Actually more a fireproof box but will be quite interested in making it as secure as I can. It is mainly for a small amount of cash and say passports and just a few household documents. I am trying to build something which in the event of a fire the documents dont go up in flames or at least would have a better chance of survival than the cardboard box my wife currently keeps them in. Also trying to use whatever materials I have at hand.
Initially I would start of with a metal box aprrox 12 inches sq I then thought to line the exterior with a couple of layers of plasterboard. And then a layer of chipboard.
For security I was then thinking of encasing this in some concrete just to make it heavy and bolt it onto floor/wall or wherever I decide to locate it.
The door I havent planned yet.
Any thoughts on this or anyone done something similar?
Is it worth it? You can buy something with a 30 min fire rating for pape= r at around =A350...
formatting link
google link showing a range of boxes.
The problem with a fireproof box is keeping the inside cool enough to stop the paper inside oxidising/charing. Remember a good domestic fire will get to around 1000C and when the brigade arrive lots of water...
I was involved in specifying commercial ones many years/jobs ago. I would suggest reading up on those a bit. In particular, you need some thermal insulation, and inside that some substantial heat capacity to delay temperature rise in the safe so it won't get too hot before the fire is put out. ("Too hot" depends what you're storing in there, of course.) Also needs remain waterproof when firemen spray a hose on the red-hot outer surface, if the contents would be damaged by water.
A lot was learned about fire safes during the Northern Ireland troubles, where many were put to the test, and there were many previously unanticipated failure modes. One of the most common was where the safe protected the contents from the fire just fine, but the contents were destroyed by the efforts to open the safe afterwards. This typically happens when a fire safe falls through floors of a burning building or a building collapses on top of it, and the doors will no longer open without the use of welding torches and angle grinders.
When you're considering the "too hot" temperature, paper will survive up to about 200 C depending on the ink used, while most thumb drives will expire at below 100 C, and magnetic media such as floppies or hard drives will lose their data at not much more than 60 C. Writeable optical media are less predictable, and less stable than magnetic ones.
Line with several layers of ceramic fibre, something like
formatting link
and scroll down.
Use insulating concrete on the outside? Something like ordinary concrete but the aggregate replaced by exfoliated vermiculite and/or horticultural perlite available from most garden centres. See
formatting link
the concrete with several coats of intumescent paint? See
formatting link
the time you've done all of that you'd have been better off buying a commercial fireproof safe, as DL says.
The standard material to fill the inner/outer gap is plaster. When heated e= nough it gives off a lot of water, absorbing a lot of heat before it fails = by letting the high temps through. Chipboard is one of the more fire resist= ant diy materials. Papercrete is also good, and a good insulator, and small= amounts are soon made with a kitchen blending wand. For fire protection I'= d use a lot of cement in it, or maybe plaster would be better than the ceme= nt content. Cost? For papercrete, next to nothing.
enough it gives off a lot of water, absorbing a lot of heat before it fails by letting the high temps through. Chipboard is one of the more fire resistant diy materials. Papercrete is also good, and a good insulator, and small amounts are soon made with a kitchen blending wand. For fire protection I'd use a lot of cement in it, or maybe plaster would be better than the cement content. Cost? For papercrete, next to nothing.
Thanks for all replies, yes maybe easier just to buy a safe but that wont happen, its a DIY project for me and as previously mention better than my wifes cardboard box.I have lots of left over material from a few DIY projects.
There are three genuinely good fireproof things I've come across. SOME vermiculite. That's the stuff they pour into Agas to stop the heat getting ouut - mostly! then there is rockwool I already mentioned in the last post. I've used rockwool behind a pipe when soldering up plumbing. It bloody well works.
Finally there is masterboard and/or multiboard/ Tht also I have used to do blowtorch work on
formatting link
biggest problem with a safe is the opening part - that represents a vulnerability.
Much of what needs security doesn't need fire & v.v., so it's often easier = to build two, one of each.
Whatever you make, make some lift-out boxes that fill the safe neatly. You'= ll get twice as much useful volume that way. You can also store jewellery i= n rolls or a case, not individual boxes.
For fireproofing, plasterboard and very small clearances is good, all wrapp= ed up in intumescent paint. Poured plaster is even better (the cardboard of= plasterboard can form a leak). I wouldn't use chipboard for a liner - if I= really wanted to line the plasterboard, I'd use oak.
If you need solid security, in some ways it's easier to build a safe in sit= u than it is to install a ready-built one. You can do things like concrete= pours, or tungsten carbide aggregate (old milling machine tooling bits). T= his also allows you to build to a custom size. I've got a gun safe to build= soon, which is relatively simple tech, but it will be good to make it as a= built-in filling a suitable brick cupboard space.
Mostly though, you need welding and ideally plasma cutting too. Building a = safe from mild steel is a waste of time, you might just as well buy one. St= ainless steel used to be a useful anti-drill material, but angle grinders n= ow make short work of it. So really you need to find some plate that's resi= stant enough to make it hard to work (hence the plasma), or else pour a har= d aggregate. Another good trick is to use mild steel, but to hard-face it w= ith a suitable stick welder rod.
If you're after a floor safe, then hefty mild steel is available quite easi= ly from gas cylinders (caveat opener!) and you can drill proof the sides wi= th aggregate. This just leaves you with a lid to make resistant.
Some people have used ceramic armour plate to make safes, but you have to w= ater jet cut this.
Locks are fairly easy, you just buy them. Often from a S/H safe. Most of mi= ne use combination locks, for which I use Chubb Manifoils as they're well k= nown and better than most other mechanical combination locks. If you're do= ing it seriously, then use a lock with bolts on both sides (so it doesn't r= ely on the hinges) and just use simple weld-on external hinges. More simpl= y (but still fiddly) you can use internal hinges and a one-point lock. This= has to be rigid though, or it's too easy to lever it open.
Surely, for fire protection, you put it in your underground swimming pool? If you don't yet have one, that would make a good project. And remember to make the safe waterproof...
However, it can be covered in burning rubble when the house collapses on it. The best place is in a different building from the fire. I have a fire safe in a brick built shed that is fitted with a security door and has no possible sources of ignition inside.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.