I cant say that I have ever welded much at all , and always thought that you had to disconnect your battery before welding on a car ? Is that the case or not and is it the same on a caravan , I want to get a cross bar added to my a / frame for attaching a bike holder , previously had them on the back and the bounce all round the place . So calling on any welding buffs .
blaze said
12:48 PM Jan 3, 2018
Just make sure the earth lead is attached as close as possible (ideally onto the piece to be welded), also make sure the eath contact is clean shiney steel to get good contact. The same applies to welding on vehicles but disconnecting the battery negative lead gives added security
cheers
blaze
John and Lynda said
12:54 PM Jan 3, 2018
It wouldn't hurt to disconnect the battery if you are either MIG or Arc welding.
Also, ensure gas bottles are removed from the area, all combustibles, such as covers etc are removed and have an extinguisher on hand also.
The key is to ensure you have a really good earth as close to the weld site as possible. You might have to grind off some of the surface protection to attach your earth to and grind off the protection at the weld site.
Then treat all exposed metal and welds with a good coat of cold zinc once cool to prevent any rusting happening.
PeterD said
12:59 PM Jan 3, 2018
mezza56 wrote:
I want to get a cross bar added to my a / frame for attaching a bike holder
Don't forget the wiring in the RHS of the A-frame. The caravan workshops remove and replace this for the duration of the process, although on one quick they flooded the frame with water for a quick weld.
Kebbin said
03:02 PM Jan 3, 2018
Don't forget that welding will weaken the metal and A frame, far better to clamp the rack into place after all it will compromise safety and resale value. But you know this already don't you.
elliemike said
05:29 PM Jan 3, 2018
I have had two instances in my career as a Fitter /Welder, when welding on vehicles, Both were trucks.
Just doing a Quick Weld far away from the battery. She'll be right mate your only going to weld for 30 seconds. Clean the metal and make a GOOD Earth for the clamp.
One Battery Blew the side wall out of the battery case with a very loud POP. I was welding in the truck tipper tray.
The other truck (years later) was another quick "She'll be right mate" job. Earthing clamp on good clean metal by the weld. That battery split with a soft POP. I was laying under the Truck on the concrete, with the welding helmet on, and got soaked with battery acid.
Always, ALLWAS, disconnect them is my advice.
For 10 minutes extra effort to disconnect and reconnect the battery. Think of the$$$ for a replacement battery.
On the other hand "She'll be right mate" How many times have i heard that.
Moonraker said
07:38 PM Jan 3, 2018
If youve not done much welding before then dont weld. Use U bolts and clamp the cross beam for such items as bike racks etc. You could do a lot of damage to the Aframe and create stress points even if the welds look OK. Plus you can remove it at a later date if you dont want it anymore without grinding it off causing even more issues.
-- Edited by Moonraker on Wednesday 3rd of January 2018 07:41:10 PM
Hetho said
10:11 PM Jan 3, 2018
Hi Mezza56.
I agree with all the advise given, and should be considered.
However; "Never", "Never" weld across the chassis rails, always weld along the rail.
Cheers.
Hetho.
blaze said
02:35 AM Jan 4, 2018
Hetho wrote:
Hi Mezza56.
I agree with all the advise given, and should be considered.
However; "Never", "Never" weld across the chassis rails, always weld along the rail.
Cheers.
Hetho.
how do you think chassis are extended
cheers
blaze
mezza56 said
08:02 AM Jan 4, 2018
Thxs for all the info guys , I wasn't going to weld it myself , sorry if I gave that impression , I was going to get it professionally done . I asked the question because I have twice seen a mobile welder come to the park and weld peoples vans without disconnecting the battery . Unless the owners did it before they got there . Anyway i hadn't considered u/bolts that may be a possibility . On the other hand on quite a few vans I have seen a cross member welded on an a/frame with the jockey wheel assembly attached and I assume that came from the manufacturer ?
