Cadillac Exhaust System

It’s always enjoyable building functional art and in this case it’s a Cadillac exhaust system built for a straight up show car.   The requirements for this project are:

• everything must be 304 stainless steel
• everything must be tucked tightly to the underside of the car as it can lay on the ground (has bags)
• all welds must be blended and not visible
• must be polished

And that’s it!  Working with raw materials and getting it to this level of quality takes a considerable amount of time.  Building a stainless exhaust alone requires the material to be TIG welded, properly backpurged and with the additional requirement of blending the welds, sanding and the final polishing.

The Cadillac was dropped off with a donor floor pan on it, many mock up parts and a simple primed frame.  This allowed a clean slate to allow fitting this 2″ tubing as tight as possible to the underside of the car and snaking it through the rear axle area.  First off we unload all our materials to begin!

Second was unloading the car off the flat deck and onto the hoist.  We had to get a bit creative as the rolling chassis didn’t have any springs in place and only had wood blocks to keep the wheels from rubbing and the rails from completely dropping to the floor.

Fabrication

This system was built in four separate sections to allow for easy assembly/disassembly.  Below are a few photos of the hours of mock up, tacking, welding and blending process.

Take special note at the Kapton tape on the flex section.  This is for two purposes, one to protect the woven stainless steel from arcing while tacking/welding and also eliminating snags and potential damage during sanding/polishing.

Since the exhaust is tucked so tight there has to be minimal movement, one mounting location the exhaust will be hard mounted to is this bushing location.  First a cardboard template is made and then it is CNC cut on the plasma table, and then welded on.  With the CNC cutting the hole is slotted to allow for some wiggle room during installation.

  

Note the existing hole right just above the rear exhaust tip.  That hole was already existing, instead of drilling new holes along the frame that hole was used (along with a necessary one drilled adjacent to it) to allow for securing the rear of the exhaust.

Prepping the rear section for final welding.  Kapton tape used to ensure no air is brought inside the tubing during purging, and also to reduce the waste of argon.  Kaptop tape has a decent temperature rating, so if it’s close to another weld and gets a bit warm, when it’s removed it doesn’t leave any adhesive behind.  This saves time having to clean up adhesive residue and just allows us to get on with welding right away.

Once the welding was completed the tip was polished prior to the hanger being welded on.  Once the hanger is installed it is very difficult to polish the pipe, so all the hanger sections have to be pre-polished prior to the hangers being welded on.  Then the area is protected and ultimately repolished when the rest of the exhaust system is polished.

And welded on.  The hanger was also CNC cut and is slotted to allow for some movement during installation.  The hardware threads into two Rivnuts installed on the frame rail.

One last modification.  Removing a bit of material and welding in a section to allow the pipe to tuck tight enough under the car to allow it to sit on the ground.  Material removal is done with a handheld plasma cutting torch, then the surface is sanded flat and deburred.  The hole is then transferred to a piece of paper and then ultimately to a sheet of stainless that is cut by hand in the bandsaw.  It is welded on with a taller than normal bead to allow for blending.

 

Once the system is fully welded and all the hangers are on, then the bulk of blending, sanding and polishing comes into play.

Some of the many many belts that were used to sand and polish the tubing.

A neat trick to share.  Spray machinist layout fluid on the tubing in order to see where you have sanded and where there may be small divots in the tubing (you can see one easily in this picture).  the layout fluid is essentially like very thin quick drying spray paint.  However unlike spray paint you can take it off with a remover as well, in this case it was just sanded off.  It’s thin enough that it doesn’t clog the belt even at the finer grit levels.

  

Not a lot of exhausts get this form of treatment but when you’re building a piece for a show car, it has to shine!  Here’s a picture of the car (courtesy of the owner __dekay__ on Instagram) at the first car show it was entered in:

This car will be insane when it’s completed.  Thanks for looking!

Trade Show Racking

This was a unique project.  Create trade show racking that would be able to be self standing, able to hang at least 160 scarves or headbands from and be somewhat easy to assemble.  This project was completed for Möbius Threads; a scarf/headband company for use at trade shows all across the province.  First we need to cut some hangers.  14ga hot rolled steel, heavily nested with very little scrap!

Not much work needed to clean them up off the table.  We cut a lot of 14 ga steel and they come off the table virtually dross free, these went in an acid bath to strip off the mill scale and any minute dross.  The only problem with acid bathing parts with very little dross is that the parts tend to stick together and don’t get 100% clean, so they need to be agitated from time to time to ensure all the surfaces are exposed to the acid.  Heavier dross parts don’t have this problem as the dross naturally spaces the parts apart while the acid removes the mill scale and ultimately the dross falls off at the end of the process.

Here we have the feet.  They are designed in Solidworks as a solid body, then converted to a multi-sheet metal part.  So in this case each leg has five pieces split apart from one model. This allows the part to be easily fabricated and functions exactly as intended.  Having the bends where the tube will slide into the “receiver” portion is nice as it’s a smooth radius, not a welded edge that would then require blending to make totally smooth.  Just simple tweaks to making a simple to produce part.  Here they are being tacked and partially welded on the inside.  Utimately the perimeter is welded and the welds are blended away.

