Thread: New steel paint? removal for welding?

Originally Posted by martrix

What do professional welders do? Weld straight through it?

I believe so.

Originally Posted by Dan

I believe so.

Ive thought about that and have done it a few times, but what about the fumes from the paint when it burns? Hence my question about what type of paint...

I guess the resident expert G. Collins hopefully can shed some light.

the new light steel beams from metalcorp/smorgon are coated with envirokote and they say you can weld through that with no fumes.

cheers
pulse

It really depends on which ones you are talking about.

RHS or SHS which is blue primed is fine to weld as is. Red primer is normally fine.

Normally the gal primers and two pack are the ones you have to worry.

OK, it sounds like its acceptable to just weld through the paint.

Back out in to the sun for some more welding. I have to try and finish my welding while the weather is mild. Had a tiny little grass fire (size of an A4) yesterday which went out by itself. I'm pretty sure it was from grinding, its just so dry .

I have at hand a fire extinguisher and a bucket of water should Willy wildfire show his face .

One more question, does welding through the paint affect the weld at all?

Inhale enough of the wrong chemical and it will damage you. Just how much it will damage you depends of course on what you are inhaling.

Paints, plated surface coatings, and the metallurgical alloys that make up the various sorts of steels are toxic with sufficienct exposure.

I can only recommend that any welding procedure takes into account the metals being welding and an effective methods of barring inhalation of welding fume .

I suspect the next big health scare for welders will come from that type of hazard. We have people in this forum agonizing over what eye problems can develop because of cheap auto darkening helmets. That particular hazard seems to be well recognized Vis a vis the Codes and standards that apply there.

I believe the potential for bodily intake of heavy metals given off by the welding processes and particulary home
welding goes largely unrecognized.

I heartily recommend that whatever welding process you undertake ,consider your ventilation.
The metalworkers union produced and excellent document in collusion with one of the universities.
It made good reading for those involved with welding.It was called Hazards in Welding from memory.

take care my friends
Grahame

oops i was on my hobby horse and forgot to answer the question completely.

Paint can have and affect on welding as can any other coatings.
Even on piddly little home jobs I always scuff the weld area with a grinder.
Grahame

It may not affect the weld relative to what you are doing, but ultimately to make sure, clean metal is always the best way to approach the job.

Thank you G.C. and Peter for the advice. I don't weld all that often but the effects of inhalation of nasty fumes does weigh on my mind.

It does seem to flow better on freshly ground steel.

I have a Norton dual cartridge respirator, but wouldn't that be a bit difficult under the face mask?

What would be a suitable cartridge?

What options are there available to minimise fume/vapour inhalation?(MIG welding)......excluding exhaust/fume hoods.

On a side note, just realised Ive got some sunburn on the inside of my arms from todays session of welding. Never had that before, but thats probably because Ive never welded in summer before and would usually wear a long sleeve jumper during the cooler months.

When I am welding I my preference is to either weld somewhere with a good breeze or place a fan behind me to blow the fumes away, but you must be careful with MIG to make sure that the breeze is not strong enough that it will disperse your gas shroud.

Flannel shirt is minimum option to protect yourself from UV burns related to welding.

Welding painted steel I would not say is safe, but here is some info on zinc coated metal.

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When zinc is raised to a high temperature (at or above its boiling point around 900C), it burns and forms zinc oxide smoke. Like any kind of smoke, zinc oxide will irritate the lungs, leading to difficulty breathing: This is not a dangerous situation and it clears up immediately when you move away from the source of the fumes. People exposed to high concentrations of zinc oxide over a prolonged period of time can also develop a condition known as the "zinc chills", "metal fume fever", "brass-founders ague", or a number of other colorful terms. This involves fever, tremors, and other unpleasant symptoms.

However, metal fume fever, which is rarely seen these days, is a purely temporary condition that clears up without any known long term effects or complications. It's certainly nothing to laugh about, but the maximum downside to zinc exposure is fever and shakes that go away and then you get better. It's not like lead or sun tanning that can have life-threatening consequences down the road, or like carbon monoxide that can kill you on the spot.

And you can't even get zinc chills from melting and casting pure zinc.

Welding galvanized steel generates zinc fumes because welding happens at very, very high temperatures: The zinc plating for an inch or so in every direction from the weld is burned off in billowing white clouds of zinc oxide. Anyone who has learned to weld will have been warned many times to wear a special mask when welding galvanized steel, and that's a good idea. I use one always when welding galvanized plate.

Martrix
3M make a good dual cartridge respirator. The "normal" cartridges for it are a rhombus shape (more surface area) and lower profile than the usual cylindrical ones. You might be able to fit it under your welding helmet. They also have a soft pancake shaped cartridge which will easily fit under your helmet. I don't wear flannel shirts any more for welding after I had a few catch fire. I used to wear them all the time in the colder months for work. Either wear a leatehr welding jacket or a king gee type long sleeve shirt.

Mick