Woody n Sue said
08:34 AM Jan 4, 2018
All the above is valid advice and a qualified welder should be only too aware of these points , however one that no one has mad is make sure the tug is not connected as you my fry the engine control unit ECU and there is big $ in replacing them
Woody
Jaahn said
08:56 AM Jan 4, 2018
Kebbin wrote:
Don't forget that welding will weaken the metal and A frame, far better to clamp the rack into place after all it will compromise safety and resale value. But you know this already don't you.
Hi Kebbin
Professional welding will not weaken the metal or the A frame. The chassis and A frame is constructed by welding the individual metal pieces together at the factory.
The problem is with the "experts" who think they know how to lay down some metal with an arc. Sometimes that's all they do
Jaahn
PeterInSa said
09:29 AM Jan 4, 2018
As well as disconnecting the battery, disconnect your Sola (if fitted) using the 3 step disconnect method
Peter
Kebbin said
05:39 PM Jan 4, 2018
Jaahn wrote:
Kebbin wrote:
Don't forget that welding will weaken the metal and A frame, far better to clamp the rack into place after all it will compromise safety and resale value. But you know this already don't you.
Hi Kebbin
Professional welding will not weaken the metal or the A frame. The chassis and A frame is constructed by welding the individual metal pieces together at the factory.
The problem is with the "experts" who think they know how to lay down some metal with an arc. Sometimes that's all they do
Jaahn
Jaahn, you were obviously reading someone else's post as I didn't mention Professional Welders nor did the OP, having worked with Boilermakers however I would trust some of them as they usually have far more knowledge than the average welder professional or ticketed.
Aus-Kiwi said
05:46 PM Jan 4, 2018
Weld short lengths at a time . Donât weld near 90* area . You will be fine .. Repaired many truck ( Proline) chassis.
TAJ said
07:23 PM Jan 4, 2018
I WAS A BOILERMAKER FOR 47YEARS DONE A VARIETY OF JOBS
REMOVE EARTH FROM BATTERY CLEAN WHERE EARTH CLAMP FROM WELDER IS TO BE CLAMPED TIGHT
NEVER WELD ACROSS A DRAWBAR JOINING CHASSIE STEEL FOR LENGHT DOES NOT STRESS FRACTURE
WELDING ACROSS COULD CAUSE THE A FRAME TO CRACK BESIDE THE WELD
TAJ said
07:26 PM Jan 4, 2018
I WAS A BOILERMAKER FOR 47YEARS DONE A VARIETY OF JOBS
REMOVE EARTH FROM BATTERY CLEAN WHERE EARTH CLAMP FROM WELDER IS TO BE CLAMPED TIGHT
NEVER WELD ACROSS A DRAWBAR JOINING CHASSIE STEEL FOR LENGHT DOES NOT STRESS FRACTURE
WELDING ACROSS COULD CAUSE THE A FRAME TO CRACK BESIDE THE WELD
blaze said
09:08 PM Jan 4, 2018
and if it has a crack across a chassis how do you fix it, with bubble gum?
cheers
blaze
Moonraker said
11:34 PM Jan 4, 2018
TAJ is correct. It is bad practice to weld across the grain on RHS (90deg to its length or acrodd the beam) if that RHS beam section is being used to take loading such as on an A frame.
Any repair to an existing crack in this situation would most likely involve welding steel plates to repair ensuring again that any welds are not placed across the grain thats if its not practical to cut out the cracked section and welding in new.
