Why Nozzle Anti-Spatter Sprays Could Be Doing More Harm Than Good

Weld Affairs

Delicate torch head attachments (or consumables) – including diffusers, shrouds, contact tips and shielding gas nozzles – are at the frontline of the welding system, in direct contact with the welding wire before it enters the weld pool.3 The integrity of these frontline consumables is crucial to maintaining consistent weld quality and maximal utility of labour.

Critically, both MIG and MAG welding rely upon a steady supply of shielding gases to prevent oxidative damage to the weld seam. During the welding process, spatter can adhere to the contact tip and torch shroud, and quickly solidify around the head, obstructing the consistent flow of these protective gases. Solidified spatter can also short out the contact tube to the gas nozzle, reducing the concentration and effectiveness of

shielding gases.4 What’s more, excessive turbulence – caused by spatter-obstructed gas – may contaminate the weld seam and, in extreme cases, lead to porosity.

The inevitable build-up of spatter impairs connectivity between these delicate torch head mechanisms, resulting in inconsistent electrical transfer and increased incidence of burnback (the formation of a weld inside the contact tip) - a chief source of operator downtime.

Selecting high-quality consumables is a vital first step to ensuring contact tips and diffusers can be secured in proper alignment, maximising the consistency of welds.5 However, judicious use of anti-spatter solutions is considered necessary to ensure adequate spatter resistance for delicate torch heads and consumables.

More Than Mess: Torch Head Damage, Impaired Weld Quality & Downtime

A persistent bugbear of today’s welding process is the release of ‘spatter’: particles of molten metal expelled from the welding arc and deposited throughout the weld area.

The build-up of these ostensibly benign molten particles has the potential to diminish the quality and durability of weld joints, requiring immediate repair or, in many cases, complete re-welding. A recent survey by one of India’s largest auto component manufacturers, Badve, observed that 12% of robot MIG welded parts were

deemed defective due to spatter-related defects, an unacceptably high defect rate of for today’s efficiency driven businesses.1

Reworking or scrapping sub-par welds can sap hours of productive labour from your workforce. Indeed, if a weld operator were to spend just four hours per week repairing defects, this ‘non-production’ time would equate to approximately $6,240 per year in lost labour.2

An Enduring Challenge for Today’s Welders

[I]f a weld operator were to spend just four hours per week repairing defects, this ‘non-production’ time would equate to approximately $6,240 per year in lost labour.

Aerosol-based anti-spatter sprays have long been regarded as a versatile, cost-efficient, and fast-acting solution for overall spatter resistance. Yet despite industry-wide adoption, welders have been quick to recognise their limitations, particularly when applied on delicate torch head consumables.

Conventional nozzle anti-spatter sprays are formulated with an active silicone, petroleum or solvent base; owing to the volatile properties of each chemical base, these anti-spatter formulations are not only highly noxious, but require frequent and time-consuming re-application (upwards of 25 re-coatings per shift6) to ensure continual protection of welding equipment.

Indeed, one of the critical drawbacks of anti-spatter sprays is their poor performance on consumable surfaces. Being highly reactive to heat, conventional nozzle anti-spatter sprays evaporate quickly during the weld, offering little protection against spatter accretions

in the torch head; the necessary manual removal of spatter build-up requires frequent operational stoppages (every 15-30 minutes), a major drain on productivity.

What’s more, both silicone- and petroleum-based solutions are notorious for the deposition of greasy residues across the weld torch, extending the post-weld cleanup time significantly.

Of course, whilst anti-spatter ‘Tip-Dips’ provide a more reliable alternative for the protection of torch heads (offering excellent thermal properties), these cream-based solutions are not only difficult to apply, but leave behind unseemly residues. The question remains: is there a viable alternative to ‘anti-spatter’ that can be applied across small- and large-scale industrial processes?

The Problem with Conventional Nozzle Anti-Spatter Treatments

Owing to their exceptional thermal and micro-spatter resistant properties, composite ceramic coatings have seen widespread adoption in precision laser drilling and laser welding applications over the last decade.

Consumable producers have been quick to recognise the outstanding potential of ceramic-based aerosols as a safe and highly effective spatter-repellent for a broad range of welding equipment, offering marked benefits over traditional nozzle anti-spatter sprays.

Independent studies reveal that even low concentrations of ceramic particles can vastly improve the resistant properties of conventional anti-spatter coatings.

