To Weldi auto frame is not simply hard yet i brings up a multitude of concerns including:

Whether welding ~ above a structure is legal?If welding top top a framework can an outcome in a solid product?And many an ext questions regarding best practices.

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There are countless questions that can be asked around welding ~ above a auto frame, yet this write-up will attend to the top 5 questions ranging native the legality the welding ~ above a automobile frame to even if it is welding on a automobile frame will injury the vehicle’s onboard computer.

While mentioning the height 5 questions we will also provide some “Pro Tips” follow me the way!

Photo and also Build through Billy Drake of Ft. Worth, TX

Is it Illegal to Weld a automobile or automobile Frame?

To comment on this question, we will break the question down into two subcategorie:

The legality of operating a auto on the highway through a welded frameThe legality of offering a automobile with a welded frame

First, a disclaimer concerning the answers listed in this “legality” section: This article only provides discussion on the topics of legality and also does not carry out legal advice in any type of way, clearly or implicitly. You should consult a experienced legal advisor once needing true legitimate advice on this subject.

Welding on any type of vehicle frame should be very closely performed using the suitable preparation procedures, equipment and also best practices.

Operating a commercial car (bus, big truck, 18-wheeler, etc.) top top a highway with a welded structure is not technically enabled per the federal Motor carrier Safety administration Title 49: inscription B: chapter III: Subchapter B: component 393.201 (d), unless it is in accordance v the car manufacturer’s recommendations (which is uncommon).

This is no surprising considering the strict regulations that are implemented on advertisement vehicles – usually because of safety risks.

This same short article from the FMCSA says that “no holes shall it is in drilled in the optimal or bottom rail flanges, other than as stated by the manufacturer,” i m sorry is a usual thread in between commercial and also light-duty customer vehicles.

Once any kind of vehicle’s frame rails have been cut, re-welded, drilled, or otherwise amendment or repaired, there is a opportunity that that car may no longer permitted to drive on the highway.

Granted, if this vehicles with modified frames room no longer enabled to run on the highway, a auto can be registered together “off-highway only” and also restrictions end up being much much more relaxed.

In the hands of a default fabricator, however, the structural integrity will frequently be enhanced.

If girlfriend are captured operating a automobile on the highway that must not be on the highway as result of having one unlawfully welded frame, you have the right to be sent to the state automobile referee who will examine your auto in depth and also find something unlawful about it and impose hefty fines for not following laws and also regulations.

The last point you want to occur is to get into a collision and your vehicle insurance autumn your policy after detect poorly done welding repair to your automobile frame.

Worse yet her collision causes bodily harm to others. 

Is it illegal to offer a automobile with a welded frame?

It is commonly not illegal to offer a vehicle with a structure that has been welded ~ above (please consult your local legislations – this article is no to be taken into consideration as legit advice), but it is unlawful to sell a automobile that has actually a welded framework or with frame damages without informing the buyer first.

The reality that offering a automobile with a welded structure can be considered unlawful becomes noticeable when the vehicle’s safety and security and/or value room questioned.

For example, if a person has actually a pickup truck and decides come weld a tubular pre-runner bumper ~ above the prior of the truck, then later sells the van to a buyer, the must fully disclose the the structure has to be welded on due to the fact that there is a danger that the safety and security of the vehicle has been diminished (non-OEM auto parts were added).

Not only this, yet there is always the question around the value of the auto after a framework has to be welded – even if the welded structure is perceived to include value (such just like the pre-runner bumper).

The true deciders the the worth of a auto are a automobile dealership (only sometimes), a bank (commonly once the vehicle is still bank-owned), and the auto insurance suppliers (always).

TIP: If you are marketing a vehicle with a framework that has actually been welded, the is constantly a an excellent idea to compose a explain of automobile condition, noting the problem of the vehicle’s frame, and possibly adding some picture to the document. If you have actually the the person who lives of your auto sign that record acknowledging the condition, your bases need to be spanned in instance your buyer gets into an accident or wants to file an auto fraud claim versus you. This signed document, even if it could not truly be legally binding in format, shows the seller’s full disclosure and the buyer’s acknowledgment, which need to go a long means in a legal dispute.