The manufacturing process of RHS and other tubular sections of steel create a product that is highly stressed good boilermakers and product design engineers will ensure fabrications made from these types of steel section are welded together taking this into consideration.
oldtrack123 said
11:47 PM Jan 4, 2018
blaze wrote:
and if it has a crack across a chassis how do you fix it, with bubble gum? cheers blaze
You repair it with great care
But best to get an experienced welder, who understands what welds can do to sections constantly being stressed
Ensuring that you do not create stress raisers
Make sure the weld is full penetration. but with no big lumps on the inside
Best done with MIG welding
Grind the finished weld flush with the surface & then dye check it to make sure there are no cracks or lack of fusion
You could consider a reinforcing plate over the weld area BUT if not done right can cause even more problems
From an Ex fully qualified class 1 welding supervisor of pressure vessels cranes etc etc
& as you asked such a question ,I suggest you do not weld any sections under stress from bending etc.
oldtrack123 said
11:52 PM Jan 4, 2018
blaze wrote:
and if it has a crack across a chassis how do you fix it, with bubble gum? cheers blaze
You repair it with great care
But best to get an experienced welder, who understands what welds can do to sections constantly being stressed
Ensuring that you do not create stress raisers
Make sure the weld is full penetration. but with no big lumps on the inside
Best done with MIG welding
Grind the finished weld flush with the surface & then dye check it to make sure there are no cracks or lack of fusion
You could consider a reinforcing plate over the weld area BUT if not done right can cause even more problems
From an Ex fully qualified class 1 welding supervisor of pressure vessels cranes etc etc
& as you asked such a question ,I suggest you do not weld any sections under stress from bending etc.
oldtrack123 said
12:03 AM Jan 5, 2018
Kebbin wrote:
Jaahn wrote:
Kebbin wrote:
Don't forget that welding will weaken the metal and A frame, far better to clamp the rack into place after all it will compromise safety and resale value. But you know this already don't you.
Hi Kebbin
Professional welding will not weaken the metal or the A frame. The chassis and A frame is constructed by welding the individual metal pieces together at the factory.
The problem is with the "experts" who think they know how to lay down some metal with an arc. Sometimes that's all they do
Jaahn
Jaahn, you were obviously reading someone else's post as I didn't mention Professional Welders nor did the OP, having worked with Boilermakers however I would trust some of them as they usually have far more knowledge than the average welder professional or ticketed.
Having worked with & supervising 100's of boiler makers, & Certified "A" grade welders ,in the heavy steel fabrication industry [including pressure vessels for power houses, oil refineries , components for the pumps & turbines for SMEC [Tumit] & Wivenhoe ] ,would not leave most of of them anywhere near critical welding
-- Edited by oldtrack123 on Friday 5th of January 2018 12:07:53 AM
iana said
10:11 AM Jan 5, 2018
mezza, "U" bolts to attach to the "A" frame would be the safest, then welding of the attached frame, anyone could do it who was a competent welder.
TAJ said
01:45 PM Jan 5, 2018
I suppose oldtrack is referring about me as one of his hundreds of boilermkers
which he knows nothing about me or my quilifications going to join macca seems when specialists in there field answer they always get knocked down
Aus-Kiwi said
01:50 PM Jan 5, 2018
Haha yes . Pre heating and grinding out cracks etc . But telling how to do it is like telling how to do electrical work !! We know where that goes .,
oldtrack123 said
03:40 PM Jan 5, 2018
TAJ wrote:
I suppose oldtrack is referring about me as one of his hundreds of boilermkers
which he knows nothing about me or my quilifications going to join macca seems when specialists in there field answer they always get knocked down
I was referring to no one in particular on this forum, but if the cap fits
I have had many top class boilermakers working under me[ That was the type of work we did] & none of them were top grade welders or knew much about top grade welding,nor did they want to.
Referring to your post ; I see nothing wrong with it .nor have I made any comment on it. but perhaps you could have added a little more detail
Like :
Making sure the earth /return clamp is as close to the weld as possible ,with NO bolted or similar joints between it & the weld area
That is the most important point with any thing that has electrical wiring .Simply because of the damage that can be done to the wiring due to it shunting some of the welding current& overheating /burning the cables out
In extremely critical cases where the parts ares not electrically continuous , connect an earth /return clamp each side of the weld area
The term earth should not really be used,as any connection of the welding circuit to "earth " should be avoided, but not always possible.