Indeed, numerous spatter tests have shown that while 0% ceramic concentrations (silicone elastomer base) sustained ‘excessive transverse burning’ across coated surfaces, a progressive increase in ceramic filler saw drastic improvements in the spatter resistant properties of the coating: at 36% ceramic filler concentrations, coated surfaces revealed next-to-no spatter deposition.7

Due to their unique low-residue and thermally resistant properties, ceramic-based sprays can be freely applied across all welding equipment surfaces – including torches, consumables and welding robots – with minimal post-weld cleanup. >>

‘Ceramic Shield’: Superior Nozzle Spatter Protection for the Modern Welder

[A]t 36% ceramic filler concentrations, coated surfaces revealed next-to-no spatter deposition.

Henkel launched its groundbreaking Loctite SF 7900 Ceramic Shield* in June 2014. As the world’s leading producer of engineering adhesives and sealants, Loctite is steadfastly committed to delivering quality industrial solutions that maximise business efficiency and reduce costly overheads. As a natural successor to traditional ‘nozzle anti-spatter’ sprays, Loctite’s Silicone-Free SF 7900 Ceramic Shield offers superior anti-spatter protection for today’s industrial welding equipment.

To learn more about Loctite SF 7900, please contact 1300 885 556 or visit us at www.loctite.com.au/sf7900

The LOCTITE Solution

*Please note: LOCTITE SF 7900 is not recommended for anti-spatter protection on welding surfaces.

>> Resistant to the heat extremes of the welding torch, ceramic sprays provide unsurpassed spatter-resistance for shrouds and contact tips, drastically reducing cleaning time (a nearly 20-fold decrease) and replacement costs.

While conventional anti-spatter nozzle sprays require continuous re-application (up to 25 re-coatings per shift), a single application of ceramic shield for contact tips and shrouds can resist spatter incursions for up to 8 hours (including the thermal extremes of the torch head), allowing uninterrupted welding for a full workday.8

In terms of real-world commercial benefits, ceramic shields offer unrivalled efficiency and cost dividends for business: industry surveys reported a 7% increase in productivity and a 40% reduction in running costs for consumables as a direct result of using ceramic-based sprays.9

Conventional NozzleAnti-Spatter Spray

With LOCTITE SF 7900 Ceramic Shield

No. of replacements of shroud and contact tip per shift 1.5 0.87

No. of coating applications per shift 25 0.87

No. of shroud cleaning operations per shift 37 0

No. of contact tip cleaning operations per shift 7 0

Time need for cleaning and coating of shroud and contact tip per shift 32 min. 1.40 min.

Loctite SF 7900 Ceramic Shield vs. Conventional Anti-Spatter Spray

Source: REFA Consulting

www.loctite.com.au

1. H. T. Goud, ‘Minimizing Excessive Spatters in MIG Welding’, Badve Auto Company.2. Bernard Welds, ‘MIG Gun Mythbusting: Separating Fact From Fiction’, Bernard Welds, 2012. http://www.bernardwelds.com/mig-gun-mythbusting--p152081#.U84YN_mSyXx3. Ibid.4. L. F. Jeffus, Welding: Principles and Applications, Cengage Learning, December 2002. pg. 266.5. Bernard Welds, ‘MIG Gun Mythbusting: Separating Fact From Fiction’, 2012. 6. Loctite UK, ‘Loctite SF 7900 Ceramic Shield’, 2014, http://www.loctite.co.uk/loctite-sf-7900-ceramic-shield-8880.htm7. D.K.Y. Low, L. Li, & P.J. Byrd, ‘Combined Spatter and Hole Taper Control in Nd:YAG Laser Percussion Drilling’, in Laser Materials Processing, ICALEO 2000 Proceedings, Vol. 89, Laser Institute, pgs 11-20; D.K.Y. Low, L. Li, P.J. Byrd, ‘Spatter prevention during the laser drilling of selected aerospace materials’, Journal of Materials Processing Technology, Vol. 139, Iss. 1–3, 2003, pgs 71–76.8. Loctite UK, ‘Loctite SF 7900 Ceramic Shield’, 20149. Henkel Australia (in Ferret), ‘Loctite develops new spray on ceramic shields for welding’, 29 April, 2014. http://www.ferret.com.au/c/loctite-henkel-australia/loctite-develops-new-spray-on-ceramic-shields-for-welding-video-n2513858

References

Henkel AustraliaAdhesive Technologies 135 – 141 Canterbury Rd,Kilsyth VIC 3137P: 1300 88 555 6F: +61 3 9761 4539

© 2014 Henkel Corporation. All rights reserved. 9294/LT-5021 (9/13)

Henkel New ZealandAdhesive Technologies2 Allens Road, East Tamaki, Auckland 2013P: +64 9 272 6710 F: +64 9 272 6735

www.loctite.co.nzwww.loctite.com.au