Well, THIS can't be good...

[splyb]

Actively removing the subfloor on our 68 Safari Land Yacht. Started inside the door and worked backwards, taking out the first three perimeter feet or so, taking stock of rust, rot, etc. , especially near the ends of the outriggers, as I went along. Everything looked OK - surface rust, of course - but when I took out the curbside wheel well, I was disappointed to see what appeared to be a gaping, vertical crack in the main (front to back) beam on the curbside. Kinda like this:




(These photos are sideways.) The hole at the top of the crack was where an elevator bolt was.The crack went from there, across the top of the beam and then downward almost all the way to the bottom of the beam. It's more or less perpendicular to the beam.

First thoughts were:
1) I doubt this is a feature. Probably a bug;
2) I ain't qualified to fix this;
3) If I jack up the beam from the furthest aft point possible, the bending force should close up the gap and I can then get Popeye over here with his big commercial welder and he can stitch it up;
4) Better check out the other side before I call Popeye, so he can fix both sides at the same time, and;
5) So this is rear-end sag?

Any thoughts?

Jay & Lisa

[Wingeezer]

I have no experience with AS frames, but I do a little welding from time to time with equipt.left over from earlier years when I fixed up old Brit sports cars as a hobby.

I would do just as you suggest - jack it appropriately to close the gap and then weld.

I'd probably weld a doubler a plate over the area too just to be sure! Couldn't hurt!

Small welders such as a 140 or 180 amp Lincoln MIGs are not expensive these days and pretty easy to use. I prefer using solid wire and gas rather than flux core wire when I can - makes for a nice neat weld!

Small MIG's are pretty handy units to have around the house anyway for all kinds of jobs - I seem to still use mine quite often either for myself or friends and neighbours!

I don't think you'll have any problem.

Brian.

[Minno]

Chris says "ditto" on Wingeezers advice to jack and weld. He said to add the plate on the inside of the frame so it doesn't interfere with the plywood floor on top. The main frame wasn''t cracked on ours, but there were some outriggers that were, and we had to weld and repair. Not hard to do. No one will see it once you seal things back up, so you don't have to be pretty with it.
Probably not due to rear end sag with your size trailer.

Kay

[splyb]

Yeah, I bought a 120V AC welder a couple years ago at HF, but I'm assuming it won't have enough oomph for a job like this. The doubler plate(s) is/are a good idea. Can I get one that will mimic the shape of the beam?

[rugjenkins]

The harbour freight welder will do the job perfectly! The frames are not that thick and the welder can weld up to 3/16 material! I welded my whole frame with one. Replaced outriggers, new tank placement, and re-engineered frame. I 2nd the idea above👍😄

[rugjenkins]

Get some angle iron 1/8 x 2 x 3 or 3 1/2

[DFlores]

I welded a plate to the inside of our frame. Used a Miller 175 Mig welder, while I had the gas and solid wire, my work space was outside, therefore the flux core wire worked better for me because the wind would blow my shielding gas away causing really bad welds.


Sent from my iPhone
David & Diane

[DFlores]

One other thing to consider, I also have a 68 Safari, I wanted to install a grey water tank between the main framing members. When I put in the reinforcing plates, I just got lucky that there was enough room to squeeze in the tank and the ducting for the furnace running yo bathroom.

You have the opportunity to plan better than I did.


Sent from my iPhone
David & Diane

[splyb]

Thanks for the comments and encouragement. May I CAN fix it by myself. Reminds me of the time a friend called and asked me to play in a charity golf tournament. My game was a bit off at the time so, at first, I declined. But then he told me the tournament was for blind and crippled children, and I thought: "Hey! I could win this thing".

I take it the main beams are 1/8"?

Any opinions as to what may have caused this?

Jay & Lisa

[A W Warn]

To me, the break near the top portion looks so smooth it could be cut. And, the edge of vertical portion near the bend looks like the metal is flared outward, like a saw would do. Maybe someone accidentally cut it at the factory?

