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Weatherproofing in a can

Started by mordrogyn, Jan 14, 2012, 09:30 pm

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Jan 14, 2012, 09:30 pm Last Edit: Jan 14, 2012, 09:31 pm by mordrogyn
I am going to go out on a limb here and say...

I have solved the age old problem of how to make your tardis water proof.

Though I have yet to test it on a fully constructed outdoor build (I have tested the stuff on scrap wood).

The solution:

Rubberized car body undercoat!
You can buy it from Autozone, O'Reilly's or I would imagine ANY car accessory/parts shop.

It is usually black, however it IS paintable.
By painting your roof section with this after it is constructed it will seal all the joints and seams.
Price wise is it between $3 and $8 a can depending on the brand, some are thicker than others so make sure you buy the same stuff or it may look patchy.  However if applied right it can produce some interesting textures which would be ideal for certain builds.

The only build I can't see this working for would be the Matt Smith box because obviously it will not allow you to see the wood grain in the paint.  Though it should still be useable for the roof.

This will be the method I will use for weatherproofing my box when construction restarts this year!


Sounds interesting. How did you go about testing this stuff?

Also, how do you apply it, brush or sprayable?


It comes in an aerosol spray can and applies just like regular paint, though depending on the brand may be a little thicker.
Here is the stuff I was messing with though there are many out there Not all are paintable so be careful

As for testing I have some scrap wood left over from when i built my walls (which remain under the bed lol) and pretty much just gave a piece a thin coat, waited 24 hrs for it to dry and then set about liberally soaking it with the garden hose, as well as leaving it in a bucket for an hour or two.
The treated wood remained dry.  Water just runs off it, as you would expect with a rubberized surface.  I havent as yet tried to paint the piece though I imagine it will work fine, if require a few coats to hide the black.


Something else I discovered that I was meaning to ask the forum about, a few months ago I came across a site that sold all things maritime. They sold all sorts of things for maintaining boats one being a range of products to waterproof the hull of a boat. These came as what looked like clear varnishes, surely if these are are good enough for a boat then waterproofing a tardis should be simple. Anybody got any thoughts on this?



Jan 15, 2012, 02:26 pm #4 Last Edit: Jan 15, 2012, 09:44 pm by mordrogyn
I considered this a long time ago.  It would work but at the same time would make repainting the box later on a little more tricky, as you would have to remove that coat of varnish first.  This stuff would be the first coat, with your finish Color being the last, so any future repainting would be simpler


Jan 16, 2012, 05:51 am #5 Last Edit: Jan 16, 2012, 06:07 am by galacticprobe
A note on Maritime products: yes, if it can protect a boat hull from the ravages of the sea, it can probably protect a TARDIS shell from things like snow, falling acorns and pinecones, acid rain, etc. (Not sure about meteors, though.) However...

Coming from a nautical background, I would suggest caution when buying anything from a marine supply store. They can be notoriously and vastly overpriced on many of their wares. (Not all suppliers, mind you, but many of them.) When I was restoring an old wooden skiff for a local historic house that's now a living history museum, all of the local marine suppliers wanted gobs of money for a 5 lb box of oiled oakum which is used in traditionally caulked carvel planked boat construction (like the skiff, and even larger vessels like the USS Constitution in Boston, or the Charles W. Morgan in Mystic, Connecticut). And by gobs of money I mean in the 3-digit range.

A friend of mine found a 5 lb box of the same oiled oakum in a plumbing supply store for $20 USD. That box had enough oakum in it to re-caulk a 20-ft skiff, and still have over 4 lbs left over. Now my point: do your pricing research carefully before jumping on marine-grade items from a marine supply store. Chances are that you can find the same product from a different source for far less money.

And as Mordrogyn says, varnishes would make repainting a hassle when the time came. If used as the "overcoat", you'd have to sand all of that varnish away before being able to repaint. If it was used as the undercoat to seal the wood the top color of paint would likely flake off of a varnish. Stick to good wood sealers and primers. Your top color of paint will stick to them.

