How to weld plastic pallets
Plastic pallets are welded because HDPE is hard to glue. A weld joins two plastic faces by melting them into each other, and a good one is a fused seam while a bad one is a stuck-on bead. Here is how to tell which you are buying.
- Why weld
- HDPE is hard to glue
- HDPE melts at
- About 131.8 C
- Good weld
- Fused seam
- Bad weld
- Surface bead
What a weld is
A weld heats the faces of a crack until they melt and flow together, then lets them cool as one piece. HDPE has a melting point of about 131.8 C and a density of 930 to 970 kg/m3. It does not bond with adhesive, which is why welding is the normal repair for cracked parts.
We describe welds that the buyer can see. We do not weld pallets here, and this page is not a how-to for the work.
Reading a weld on a lot
| You see | It suggests | Ask |
|---|---|---|
| A raised bead along the whole crack | A fused seam with added material | Who welded it and when |
| A thin line with burn marks | Overheated plastic | Whether it has been loaded since |
| Bead only on the surface | A poor joint | Reject the pallet |
| Matching colour fill | Careful repair | Whether the part is the maker's |
| Welds at a leg or foot | A load path repair | Not for racking |
How we count welds in a lot
In a lot description we give the number of pallets with at least one weld, the number with more than one, and where. A lot with many welds goes in the repaired grade even when each weld looks neat.
- Pallets with one weld
- Pallets with several
- Weld locations
- Pallets rejected for poor welds
Welding as a yard method
Welding fuses plastic with heat and a filler rod of the same resin. Done well, it leaves a smooth bead and a flat surface. Done badly, it leaves a weak spot with sharp edges. Check that the filler matches the pallet's resin, since HDPE and PP do not bond well. A bead that has not fully fused will break when stressed, and it is easy to miss until it does.
Practice before the pallet
Practise on scrap before welding a pallet you plan to use. Learn the temperature at which your resin flows without smoking, the feed rate of the rod and the angle that gives a flat bead. Test the practice weld by trying to pull it apart. A weld that breaks at the bead is not ready; one that breaks beside it is stronger than the plastic.
On the receiving dock
- Count stacks before pallets, then count the pallets in two stacks to confirm the tally.
- Lay a tape across the deck and along the runners of three pallets from different stacks.
- Look for pooled marks, bar codes and moulded owner names before anything is put away.
- Sign for the count and note any shortfall on the delivery receipt in the driver's presence.
- Photograph the stacks from both ends while the trailer doors are still open.
Paperwork to keep
- The written lot description and the date it was sent.
- Your own count, signed and dated by whoever received the load.
- Photographs of stacks, plates and any marks, stored with the order number.
- The maker's papers for resin, colour or rating, where the job needs them.
- A line naming who agreed to which exceptions, so a later dispute has a record.
Walk-around checklist
The same four stops for every lot, in order. Tick each as you go.
- 1Deck: every weld located on the deck
- 2Corners: welds near corners checked for secondary cracks
- 3Runners: welds at runners checked for flatness
- 4Fork pockets: welds at pockets checked for distortion
- Weld count written
Words used on this page
- Fork pocket
- Opening in the pallet where the forks go.
- PP
- Polypropylene. More rigid than HDPE and better with heat and harsh chemicals; used where rack stiffness matters.
- Runners
- Bottom rails that touch the floor or rack and carry the load.
- Welding repair
- Plastic is hard to glue, so cracked parts are normally welded.
- Racking load
- Weight a pallet carries bridging an open span in unsupported racking. Often the lowest rating.
What the sources say
- HDPE has resin identification code 2, a density of 930 to 970 kg/m3, melts at 131.8 C and is hard to glue, so joints are usually welded. en.wikipedia.org
- HDPE is the most common resin in plastic pallets; PP is more rigid and the page recommends it for unsupported racking. nelsoncompany.com
- For products touching the pallet directly, stricter federal requirements may call for non-blended virgin HDPE; recycled pallets often meet general FDA needs. nelsoncompany.com
- Static capacity is the highest of the three ratings; racking is often the lowest; dynamic is always lower than static. nelsoncompany.com
How a request works
- Pick the footprint, then the grade you can live with.
- Say what the pallets will carry and how many you need.
- Read the written lot description that comes back.
- Agree the lot before anything moves.
The four grades, in a line each
- Like new. A few trips only. Clean, no cracks, no missing parts, deck and runners flat.
- Used and clean. Many trips, scuffs and colour variation, but whole and usable for general-purpose or closed-loop work.
- Repaired. A cracked or chipped part welded or swapped. Some designs use snap-lock parts for repair.
- Mixed lot. Mixed makers, colours and sizes sold by the truckload, sorted by footprint.
Questions people ask
Can you weld plastic pallets?
Yes. Plastic is hard to glue, so joints are usually welded.
Is a welded pallet as strong as a whole one?
Not necessarily. We call out welds so a buyer can judge.
Can welded pallets go on racking?
We do not describe them for racking.
Ask for a lot
Pick a footprint and a grade. The reply describes a matched lot in writing.