Welding on Unibody

[*Jonathan]

I'm not sure if I'm posting this in the right section but does anyone have any tips on tac welding to the unibody?

I have a JCR skid plate that uses 6 rivet nuts (3 on each side) and the ones that they provided didn't work all that well for me. There was no lip on the rivet nut to prevent it from falling into the hole, and there was not much grip from keeping it from spinning when loosening the bolt. I bought these: http://www.mcmaster.com/#95105a169/=9bxlc9
since they have a nice lip on them that I could tack weld to the unibody.
Any of you advanced fab guys have any tips for a newb welder with a Flux core mig welder? I'm deathly afraid of burning through.

 

[jmaxj]

http://www.mallcrawlin.com/forum/showthread.php?t=5878

kind of an idea,

 

[Stukboy]

Good link!!
Keep a lower heat and you should be fine.

Practice on some scrap that is the same thickness until you feel comfortable.
Stukboy

 

[POSJ]

That is one of the best write-ups I've ever read...

 

[TRCM]

Only issue I see is telling you to use brake clean to clean the area. There have been several issues with the resdiue left (yes, it does leave a residue) creating poisonous gases when welding.

Be careful

 

[kastein]

Only issue I see is telling you to use brake clean to clean the area. There have been several issues with the resdiue left (yes, it does leave a residue) creating poisonous gases when welding.

Be careful

VERY important! You can die or be permanently disabled by these fumes.

Depending on what kind of brake cleaner you use, or for that matter, other solvents as well. ANY solvent containing halogens (fluorine, chlorine, iodine, etc) is not something you want to use in weld prep. solvents containing only hydrogen, oxygen, and carbon should be fine if used in a well ventilated area, as the only bad gas that can be created from these is carbon monoxide, which is nowhere near as deadly as phosgene/other halogen based toxins. If you are not sure / do not have the chemistry knowledge to tell if a chemical cleaner contains halogens, do not use it!

The cleaner I use only contains propane (propellant), heptane (solvent, detonates explosively when ignited however), and acetone, so I feel comfortable welding after using it. Make your own decision and above all else err on the side of caution.

 

[mcantar18c]

X100 on the solvents.

http://www.brewracingframes.com/id75.htm

The amount you need to inhale for it to be harmful or deadly is shockingly little... I don't recall the exact PPM, but its not very much at all.

I grind everything really clean with a fine grit flap disk, then go over it with a wire wheel, then wipe it down with water on a paper towel. No chemicals of any kind to worry about.

 

[asp]

Yep. I know a guy who has a cough that doesn't go away. He blames it on weld prepping with brake cleaner...

 

[kastein]

The fumes (phosgene, anyways - there are other byproducts that range in toxicity) have a TLV of 100 parts per billion. This is the level at which day to day exposure will result in illness. Problem is, even a person with a very good sense of smell can only detect phosgene at 400 parts per billion concentration. So you're over the allowable exposure limit by a large margin by the time you even know you've been exposed.

The LD50 (level of exposure at which 50% of people will die, immediately) is 800ppm. If it comes in contact with water, it produces other toxic chemicals, including chlorine gas - which it will produce when it comes in contact with your lungs. The IDLH (immediately dangerous to life or health) is only 2ppm.

Overall it is really bad shit and you want to avoid it at all costs.

http://www.vngas.com/pdf/g67.pdf for reference purposes