[McArthur]

From having dealt with things like this in the past, I also think that looks more like a cut than a crack. Only some close looking with a magnifying glass would tell. I would investigate because I would be happier if it was a cut.

[splyb]

Me too but. of course, it has to be repaired one way or the other. If it is a cut, it's amazing that the frame hasn't failed in all these years, i.e. the back right end virtually falling off at speed. How is that possible?

[tevake]

First of what a delightfully wicked sense of humor. The golf story had me laughing out loud even the second time I read it.

As to the cause of the broken frame. It is a very clean break if that's what it is.
Any sign of a rack being mounted on the back of the trailer? I'm picturing three or four bikes bouncing around on the back, could possibly do it.

Do you see any thing amiss on the other side? Does the broken part of the frame just hang down taking the bumper with it? Or is it attached further aft.

At any rate some welding and a backup plate as mentioned earlier are in order.
I'd consider putting a plate on the other side too while at it. It does seem a light section beam wall.

Let us know how the repair goes.

Cheers Richard

[Al and Missy]

Years ago when I was involved in building some mobile communications centers I was told by a vehicle up-fitter that one should never weld on a frame. The reason was that the frame members were heat treated and welding would anneal the metal.

These were GM cab-body trucks that were to have shelters mounted to them. Are Airstream frames mild steel so that it is OK to weld, or is there risk of damaging the frame by welding to it? Just curious to know as I may want to add a rear hitch or something in the future.

Thanks,

Al

[Ray Eklund]

Chevrolet mounted their differentials on Corvettes the same for a 327 or 427 big block in the mid 1960s. The big blocks could actually tear the differential from the frame as GM was too cheap to change the design for the 396's and 427's at the time, in my opinion.

Welding angle iron on both sides took care of the problem, permanently.

This seems to be a similar option for a frame repair. It is better to try to fix the problem than avoid it. Make the repair with more than needed. Going to need plenty of prep work on the rust and that will make it weaker to get to metal. Someone who had found a 'garage mechanic' solution is your best option. I am always impressed with the brilliant minds on this Forum. Mine, of course... excluded from this group.

[Alumineer]

Originally Posted by Al and Missy

Years ago when I was involved in building some mobile communications centers I was told by a vehicle up-fitter that one should never weld on a frame. The reason was that the frame members were heat treated and welding would anneal the metal.

These were GM cab-body trucks that were to have shelters mounted to them. Are Airstream frames mild steel so that it is OK to weld, or is there risk of damaging the frame by welding to it? Just curious to know as I may want to add a rear hitch or something in the future.

Thanks,

Al

I would be surprised if the Airstream (or any other travel trailer) used anything other than mild steel for the frame members. The nice things about mild steel are that it's easily weldable, and it's somewhat forgiving of repeated stresses.

My guess (as a guy who has done some welding and amateur race car fabrication) is that this particular situation looks like it was initiated from the elevator bolt hole being too close to the open edge of the frame rail. Then the crack just propagated from the bolt hole, around the corner, and down to where it currently is.

Repair: Drill the *very* end of the crack with a 1/4" drill bit to take away the sharp edge of the crack. Grind off all rust around the cracked area, then jack it closed. Weld up the crack, but then add a doubler of equal thickness (the angle doubler suggestions are good) for 4 to 6 inches on each side (8-12" total) and weld only along the top and bottom edges. You want the weld to be in shear, not in tension. And, you don't want to create another vertical weak zone in the frame member.

Book recommendation: "Engineer to Win" by Carroll Smith. Lots of good info in there about materials properties, as well as anecdotes, by a legend in race car fabrication and preparation.

[splyb]

Originally Posted by tevake

First of what a delightfully wicked sense of humor. The golf story had me laughing out loud even the second time I read it.

Thanks. I wondered if anyone noticed.

There's no evidence of anything having been mounted on the back, so I just can't say. I've yet to remove the floor on the other side, so I don't know about that either. Yet. But when I do, this board will know about it.