K9 Diaries - Glass Half Full

Left Side Done

My fibreglass isn't getting any better. I just hope it's good enough to do the job.

I applied the gel coat, then realised I hadn't cut any bits of fibreglass matting to shape ready, so I had to wing it a bit and it was a bit hairy.

Just the far side to go.

Only a few more days before I'll be able to progress onto actual body shell making rather than, a pattern for the body or a making a mould from the pattern. It'll be the actual body.

More resin has been ordered together with some slightly heavier weight of matting, from East Coast Fibreglass Supplies, so I should now have plenty to complete the task.

I'm sure the mould should have had more layers to make it more robust, but as it's not intended for a production run of hundreds, it should be OK I hope, fingers crossed.

I've also not progressed the head any, so only half a job today, but it is a week night so just glad I could get some done.

I'll push on tomorrow, but prep time seems to be a lot longer than you would think.

K9 Diaries - Saturday Morning and All is Well

K9's head ready for more glass

K9's head was a bit of a mess, as I'd managed to get runs of resin on the sides and top as well as bits of fibreglass strands stuck on here and there. Fortunately they cleaned off fairly well, but it's something to look out for in the future. I'll have to look over the areas I'm not working on after, and clean off any spillage before it sets.

Front, with dams.

Today I was supposed to crack on with K9's fibreglass, but life conspired against much progress.
I did manage to start preparing the front end of the body shell, which takes longer than you might think, but then had to stop, as the fibre glassing can take 2 or 3 hours, when you take setting time of gel coat and clean-up time etc.

So Sunday morning I managed to get back into the garage and get some glass on.
First you cut out the fibre glass into the sizes you think will best suit what you're going to cover. Then you mix the gel coat apply that and wait 45 minutes. I went for a walk in this time. I've taken to doing a 5 km walk at a brisk pace to try and get into shape, so this was an ideal time. On my return, it was straight on to mixing a batch of resin, applying a coat and starting with the first layer of fibreglass.

Front completed.

Getting into corners is always interesting. On some of the hardest ones on the head I've used chopped strands of fibreglass then applied resin. It can be a bit messy as the strands like to stick to your paint brush. It does seem to be a good way to get into corners though.There was the usual misalignment's and patching.

It's getting quite exciting now, just the sides remaining, which might take less time as there are boundaries to set-up as they are already there. Just a strip along the bottom.


I've not decided how to handle the panel cut-out yet. Perhaps I should set up a boundary of some kind where it'll be cut-out? It seems a waste to cover an area that isn't required.

The same with the monitor aperture, it will take a little extra setting up time, but will save materials.

K9 Diaries - Does My Bum Look Big In This?

After work today, I was eager to get into the garage to see it I can peel the boundary pieces off.
and here is K9's bum, coated in fibreglass :), as you can see the boundary pieces pealed off easily with no problems, so that was quite a relief.

Also K9's head pattern, with one section of the mould attached.



Work stopped for the rest of the evening because we went to see Wyrd Sisters, a play adapted from Terry Prachett's book,  so back to it tomorrow.

I can see these moulds being finished in a few days, but there is still the side panel and control panel to consider. Only five weeks and 1 day remaining until Whooverville 9. If I keep at it I might just make it. As long as there are no disasters along the way.

Debs is telling me that I should splash out on the proper lights/switches on the control panel. I was going to try 3D printing some bezels and using the lenses I'd sourced, I will have to mull it over, but quickly.

K9 Diaries - Trying New Things

As I mentioned before there was a wax on then way off process. This is to build up a layer as part of the mould release, so the fibreglass resin doesn't stick to the pattern.  But this takes several hours as once the wax is applied you have to wait 5 to 10 minutes before polishing off then another 4 layers with 30 minutes in between each layer. And this has to be done for each section where fibreglass is applied.

In an attempt to cut down the time required, I’m trying the release agent recommended by Easy Composites. This is just applied then given a rub over to level any uneven coating. So instead of the hours it takes for wax and the hours it takes for PVA to dry, easylease dries in just 5 minutes Yay.

I've also switched to using putty wax rather than plasticine which is a lot easier to work with. Here I've filled the seems all round, and just need to add some keying features.

I'm a bit nervous about the release agent, as you can't tell that it's there! I don't think I'll have time tonight to finish this section so I started work on the head as well.

Thursday 27th July 2017 and it's gel coat time. I'm really nervous about this release agent, but here we go. Here's the gel coat applied, now wait 45 mins approximately.

And then the glass, it took a lot more resin than I thought as well, I can see another order for resin happening in the near future.

