solid v/s sandwich question.

[SteveH]

Jeff,

The radius on the lowers is small, but I don't remember exactly. I think it is 2" because that is the height of the frame I was trying to hide.

[SteveH]

I'm building everything as a sandwich these days. Floor, walls, even bulkheads and cabinet frames.
The next T/D I do for myself will be built with 1/8" skins, instead of my usual 1/4" skins.
When I built Mike's 'Diner, I weighed a wall panel (4'-6"-by 11'). It weighed about #70, the same as a 4-by-8 sheet of 3/4" ply!
The sandwich is 1/4 ply, minimal 3/4 framing and foam, then 1/4 ply.
Floors are 3/8" ply on the top, foam/framing, then 1/4 ply on the road-side.
Some will disagree with sealing the bottom. I do mine in wood, then epoxy/paint. No voids for moisture to get in. Just the way I do it.
As MadJack says, "Your Mileage May Vary"!

Steve,

Questions...have you ever put the pencil to the cost of your built-up panels vers straight plywood? Also, have you ever kept track of the man hours required to build a typical wall panel?

Just curious. Thanks.

[toypusher]

.................
Questions...have you ever put the pencil to the cost of your built-up panels vers straight plywood? Also, have you ever kept track of the man hours required to build a typical wall panel?

Just curious. Thanks.

I don't know about the costs, but the manhours will vary quite a bit, depending on how you build a sandwich wall. Bench built, in my opinion, is the better way to go and it takes some time, but when done, mine contains wiring and is finished, just put it up and you are done!! Putting up a sidewall and then adding framing and insulation and then the interior skin would take much longer and be much more difficult! So, even though I don't know the hours that I put in, my guess is that the time is approx 3 times that of just cutting out a single layer of plywood and putting a finish on it! JMHO, YMMV!!

[jeffwholmes]

Thanks steveH, I was thinking about a 2” radius.

When I build my frame should I make it 102” so I will have a 3” over hang at both ends?

Will that be enough room to make my radius so it hides the frame, and if so will luan bend around that?

Thanks Jeff.

[SteveH]

Thanks steveH, I was thinking about a 2” radius.

When I build my frame should I make it 102” so I will have a 3” over hang at both ends?

Will that be enough room to make my radius so it hides the frame, and if so will luan bend around that?

Thanks Jeff.

Jeff,

I'm sure that dimention will work. All I can tell you for sure is how I built mine...it is an 8' frame, with a 9' body, and a long tongue. It's really just an asthetics type of thing. The radius is about 9" on the rear, and 3" on the front in length. I did not use any plywood backing on the lower radius. I used light "Valley Tin" aluminum and after it is curved at such a small radius, is plenty ridgid. Sure it would bend if it is hit with by something, but it is also easy to replace. That is just the simplest and easyest way I came up with to do it, and it has worked out fine.

[angib]

I am going to estimate my overall weight at 1500 lb. / 682 kg.
Strength needed is 0.5 x 1500 = 750 x 48 = 36,000.

The 2”x2” is only rated at 20,900 lb/in vertical capacity, think I could use 2.5”x2.5” it is rated at 35,600 lb/in vertical capacity.

Jeff,

Several thoughts:

- Your calcs are right. But.....

- The Aussie rules were created for things like utility trailers that lead hard lives. Discussions on this forum lead me to believe that it's reasonable for a teardrop to use a tongue that's only half as strong as the Aussie rules require - and some commercial teardrops use less than that. So the 2"x2"x3/16" should be enough (you are talking about a single tongue, right?).

- The bigger size but thinner wall tube will always be a stronger choice for the weight/money, plus you get the benefit of even greater stiffness which should prevent some types of shimmy.

- One problem with a square tube single tongue connecting to a angle iron frame is that the weakest point is likely to be not the tongue but the rear of the two cross-members that the tongue fixes to. Exactly this problem has been reported on the forum with Tractor Supply trailers of this design. Two ways to avoid this are: to set the second cross-member a long way back from the front of the frame so it's more lightly loaded, or to use a tube cross-member at this point (only). Angle iron is fine everywhere else and would be fine everywhere if you were using an A-frame tongue.

Andrew

[jeffwholmes]

Steve thanks again for your replies, you have been very helpful.

Jeff.

[jeffwholmes]

Andrew thank you for your replies, certainly gives me some food for thought. I will run the numbers and look at an A-Frame tongue.

Thanks again Jeff.

[ARKPAT]

The door blanks I'm using time. How long does it take to cut the profile in a sheet of plywood? Then the ajoing front, back floor,top. doors and cut holes for the windows.

