Newbie with some materials/construction questions....

[Robbie]

Hey guys, newbie here. I am just getting into the whole teardrop trailer thing and have been doing some research about building one. I’ve read through the generic benroy plans and have decided that is the style I want to build. I work as a draftsman at an architectural woodworking company so I’m drawing my design out in AutoCAD and then will model it in Inventor for ease of construction understanding and to make sure everything will work. I am planning on using the 4x8 Harbor Freight trailer as my chassis/platform as I have access to one for very cheap and it can be easily towed behind my Subaru Outback. I am planning on keeping this trailer very simple with no rear hatch or galley. Maybe 2 cabinets towards the foot of the sleeping area for inside storage but not much else. My wife and I use the camp fires or little camp stove for cooking and will just bring a cooler instead of installing a fridge. Also I do not plan on running any interior wiring but rather use those tap lights attached to the walls inside for interior lighting. I know the batteries will need to be replaced but I’m going for simplicity. We hate tent camping so we basically just want something rigid to sleep in. Ok, enough background, on to my questions.

For the floor I have it drawn with a ½â€

[GPW]

Robbie, sounds like you've got it all figured out !!! ... and Free is GOOD !!!
Are you planning on cutting it out with a CNC ?? That would be Super and Accurate , eliminating any need for re-fitting ... Once the drawing is worked out /tuned of course ..

OSB is used on a LOT of RV floors now , and not the good stuff .. sealed well it should be OK !!

[Robbie]

Great then OSB floor it is! And yes I am going to have the sides CNC'd cause I know my not so steady hand will give me 2 different shaped walls. And since its here I may as well use it.

So that gives me the flooring solution. Any ideas or advice as to the wall material? Lite-ply or Birch?

Thanks again for your help!

[Wolffarmer]

Rob, for your outside top covering, one layer of 1/8 birch is plenty. That is what I used and I would do it again. I think an 8 footer with no galley will leave you with a huge mostly unusable space inside. I would say to make a galley hatch when you build it then finish a galley if you find you might like it. Would also make access to that empty space a whole lot easier. Or make the trailer about 6.5 feet long.

Bobhenry has made his tear from OSB and has no problems. Would not be my first choice of materials, unless they are free.

[HandyAtLeast]

I agree 100% with Wolffarmer: build a galley hatch, even if you don't use it. Heck, don't put a hinge and screw and seal it down until if (when) you decide you would like the galley option.

[Robbie]

Well the extra access into the trailer would be pretty nice. I think you guys talked me into it. I'm gonna give some more thought into the OSB. Sure its free but it just doesn't seem that durable to me. I remember building bike ramps out of scrap OSB when I was little and leaving them in the rain a couple times and they would just fall apart. I'm gonna stop by HD tonight and see what they have in leiu of hardwood plywood and price them out there and from my work and then make my decision.

[GPW]

If you thoroughly SOAK the OSB with the cheapo waterproofing mix (75% Mineral Spirits, 25% polyurethane varnish ) you should be just Fine on the floor ... Once you see the ply prices (and that's not even the very GOOD ply) , the free OSB will look pretty Good ...

Now I don't know for sure , but it seems there's different grades of OSB... some looks Untempered, the stuff I used on my house was more "treated" and the scraps i left outside did hold up well even after some time ... Might check that out ...

[48Rob]

Robbie,

OSB is not durable in an exterior application.

For home decking, sheathing, etc, it is okay, because it is weatherproofed by other materials, and or is not exposed to the elements.

Painted OSB will last slightly longer than untreated, but will still come apart, literally.

Well sealed may work, or may start to come apart a year or two after you get done building the trailer and are really enjoying it, at which point you may say to yourself; why didn't I just spend an extra $40 to do it right...
Saving money and being thrifty is good, but if you are going to cheap out on something, it may be wise to do so on a part of the trailer that can be easily replaced, without tearing it down to the ground to access the part.


Rob

[GPW]

49Rob, Gee!!! I don't think it's fair to dismiss a material like OSB from the get go ... Rob , I Totally Respect your building skills and TD efforts (CC is one of my all time Favorites) ... but I think this OSB thing needs more investigation ... Seems a lot of guys have built things with this material successfully ... The OSB I used on my house was pretty TOUGH stuff , and scraps left in the yard just stayed there , no problem except turning a little gray-ish over the years ... So are there different kinds of OSB??? How should it be treated (what others have done) ???
The OSB on the floor of my Jayco is total Crap , already had to repair that .... that stuff just disintegrated as you describe... Mush !

The other consideration is , Robbie is getting it for FREE !!! Maybe he could get a sample and test it (in a bucket) , maybe seal a piece and test that ??? I dunno ... plywood doesn't seem to be much better , unless you get the ridiculously expensive stuff ...

[bobhenry]

Oh Damn

[Robbie]

Plywood seems like a more rigid panel than the OSB. But they do make OSB panels that are treated for exterior specific applications. However, I do not think the OSB we have is treated or rated for outdoor use. I think I've decided to use a 19/32" Fir Ply panel with a 2x2 sub-floor for the trailer floor and then use 3/4" Baltic Birch Ply for the walls. It will be a little more expensive but I know you can finish the Birch to look good and it is pretty strong so it should help to make the trailer stable. Especially since there aren't any interior upper cabinets there to add side to side rigidity. I will still use the 1.125" Poplar blocking for my roofing spars since we have a grip of those here at my work for blocking.

I also found a nice vinyl floor sheet that I will use to cover the bottom. And I'm still planning on painting the entire exterior with a Marine grade paint, after I seal it with Epoxy or something. And then maybe add a piece of 18 gauge aluminum from the first radius in front over to the back radius on the roof.

[bobhenry]

Zip panel is some interesting stuff. A fiberglass faced dense osb.

http://www.zipsystem.com/

I am using it on my 4x7 and the chuck wagon

[GPW]

Hey Robbie , I got a question for you .... How would you take a regular ink drawing and scan it to a bit map for CNC use ... Any ideas ... Have access to Rhino ...

[Robbie]

I honestly don't have any idea? Everything that I've ever had CNC'd has all been right out of either AutoCAD 2006, 2010, Inventor 2011, or Solidworks 2010.

Actually, Now that I think of it. I know you can bring an image in as either bitmap or jpeg and then trace it in AutoCAD and scale it to correct size and then you'll have whatever was on the paper in AutoCAD's line layers. I've had to do that before on a few projects. If you'd like you can email me the bitmap image and I can try it out for you? My email is [email protected].

I took my final design idea and started modeling it out in Inventor 2011 just now to see how everything is going to mate up and possibly work a hatch into the back of it. I will post some model pics when I get home from work today!

[GPW]

Thanks Robbie !!!