Laws regarding the sale of a auto can vary depending upon the state that you space in, yet it is strong recommended come seek experienced legal advice as soon as selling a automobile with a questionable condition.

Especially if the vehicle’s worth is high, such together with huge trucks or also 18-wheeler tractors.

Photo and Build by Billy Drake that Ft. Worth, TX

How to effectively Weld auto Frame pieces Together?

If a vehicle’s frame needs to it is in welded with each other either because that off-highway usage or if performed per the automobile manufacturer’s recommendations, there are some general recommendations that should be followed in stimulate to aid prevent cracks in your auto frame.

The number one ascendancy for the welding technique on a auto frame is to avoid a solitary vertical target joint wherein the 2 halves of a frame are joined together from top to bottom through a solitary weld.

Vehicle frames of every shapes and also sizes come under good load during their lifetimes, and also having this kind of butt weld is the sure way to have actually your frame crack.

More perfect techniques because that welding framework pieces with each other make the joint much stronger so as to avoid further breakage.

Conventional wisdom on welding framework joints is come make sure the joints (sides, top and also bottom) space at an edge close come 45 levels so the there is maximum weld bead and also surface area to spread the stress load on the weld joint. Additional strengthening techniques include fish plating end the peak of the welded area, and/or including structural tube or channels either inside or end the top of the structure rails. You can not over-strengthen/over-engineer your repair area, however you deserve to weaken the steel surrounding the repair area because of welding heat potentially resulting in other areas to cracked – be careful of her heat influenced zone.

These frame strengthening methods are common in between smaller and larger vehicles, that course bigger vehicles require thicker increase plates and also channels (if the car manufacturer proposal it).

How to Weld bigger Truck Frames?

One concern with bigger trucks is that their frame rails room sometimes heat treated to an accurate specification come optimize their strength.

Welding on these frame rails tote a high-risk factor because the heat-treated frame rail product right alongside the fix plate/channel product might reason cracking because of the dissimilarity between the 2 metals.

If the fix is truly a “bush-fix” climate annealing the heat-treated rail product surrounding the weld repair area v a torch should enable for great weld penetration. Anything other than a “bush-fix” on warmth treated frame rails is a bad idea and you must seek skilled advice.

NOTE: large trucks which have actually heat-treated framework rails, such as semi-truck tractors, are very closely regulated by the period in the unified States and you might end up not being able come pass succeeding DOT inspections with the repair you do on her frame.

Photo and also Build by Billy Drake the Ft. Worth, TX

As long as you have actually your usual welding outfit including: welding PPE, welder, gas, grinder, etc., you do not do it need any type of special tools to accomplish a an easy weld on a automobile frame – but there space exceptions. 

In the situation where you space welding a item of structure tubing or channel inside or onto the automobile frame, some special fit-up jigs can be beneficial tooling to add to the devices at her disposal, and also a plasma cutter.

Special fit-up jigs can be especially advantageous for welding top top a auto frame as soon as the human body of the auto is tho attached due to the fact that there have the right to be very restricted maneuverability in between the framework rail and also the automobile body.

This special tooling have the right to look like vise-grips format clamps or big adjustable C-clamp layout in order come temporarily affix the pipe or channel to the auto frame rail before and during the weld.

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In the instance of automotive restoration shops whereby vehicles are restored from the soil up, a common tool is a car rotisserie.


Car rotisseries are offered to rotate whole vehicle while attached native the front and rear end to a big frame, in a similar means that food rotisseries function.

Being able to turn the automobile as a whole makes it easier on the technician functioning on the auto so that operations under the auto don’t have to be carry out overhead while a automobile is ~ above a classic vertical vehicle lift.

PRO TIP: If you are not certain what amperage to use with a details piece the material, whether thick or thin, aluminum or steel, the is constantly a good idea to practice a weld bead top top a scrap piece of material similar to the final metal workpiece you intend to weld. This small amount that time practicing will conserve you time grinding the end your weld ~ you find out the your weld does not have actually a correct amount that penetration because that the thickness of product you are welding. 

Should i MIG or TIG Weld My automobile Frame?

