Broken Aluminum Frame

[Selkirk]

One of my favorite YouTubers just released a video that chronicles the discovery and repair of the near-catastrophic failure of the aluminum frame on his Trillium Outback. I found it interesting to watch....especially since several other manufacturers either already use aluminum frames or (in ETI's case) have plans to do so .

https://www.youtube.com/watch?v=Yg55GXksEnY

This particular frame was retrofitted by Outback in place of the original steel version a couple of years ago.

Those who follow Slim's travels will know that he doesn't baby his trailer. However, Based on his channel content, I've never seen him do anything extreme enough to warrant this kind of failure. I doubt his rig weighs any more than 2000lbs. He doesn't use a WDH either.

The video suggests that excessive tongue weight might have played a factor, though I'm not sure if that's the case.....

[hondasaurus]

No video...but...
Aluminium frame are good if they are were well engineered since aluminium welding reduce the structural capacity of the tubing used in the welding zone. This does not happen as much on steel.

From my experience there is not much gain in using aluminium in frame except for corrosion resistance. To have the same capacity with aluminium you have to use thicker gage (heavier) and make sure of your welding since it is more prone to bad welding with more consequence thant with steel.

[Carmel Clown]

I love Slim Potatohead. His narratives are the best.

[SageRpod]

I would be interested to know where the frame broke. Rpods are notorious for broken frames and bent axles in and around the area where the axle bolts to the frame. The axles bend because they are cantilevered out from the frame due to the Rpod body being so narrow and the wheels being outboard of the body. The frames bend at the axle joint because there is no bolstering of the frame there.

IMHO, the materials are perfect for the application but the engineering failed.

[Ron in BC]

Originally Posted by Selkirk

.especially since several other manufacturers either already use aluminum frames or (in ETI's case) have plans to do so .

.

Quite a difference between that dinky frame and the massive one on the 23.

Ron

[NEWYORKHILLBILLY]

Oliver trailers use a aluminum frame, But the axels are mounted to a galvanized steel sub frame.

[Civilguy]

I would be interested to know where the frame broke.

This is a common location for frame failures.

Interestingly, the frame appears to have a doubler plate welded on to reinforce the specific area that failed.

Anyway, as Leslie Nielsen once said, "That's no gouda".

[Centex]

Originally Posted by Civilguy

This is a common location for frame failures.

In fact didn't ETI during the R&T era suffer some similarly situated failures of their steel frames on a certain model (which Reace undertook to remedy with a weld-on 'scab' reinforcing plate)?

Glad to understand that in those cases as well as in the case that's the subject of this thread there were no seriously traumatic outcomes.

IMO the lesson learned is that the base metal is neither a panacea nor a curse - proper engineering is required in all cases and either can be great when that goal is met.

[Carmel Clown]

It wasn’t at the axle. It was where the frame starts to bend at the tongue.

[Doug2000]

I am a welder, mechanic and machinist with 25 years fabrication experience. I politely commented on Slims YouTube video 2 years ago when he got the aluminum frame. I noted it was under size and I did not like the weld joints and the method the fish plates were attached. Square corners leads to stress cracks. To build a frame like that I would use 5" x 2" x 1/4" wall square tube as a minimum and be very strategic with gussets and stiffener plates. From what I can tell the frame was almost a copy of the steel frame. Where I work, we have 200 skilled welders and when a new product is released it is rigorously tested before production. The tooling used is tested well beyond it's rated capacity with strain gauges. This was not the case with Trillium Outback.

I will add from Escapes videos, the aluminum frame Escape is going to use on the new 23 is impressive.

[Ron in BC]

Originally Posted by Doug2000

I will add from Escapes videos, the aluminum frame Escape is going to use on the new 23 is impressive.

I agree and there's no comparison between the two situations.

