How to Choose the Right Welding and Fabrication for Your Aluminum Case

A lighting rental company in London was ordering a batch of 40 rack cases for their new LED wall system. The cases needed to be structurally rigid enough to survive being loaded and unloaded from trucks 5 nights a week, but also light enough for two technicians to carry. They sent the drawing to two shops. Shop A quoted riveted construction at $180 per case. Shop B quoted welded construction at $220 per case. The buyer went with Shop A — $40 savings per case, $1,600 total savings. Four months later, 11 of the 40 cases had loose rivets at the corner joints. The rivets had worked themselves loose from repeated impact and vibration. The cases were still structurally sound (the panels were held together by multiple rivets), but the loose rivets rattled, scratched the LED panels inside, and looked unprofessional to clients. Repair cost: $35 per case to re-rivet and reinforce, $385 total. Plus, 3 cases had to be taken out of service during a busy rental season. The $1,600 “savings” cost $385 in repairs and lost rental revenue. The welded cases would have cost $40 more upfront but required zero repair in the same period.

Welding and fabrication method is one of the most important decisions in custom case manufacturing — and one of the least discussed. Buyers focus on material, foam, and hardware, but the way the case is put together determines its structural integrity, weight, cost, and repairability. This guide covers the main fabrication methods, where each makes sense, and how to choose based on your case’s requirements.

The Main Fabrication Methods

1. Riveted Construction

Riveted cases are assembled with pop rivets (blind rivets) at the panel joints. The panels are cut, bent, and then riveted together at the corners and edges. Riveting is fast, cheap, and doesn’t require skilled labor.

• Structural integrity — Good for light to medium duty. Each rivet carries a shear load of 200-400kg (depending on rivet size and material). A typical case corner has 4-6 rivets, so the joint can carry 800-2,400kg in shear. But rivets can work loose under repeated vibration — the rivet hole elongates slightly over time, and the rivet loses its clamping force
• Weight — Light. Rivets add minimal weight (5-10g each). A typical case has 40-60 rivets, adding 200-600g total
• Cost — Low. Riveting is fast (a skilled worker can rivet a case in 15-20 minutes) and doesn’t require expensive equipment. Rivets cost $0.05-$0.15 each
• Repairability — Excellent. If a panel is damaged, you drill out the rivets, replace the panel, and re-rivet. No special tools or skills needed
• Appearance — Visible rivet heads on the exterior. Some buyers consider this “industrial” looking; others consider it unfinished. Rivet heads can be covered with corner protectors or trim
• Best for — Light to medium duty cases, instrument cases, briefcase-style cases, cases that need to be repairable in the field

2. Welded Construction

Welded cases are assembled by welding the panel joints (TIG or MIG). The panels are cut, bent, and then welded together at the corners and edges. Welding requires skilled labor and specialized equipment.

• Structural integrity — Excellent. A welded joint is as strong as the base material (when done correctly). The joint doesn’t have fasteners that can work loose. Welded cases can survive repeated impact and vibration without joint degradation
• Weight — Similar to riveted. Weld material adds minimal weight (the weld bead is usually 2-3mm wide and 1-2mm tall). But welded cases often use thicker panels because the welding process can warp thin panels
• Cost — Higher. Welding is slow (a skilled welder takes 30-45 minutes per case) and requires expensive equipment (TIG welder, gas, filler wire). Labor cost is 2-3x riveting
• Repairability — Poor. If a panel is damaged, you need to grind out the weld, replace the panel, and re-weld. This requires a skilled welder and specialized equipment. Field repair is not practical
• Appearance — Clean, smooth joints. Welds can be ground and polished to be nearly invisible. Welded cases look more professional and “finished” than riveted cases
• Best for — Heavy-duty flight cases, rack cases, cases that see repeated impact and vibration, cases where appearance matters

3. Bolted / Screw Construction

Bolted cases are assembled with machine screws or bolts at the panel joints. The panels are cut, bent, and then screwed together with threaded inserts or nutserts.

