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Saturday 30 January 2016

Engine Water Ingress

Well, our poor car is off to get a reconditioned engine.

At least we know the cause, this time. It is the air filter housing.
The raised air intake (snorkel) was pointless because, unknown to us, the air filter did not fit the housing properly and water was sucked in from under the bonnet.

It is evident, if you open up the air filter.

The mud from the last outing is obvious.

The previous owner had fitted a high performance lifetime air filter, so it was rarely looked at. It also never occurred to me that it might be less suitable for off-roading.
We will be going back to a standard Land Rover filter.

This got me thinking.
Why don't engines designed for off-road use have a pressure release valve to avoid Hydrostatic Lock (Hydrolock) caused because water does not compress but air does!

To my mind it would be a fairly easy design.
Just an idea.

Thursday 28 January 2016

Said in Jest

One of my favourite work related bits of humour is about an engineer and a manager.
Normally this is in written form. I have been looking for a cartoon version for many years. There are a couple but none quite in the style I wanted.

I eventually created this myself.
The text and the clip art are all other people's. All I did was put it together.
Click on any image on this page to get a larger view so you can read the text.

The above style is to complement another cartoon joke that many will recognise.  I do not know who the author is but they have done an excellent job. I keep a copy of this handy to remind myself and others to keep things simple when managing projects.

Lastly for today, while looking for the text of the manager's joke, I came across another engineering funny. Again, I do not know the original author but many thanks for the laughs.
This particularly applies to the repair of Land Rovers.

I hope you enjoy this little selection.

Sunday 24 January 2016

3D Print Finishing with Resin

I've been struggling for some time with the finish of 3D prints. The layers used to create 3D printed models results in uneven unsatisfactory surfaces.

I've tried to sand down the peaks and I've tried using high build primer followed by sanding and I have not been able to get a good smooth finish. It needs so much sanding that any detail is lost!

I think I now have a solution. I can't claim it was entirely my own idea. I've been searching the Internet. One of the most promising sounding was what follows.

I've used a thin layer of two part epoxy resin painted on and sanded down.
There are several resin products mentioned in other Internet tutorials, some are specifically for the purpose however I struggled to find some of them in the UK at acceptable prices.

I settled on Z-poxy PT-39. I was able to get this from Amazon. It is advertised as an adhesive but it was easy to mix and paint on a thin layer. I cleaned the brush after using Isopropyl Alcohol.

The PT-39 epoxy resin claims to dry in 30 minutes and probably does, however I left it for 24 hours before sanding it smooth.  It was very easy to sand getting a smooth feeling surface without much effort.

At the moment I have used it on the mold for the vac formed windows for the slot car Land Rover Discovery that I am making. For the mold, I used a cheap brush to coat the plastic layers with as thin coat of mixed resin as I could manage. I only did one coat on the mold. If I was finishing off body panels I might paint on a second layer to fill slight uneven areas and then re-sand but for the current purpose the one layer sanded down a lot, was sufficient.

The end result is better than I was expecting. It is hard to show in a photo but the resin felt smooth to the touch. The surfaces of the resulting vacuum formed plastic windows are now evenly clear.

On the subject of vac forming I have tried 0.5mm PETG and 1mm PETG clear plastic. Much to my surprise both thicknesses worked well. I was expecting the 1mm to be too thick for my heating ring but it was fine and the end result of the 1mm, as could be expected, was a bit stronger especially in the corners.

From these results I think 0.75mm clear PETG would be the most effective on my machine.

It is necessary to let the 1mm A4 sheet heat up so it droops down at least 20mm and then move it over to the vacuum former, just before it get too soft and touches the ring! I find having the vacuum on before putting the plastic over the mold works best.

You can see in the photo the difference between the surfaces where resin has been applied and where it has not. It was difficult cutting the plastic off the mold because of the tight overhangs but I am pleased with the end result. I intend to glue in each window in the vehicle separately.

Synology OneDrive Sync

I've had a lot of trouble recently synchronising my files from my Synology NAS box with my OneDrive cloud storage.

It used to work but over the last month or so it has just stopped. I am not sure it is the Synology at fault because my phone, even using the official OneDrive apps, has had a similar issue over the same time period.

From time to time I have been able to coax the Synology to download files but it has refused to upload any! Today I think I have managed to improve things.

I found a restart of the NAS box triggered a sync. I don't know if that will be required each time but I've made a few setting changes.  I also think that changing from bidirectional to one way will also trigger the sync., if necessary.

The following are things I've now tried to get it to work more reliably:

  • Increase the size of the log. I got the feeling it might have just stopped because the log file was full. There are no settings about what should happen when the log reaches its limit.

  • I've reduced how often the application checks to see if files need synchronising. The default is to check every 5 seconds. If it does this while another sync. is in progress there could be thousands of overlapping processes. I've reduced it to only once every few hours. 10,000 seconds.

  • I reduced the number of files that need to be sync'd. I think I was trying to do too many at one time.  By removing some folders that did not change very often I reduced the count from over 200,000 files to less than 4,000 files. I'll get it up to date in batches.

  • I've also set a 5GB limit on the file size that will sync. but as I have few files that large, it is unlikely to make much difference.

It is, at the moment, uploading files, so for the time being it is working.