"What's wrong with being childish?! I like being childish." -3rd Doctor, "Terror of the Autons"


The car undercoat sounds like a novel solution.  There was an older thread on a TARDIS build that I will further mention as a solution before going on to how I chose to skin this cat.

At Lowe's or Home Depot or whatever your hardware store is, they'll have a roofing section.  There, in addition to shingles and tar, they'll have a sort of rubber roof patching compound.  I've used it on a nearly flat garage roof to cope with some leaks and have to say it is good for that.  The woman who used it for the roof on her TARDIS seemed to have good success with it (sorry, I don't remember what build it was, someone bumped it to point out sillysparrowness wasn't the only female TARDIS builder). 

Anyway, before I joined this board but after I started building my TARDIS, I had some scrap roofing materials laying around from the aforementioned garage roof.  What I wound up doing was cutting consecutive triangles of tar paper in shapes that would cover 2 sides of my roof (I wanted 4 triangles, but I ran out of material after 3).  I tarred the roof and then layed on the tar paper, stapling it along the bottom edges.  Then I tarred one of the unfinished roof sections as well as an adjacent one, already covered by tar paper and layed on the next sheet of tar paper.  This way I had overlapping seams. 

I just caulked the bejeezus out of the roof "steps". 

Now I will say, my TARDIS isn't as nice as some of the ones here and the tar paper has bubbled and shifted a little bit on me, but since it is the tip-top of your build, you don't look at it that much and it looks fine in my opinion.  (It did soak up a lot of paint I must say.)

That said, were I doing it again, I think I'd try some kind of rubberized waterproofing like the car underbody spray or roof patching material.  I'd also give "orange peel" drywall texturing spray a try for creating a concrete texture on my walls.  And/or sand or sawdust or some kind of texture in my topcoat.  But that's another story. :)
"My dear Litefoot, I've got a lantern and a pair of waders, and possibly the most fearsome piece of hand artillery in all England. What could possibly go wrong?"
-The Doctor.


Little update...

My "test timber" was painted with regular oil based undercoat (the remains of what I used on my windows) and has been sitting outside for the last 10 days, and let me tell you we have had some torrential rain here.

The undercoat covered the black rubberized spray nicely.
Watching the rain pound on it the other day it pretty much just beads up and runs off.

If applied to a constructed roof price the spray would fill and seal all the cracks nice and neatly.
Now that I know that the paint will cover this stuff properly, this will be the method that I will use when I recommence my build


Good news! I was worried about how I was going to waterproof the roof but this stuff sounds like it will do the trick.
so with this would you:
-sand and fill the big gaps/holes, caulk the corners
-spray on the rubberized undercoat
-when its dry paint over it with a few coats of exterior latex paint? (no primer?)



This is exactly what I'm going to do with mine... Whilst I was attacking my joints with a sealant gun the other day I noticed that some of the roof sections have started to bubble where water has gotenin under the paint. My plan is to sand the roof back to get rid of the lumpy bits, re-seal and fill all the joints then spray on a liberal coating of the rubberised paint.

I managed to track down a couple of cans from Halfords (in the UK) it was only £7.99 a can :)

I'll let you know how I get on...


@daveninja  when I tested it i used some left over oil based primer to cover the rubberized layer, you should be able to get away without it I think, however you will get a cleaner finish in fewer coats if you have a coat tinted closer to the final color over the rubberized stuff before you go for your finish color.


I ended up spraying the rubberizer on and then using a latex primer and then 3 coats of the exterior latex blue paint. its held up well during all the thunder showers of last week. my bigger concern now is how it will react to the summer heat


I would expect no issues, it is flexible and if you think about it has to withstand the heat from any nearby exhaust pipe...


I'm more worried about the the blue paint sticking to it but it will likely be fine. it is up like 9 feet high so its not like i can see it in any great detail :)


Well. My test wood has been sat outside for the last 3 months through all kinds of weather, the paint hasn't chipped or bubbled yet.