I like the idea of the Valspar Bonding Primer/Sealer. Not sure I need to add that step, I'm in a fairly dry climate; at least not a wet one. After it is totally dried out and has several coats of exterior paint I will submerge it and monitor it until I see separation.



Tim

[TimC]

Questions about 2"x4'x8' foam...

At my local HD I see faced and unfaced foam board (thought this was a fiberglass batt thing, not foam). HD has 2" R-Tech "faced" rigid in a R7.7 rating. And they have 2" un-faced Owens Corning R10. One version of the Owens Corning is scored at 16" centers. I am assuming I don't want scored foam for a wall build. Is the faced vs un-faced the thin plastic layer on top of the foam? Is that something I should avoid? I really don't trust HD descriptions at all. Seem that product web pages are often populated with info that leads me to believe the person doing so never used the product.

R-Tech is $21.68.
Foamular 250 is the scored product going for $28.37.
Foamular 150 non-scored $37.63

Anyone know the difference with 250 vs 150. HD web site doesn't list puncture resistance.
Edit, Menards has more info... Foamular 250 is 25PSI strength.

Thanks, Tim

[Pmullen503]

You definitely do not want faced if that means a plastic film. You should really sand down the shiny surface of the foam to get better adhesion of the canvas.

[ghcoe]

George, in a past post on G Gripper and TBII and primers it was mentioned that drip edges solved some problems with standing water degrading TBII. I can picture what you are talking about, but, just want to be sure. Are you talking the bottom edges of the walls holding water, dew or condensation for extended periods after a rain or early morning drying spell? It makes perfect sense, just want to be sure I understand.
Tim

Not sure how you are going to mount your body to your trailer, but yes you should add a drip edge just in case. If you are mounting the body flush with the trailer frame I recommend raising up the body 3/4" to allow a drip edge and to keep the body and frame from rubbing on each other. I found that the canvas will rub the paint off the trailer and then I would suspect the trailer will rub a hole into the canvas exposing the wood to moisture. This area is also a moisture trap. By lifting the body up 3/4" will allow the area to dry out. If the body is overhanging the trailer then you could probably just add a drip edge around the perimeter the body.

I use drywall end edging for a drip edge. I use truss screws to screw it to the floor. Before I tighten the screws up I squirt in some Dap Latex Caulk between the edging and the body then tighten the screw. This fills in the voids and seals the screws.

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[TimC]

Thanks George. The drywall corners being galvanized should hold up well. I've seen plastic corner bead as well which might be good as well.

Tim

[ghcoe]

Thanks George. The drywall corners being galvanized should hold up well. I've seen plastic corner bead as well which might be good as well.

Tim

I actually went to use the plastic ones, but they do not hold their shape well. Went back to the galvanized.

[GPW]

George , we used your drip edge on the FS and it works GREAT !!! Many Thanks !!!