Choosing a sanitary welding company is different from choosing a general welding shop. A structural weld only has to be strong. A sanitary weld also has to be cleanable: smooth, crevice-free and corrosion resistant on every surface your product touches. This checklist covers the questions that separate true sanitary fabricators from shops that simply weld stainless, and it’s the same list we’d want a buyer to use on us.
It’s written for engineers, quality managers and buyers in pharmaceutical, nutraceutical, supplement, and food and beverage manufacturing.
1. Do they back purge every full-penetration weld?
When stainless steel is welded, the inside of the joint oxidizes unless it’s shielded with an inert gas such as argon. Severe oxidation, called “sugaring”, leaves a rough, crusty root that traps product and resists cleaning. Lighter heat tint still reduces corrosion resistance.
Ask: How do you purge tube and closed sections? How do you confirm the purge before welding? What do the roots of your welds look like? Ask to see examples.
2. How do they control and judge heat tint?
Some discoloration is normal. What matters is the limit and how it’s judged. Many sanitary specifications set heat-tint limits, often referencing a color chart such as AWS D18.2 for stainless tube.
Ask: What discoloration limit do you work to? How do you remove heat tint when it exceeds the limit: mechanical cleaning, chemical pickling or passivation?
3. Can they deliver, and verify, your surface finish?
Product-contact surfaces are usually specified by roughness (Ra). Food equipment is commonly specified around 32 µin Ra or smoother, and pharmaceutical product contact is often smoother. Some parts also require electropolishing.
Ask: What finishes do you deliver on welds and surrounding surfaces? How is finish verified? If electropolishing or passivation goes to a partner, who is the partner, and what certificates come back with the parts?
4. How do they prevent contamination?
Carbon-steel particles embedded in stainless will rust and can look like corrosion of the stainless itself. A sanitary shop keeps stainless separate.
Ask: Do you use stainless-only brushes, abrasives and tooling? How is stainless work separated from carbon steel in the shop?
5. Do they design for cleanability, not just build to the drawing?
Good sanitary fabricators flag design details that will cause sanitation problems:
- Continuous welds in product zones, never stitch welds or lap joints
- Sealed hollow sections with no open tube ends
- Radiused internal corners and sloped, drainable surfaces
- No horizontal ledges where powder or liquid collects
- Clamp connections on parts removed for cleaning
Ask: What would you change about this design to make it easier to clean?
6. What documentation do they supply?
Regulated manufacturers need a paper trail. Depending on your quality system, that may include:
- Material test reports (MTRs) with heat-number traceability
- Weld records and inspection photos
- Finish verification, and passivation or electropolish certificates
- Certificates of conformance
Ask: What documentation do you supply as standard, and can you match our format?
7. Manual TIG or orbital welding?
Pharmaceutical and biotech process tubing is often specified for automated orbital welding, which produces highly repeatable welds and supports weld logging. Hoppers, chutes, enclosures, frames and equipment components are typically manual TIG welded by a skilled welder.
Ask: Which process does my specification require for each part? If orbital welding is required, is it done in-house or through a partner, and who manages the project?
8. Have they worked in environments like yours?
A shop that has installed equipment around tablet presses and capsule fillers, or worked in wash-down food plants, understands gowning, access rules, shutdown windows and the cost of a delayed changeover.
Ask: What similar work have you done? Can you work within our facility’s access and documentation requirements?
9. Can they go from one-off to production?
Sanitary projects often start with a single replacement hopper or chute, then become recurring parts for several lines.
Ask: Can you fixture repeat parts and hold consistency across orders? Do you offer blanket orders?
Red flags
- Stitch welds, lap joints or gaps in product-contact zones
- Sugared, dark or crusty weld roots on tube or closed sections
- The same grinder and brushes used on carbon steel and stainless
- Open tube ends and unsealed frames on wash-down equipment
- Vague answers about finish, heat tint or documentation
How Weld Creations answers these questions
We TIG weld sanitary stainless with argon back purging on full-penetration joints, use stainless-only tooling, finish welds to your specification, and coordinate passivation, electropolishing and orbital welding through specialist partners, so you get one supplier and one purchase order. Our work includes hoppers, chutes, frames and equipment for pharmaceutical, supplement and food production. See sanitary welding, pharmaceutical equipment fabrication, food grade fabrication and supplement manufacturing equipment, or download our capabilities.