New trailer build

[saltbranch]

My 20' frame has cracked in 2 different places and after thinking about it. With the crossmembers that have been added over the years and other custom weld ons. Recent new 5200 lbs axles and new 10 ply tires. I think I am going to scrap the repair and build another trailer. I already have 2-20' sticks of 3x3x1/4 square tube, that will form my box, plan on notching 4" channel (on 16" centers)to where they will fit 1-1/2 deep into the square tube, which would make my floor fit flush with top of square tube. Use 6" channel for a full wrap tungue with 2-5/16" coupler. Will go with the heavy fenders like in my other post. I can mount all my marker lights and tail lights in the square tube along with running my wiring harness through there too. Thinking of incorporating some 2" receivers into the trailer for ability add/build racks etc for later uses any other ideas? I plan on welding D eings down each side to the top of the 3x3x1/4" for tie down points. just fishing for other "must haves" that could be thrown in the pot.

Thanks

 

[Diamondpilot]

I am not so sure I would use "box" tubing for the main frame. I have had bad luck with box framed trailers in the past and it seems to me the I beam and C channel trailers last a lot longer.

Chris

 

[Dr Dave]

Add a receiver in the front for a winch. Your not going to cut into the square tube, are you?

 

[bcp]

Treat the interior of the tubes like aircraft builders do.

From:
Rust Protection

Protection For Welded Steel Fuselages

Traditionally, the interiors of tubular steel fuselages are shielded from rusting by a protective coating of linseed oil. After all welding has been completed, the tubing interiors are then flushed with hot linseed oil. The oil, heated to approximately 160°F. is forced into the tubular structure by squirting it in through the small holes previously drilled into the tubing. A small capacity trigger type oil pressure pump can works fine (see Figure 1).

The amount of hot linseed oil you introduce into the fuselage’s tubular structure should be measured before hand so you will be able to determine, later, that most of the excess hot linseed oil has been drained out after treatment.

Feeling for the warmth and coolness in various sections of tubing, as the hot oil is introduced, will give you some indication of the presence, or absence, of the heated oil.

Rotate the tubular fuselage as the hot linseed oil is being introduced to ensure its insides will be completely oil coated.

After two or three minutes, you can drain the excess oil. When you have determined that most of the oil has been drained out, plug each hole. Use short cadmium plated self-tapping screws to prevent moisture from re-entering the tubing and nullifying your rust-inhibiting oiling effort.

After your tubular structures and assemblies receive their hot linseed oil treatment and have been sealed, the entire tubular welded structure should be cleaned-preferably, sandblasted.


------------
From:
Aircraft Welding and Steel Tube Fabrication - Part 9

Rust Prevention
Preventing the rust on the insides of welded tubes is something that everybody knows is necessary, although not everybody does something about it (See Figure 5). Many tube fuselages are assembled in such a way that before the tubing is welded, holes are drilled at the intersections, inside each piece of tubing, so that oil can be poured in an inlet at one end of the longerons, and it will eventually find its way in to all of the tubing. In the past, this oil has been nothing more than boiled linseed oil, but now there are several commercially prepared oils that do the job even better.

-------------------
CORROSION PROOFING OF LAND PLANES CONVERTED TO SEA PLANES
www.velocityxl.com/wiki/images/1/17/2r-ch6_13.pdf

c. Protect the interior of structural steel tubing. This may be done by air and watertight sealing or by flushing with hot linseed oil and plugging the openings.

 

[saltbranch]

Treat the interior of the tubes like aircraft builders do.

From:
Rust Protection

Protection For Welded Steel Fuselages

Traditionally, the interiors of tubular steel fuselages are shielded from rusting by a protective coating of linseed oil. After all welding has been completed, the tubing interiors are then flushed with hot linseed oil. The oil, heated to approximately 160°F. is forced into the tubular structure by squirting it in through the small holes previously drilled into the tubing. A small capacity trigger type oil pressure pump can works fine (see Figure 1).

The amount of hot linseed oil you introduce into the fuselage’s tubular structure should be measured before hand so you will be able to determine, later, that most of the excess hot linseed oil has been drained out after treatment.

Feeling for the warmth and coolness in various sections of tubing, as the hot oil is introduced, will give you some indication of the presence, or absence, of the heated oil.

Rotate the tubular fuselage as the hot linseed oil is being introduced to ensure its insides will be completely oil coated.

After two or three minutes, you can drain the excess oil. When you have determined that most of the oil has been drained out, plug each hole. Use short cadmium plated self-tapping screws to prevent moisture from re-entering the tubing and nullifying your rust-inhibiting oiling effort.

After your tubular structures and assemblies receive their hot linseed oil treatment and have been sealed, the entire tubular welded structure should be cleaned-preferably, sandblasted.


------------
From:
Aircraft Welding and Steel Tube Fabrication - Part 9

Rust Prevention
Preventing the rust on the insides of welded tubes is something that everybody knows is necessary, although not everybody does something about it (See Figure 5). Many tube fuselages are assembled in such a way that before the tubing is welded, holes are drilled at the intersections, inside each piece of tubing, so that oil can be poured in an inlet at one end of the longerons, and it will eventually find its way in to all of the tubing. In the past, this oil has been nothing more than boiled linseed oil, but now there are several commercially prepared oils that do the job even better.

-------------------
CORROSION PROOFING OF LAND PLANES CONVERTED TO SEA PLANES
www.velocityxl.com/wiki/images/1/17/2r-ch6_13.pdf

c. Protect the interior of structural steel tubing. This may be done by air and watertight sealing or by flushing with hot linseed oil and plugging the openings.

Thank you for the info. I was undecided on how to treat the inside of the tube. Definety gives me a direction to go for treating it

 

[ericher69]

Bcp;

What about when you go and weld on the tubing that you have internally coated? Doesn't the heat cook of any oil/coatings and nullify the effort?

 

[Diamondpilot]

Yes, it cooks off and so does time. Lining tubing with oil is nothing new for both boat trailers and airplanes, something I handle both of for a living. Nothing is full proof. I can tell you though with about 25 years in the trailer business and 100's of trailers I have worked on of which 60% or so were boat trailers, that the tubing trailers last about 1/2 the time that the C Channel or I Beam trailers do.

Yes, tubing makes a nice finished product but dirt and moisture always seem to find its way in and sooner or later there is issues.


Chris

 

[bcp]

before the tubing is welded, holes are drilled at the intersections, inside each piece of tubing, so that oil can be poured in

...Poured in after welding

Holes are drilled, then welding is done, the oil is put in the tube, oil goes from tube to tube through those drilled holes at the intersections, the excess oil is removed, then the tube closed. After a while, the linseed oil dries.

The linseed oil both coats the interior surface and then absorbs oxygen as it hardens. Two strikes against rust.

From:
Linseed oil - Wikipedia, the free encyclopedia

Having a high content of di- and triunsaturated esters, linseed oil is particularly susceptible to polymerization reactions upon exposure to oxygen in air. This polymerization, which is called "drying," results in the rigidification of the material. The drying process can be so exothermic as to pose a fire hazard under certain circumstances.
...
Most applications of linseed oil exploit its drying properties, i.e. the initial material is liquid or at least pliable and the aged material is rigid but not brittle. The water-repelling (hydrophobic) nature of the resulting hydrocarbon-based material is advantageous.

Bruce

 

[saltbranch]

Any idea on how much Linseed oil for each 20' square tube? I will be using the square tube for each side and have 4x4x1/4" angle for the front & back to cap and complete the "box".
I understand square tube is not as ideal as C-channel, but I have it sitting here. It will last as long as I need it.
Thanks for the ideas and advice everyone.