I’ve been fortunate to be able to get my hands on an old large mower for $200 AUD. Where I live this is very rare. One that barely works, or might only have 1 season left on it’s reel, starts around $750. This is going to be a little weird as I bought it when I was going through some stuff and yes it was my emotional support mower. This is by far the widest lawn mower I own. I gave ‘her’ the personality of a THICC older lady who’s “seen some things” while trying to make ends meet. That statement explains “Nip and Tuck” in the title. Is that weird? Probably…I present to you < drum roll > Bertha
Bertha is an “Alroh 28BCT” – 28 inch cutting reel, and BCT I think stands for dual clutch – one for driving the rear roller and one for the cutting reel. It also originally came with a seat that has been lost to time. As far as I can tell it was manufactured in 1978 or 1979, It still has the original engine (Honda G300), although it has had alterations (more on this later).
The first thing I noticed when disassembling it – all the screws are metric (yay) coarse (boo). That lead to a series of nut and bolt purchases. I have replaced some with non-coarse metric varieants.
I used hammer finish paint again as it covers a lot of sins. For the record it definitely says Green on the label and not teal (or variations of it).
While the pain was drying, attention was back to the engine – a Honda G300. I was told the engine was partially seized, but I was able to get it started while it was on the frame by loosening the 3 belts to the main drive shaft. Adding tension back to the belts made it near impossible to pull start it. That’s where the alterations where made – The engine had been converted to a pull start engine and the fan was left exposed so if was damaged. From the factory it was key start. That’s right, Bertha would have been royalty in her heyday. “Pull starts are for peasants”. I over paid $100 AUD just for the engine fan and didn’t want to spend stupid money on an OEM fan grill, so I went down the custom 3d printed anti-finger shredder option. This allowed me to reflect more personality into the build.
The chain cover is usually iconic for each mower model. the cover that come with Bertha was heavily damaged on the bottom and couldn’t be repaired. After much thinking I ended up going with a replacement custom made cover from fibreglass. This whole process took a few weeks to figure out.
- Using images I was able to trace the original cover into Fusion 360.
- From there I was able to cut 1 test and 1 final layout on the CNC to test the hole layout.
- The test grey and back print out was used to test the 3D dimensions.
- Then that model was inverted to make a mould, with custom labelling.
- This is where my inexperience could have changed the out come. The mould was painted with white paint that stated “no priming, and bonds to plastic” and then I sprayed the mould with wax release spray.
- I added 3 thin woven layers of fiberglass, one after the other and then a rough cut layer to thicken the walls. I should have allowed more time between layers and I had issues with the last layer being so thick and the resin going off quicker.
- Did it release from the mould easily? Nope. I spent $47 AUD on the release agent. I had to use metal strips to push between the mould and the fibreglass to free the shape. In places it rips the paint from the 3d mould. The mould was destroyed after the separation.
- Was the Lettering any good? Nope. After about an hour I printed another stencil that was 1mm bigger than the original lettering to sit around it and used double sided tape to hold it down. I was able to fill the stencil and then sand it back and used a heat gun to remove the stencil off the fibreglass. It was fairly easy to pick off unwanted black resin leakage using a scalpel.
- I have also included thermal images taken while the black resin was drying.
- The black resin only needed very small patch jobs, then painting with hammer paint and hand painting the lettering white using the blotting method because the hammer paint was not really dry enough.
Thank you for reading my journey from impulse purchase to mower with an imagined personality of a seasoned pole dancer. This was the perfect project, and exactly what I needed. If you’re wondering, Bertha can bludgeon grass, but as of this date (25/02/26) Bertha still doesn’t have a sharpened reel. Other than that, she stands majestically, and a proud member of my growing mower collection.
If you have an Alroh and it’s any of these models: 20BCT, 24BCT, 26NBCT, 28BCT, 30BCT, 30NBCT or 36BCT – I have been told that they all use the same chain cover/guard. If you’re interesting in making your own in fibreglass please check out the mould I made. You can 3D print your own mould.
Cheers.