And while I was at it I did a bit on K9's head as well. I has some issues with consolidating the layers.

I've bought these rollers, but they seem to push the fibre glass about rather than squishing the air out, lets just hope It'll turn out alright.

So, only three more sides for the body mould, and three more for the head.

K9 Diaries - New Experiences

K9's Top

Fibreglass, a new experience for me. I've been putting it off for far to long. K9 did need the extra work to get him all smooth so that I could get to this stage, but maybe if it wasn't completely new I would have been a lot quicker.

But here we are. Above, as can be seen is the top, with dams added to act as boundary for the fibre glass.

My First Fibreglass.

K9's mould has to be made in 5 sections as otherwise k9's body shell just wouldn't come out of the mould, due to the recesses.

I'm starting on the top as it's a relatively small straight forward area to do.

As you can see the PVA mould release didn't cover well on the wax, leading me to believe that maybe I could have done without.

Showing dam clean surfaces.

You can also see the keying features, made from plasticine, cut into flat topped pyramids. These are to ensure that the moulds fit together exactly the same as they came apart.

Here is the same with the dams removed. The double sided tape That I attached the dams with left a sticky mess, which took some cleaning off, so I need to look for a better solution to fixing these in  place temporarily.

K9 Diaries - The Return of the Wanderer

K9's body has returned from Manchester, where Matt has been making him sooth and sleek ready for the mould making, and what a lovely job he's made of it.

So much so that it seems a shame to plaster fibreglass all over it. I could almost just add a coat of spray and mount the head and we'd be away.

But no, I must resist the urge to cut corners, and so starting on the top, I'm now doing the old, wax on, and wax off, routine, like a character from the Karate Kid!

This is followed by PVA release agent. Sadly the process didn't go brilliantly, because the spray gun didn't deliver the fine mist I was anticipating, and the PVA tended to pool in blobs rather than leaving a nice, smooth even coating.

So I spread it around as best I could with a cloth and hoped for the best. He he!

K9 Diaries - Accessorise

CAD Assembly of Antenna

Prominent on K9's head are his ears or more accurately his radar dish antenna.  I modelled a frame to mount the 2 mini servos, as well as the collars and clamping bit, to make up an experimental assembly.

I plan to have an Arduino Nano to control the position of the Ears, receiving instructions via I2C instructions from the Raspberry Pi.

The Arduino is going to have several sequences which can be called on, possibly with optional speed settings.

After procuring some mesh and some coat hangers I had a go at silver soldering, which wasn't too bad but could be better.

The results are not the finished article but something that could be pressed into service if time runs short.




Then it was on to the nose laser. I'm not sure how that's going to be mounted yet, but I'm sure it will involve more 3D printing.

I've also devised a tail mechanism and printed some parts but not assembled yet, photos to follow.

K9 Diaries - Filling Time

K9 Traction Unit CAD Model

Alongside the body shell building, there are also the other systems, notably the base with the drive system, I'd done the modelling, so now it was time to export the parts and 3D print them.

The speed of the motors requires a double reduction. The chain output sprocket has to be matched to the same spec of sprocket and chain. The seconds chain will be the old sprockets from Chompalot, from when it had 4 wheel drive. The bits I needed to make on my printer were the interfacing bits, such as between the wheel and sprocket, or between the intermediate sprocket and the shaft. Also holes for the bearing.

After much printing and adjusting and reprinting I finally produced the platform which K9 would sit on. 

Initially I tried using the motor controller I had originally sourced, however it soon proved not to be up to the task, and with a puff of smoke, the decision to buy a 2x32 Sabretooth was made. Once it arrived it was swiftly plumbed in, and worked beautifully.

Also progress was made on the side screen to be driven by a Raspberry Pi. Below is the rear of the assembly showing the Pi mounted on the back of the display. an 8 inch 4:3 ratio LCD HDMI input monitor, again source from eBay.

K9 Diaries - The Beginnings Of A Pattern

K9 Build in Progress 01-Jun-2016

There are a surprising number of chamfers required before the body can be glued together and some of the bits needed supporting structures, just to make sure they were secure whilst the glue was drying.

Smooth Operator11-Jun-2016

After much taping and gluing I had a body shell shape, which would still need a fair bit of filling and sanding to be good enough to make the mould from. Fortunately the sun was shining.

After what seemed like an age, probably because it was. It was time for the primer, I had to seal the surface and make it smooth as any imperfections in the pattern will be replicated in the finished part.

