Sorvan's TARDIS

[purpleblancmange]

Hey, that's going great guns - it looks like a solid build there.  Do you know, I don't think adding GRP with really be all that necessary, so long as the edges are a tight fit and you have a good coating of paint on the outside, it should be okay.  All you'd need to do is re-coat it with fresh paint each summer - I observed my unpainted roof during torrential rain and there was not one leak, though the gaping window holes didn't help matters.

Mind you, I think you should do this with whatever measures you feel confident with.  I can't wait to see you tackle the walls next - when you get to that stage!

[TG]

so long as the edges are a tight fit and you have a good coating of paint on the outside, it should be okay.  All you'd need to do is re-coat it with fresh paint each summer

Now you tell us Purple!

But I do think your roof looks exceptionally well put together Colin - I'm really impressed.

[Sorvan]

To be precise, it'll be GRE not GRP (I'm using Epoxy).  In any case, I agree that it's probably not nessesary as such.  My roof has no horizontal surfaces, so rain will easily flow off of it.  I'm a little more concerned with the effects of snow which will pile on top - since there isn't that much of a slope, but I don't think that's a huge problem either.  I'm sure it would be fine if I left it as is (seeing that I've already coated the roof in epoxy), but I'll be putting on the fiberglass cloth anyway.  As I've said before, if I'm going to build it I might as well overbuild it. 

Adding fiberglass will mean increased strength.  It's probably stronger than it needs to be at this point, but besides keeping the pieces together, it'll provide a harder surface so that if something bangs into it, the wood won't dent.  The epoxy I'll be using with the fiberglass will make it really waterproof, so I won't have to worry about the possibility of water seeping in somewhere and cracking something when it freezes.  Repainting every year would work, I'm hoping that the fiberglass will allow it to stand up to more abuse so I don't have to repaint for a long time.  Also, I've also never used fiberglass before, and I like trying new things. 

Will I take pictures when I eventually get around to fiberglassing (in a few months)?  I suspect I'll have my hands full, but I'll certainly try to get someone to take some action shots.

On the topic of paint and primer.  I don't know what it's like for you but when I buy paint, the cans on the shelf are white and only gets colour added when I go to the counter and tell them what colour I want.  They then open it, pour some colourant into it, close the can, toss it into a mixer and when it's done shaking up, they give me the bucket and a stir stick telling me to make sure to stir the paint before using it (very important!).  If you buy primer, it's also white and guess what... they can also add colourant to it.

The primers that I picked up for so cheap are: Zinsser Bulls Eye 1-2-3 Primer, and   Zinsser Bulls Eye 1-2-3 Deep Tint Primer.
 

I've already mentioned that I'm using West Systems epoxy.  As for the fiberglass cloth, I have no idea what brand it may be, as I just went to a "marine" store and picked up what they had (since they are a West Systems dealer, I thought it safe to assume that this cloth would be good with their epoxy).

I haven't picked up anything for casting the windows, but people have been recommending that I check out Smooth On, so I may go with one of their "Crystal Clear" urethane casting resins, even though they keep pointing out that they're NOT FOR HOME USE - industrial use only.  I'll probably buy myself a new respirator if I do this (or at least different filters for my current respirator) and do all the casting outside.

Colin

[Mark]

Nice bit of work there Colin.

I do like the fact you've added the slopes to each step, they're on the prototype so must be pretty usefull! :-)

Also of interest, the Earls Court police box that was put up in the 90's, was built of timber and the roof has some sort of cladding in place. I think it's some sort of felt and tar, like on a garden shed.

I'll try and post a picture when I find it, show you what I mean.

[Sorvan]

Today was the day to start working on the window frames again, and the whole house now smells lovely (the smell in the basement is especially strong, but since I have a forced air furnace, even the second floor smells of cedar).

Just over two months ago, I received the package of Yellow Cedar from my father which I stacked in the living room to let dry.  About a month ago I used a caliper to record the dimensions of each of the pieces.  Yesterday I set up my router table (my router finally came back from my dad).  Today I sorted all the bits of wood by thickness, and decided which pieces should be used where.  Before taking them down to the router, I indicated on the face of each piece which window it'd go with, and on the sides indicated what needed to be trimmed off - so I wouldn't make any mistakes.
   

I sorted them into the different types of pieces that I needed and took the lot into the basement, set up the router and started working on it.


My dad built me the router table, it's very nice.  Those things holding the wood down on the top are called "feather boards" and serve two purposes - holding down the wood and preventing kickback (the blade catching on the wood and flinging it in the opposite direction).

