By guest blogger David H.
Having worked in shipyards for seven years, I’m familiar with how dirty this type of job site can be. Ship repair worksites and welding surfaces are often filthy with rust, dust and other contaminants. Even in shops and yards where fabrication is ongoing, cleanliness is often lacking. If fabricated or refurbished pieces are being installed onboard, the surface to which the piece will be welded could be rusty, coated with scale, or have other types of corrosion.
It is hard to overstate the importance of having a clean surface when welding. Welds made on unclean surfaces can become contaminated and fail; this is especially true with certain metals, such as aluminum, and certain types of welding, such as TIG, but for all welds at least some level of cleanliness is important.
Methods and Equipment
There are numerous methods available for cleaning surfaces. The most basic are simple wire brushes and scrapers; these are ineffective beyond removing common dirt and simple surface contamination. Some hand-held tools, such as grinders and reciprocating needles are slightly more effective.
A surface that is properly prepared by blast cleaning can help you ensure fewer problems with weld quality.
Deeper cleaning processes can help to ensure high-quality welds. This is particularly important where a failed weld could be costly or create shipboard dangers for the crew. For corroded or contaminated surfaces something stronger is required. Some of the best systems available are blast cleaners. Red-D-Arc has a number of blast cleaning rental options. Dry-ice systems are environmentally sustainable, non-destructive, and use inexpensive, readily available dry-ice pellets. Recycled glass systems, which reduce dust by as much as 95% compared to dry-blasting, are available too.
Take a look at our selection of rental blast cleaners which can powerfully clean up the dirtiest weld surface. A surface that is properly prepared by blast cleaning can help you ensure fewer problems with weld quality.
Importance of Preheating in Welding – Equipment Options
Preheating reduces the risk of cracking in weld metal and heat-affected zone (HAZ) by:
- Lowering the cooling rate of the weld – prevents formation of brittle weld metal/HAZ, allows more time for hydrogen to escape the molten weld.
- Removing moisture (hydrogen source) from the part.
- Reducing shrinkage by lowering the temperature differential.
Preheat or not?
The requirement and level of preheating for steel is determined by the relevant welding code and is dependent on the weld heat input, chemical composition of steel (carbon equivalent), thicknesses, diffusible hydrogen etc. Non-ferrous materials generally require preheat because of their high thermal conductivity.
Red-D-Arc supplied three 125 kVA power generators and one 70 kVA power generator to the recent Stars and Thunder music festival. The generators were used for lighting and backstage power throughout the entire 8 day festival.
Stars and Thunder music festival took place in Timmins, Ontario June 24th-July 1st 2017 to celebrate Canada’s 150th birthday. The festival spotlighted Canadian groups such as Michel Pagliaro, David Wilcox, Sass Jordan, Tom Cochrane, April Wine, as well as some international acts like Keith Urban.
Red-D-Arc offers a full line of engine-driven, parallel ready generators including diesel generators, natural gas/LPG bi-fuel gaseous generators and diesel/natural gas dual fuel generators for rent, lease and sale. Learn more about Red-D-Arc power generators.
By guest blogger David H.
How important is it to remove welding smoke from the work area? Ask a welder, or ask someone who has to work in the vicinity of welders working in enclosed or semi-enclosed areas.
I recall some years ago working on a Navy general cargo ship. The ship was was undergoing extensive renovations and the hold of the had four or five levels. My employer, a small repair yard in San Francisco, unfortunately did not take air quality in the work area seriously. There were more than 20 of us working in the hold, and some number of us were welders. From a distance you could see where the work was being done — smoke and fumes drifting up out of the hold! In those days, safety requirements weren’t always top of mind. OSHA and other regulations aside, taking care of your workers by providing a safe work environment is simply the right thing to do. Without them your business can never be profitable. By failing to provide a safe workplace, you may lose workers due to health issues and employee turnover or face consequences for not complying with standards.
“respirators are hot and uncomfortable, and many welders simply refuse to use them”
There are a number of ways to deal with welding fume issues. One approach is the use of respirators. I often wore one, but they are hot and uncomfortable, and many welders simply refuse to use them. They can be remarkably expensive, over the long haul, given that filters must be replaced daily. If the mask is a disposable type, the entire mask must be replaced daily.
Portable smoke extractors – sometimes referred to as smoke eaters – are a far better solution. They extract a higher percentage of the fumes than respirator masks and protect everyone in the work area, not just the welders. They can be moved around the job site and from one job site to another, but can also be set up at permanent work stations. These machines can help make sure that your work space is a place where people can get their work done safely. Your employees will thank you.
To view the smoke extractors Red-D-Arc offers for rent head over to our smoke extractor rental page.
We also have used smoke extractors for sale on our used equipment page.