This didn't go so well as I'd bought a cheap compressor and spray gun off eBay and I'd no experience of spraying, so initially I couldn't get it to spray even water.

In desperation I decided I'd have to apply the primer by brush and sand it smooth.

Smoothish Primer 04-Apr-2017

I soon realised my mistake when I saw the results, and decided to  have another look at the spray gun, and discovered that the second spray gun that came with the compressor worked.

So I mixed up a fresh batch of primer and was away, until I threw it on the a slab. I quickly wiped up most of it with acetone and tried again.

This was more successful but unfortunately I didn't clean the spray gun out well enough so it wouldn't work again. This was unfortunate as I'd rubber through the primer in places trying to smooth the surface.
 
A couple of days later, Debs said "Have you seen my scrubbing brush Hon?" an image of me scrubbing feverishly at the primer, on the still discoloured slab swam before my eyes, "Ummmm, no dear" I replied. Unfortunately I'd forgotten to dispose of the ruined scrubbing brush, and the incriminating evidence was found the next day.

It was now that I asked for help from my Brother-in-law Matt, a talented sprayer who could help me with my predicament. So off to Manchester we went to drop off K9 for his rejuvenation.

Picture Archive

The latest is the acquisition of some mesh for the radar disc like ears, although I think it's a bit coarse.

And some potential handles.

I like the hexagonal mesh, but wouldn't be to K9 spec, so may try ordering some finer mesh.

I've also found the tail gaitor which I'd bough years ago

modelling K9 in preparation for making a mould for a fibreglass bodyshell

 x

 A 3D tracked platform to test bluetooth control as a possible K9 controller

Whilst watching some of the special features I did notice that K9 has a straight section tube coming out of his head to join the flexible neck tube too.

 

So I decided to stop prevaricating about the bush and get into the garage and make a start.

I have a rasp and I'm not afraid to use it

K9 Stash

here's the current state of play

 

A few more bits glued into place,the next bit on the list is the curved top. I think I may need to add a couple of supporting ribs.

 

Here's the latest state of play with my build, the bendy MDF has finally been glued on top. Featuring the return of the table lamp, it's just the right heigh

 

x

 

I now have 4 different potential radar dish / ears meshes

 

Still sanding and filling, although rain stopped play for a while.

Filling and sanding proceeding

x

x

x

 

x 

 

Not much K9 progress today. we dropped off the Pangolin at the museum, sadly not as animated as I had hoped, but maybe for next year.

Just a little progress today, one intermediate shaft fitted along with the 3/8th chain.

The second wheel intermediate shaft fitted today, but I’ve had some issues with chain tension,

so I’ve had to modify the bearing carrier so that there is more range in adjustment.

I wired up the motors /controllers, and dug out some old NiCads, which used to power Chompalot, sadly they are well passed their best,
but good enough to hold a little charge to test out the motorised base.

I also borrowed the receiver from the practice bot, I built for Debs to practice driving fro the Iron Maidens tounament. These days it gets more use at the young roboteers.


During testing, all was going well, I even stood on it to see if would take a load, being in the kitchen it wasn’t a definitive test just a few feet, but seemed fine.
but I was in danger of falling off so I discontinued that line of testing.

Using the inbuilt mixer was odd as you couldn't steer without using the forward or reverse as well, so maybe I will use an alternative mixing method.

Then it died and there was a burning smell, it looks like the BEC circuit which supplies 5V to the motor control has died so not a problem.
It's more of a problem that I have to provide 5V for the motor controller and it doesn't do it for itself'

So, this is the preliminary idea for the ear mech. I was considering printing gears with angled faces to mesh but then though it might be fun to have independent ears.

Today I had a go at some ears, not very succesfully, but as a first attempt I guess there are not so bad. I bought some coat hangers and bent into shape,

then cut the mesh with tin snips. I then attemtped to silver solder the two together, with varying amount of success.

Now the sun has come out, I’ve managed to get back into the garage to do a bit more on the body shell.

I'm just adding some strips around the bottom to contain the base board depth. Once these are attached there will be another layer for the bottom of the fibreglass mould
and then after adding a few radii and a bit of filling and sanding, it will be primer coat time.

The supplies have arrived! Hopefully I've bought everything I need, if not it's tough, and I'll just have to make do.

After the debacle, I decided to mix some more primer and apply by brush

I realise that it's going to mean a lo more sanding, but progress needed to be made.

More 3D printing, this time a prototype nose laser extending mechanism

A little work on mounting the Raspberry Pi and associated boards and the screen, now all mounted in a 3D printed chassis ready to mount in the bodyshell.

and from the frontish