DIY Mower Deck Repair – Fixing Rust and Patching Holes 1


It is tough when you have a mower that still runs good but is starting to rust out. This mower was still working fine, but the deck had a couple of large holes in the front due to rust. Read more to see how we got it fixed and back on the lawn!

Side note: What is the #1 way to make your mower last longer?

Clean it regularly. The best medicine here is prevention. Get all of the grass out of the mower deck before storing it and DON’T USE SHARP TOOLS TO CLEAN THE UNDERSIDE OF THE DECK! (screwdrivers, putty knives, etc.) This just scratches the paint and allows more rust to form. Also, once a year or so when you have it really clean underneath, get under there and spray any bare metal spots with spray paint.

The subject of today’s discussion:

DIY Mower Deck Repair Welding Patches
How did he get in there?

This 42″ Dixon riding mower deck is pretty ate up. Mostly due to rot and age. However it does seem (mostly) structurally sound. There is little to no rust around the bearings or around where the blades themselves are which is good for or purposes of repairing.

One consideration when looking at repair vs replace is if the part is even available. If the manufacturer has gone out of business you might be out of luck. In this case, I searched for the Dixon 42″ mower deck part number 209848 printed on it and came up with NOTHING. None new, none used. I didn’t call the manufacturer or dealer but I’m willing to bet IF you could get a replacement deck it would be expensive enough to make you replace the mower instead (I would guess at least $400 not including labor to transfer the parts over to it and install).

DIY Mower Deck Repair Welding Patches
Yep, she’s pretty rough…

Safety note: If you are looking at repairing a mower deck and it doesn’t seem safe or is rusted in critical areas (close to the deck bearings or blades) you should probably consider replacing it instead.

Cutting out the patches

I decided that I was NOT going to bother with trimming the holes perfectly and inserting filler plates. Due to how thin the metal was in some spots, I decided to just cut the patches with plenty of overlap so I was able to weld where there was good thick steel.

My favorite design tool for these projects is poor man’s CAD (Cardboard Aided Design). Typically it is a diaper box but this happens to be a special occasion where I used a car-seat box instead.

DIY Mower Deck Repair Welding Patches
Cut – fit – repeat

Do a good job cutting out your cardboard or you will cause more work for yourself down the road.

DIY Mower Deck Repair Welding Patches
The middle piece was tricky since it was behind a bracket and had a bend in it.
DIY Mower Deck Repair Welding Patches
I figured out that I was able to put a slice in the cardboard so I could bend it around the curve in the deck and around onto the top. The two pieces will just overlap.

I have said it before, but LABEL YOUR TEMPLATES. It is easy to forget which piece went where when you take them off. I labeled in sharpie both my cardboard and on the deck with 1, 2, 3. When the number was right side up it was in the correct position. I have also been known to draw up arrows or marks that line up when the template is in place (better for when you don’t have a reference point).

DIY Mower Deck Repair Welding Patches
Next up was marking it out on the steel to be cut. I still have a sheet of 14 gauge from my fuel tank relocation project which should work just fine. Much thicker than this and it gets difficult to bend and cut, any thinner and it won’t last very long or will be flimsy.
DIY Mower Deck Repair Welding Patches
Got out the electric sheetmetal nibbler to make all of the major cuts. Man this thing makes sheetmetal projects easy to cut out.
DIY Mower Deck Repair Welding Patches
The sheetmetal nibbler takes off about a 1/4″ strip of material. So for the piece in the center that needs bent and overlapped, I just cut a single line halfway in (you can see my cut line marked two pictures prior) then cut off the curly tail. Once I cut it off I found that my pliers fit in the gap perfectly to bend the end back down flush with the plate.

Bending the filler plates

I totally forgot to take pictures of bending these. I DID however take a time lapse video below of the entire process which includes me bending the plates, so keep reading.

In this case I used my sheetmetal bender, also called a finger brake to bend the filler plates. However this tool is not required, the corner of a workbench and some hammering/hand forming could get the job done.

I quickly realized that it takes about 10 bends to make the bend look consistent. If you look hard at the picture below, the left patch is the one I made first which only had ~5 bends and you can see each bend. The other two plates had about 8-10 bends which looks smoother.

DIY Mower Deck Repair Welding Patches
Cut out, bent up, and laying in place.
DIY Mower Deck Repair Welding Patches
Once I was done cutting and shaping the filler plates, I painted the backsides of them and let them dry overnight.

It is important to paint the backside also! This way it doesn’t rust out faster than it should. The grass will still get up in there and rot it out if you don’t protect it.

Welding the filler plates

The welding itself was mostly uneventful. My welder has 5 settings and I had it on 1 to minimize burning through. You will have to do some testing to figure out what settings work for you and your project. Here are some notes on the difficult areas though:

DIY Mower Deck Repair Welding Patches
Welding the patches on. I discovered some thin spots that were too thin to weld to. The patch was close to the front main bracket though so I wanted to make sure it was strong. I had some 1/4″ mild steel rod that I cut a piece off of to fill the gap and make it stronger. If you don’t have a piece of rod, a bolt with the head cut off would work fine too. (I welded all the way down both sides, just don’t have a picture of it)
DIY Mower Deck Repair Welding Patches
Here is another spot where I had to add a rod to bridge the gap and have something to weld to.
DIY Mower Deck Repair Welding Patches
Came out alright.

Time lapse video of the repair

Here is a quick 2 minute time lapse of the repair start to finish. I thought it was kind of cool and got some video of using the bender on the patches. Take a look and like/subscribe!

If you want a fun game to play during the video, count the number of times that Gertrude photobombs and drops her frisbee in my workspace.

Finished product

DIY Mower Deck Repair Welding Patches
All painted up pretty and ready to tackle the lawn!
DIY Mower Deck Repair Welding Patches
This should give it another 5 years of life or at least until something else breaks.

A word about quality standards

I am all about doing the best work possible, but I am also conscious about the intended purpose vs the time invested. In this case, the lawnmower is given a new lease on life and I only invested a couple of hours. Could I have spent more time on it and made it beautiful? probably but there would be no advantage in doing so.

By all means, if it is a safety hazard, flies, goes fast, or holds things in the air, spend all the time you need to. However it eventually comes down to a decision to just be good with good enough vs over analyzing the crap out of it and never getting it done or wasting a bunch of time.

Conclusion

We have become a disposable society, but if you have the right tools and a little bit of gumption you can really make things last. It is also fun to find good deals when others don’t feel like fixing things and sell them cheap. Hope this is helpful to you. Thanks for reading this far and I hope you comment below and subscribe for future posts/videos!

Now YOU, go outside and fix something. You don’t have any excuses now that the whole world is on quarantine for the time being!


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