A requirement under the Standards for many years now
-- Edited by oldtrack123 on Friday 5th of January 2018 03:59:54 PM
Aus-Kiwi said
04:23 PM Jan 5, 2018
Polarity AC or DC type welders come into it .. But often the clamp type can be a little taken for granted . A bolt through lug as close to welding as said . Grinding off any paint etc .,
Kebbin said
09:12 AM Jan 6, 2018
Can you tell us Aus-Kiwi are you a certified Welder or a Boilermaker?
dogbox said
05:39 PM Jan 10, 2018
sounds like most of the grey nomads are /were wielders of one class or other at some point in their lives
I cant say that I have ever welded much at all , and always thought that you had to disconnect your battery before welding on a car ? Is that the case or not and is it the same on a caravan , I want to get a cross bar added to my a / frame for attaching a bike holder , previously had them on the back and the bounce all round the place . So calling on any welding buffs .
cheers
blaze
Also, ensure gas bottles are removed from the area, all combustibles, such as covers etc are removed and have an extinguisher on hand also.
The key is to ensure you have a really good earth as close to the weld site as possible. You might have to grind off some of the surface protection to attach your earth to and grind off the protection at the weld site.
Then treat all exposed metal and welds with a good coat of cold zinc once cool to prevent any rusting happening.
Don't forget the wiring in the RHS of the A-frame. The caravan workshops remove and replace this for the duration of the process, although on one quick they flooded the frame with water for a quick weld.
I have had two instances in my career as a Fitter /Welder, when welding on vehicles, Both were trucks.
Just doing a Quick Weld far away from the battery. She'll be right mate your only going to weld for 30 seconds. Clean the metal and make a GOOD Earth for the clamp.
One Battery Blew the side wall out of the battery case with a very loud POP. I was welding in the truck tipper tray.
The other truck (years later) was another quick "She'll be right mate" job. Earthing clamp on good clean metal by the weld. That battery split with a soft POP. I was laying under the Truck on the concrete, with the welding helmet on, and got soaked with battery acid.
Always, ALLWAS, disconnect them is my advice.
For 10 minutes extra effort to disconnect and reconnect the battery. Think of the$$$ for a replacement battery.
On the other hand "She'll be right mate" How many times have i heard that.
If youve not done much welding before then dont weld. Use U bolts and clamp the cross beam for such items as bike racks etc.
You could do a lot of damage to the Aframe and create stress points even if the welds look OK. Plus you can remove it at a later date if you dont want it anymore without grinding it off causing even more issues.
-- Edited by Moonraker on Wednesday 3rd of January 2018 07:41:10 PM
Hi Mezza56.
I agree with all the advise given, and should be considered.
However; "Never", "Never" weld across the chassis rails, always weld along the rail.
Cheers.
Hetho.
how do you think chassis are extended
cheers
blaze
Thxs for all the info guys , I wasn't going to weld it myself , sorry if I gave that impression , I was going to get it professionally done . I asked the question because I have twice seen a mobile welder come to the park and weld peoples vans without disconnecting the battery . Unless the owners did it before they got there . Anyway i hadn't considered u/bolts that may be a possibility . On the other hand on quite a few vans I have seen a cross member welded on an a/frame with the jockey wheel assembly attached and I assume that came from the manufacturer ?
Woody
Hi Kebbin
Professional welding will not weaken the metal or the A frame. The chassis and A frame is constructed by welding the individual metal pieces together at the factory.
The problem is with the "experts" who think they know how to lay down some metal with an arc. Sometimes that's all they do
Jaahn
Peter
Jaahn, you were obviously reading someone else's post as I didn't mention Professional Welders nor did the OP, having worked with Boilermakers however I would trust some of them as they usually have far more knowledge than the average welder professional or ticketed.