• Structural integrity — Good, but depends on the fastener. Machine screws with nutserts can carry 100-300kg in shear each. But screws can vibrate loose (unless thread-locked) and nutserts can pull out of thin panels
• Weight — Similar to riveted. Screws and nutserts add 5-15g each
• Cost — Medium. Screwing is faster than welding but slower than riveting (20-30 minutes per case). Nutserts require a special installation tool
• Repairability — Excellent. Panels can be removed and replaced with a screwdriver. No special tools needed
• Appearance — Visible screw heads. Can be covered with trim or corner protectors. Countersunk screws give a cleaner appearance
• Best for — Cases that need to be disassembled for shipping or storage, modular cases, cases where panels may need to be replaced in the field

4. Adhesive Bonding

Adhesive-bonded cases use structural adhesive (epoxy or polyurethane) to bond the panel joints. The panels are cut, bent, and then bonded together with adhesive and clamps.

• Structural integrity — Good for static loads, but poor for impact and vibration. Adhesive bonds can delaminate under repeated shock. Not recommended for cases that see rough handling
• Weight — Lightest. No fasteners, no weld material. Adhesive adds minimal weight
• Cost — Medium. Adhesive is expensive ($20-$50 per case), but labor is fast (10-15 minutes to apply adhesive and clamp). Curing time is 4-24 hours, which adds to lead time
• Repairability — Very poor. Adhesive bonds are difficult to disassemble. Damaged panels usually require cutting the bond and re-bonding, which is messy and time-consuming
• Appearance — Cleanest. No visible fasteners or welds. The joints are smooth and seamless
• Best for — Display cases, demo cases, cases that don’t see rough handling, cases where appearance is the primary concern

How to Choose the Right Method

Consider the Duty Cycle

The most important factor is how the case will be used. A case that sits on a shelf in a lab and is opened once a month has very different requirements from a case that’s loaded and unloaded from a truck 5 nights a week.

• Light duty (occasional use, handled by owner) — Riveted is fine. The case won’t see enough vibration to loosen rivets
• Medium duty (weekly use, handled by trained staff) — Riveted with reinforced corners, or welded. If the case sees regular transport, welded is more durable
• Heavy duty (daily use, handled by multiple people including untrained venue crew) — Welded. Rivets will work loose under this duty cycle. Welded joints don’t degrade

Consider the Equipment Value

The value of the equipment inside the case should drive the fabrication method. A $200 tool set doesn’t need a welded case. A $50,000 test instrument does.

• Equipment under $2,000 — Riveted is adequate. The case cost should be 5-10% of equipment value
• Equipment $2,000-$10,000 — Riveted with reinforced corners, or welded. The extra $30-$50 for welded is worth it for equipment in this range
• Equipment over $10,000 — Welded. The structural integrity and joint durability of welded construction are worth the premium. A joint failure on a $50,000 instrument case can cost $10,000+ in repairs

Consider Repairability Needs

If the case will be used in remote locations where repair facilities are limited, riveted or bolted construction is better. A loose rivet can be fixed with a $20 rivet gun. A cracked weld requires a welder, gas, and filler wire — equipment that’s not available in the field.

Consider Appearance Requirements

If the case will be seen by clients (e.g., a demo case for sales visits, a case that’s opened in front of customers), welded construction gives a cleaner, more professional appearance. Rivet heads can be covered with corner protectors, but the joint line is still visible.

What We Recommend

For our custom case line, we use:

• Riveted construction for instrument cases, briefcase-style cases, and light-duty transport cases (equipment under $5,000, occasional use)
• Welded construction (TIG) for flight cases, rack cases, and heavy-duty touring cases (equipment over $5,000, regular transport, multiple handlers)
• Bolted construction for modular cases and cases that need to be disassembled for shipping or storage

We don’t use adhesive bonding for structural cases — it’s not durable enough for transport applications. We use it only for display cases and demo cases where the case won’t see rough handling.

The fabrication method is the foundation of the case’s structural integrity. It determines how the case will perform over its lifetime, how much it will cost to maintain, and how professional it will look. Don’t treat it as an afterthought — specify it on your drawing, and make sure your manufacturer uses the method that matches your case’s requirements. A case that’s built with the wrong fabrication method is a case that will fail — not today, not tomorrow, but after 100 load-ins, when you need it most.