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-   -   Long travel trailer frames - why splice? (https://www.irv2.com/forums/f50/long-travel-trailer-frames-why-splice-146859.html)

jbenoit28 12-30-2012 09:03 AM

Long travel trailer frames - why splice?
 
Our TT has a long frame (in our opinion) at 36'. It appears to have been made by welding extensions to a shorter trailer frame. My guess is about 8' of length was added. Both pieces were butt welded to the longer part, then a plate was welded across the joint. I wanted to know if this is a normal thing for the TT industry when building longer trailers? In construction, we just order the steel to the length and size we need. 36' doesn't seem very long in terms of what can readily be delivered by truck. Also it would seem you have to spend more time to weld up the extensions, than just ordering pieces the correct length? It is a concern for us since the rear of our trailer has the bunkhouse slide, and outside kitchen all on this extension that is cantilevered behind the axles. We have already had several door assignment issues and a broken slide out joint in the rear of our TT. I'm not a structural engineer so I don't know if this is a big deal or not. Does anyone else have a long TT built like this?

Joe

JIMNLIN 12-30-2012 07:26 PM

The two main frame rails should be a one piece length. Sounds like a screw up at the frame supplier. How strong it will be depends on where its located. If its just behind the spring hangers I would be concerned.

Now having said that some frames can be repaired by butt splicing and adding a inside tube. The butt weld and fish plating welded across the joint make a strong repair however why repair a new '12 unit.

I would look at other same '12 models as yours. If their a single piece main frame rails I would first talk with the dealer about these concerns and then get the trailer mfg involved.

You also might approach a big rig trailer frame repair shop for their input on the issue.

papaw.1 12-30-2012 07:36 PM

papaw.1
 
xx2 What jimnlin posted.Something just does not sound right.If you are already having problems then I would not hesitate to start looking into the issue.Good Luck and safe travels:dance::whistling:

KSCRUDE 12-30-2012 07:54 PM

That the same way my 13 Newmar MH is built the last four foot was added to the frame. It is a little smaller and goes inside the main frame about 1 foot and is welded. The way yours is fish plated and butt welded it is probably as strong as one long frame. They probably build them all like that as Newmar does it too. You problems are probably unrelated to the frame extension.

Ray,IN 12-31-2012 07:46 AM

I too would be quite concerned about frame extensions on a new trailer. Nearly all trailer frames are outsourced by trailer manufacturers.Lippert Components Inc. is perhaps the largest trailer frame supplier. You can measure the original frame rails and look up the strength of the beams on the internet. One such site is: engineeringtoolbox.com

JohnBoyToo 12-31-2012 08:27 AM

Nice tow vehicle you have there !
when we had our open range tt,
we used the Ex and RAS to go with the Propride hitch for a great towing combo :)

To your question,
I would guess it's a cost saving measure just like with lumber -
anything over 16' is much more per foot than say an 8' board....

and joints, done properly, can be stronger than the original.....

SmokeyWren 12-31-2012 08:50 AM

Quote:

Originally Posted by JohnBoyToo (Post 1415475)
...and joints, done properly, can be stronger than the original.....

Agree. The welded joint is probably not the problem.

If your trailer is a so-called lite or ultra-lite, then I suspect the entire frame was made out of thinner steel to save weight.

336muffin 12-31-2012 09:04 AM

Steel comes at a 20ft. industry standard. Anything over that starts to raise the cost very fast. If done correctly the welded joint is stronger than a continuis piece. This as a way to control cost rather than a way to cut corners. Class C's are usually added to the original chassis in the rear in the same manner for the same reason. Most class A's are even jointed as to save money but are bolted instead of welding.

jbenoit28 12-31-2012 12:12 PM

Thanks for all the responses. It is a good point about the cost going up with the length. Our trailer is not a lite version TT, we decided against those due to the truck we have and options we wanted. It really doesn't weigh that much more than the lite versions we compared it to. I feel a little better knowing they do stuff like this on a MH.

We will have the dealer check out the joint so we can have a record of that concern, then we will have a certified welder look at it. Maybe we can bolt through the plate they welded on for more strength or box out the I-beam area around the joint.

From memory, the frame was a 10.25" I-beam. The steel was a strong 1/8" thick. I will use that site to see what that beam can handle. We wanted to add a rear folding rack like Forest River does, but don't want to compromise our frame.

I'd still like to see if anyone has our same or similar model TT without a spliced frame.

wonderer1 12-31-2012 12:33 PM

it was probably the frame manufacture that bid the frames only had a 25 ft. brake to form the rails. a welded frame is not the best one. but welding a frame to lengthen it is done all the time. if you're nervous keep your eye on the top flang at he weld. this is probably where the break will start if it's going to happen. thinner rails are made out of higher tensile steel. the higher tensile you go the more brittle the steel.

TXiceman 12-31-2012 02:27 PM

If the splice joint is done correctly it should not be a problem. I would want the slice continuously welded and no skips or stitch welding. If it is not completely sealed there is a source for corrosion within the joint.

Ken

336muffin 12-31-2012 02:52 PM

MH frames are either bolted or Huckbolted. the drilling or punching of the holes are done BEFORE it is heat treated for strength, never after. If it complies with RIVA and DOT I myself would not alter. I'm not a Metallurgist, but I have steel working and fabrication in my background.

scgator 01-01-2013 07:48 AM

According to the NWS (National Welding Society), butt welding with a scab plate is structurally sound and accepted practice. The standard lengths for structural steel in given length is 21'. So, if you want a 36' "single" piece, look for higher manufacturing costs, higher handling costs, and higher transportation fees; of course you would never see these fees as they would be added into the overall cost. Butt welding with a scab plate, may not be the most appealing cosmetically, but, it is safe.

Ray,IN 01-01-2013 05:59 PM

Quote:

Originally Posted by 336muffin (Post 1415830)
MH frames are either bolted or Huckbolted. the drilling or punching of the holes are done BEFORE it is heat treated for strength, never after. If it complies with RIVA and DOT I myself would not alter. I'm not a Metallurgist, but I have steel working and fabrication in my background.

Quote:

Originally Posted by scgator (Post 1416407)
According to the NWS (National Welding Society), butt welding with a scab plate is structurally sound and accepted practice. The standard lengths for structural steel in given length is 21'. So, if you want a 36' "single" piece, look for higher manufacturing costs, higher handling costs, and higher transportation fees; of course you would never see these fees as they would be added into the overall cost. Butt welding with a scab plate, may not be the most appealing cosmetically, but, it is safe.

After some thought, you two are right. I remember watching several HDT, OTR frames modified/stretched by welding in frame material to lengthen the truck frame.


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