This picture also shows the scrap bits of wood I use to 1) keep the yellow cedar against the fence and 2) push the yellow cedar along so my fingers don't get anywhere near the blade.  It also shows a large hose coming out of the back which leads to my shop-vac.

This is really nice since not only does it reduce dust, but also debris which can get in the way of what I'm doing.

I took two passes to cut the wood to where I wanted it.

It's usually best to cut things like this over several passes.  In one of my test pieces I tried doing it all at once, but it didn't work that great - it tore out chunks in some places.


I've also been thinking more about window casting.  One of the issues that gets talked about when casting clear resin is that of air bubbles.  To get rid of these, the experts seem to do two things: place the freshly mixed resin in a vacuum chamber to try and suck out all the bubbles, and let the resin harden in the mold inside a pressure chamber to try and make any remaining bubbles microscopically small.  After doing a bit of research it has become apparent that purchasing a pressure chamber is incredibly expensive, and a diy pressure chamber would be incredibly dangerous (I get the impression that in the likely chance that it would fail, it would probably take out a sizable chunk of the house and kill anyone that was too close).  A vacuum chamber on the other hand, is a project that isn't too expensive (around $60) assuming I can borrow an air compressor from someone.

Here's a couple of sites talking about diy vacuum chambers:
http://www.clevelandfx.com/crazylou/tutorials/vacuum.htm
http://www.bnglifecasting.com/diy/chamber/

Colin

[Sorvan]

Hi Matt,

I've been doing some digging around on the net for resin information as well as talking with a few people, and I've come to a few (perhaps inaccurate) conclusions.

There seem to be two main types of clear casting resins out there: polyester and polyurethane.  Polyester appears to be cheaper (and easier to find), but isn't as clear and may not be UV stable (it may turn yellow in sunlight).  Polyester is catalyzed with a small quantity of MEK (hardner).  Polyurethane is more expensive, but is inherantly UV stable and very clear.  It has two components that are mixed together (often at a 1:1 rate).  I've been told that if I use polyurethane, it needs to be degassed - polyester isn't as much of a problem since you can increase the cure time by reducing the amount of hardner you add.

I suppose my other options are to try and find a polyester resin that is UV stable (if such a thing exists), or to pick up a slow setting polyurethane (which will hopefully give it enough time to degass itself).  It's all a little confusing some times.  I've also been told that depending on what material I'm casting with, I may want to use different types of silicone molding compound (tin cure or platinum cure) but I can't remember what goes with what.

Hopefully by the time it gets warm enough to cast outside, I'll have figured out this stuff.

Colin

[meantimebob]

clear resin and silicone are a weird combination. Whenever i've used them the resin always remained a bit tacky where it was in contact with the rubber and took a lot of air drying outside the mould to go off, but the finish was never brilliant unless lots of fine sanding and polishing was involved.

Good luck with yours.

[Sorvan]

So I have actually done a bit of work on my windows since I last posted.  Last weekend I found some time to cut the pieces for the inner frames of the 6 opening windows and glue them together.



It might have been better had I not done this while being sick, as after cutting the tops and sides (but not the bottoms), I realized that I had made a mistake, and if I continued what I was doing and assembled them, the frames would be 1/2" narrower and 1/4" shorter than intended.  Thankfully I realized that if I cut the top piece of the frame differently, I could remedy both of these problems (good thing my dad sent extra bits of wood).



I had to cut the notches in the top pieces by hand, but I've a nice sharp chisel so didn't turn out to be too difficult.  I've obviously got to do the cross pieces next, and then the outer frames for these windows, and the frames for the windows on the doors.

I've also been doing a bit more research about resin.  Since it's highly recommended to "degass" the resin after mixing it, I want to put it in a vacuum chamber.  As vacuum pumps are generally rather expensive, my latest thought is that I'll try to make a vacuum chamber using a refrigerator or air conditioner compressor.

Unfortunately, I'm not progressing terribly quickly these days.  I'm getting married on May 13, and wedding plans keep interrupting my build! 

[Scarfwearer]

Unfortunately, I'm not progressing terribly quickly these days.  I'm getting married on May 13, and wedding plans keep interrupting my build! 

Well, if you get on with it, your honeymoon could be out of this world... 

Crispin

[Sorvan]

Well, if you get on with it, your honeymoon could be out of this world... 

