Welding on vehicle frame

Howdy, all! I'm looking for tips, pointers, and general "stay out of
trouble" ideas for welding an attachment to the frame of my 2007 Chevy
1-ton van.
My parents are aging, and having more and more difficulty getting
around. I want to weld on a pair of pipes (sch. 40 or 80) about a foot
long coming out from the side of the box-frame, and put a platform
between them as a step up for my parents.
My welding skills aren't an issue- it's that I have no practical
knowledge of vehicle electronics or how to protect them from the welding
current.
I can keep my ground clamp within inches of the welding I want to do- is
that enough?
Reply to
Tin Lizzie DL
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They usually recommend that no welds be made straight across the frame, but at a slant, to avoid stress risers.
Reply to
John B.
The frame repair section of the shop manual for my Ford gives their rules to avoid weakening the high stress areas. Can you weld plates to the ends of the pipes and bolt them to the rails, perhaps copying the pattern and hole size of the body mounts etc?
jsw
Reply to
Jim Wilkins
To bolt them on I would have to drill holes in the frame and whatever I flanged the pipe with. The frame is pretty solid, only a couple of pre- existing largish (1/2" or better) square and triangular holes spaced too far apart for what I would like to do.
I would cut the pipes so they fit at a slight down angle off the side of the frame, then weld them on with a 3/16" or 1/4" fillet around the pipe.
Which is worse? Drilling holes in the frame, or making circular welds on it?
Reply to
Tin Lizzie DL
Welding is worse. Round holes in the center of the web have very little effect on the structure. If you must weld, diamond shaped patches are preferred (all sides welded) or rectangular patches welded on the sides parallel to the frame only (2 sides only).
As for the electronics, I'd take the positive (hot) battery terminal, hook it to ground to make sure both sides of the electronics are anchored firmly to the same potential. Put the ground clamp as close to the weld area as possible to minimize stray fields. Mig or stick, not tig with HF.
Reply to
RoyJ
The vertical web of the frame sees much less stress than the upper and lower flanges, consider a truss. Drilling weakens only the region right around the hole, welding heat affects a much wider area.
If you weld off the vehicle you can clean and inspect the upper part that holds the load in tension. At my skill level that includes grind out and reweld voids. 200 lbs on the step could apply 2000 to the top of the weld.
IIRC I used a sheet metal step bit in a Sioux drill to get into the tight areas of the frame. Once I machined and hardened a very short piloted half-round drill bit out of O-1 for a difficult truck mod. Countersinks can open up holes in tight places too.
jsw
Reply to
Jim Wilkins
Is the frame of a 2007 Chevy 1 ton van heat treated? A call to the local Chevy dealer is in order here. If you can find a competent person on the other end of the phone. Do not speak to a service writer, try to speak to a lead mechanic if you can.
Remove 333 to reply. Randy
Reply to
Randy333
The clerk at the computer store recently quit to be a dealership service writer. When I asked him the job qualifications he said they wanted the ability to write, not to service.
jsw
Reply to
Jim Wilkins
snipped-for-privacy@news.west.earthlink.net...
FWIW, I fabbed up and installed to someone else's spec a set of rock sliders for a buddy's SUV. They bolted on to the sides of the frame rails, and you can jack an entire side of the vehicle off the ground using a hi-lift(farm jack) hooked under one of them. To use a word: Sturdy. My preferrence is for something that's removable and improvable.
-m
Reply to
mkzero
My piont exactly.
They should be former mechanics, but they are not.
Remove 333 to reply. Randy
Reply to
Randy333
Where I sold cars for two years, he was a former mechanic. But he was also the worst mechanic, and had a terrible reputation for finding things that didn't need to be done, but did them under the warranty program and backcharged the manufacturer. He was one of the biggest crooks next to the owner. He finally got caught in a state operated sting with invisibly marked parts supposedly being replaced, and the dealership fired him and a couple other guys. Then they moved other incompetents with flowing pens into their jobs.
Steve
Reply to
Steve B
Don't know your exact vehicle as I'm in UK. However, I've welded quite a few car repairs. As you say, the eath clamp must be close to the weld. Also try to strike on the metal that's earthed. It's not to much of a problem when you're welding a new part on but if you weld 2 existing parts of the car you can imaging what hapens if the earth is on one and the arc strikes on the other. All sorts of current paths happen, some of which may be via the car wiring. Disconnecting the battery won't hurt but doesn't protect everything.
The steel is probably suseptible to heat changes. Car steels have been getting tougher for decades now, probably due to cold working and improved steel specs. Welding can be a problem in high stress areas. It's not impossible but be careful with your design and check it routinely afterwards for stress cracking.
John
Reply to
John

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