Ron

[CE Vogel]

My current and previous trailers have/had aluminum frames. My previous trailer had a slightly undersized frame (but better than Slim Potatohead's) and eventually broke identically to Slim's Outback. Aluminum tends to 'work harden' when flexed, meaning it becomes more brittle the more often it flexes. Eventually it cracks. The trailer A-frame, under the front wall of the trailer is the point of most flex in most trailers. There is also a lot of welding in this area, and typically welds create weak spots adjacent to the weld beads. When I took my trailer to be repaired at specialist aluminum weld shop, they installed a continuous beam with tapered ends UNDER the A-frame cracked area. They said this is to avoid vertical welds in the high stress area which would initiate future cracks. The tapered ends allowed the stress from the reinforced beam to gradually transfer to the trailer frame rather than point loading at the end of a square cut beam. This repair was still good many years later when I finally sold the trailer.

[Doug2000]

I was a little harsh but get really annoyed when people design stuff when they have no expertise or training. In an extreme situation someone could have been killed.

The repair is worse than the before the break, so many failure points.

[TJMac]

Having designed boat, auto and industrial trailers in a past life, I totally agree with Doug's initial assessment and his and Craig's current comments. This frame should never have been built from aluminum for the reasons already mentioned, plus the drop in the frame between tongue and rear is already questionable not to mention the horrendous welding. The flexural strength of steel is almost infinite whereas in aluminum it is only a matter of time before fatigue leads to failure. Good call on your initial assessment Doug.

[CE Vogel]

Originally Posted by Doug2000

The repair is worse than the before the break, so many failure points.

I watched Slim's video of the repairs to his trailer. Doug is correct, it is a poor repair. Probably fine for steel, terrible for aluminum. Where the patch on the lower frame rail ends 1/2" from where the upper frame rail ends is just crying to crack. Slim may be fixing his trailer again within a year. A proper repair would have added a new frame piece about 18" long under the cracked area.

[suncoastdancers]

Originally Posted by Centex

In fact didn't ETI during the R&T era suffer some similarly situated failures of their steel frames on a certain model (which Reace undertook to remedy with a weld-on 'scab' reinforcing plate)?

Glad to understand that in those cases as well as in the case that's the subject of this thread there were no seriously traumatic outcomes.

IMO the lesson learned is that the base metal is neither a panacea nor a curse - proper engineering is required in all cases and either can be great when that goal is met.

ETI had frame failures on their older 17's that used entirely 3" box steel. Thereafter, they went with 4" up to the axle. To my knowledge, no problems since.

[Ron in BC]

Originally Posted by suncoastdancers

ETI had frame failures on their older 17's that used entirely 3" box steel. Thereafter, they went with 4" up to the axle. To my knowledge, no problems since.

Yes, but the frame size may or may not have been the sole cause. Prior to those incidents the body mounting bolts went vertically through the floor and the center of the tube. In some failures it was obvious that's where the crack propagation started.

That was the reason that ETI now welds a piece of angle iron to the side of frame and the bolt goes through it, not the frame.

Ron

[George Johnson]

The first generation Escape 19s were also recalled for frame reinforcement. The original frame on my 19 is 3" X 1 1/2" steel. It is now reinforced by a factory supplied 1 1/2' X 1 1/2" steel piece that extends 14" in front of the bend and 24" behind the bend where the frame bends to form the A-frame for the hitch. There is also a doubler welded to the outside of the 3" frame at the bend.



This was all done by a certified welder per very detailed instructions with photos and parts provided by ETI. ETI paid for the repairs after inspecting photos of the completed work provided to them by the welding shop. I hope the design was done by a qualified engineer and not just a seat of the pants patch job. So far, no problems.

[Escape_19]

Originally Posted by Doug2000

I was a little harsh but get really annoyed when people design stuff when they have no expertise or training. In an extreme situation someone could have been killed.

The repair is worse than the before the break, so many failure points.

My assumption is that you are the same "DOUGSMITH7195" in the screenshot reply to Slim ...good call on your part..interesting to say the least.
__________________

[Escape_19]

Originally Posted by Doug2000

I was a little harsh but get really annoyed when people design stuff when they have no expertise or training. In an extreme situation someone could have been killed.

The repair is worse than the before the break, so many failure points.

I see he responded.