Wednesday, February 15, 2012

New frame for the Inflation Fan

A few months back I had started to tear down an inflation fan that had a brand new 8hp motor but was on a damaged frame that had been fixed way too many times. Below is just one example of how patched up the old frame is.
I found a little time today to work on the new frame and actually made quite a bit of progress. The old frame used 1" round tubing. It looks like .095" wall. I decided to build mine out of 3/4" X .095" wall round tubing to save a little weight. I hope my crew appreciates that decision when they have to move it. The other reason I used 3/4" round tubing is because I have a 3/4" conduit bender and could do the bends myself.

I decided not to modify the frames design because the fan worked just fine before and I didn't see a point in making a new (untested) design for something as important as an inflation fan. So, I made my measurements and got to bending the front part of the frame.

Since it is a thin wall mild steel frame, I am using my gas-less flux-core MIG welder. The machine can lay down a decent bead but I am still getting used to it.

After I finished bending and welding the front frame I measured, cut and welded the front engine mount into position.

At this point I was making such great progress I forgot to continue to take pictures! Between the last photo and the next I measured cut and welded the back brace/legs onto the front frame and welded their braces into place.

Here is a comparison photo of the old and new frame at this stage of completion. I really like the look of the new frame so far.
The next and second most crucial step of building the frame is cutting and welding the back engine mount. The reason it is a little more difficult than everything else so far is because it has to be perpendicular to the front of the frame or the propeller will make contact with the tubing. I could have used a carpenters square but I decided to use my angle finders instead. I leveled out the front edge of my frame (left gauge) and adjust the back engine mount until it was level as well (right gauge).

 After I got the engine mounts welded, I took a 3/16 plate of steel I had and drilled out holes to bolt the engine to the plate. I centered the shaft of the engine between the left and right of the front frame, made sure the propeller was parallel to each face of the front frame.

Once I was sure it was lined up, I welded it into place. Here are a few comparison photos of the new vs. old.

I managed to shed a few pounds off the new frame so far. I haven't installed the new wheels yet but I will try to get on it tomorrow. All I have left is to fabricate and install a metal shroud, install new wheels and come up with a creative paint design. I think I can have it completed by the weekend as long as nothing important pops up. I'll end this post with the new frame as it sits right now.

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