This is what the feet look like in CAD, exactly like the real thing.  Very simple to produce and not requiring much effort or skill.  Just time to ensure everything is square, tight and that saves time on the blending the welds at the end.  The parts were all shot with a hammer tone paint to mask the inevitable scratches and dings that would occur setting up and tearing down at a trade show.

This is what the initial rendering looked like.

And here it is at the first Möbius Threads trade show in Saskatoon!

Thanks for looking!  If you are interested in any of our services please take your time to browse the site.  Any questions or if you want us to begin your future project, don’t hesitate to contact us via the Contact page.

Charcoal Air Filter Housings

With this project we had a client come to us with respiratory issues and had a very strict requirement for clean air.  These are two projects rolled into one, one of which we had something to improve, a premium OEM passenger vehicle pleated paper filter which is charcoal impregnated.  And the other we had to create from scratch, creating a charcoal filter basket to fit an existing housing that would be secured to the top of a motor home.

Housing number one was fairly straightforward, measuring the existing filter, mocking it up in CAD and then creating a sheet metal part that will be a slide in replacement.  The one thing to note (that the pictures don’t show) is that with a slide in metal box, there would be a concern about vibration noise, so we made the part smaller and lined two of the edges (like the OEM filter) with black felt.

Here are the 18ga 304 stainless steel pieces cut on the CNC table, lightly orbital sanded to give a consistent finish and self-clinching fasteners CLS-440 (otherwise known as PEM’s) installed.  Note you can lightly see the plate marked bend bend lines for the piece on the right.  It makes bending material so much easier and faster!  It beats having to create a flat pattern drawing and dimensioning all the bend locations, then using a pair of calipers and scribing those locations onto the part.  It’s all done during the CNC process.  Also due to the small size of hardware (#4-40) and the tolerance on the hole needed for a self-clinching fastener, all the holes were centermarked with the plate marker and easily drilled out to the correct size.  The piece of the left had the holes drilled and countersunk to allow the countersunk undercut screws to fit flush and ensure no binding when it is installed.

The OEM piece and the custom piece (still need holes drilled in the cover).  Onto the next one!

There are a few projects sitting on the table, what to take notice of is the three round pieces and the long flat piece on the right.  The flat piece is slip rolled and is used to attach two of the rings (the top two rings) together.  Then the ring on the bottom will get secured with #4-40 screws.  Note the use of slots on the bottom ring, the cover, this allowed the perimeter to be cut in one shot, allow for some adjustment while screwing the hardware in.  This will also eliminating a post drilling operation, which saves time and the customer money.

Here’s the welding time lapse video of the welding process. Just a quick 30 second snippet!

And here’s the fabrication completed and test fitted part on the housing for the motor home.  Just making sure everything fits and nothing was overlooked prior to prepping the part for powder coat.

The parts are now blasted and have silicone plugs installed to prevent powder from building up in the threads.

It worked out perfectly having two sacrificial #4-40 screws to allow the entire piece to hang horizontally during powder application and when it goes into the oven.  Note: MIG welding wire makes great disposable hanger material.

Here are the final products.  Brushed 18ga stainless steel and 14ga steel powder coated with super durable wet white powder.  Both using #4-40 stainless steel screws and self-clinching fasteners.  The client will cuts out a cotton filter which is reinforced with wire mesh that will go on the bottom of the filter cartridge, the filter is filled with high quality charcoal and then another cotton filter is placed on top.  The cover is secured and the cartridge is put in the air stream and ready to be put to use!

Thanks for reading and we’ve got a lot more to show!  So please hit that follow button if you want to keep up to date of the projects we’re working on.  Or browse through our list of services to allow us to help you create your next project!

Stainless Steel Urn

This project was for my wife.  She whole heartily supports Mint Design and understands the long hours required to build awesome projects for our awesome clients.  So I show my appreciation in many ways, but fabrication is how I do it best.  This is a small urn for my father-in-law that passed away from cancer in 2013.  I only had a few days to make the urn that would be buried, which can be seen in this blog post; Stainless Steel Urn.

Since that time my very patient wife wanted a smaller version that would be used to keep a small part of his ashes safe and secure in our home for all of time.  I took the original model, scaled it down 3:1 and changed how the text would be laid out.  Since it was three sided it seemed quite fitting to have his first, middle and last name engraved on each side.

Here we have the four pieces cut out of 18ga 304 stainless steel.  The paper templates on the top right are used as guides to show where the bend lines should be.  The Baileigh sheet metal brake we have has been modeled in CAD (it was done the first week we had it in the shop) in order to allow us to see bend sequences or raise any red flags if there was any issue with forming a part in the brake.  As you can see on the printout, there is no way to do it as one piece (which was obvious), however it did allow us to figure out the best place to split up the sheet metal piece.

Here we have all the pieces formed and ready for TIG welding.

Before welding the final result known was that all the welds would be blended away, so in order to ensure a nice radius’d corner the weld puddle was deliberately made a bit tall.  This allows for a bit more material to remove, but ensures there won’t be any divots or shallow spots on the radius being blended in.  The welds were also made short and back stepped in order to minimize any distortion, of which would be very noticeable on a brushed surface.

Here it is completed.

Rest in peace Larry.