I think I'm going to have to stick with out of this continent (North America).  I've already got tickets to Rome.


I worked a bit more on the windows today - the cross pieces this time.

I want to make all these the same, so I set up a stop so that I can cut pieces to exactly the same length.  As you can see, this consists of attaching a block of wood to a longer piece of wood and then clamping it onto the base of my mitre saw.



I needed to trim off the facing bit of the pieces so they fit into the frame properly, so I ran them through the table saw a few times (nibbling off about a blades worth of material per pass).



I started working on joining the cross pieces together, but decided that I need a small hand saw to really do a good job.  Or maybe it's just that I'm addicted to buying tools, I don't know.

Colin

[Sorvan]

Among other things today, I bought a new saw (a small dozuki), and cut all the cross pieces.



Maybe I'll have time tomorrow to glue the bits together.

Colin

[Dematerialiser]

They look excellent Colin; and an enviable collection of tools you've got there too..!

[Mark]

Your thread really is interesring Sorvan. Not only informative and practicle, but also pretty amusing!

Those windows are looking really nice, are you going to be using putty on your windows (only ask coz of the method you've constructed your frames)?

[Sorvan]

are you going to be using putty on your windows?

Yes, that's the plan.  I actually replaced the window in my back door a few months ago, and found that window putty is pretty easy to work with.  My goal is to have a Police Box that looks good both inside and outside (even if I'm primarily going to be using it to store my garden tools).  That's one of the reasons I made the roof like I did (not using internal bracing), and why I'm bothering with the details like actually using putty in the windows.

Unfortunately, this plan does lend itself to having me think about details for days on end instead of actually working on the thing.  If I did a bit less thinking and a bit more doing, I'd be a lot further along.  At the rate I'm going by the wedding I may have a completed roof and windows, but this will all be put on hold since after the honeymoon I REALLY need to fix (replace) my basement floor, which I've put off for a few years already.

Here's a picture of what I should be working on...

As you can see, I've got an improvised sump pump in a hole my dad made in the floor.  All I've really done to improve on it is to dig the trench (leading up to the left) to the area that gets a few inches of water every spring, and a bit of a groove in the concrete (down and left) which leads to another wet spot.  What I really need to do is dig down a foot in the whole basement, replace my sewer stack (it's cracked), install weeping tile, and pour a new floor.  Hopefully I'll be able to afford to get someone else to do most of this work (and leave me building my "garden shed").

Colin

[Sorvan]

With my impending wedding, I was beginning to suspect that Police Box building would be on hold until at least after the honeymoon (and probably after the basement was fixed).  Amazingly enough, I found a bit of time to haul the roof out of the basement yesterday and some time today to try my hand at fiberglassing.

I hadn't thought about how awkward moving my incredibly heavy roof out the basement would be, but thankfully I had already picked up some pullys in anticipation of hauling said roof on top of a mostly finished box, so I rigged those up and managed to haul it out of the basement without killing myself.  It's the sort of moment that in hind sight I wish I'd have taken pictures of, but at the time I had my hands full, and everyone else in the house was still asleep.  Some day I really have to weigh this piece.  It's really heavy.

Today I put up my portable shade and got all my fiberglassing stuff together.


I put the roof on blocks so that water could pass underneath it just incase it rained or something.


I draped the cloth over it, giving myself lots of extra as I thought that I'd be able to do the corners (which I later discovered wasn't the best move).


Once I put the epoxy onto the cloth, I could see what they meant in the instructions about "wetting" the cloth as it pretty much disappears.


When the epoxy cures, I'll have to put another layer on to fill in the weave.


I came to the conclusion that once you start working, it's best to keep working until you're finished, so I don't have any pictures during the process.  It's basically a matter of mixing up epoxy, pouring some onto the cloth and then spreading it around with a plastic spreader.  You want enough epoxy to "wet" the cloth so it disappears, but not much more than that so you keep spreading it around.  When I tried going down the corners I found that the cloth didn't want to take a 75° angle, but lifted off the top when I pushed it onto the sides.  The only thing to do was to trim everything close to the edges so that there wouldn't be enough cloth hanging off to get caught in the slight breeze.

I also found out that I had barely enough epoxy left.  I'm hoping that the marine store is open tomorrow (I've the day off) and I'll be able to work on it some more.  At this point, the roof will NOT be going into the basement again (it'll live outdoors from now on) so I want it to be as water proof as it's going to be.

I did stand on the roof briefly.  I think it's strong enough.

Colin