My time cutting is - about 14 hours.
bend tabs for attachment - 4 hours.
Glueing panels as you attach - 4 hours.
put it together yourself - 10.
mounting it to a HF frame - 4 hours

=



a weekend

No painting and wiring and amentiies and cabinets but a basic trailer; a Weekender - a weekend



Pat




Pat

[Esteban]

Jeff, If you stick to the Aussie Rules for a 48" long A-frame tongue 2"x3"x1/8" tube is strong enough for a 2,330 lb. trailer, yet it's a lighter weight tongue than one made from 2"x2"x3/16" tube which is rated for 1,740 lbs. per Andrew's Even Simpler Look Up Table for tongue strengths.

Per the Aussie Rules at 48" long A-frame tongue made from 2"x2"x1/8" tube is strong enough for a 1,300 lb. trailer. If, as Andrew says, the Aussie Rules are maybe double the strength really needed that might be good enough for the 1.500 lb. estimated weight for your trailer.

I just completed a frame that's 61" wide by 117" long. It has 2"x2"x1/8" tubing for the outside frame. There are 4 cross pieces of 2"x2"x1/8" angle, on roughly 2' centers (to fit the plywood floor seams). The 48" long A- frame tongue is made from 2"x3"x1/8" rectangular tube - so it's way overbuilt per the Aussie Rules for a 1,700 lb. trailer, which is my loaded up with camping gear goal weight. I added a fudge factor of about 200 lbs. for my trailer's loaded weight. That's why I used 1,700 lbs.

The weight difference between the 48" A-frame tongues for a 5' wide frame is only about 10 lbs. more to use 2"x3"x1/8" rectangular tube instead of lighter 2"x2"x1/8" tube so I went for it just to be extra safe.

[Steve Frederick]

Steve,

Questions...have you ever put the pencil to the cost of your built-up panels vers straight plywood? Also, have you ever kept track of the man hours required to build a typical wall panel?

Just curious. Thanks.

Although I can put together a set of walls, ready to install, finished inside and out, in about 30 hours time, spread out over a couple of weeks , the answers to the questions don't matter to me.
I'm not being a wise guy, but, it's just my thing. The first T/D I built required a larger panel than I could get easily. I had the materials on hand, so I developed a way to make larger panels that I could leave exposed. The next one was an experiment with thinner ply. Framing was required to keep the thinner wood rigid..Folks liked it..
Even if I never sold a trailer, I would still do it this way..Artistic preference, I guess.

You know, why would anyone build something that is otherwise mass produced, and cheaper? Must be the art??

[SteveH]

Steve,

Questions...have you ever put the pencil to the cost of your built-up panels vers straight plywood? Also, have you ever kept track of the man hours required to build a typical wall panel?

Just curious. Thanks.

Although I can put together a set of walls, ready to install, finished inside and out, in about 30 hours time, spread out over a couple of weeks , the answers to the questions don't matter to me.
I'm not being a wise guy, but, it's just my thing. The first T/D I built required a larger panel than I could get easily. I had the materials on hand, so I developed a way to make larger panels that I could leave exposed. The next one was an experiment with thinner ply. Framing was required to keep the thinner wood rigid..Folks liked it..
Even if I never sold a trailer, I would still do it this way..Artistic preference, I guess.

You know, why would anyone build something that is otherwise mass produced, and cheaper? Must be the art??

Steve,

I understand how you feel, and please don't think I'm trying to be argumentative. I actually want to know for my own purposes in possible future builds. I think from what I've seen of other people's builds that built up the walls, they are obviously more labor intensive, and may even cost more...I don't know. I wonder about the last issue, the actual weight difference between the two. Everyone always quotes the weight of a 3/4" sheet of plywood for the walls, but the fact is, about 1/4 to 1/5 of the wood is cut away, depending on the profile.

You see, I am basically lazy and impatient. If I had the actual facts of the differences between built up walls and plywood, I might be able to convince myself to do the next one differently.

[Steve Frederick]

Yes, more expensive, and for most, more labor intensive.
I think it's viable for anyone, if patience and time are there. The potential for insulation, wiring, and flexibility in wood choice all a plus.
BTW, I don't think you were being argumentative.
I wouldn't have responded if that were so.

[SteveH]

Steve,

OK, if I had an idea of how many board feet of 1X is used in the typical built up wall of, oh say 4 X 10', I could figure the rest. That basically is my unknown. Would you happen to know that? The plywood I can figure, and the insulation is easy to figure also. The 1X is the most difficult to figure, and I suspect, the most cost.

[jeffwholmes]

Thanks steveB. I got my steel yesterday for the frame. I will get the tongue steel later.
After a closer look it will be an A-frame tongue.

Jeff.