Fiberglass Cyclone Project

[Tim Campbell]

On a separate thread I posted some pictures of my fiberglass shop made machine dust fittings with a passing reference the cyclone I’d built. A number of people have taken the bait and requested more details, so here are some words and pictures to describe this project.

I had suffered for a number of years with an inefficient and underpowered 1HP bagged dust extractor and needed to improve to a more efficient system and to free up some space in my small workspace.

The cyclone is around 18” dia by 50” tall with built in inlet ramp and neutral vane for maximum efficiency. The whole setup including fan and ply waste bin just fits under my 8’ ceiling.

For reasons of cost and available power supply I used a generic 2 HP fan but built a new 8” inlet cover and modified the case to provide a 6” outlet in order to get as much airflow as possible. The exhaust from the fan is unfiltered and runs directly outside through an aluminum louver about 18” wide x 24” tall which is cut into the shed wall.

I carried out some airflow testing using a hot wire anemometer. With the fan, cyclone and louver outlet I was getting about 820 cfm at 1” static pressure which reduced to about 600cfm at 3” when this is connected to PVC ducting and flex to my machines with their upsized inlets. Our power supply is 240V 50 Hz so the same fan running at 60Hz in the US would theoretically produce about 20% higher air flow figures than these.


Cyclone setup.jpgcyclone close up.jpgblower mod complete 1.jpgoutside louvre.jpg

Fiberglass Cyclone Mark 2

There are three main differences to the prototype shown above. The first is the level of finish. The original was produced in a number of pieces around a male former and stitched together which gave it an unsightly external finish and the glued seams are a possible point of weakness. The new version is produced in a female mold without seams, making it more robust and giving it a much better finish. The other main difference are that is produced in two pieces to allow the parts to be nested, considerably reducing the shipping volume. Finally, it has a right hand entry to suit the rotation of the majority of fans around.

(Please accept my apologies for the following photos which have decided to rotate 90 degrees when I add them.)

IMG_2497.jpgIMG_2499.jpgIMG_2509.jpg


I have intentionally kept this brief so please feel free to post questions which I’ll be happy to answer.

Best regards, Tim

[Rick Potter]

Very well done Tim. Looks like fun, haven't worked with fiberglass for years, on boats and due buggies.

You got a very nice finish on the Mark II, looks like a factory job.

[Jim Andrew]

Very cool! Like how you built the ramp into the housing.

[Bill Adamsen]

Tim: Beautiful engineering and finish. Thanks for posting. It looks like you changed from the left entry on the prototype (like mine) to a right entry. At first I thought you were targeting "handed" models for coriolis effect in southern or northern hemisphere (haha).

[mike mcilroy]

That is very cool. I already have the cyclone but am interested in making shrouds and ports for different machines. I've only used fiberglass for body work but I think it would be the same for a mold but my question would be:What is the process to put the molded pieces together?

[Brian W Smith]

Thanks for posting.It looks very professional.

[Lornie McCullough]

Very cool and nicely done. You have impressive fiberglassing skills.

Lornie

[Alan Schaffter]

With a female mold, isn't the inside a bit rough?

[Tim Campbell]

That is very cool. I already have the cyclone but am interested in making shrouds and ports for different machines. I've only used fiberglass for body work but I think it would be the same for a mold but my question would be:What is the process to put the molded pieces together?

Thanks everyone for your great feedback.

In response to Mike's query I'll try to provide a brief description on two of the methods I've used for producing inlets and transitions etc.

The first method which gives the best result but also the most work is to first produce a master or "plug" of the exact size of the finished article. Once this is done a fiberglass mold is formed over this to create a negative copy of this. The final step is to build the final part against this. I don't have any WIP pictures of this but the shot below shows the various outcomes. In the background is the plug built up of MDF with the surface soaked in epoxy to allow for a hard polished surface. The red two piece mold is in front of this with the finished 6" jointer inlet in the foreground.

This was more work than was strictly necessary for a one off part but I wanted to produce a full mold for practice and incase I needed to build another one at some stage.


planer plug mold & part.jpg


The next method is quicker, rougher, easier and more appropriate for a one off part. I used this method when I modified the outlet of my fan casing to 6" to try and extract a few more cfm from it. This method would work really well to modify a complex shaped machine dust outlet such as that on an thicknesser. This is essentially a two step process starting with a plug which is the dimensions of the inside of the finished part.

The first two photos shows the new shape created directly over the fan case using a cylindrical fiberglass offcut, painters tape,, hot glue, scrap wood, some cardboard and plenty of builder's filler. In the second picture, the temporary splitter plate is visible which is used to create the parting flange. This was simply 1/4' mdf with PVC tape to create a non stick surface which was hot glued to the plug. Once I'd built the two halves of the part, these were removed from the plug, the fan case was attacked with an angle grinder to remove the unwanted piece and the two parts were then bonded back onto the case to give the finished article shown.

blower mod plug 1.jpgblower mod plug 2.jpgblower mod parts.jpgblower mod complete 2.jpg


There is an even simpler method that can be used for a simple part which is to build an easily destroyed plug from something like polystyrene covered with drywall plaster and then PVC tape for release. Build a one piece fiberglass part over this and then dig out the plug from within.

I hope that this all makes sense. Best regards, Tim

[mike mcilroy]

That's an excellent tutorial. If I use the splitter (2nd) method instead of a destroyable plug do I use more fibergalss at the seams when putting the pieces together or another adhesive like epoxy?

[Peter Aeschliman]

Holy smokes! That's a ton of work! Nicely done, but you have reaffirmed my decision to buy a cyclone off the shelf!

I have worked with fiberglass a few times and I have a sense for how much skill it takes to make something look that nice... you have obviously done this a few times before.

[Mike Tagge]

And I thought mine was pretty slick. You have blown me out of the water. I wish I knew how to do fiberglass molding.

[Tim Campbell]

With a female mold, isn't the inside a bit rough?

Hi Alan. Yes this is correct. With the female mold, the inside is rougher. This is easily fixed with a sand with a disk sander a few days after demolding when the epoxy is nice and hard.

[Tim Campbell]

That's an excellent tutorial. If I use the splitter (2nd) method instead of a destroyable plug do I use more fibergalss at the seams when putting the pieces together or another adhesive like epoxy?

Hi Mike. I usually give the mating faces of the flange a sand with 100 grit paper and then bond with higher viscosity epoxy. For extra strength, a fibreglass bandage can be applied down the inside seam.

[mike mcilroy]

Thanks for the write up and extra info. I'll see what kind of damage I can do with it in the future.