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We'll have you back in the air quickly.

With our expertise in repairing single, twin, turbocharged, radial and turbine aircraft exhaust, we'll have you back in the air quickly. You can use the exhaust catalog below. If you do not find what you're looking for, please give us a call.

Exhaust Catalog


Aircraft Exhaust - Why Choose Acorn?

It all started in a 400 sq. ft. upstairs hangar room in the early 1970s with the name Aviation and Welding Technical Services.

The company was then purchased by Frank Johnson in 1979, moved downstairs to a 1200 sq.ft. shop and the name changed to Acorn Welding. Then in 1987, the company of three employees was purchased by Don Hrabec, today's president of Acorn Welding.

"When my wife and I purchased the company we asked Frank why he called it Acorn. Frank claimed "from the little acorn comes the great oak", so we decided to keep the name and try and live up to it".

Acorn Welding has grown to become Canada's largest aircraft exhaust and engine mount company. Growing even more in 2006 with the purchase of Radial Exhaust from West Virginia, Acorn is now also the largest radial and vintage aircraft exhaust company in the world. Between 1999 and 2009, Acorn Welding successfully performed 30,353 repairs to various aircraft components. At the same time, Acorn Welding successfully manufactured 212,206 various general aviation components from small brackets, braces, and struts all the way to large riveted assemblies.

Today with a modern 50,000 sq.ft. A facility, forty full-time staff, almost 100 new manufactured products, aircraft exhaust, and engine mounts for over 50 makes and 270 models, 750 fabrication fixtures, Acorn Welding continues to grow.

"We're bursting at the seams, but a quality service and product are still our #1 and we can still weld anything but a broken heart and the crack of dawn" states Don.

Acorn Welding has grown by our commitment to providing quality products and services.

We are always striving to improve our quality, which is not always the easy way. For us, it is the only way. We have four full-time quality personnel on staff monitoring all products and repairs with a Transport Canada approved quality control program every step of the way.

With experienced welders certified to the AWS D17.1 Aerospace Welding Standard and rigid fabrication fixtures for everything we do, yours parts pass through a process that ensures quality.

Our Mission Statement

Acorn Welding is committed to complete customer satisfaction by being a reliable source of parts of unsurpassed quality, workmanship, and airworthiness. Acorn Welding will continue to expand our support of customer needs adhering to the highest standards of excellence and service.

Transport Canada Approval

Acorn Welding is a Transport Canada Civil Aviation approved Maintenance Organization #100-91. We are also one of the very few EASA approved Welding Facilities. Our approval Number is EASA.145.7212

We are also a Transport Canada Civil Aviation approved manufacturer. Acorn Welding holds ratings for Welding, Components, NDT, and Structures as well as distribution of aviation parts.

For your convenience our approval certificates are provided online.

With our expertise in repairing single, twin, turbocharged, radial and turbine aircraft exhaust, we'll have you back in the air quickly. Every part that passes through our system receives only the finest materials and workmanship.

All sheet and tube are 321 stainless steel with most of our aircraft exhaust parts made from stampings just the same as OEM parts, not an inferior spliced together part. All welds are internally purged of course.


FAA-PMA parts are often not equal replacements for the OEM parts. They may serve the same function however the service life can be reduced due to poor design. Note the difference in construction between the units below. The difference in construction can result in a catastrophic failure of the exhaust. The OEM originally used 2 formed shells to build the parts while the aftermarket PMA uses fillet welded tubes. Formed tooling is quite expensive, the parts are originally designed to carry the load through parent material rather than through welded joints.

The Pull Through

We also use the pull through extensively; this is where a smaller hole is cut instead of the standard size hole. Then a lip is extruded to move the weld up from the crack prone shoulder area. This process creates a very strong joint between exhaust members.

Here you can see the difference between a part with and without a pull through.

Cessna 300-400 Pull through AD 2000-01-16

Here you can see the difference between a part with (right) and without (left) a pull through. The part on the left is cracked right alongside the weld.

Rigid weld fixtures are used to ensure precision fit when it's time for installation. Wire bails are added where possible in outlets to prevent blockage, another little extra. Finally, a leak test is performed and then the last QC inspection. All our welding technicians are certified to the rigorous AWS D17.1 Aerospace Welding Standard.

New and Overhauled Aircraft Exhaust Parts

The combined welding experience of our technicians is a staggering 319 years with two of the original employees from 1987 still with us. Large or small, simple or complex we are your 'One Stop Shop' for all your aircraft exhaust solutions.

Special Services- Twin Cessna Exhaust AD Compliance (AD 2000-01-16)

Acorn Welding Ltd is authorized to meet the overhaul requirements of "Paragraph G". We recommend that all exhaust be replaced at engine overhaul. Exhaust components overhauled by Acorn Welding are overhauled to like new condition using OEM materials and processes. Our exhaust is designed to exceed the 2500 hour inspection interval between changes. However due to the difficulty of removing some configurations we recommend that it be changed at engine change.

Twin Cessna Exhaust AD 2000-01-16

Many components in these exhausts can be manufactured our of Stainless Steel, Inconel or a combination of the two. The Cessna Maintenance Manual requires that Stainless steel, Partial Steel, Unknown or Repaired exhaust be ultrasonically inspected every 500 hours of operations. This inspection does not apply to the tailpipes, wastegate components, or exhaust stacks. However, it does apply to the slip joints, turbo inlet wyes and most importantly, the aft exhaust elbows. AD 2000-01-16 does not exempt this ultrasonic inspection and does not require the installation of Inconel parts. You may or may not have to the 500-hour ultrasonic inspection depending on your requirement to adhere to Cessna Maintenance procedures. However, in many jurisdictions , commercially operated aircraft are required to adhere to Cessna Maintenance procedures. Acorn Welding customers can contact us for a record of the materials used on their aircraft.

Special Services- Radial Exhaust and Vintage Restorations

Acorn Welding is the world's largest manufacturer of radial exhaust in the world. We not only rebuild and repair old exhaust we also manufacture new exhaust for out of production aircraft. Acorn Welding has built radial exhausts for many aircraft from the oldest Boeing in the world to the agricultural workhorses of the world all the way to today's modern fire suppression aircraft.