I WAS A BOILERMAKER FOR 47YEARS DONE A VARIETY OF JOBS
REMOVE EARTH FROM BATTERY CLEAN WHERE EARTH CLAMP FROM WELDER IS TO BE CLAMPED TIGHT
NEVER WELD ACROSS A DRAWBAR JOINING CHASSIE STEEL FOR LENGHT DOES NOT STRESS FRACTURE
WELDING ACROSS COULD CAUSE THE A FRAME TO CRACK BESIDE THE WELD
I WAS A BOILERMAKER FOR 47YEARS DONE A VARIETY OF JOBS
REMOVE EARTH FROM BATTERY CLEAN WHERE EARTH CLAMP FROM WELDER IS TO BE CLAMPED TIGHT
NEVER WELD ACROSS A DRAWBAR JOINING CHASSIE STEEL FOR LENGHT DOES NOT STRESS FRACTURE
WELDING ACROSS COULD CAUSE THE A FRAME TO CRACK BESIDE THE WELD
cheers
blaze
Any repair to an existing crack in this situation would most likely involve welding steel plates to repair ensuring again that any welds are not placed across the grain thats if its not practical to cut out the cracked section and welding in new.
The manufacturing process of RHS and other tubular sections of steel create a product that is highly stressed good boilermakers and product design engineers will ensure fabrications made from these types of steel section are welded together taking this into consideration.
You repair it with great care
But best to get an experienced welder, who understands what welds can do to sections constantly being stressed
Ensuring that you do not create stress raisers
Make sure the weld is full penetration. but with no big lumps on the inside
Best done with MIG welding
Grind the finished weld flush with the surface & then dye check it to make sure there are no cracks or lack of fusion
You could consider a reinforcing plate over the weld area BUT if not done right can cause even more problems
From an Ex fully qualified class 1 welding supervisor of pressure vessels cranes etc etc
& as you asked such a question ,I suggest you do not weld any sections under stress from bending etc.
You repair it with great care
But best to get an experienced welder, who understands what welds can do to sections constantly being stressed
Ensuring that you do not create stress raisers
Make sure the weld is full penetration. but with no big lumps on the inside
Best done with MIG welding
Grind the finished weld flush with the surface & then dye check it to make sure there are no cracks or lack of fusion
You could consider a reinforcing plate over the weld area BUT if not done right can cause even more problems
From an Ex fully qualified class 1 welding supervisor of pressure vessels cranes etc etc
& as you asked such a question ,I suggest you do not weld any sections under stress from bending etc.
Having worked with & supervising 100's of boiler makers, & Certified "A" grade welders ,in the heavy steel fabrication industry [including pressure vessels for power houses, oil refineries , components for the pumps & turbines for SMEC [Tumit] & Wivenhoe ] ,would not leave most of of them anywhere near critical welding
-- Edited by oldtrack123 on Friday 5th of January 2018 12:07:53 AM
I suppose oldtrack is referring about me as one of his hundreds of boilermkers
which he knows nothing about me or my quilifications going to join macca seems when specialists in there field answer they always get knocked down
I was referring to no one in particular on this forum, but if the cap fits

I have had many top class boilermakers working under me[ That was the type of work we did] & none of them were top grade welders or knew much about top grade welding,nor did they want to.
Referring to your post ; I see nothing wrong with it .nor have I made any comment on it. but perhaps you could have added a little more detail
Like :
Making sure the earth /return clamp is as close to the weld as possible ,with NO bolted or similar joints between it & the weld area
That is the most important point with any thing that has electrical wiring .Simply because of the damage that can be done to the wiring due to it shunting some of the welding current& overheating /burning the cables out
In extremely critical cases where the parts ares not electrically continuous , connect an earth /return clamp each side of the weld area
The term earth should not really be used,as any connection of the welding circuit to "earth " should be avoided, but not always possible.
A requirement under the Standards for many years now
-- Edited by oldtrack123 on Friday 5th of January 2018 03:59:54 PM