There are countless variables that identify the top quality of a perfect weld, therefore, over there is no guarantee the by choosing MIG vs TIG welding there will be a preferable outcome.

There room some determining components inherent v each the the MIG and also TIG welding procedures that have a solid correlation to the quality of a weld.

The more far-ranging variables include:

Welder skillFiller material selection/interaction through the base material Welding process

it’s a fact that welding technicians flourish their an abilities in particular welding processes and might not be as skilled in various other processes.

For example, a professional TIG welder that welds ~ above aluminum boat railings because that a life doesn’t necessarily have actually the very same learned methods that an automotive human body repair technician could have.

Due to this straightforward fact, one welding technician can make a high-quality weld v a MIG device and an additional welding technician deserve to make a poor-quality weld through a MIG machine.

For the objectives of discussion, we will, therefore, take into consideration welding ability the same when looking at the various other variables.

Why I think using TIG Welding on your car frame is better?

There is a wider filler material selection for TIG welding processes which is an benefit when compared to MIG welding wherein the user demands to operation the wire with the feed tube. Much more to the point of filler material affecting the automobile frame, this is applications dependent. Many stamped stole frames deserve to be welded with either MIG or TIG welding processes, but when a automobile frame has chrome-moly tubing supports or complex curvatures such similar to racing frames or through motorcycles, TIG welding is your optimal choice. TIG welding will carry out a much superior product once welding together car frames that contain high enable steels i beg your pardon are warm sensitive and also may be vulnerable to crack in the heat affected zone. MIG welders (if not collection up properly) can create “cold starts” wherein the penetration of the base product is not complete, which creates a weld situation where the joint might be endangered in a certain area. 

If your application appears to be more of a heavy-duty industrial framework or a structure that will only see conventional commuting-to-work kind use, then MIG welding is most likely your ideal choice. If her application consists of anything much more strenuous or too much such a racing, off-road, or otherwise, climate TIG welding is most most likely your best selection for welding ~ above a auto frame. 

PRO TIP: all MIG welders are different, and also all welding applications are different. When you find your optimal weld setting for her MIG welder (for your details application, write this down on a paper and connect it to the next of your welder. This will save you native the headache which happens when one more operator supplies your machine, or the machine gets bumped and also your settings are lost. 

Photo and Build by Billy Drake the Ft. Worth, TX

Will Welding on a auto Frame damage the Vehicle’s Computer?

You deserve to weld top top the structure of her vehicle, but you have to take details precautionary steps. This common-sense measures follow electric engineering concepts, but as we have all learned through recent car recalls, automotive engineers sometimes do odd architecture decisions that might potentially adjust this common-sense methodology.

Therefore, prior to you begin welding on your car frame, or anywhere else on her vehicle, consult her vehicle’s manual and/or her vehicle’s manufacturer for pure advice. 

Always disconnect the an unfavorable battery terminal from the vehicle so the you open the electrical circuits in your automobile to her battery, therefore reducing the danger of over voltage instances which may damage your vehicle’s onboard computer.Place the welding ground clamp as close as feasible to your welding arc to minimization the electrical path between your arc and also your ground, therefore, reduce the threat of high voltage reaching your vehicle’s sensitive computer system components.Disconnect the airbag plugs under the hood of your vehicle. Over there is a slight possibility that part welding voltage reaches your airbags and also triggers castle to walk off. This is the last thing you want because airbags are not only really expensive but once airbags are deployed, your vehicle might be required to have actually a “salvage title” from then on.

NOTE: Following these precautionary actions eliminates nearly all the risk associated with welding on your auto (regarding damaging on-board computer components), but if you desire to reduce risk completely, your finest option is to fully disconnect her vehicle’s ECU. Disconnecting your vehicle’s ECU has actually its own implications such as perhaps disrupting the OBD2 system, and vehicle power/air-fuel maps.

If girlfriend have ever investigated instead of an ECU, they deserve to sometimes be very expensive. Sometimes ranging in the countless dollars!

Therefore, it is always wise to it is in conservative and careful v your onboard computer system once considering welding ~ above your vehicle frame.