1 Tesla electromagnet?

I oppose the comments which say that it is pretty risky and/or dangerous as it involves high energy fields simply because it does not !

To make a powerful solenoid :
Let's see : { $ B =k \mu_0 n I$} Increasing magnetic field strength :
1. $n$ is no of turns per unit length (m in SI), take sufficiently thin wire and you can have this above 1000 !
2. $k$ take a good core and you can have this above 1000 ! as well.

Let's assume both $k$ and $n$ are above 1000 this would give us :

$ B = 0.4 \pi I $
$ B = 1.25 I $

Lets say you took awg 38 wire, it has resistance per unit length as $2.19 \Omega/m$ so net resistance of your device will be {$ R = 2\pi r n 2.19$} here $r$ is radius of loops you are making for solenoid.

Assuming you have a nail of material with $k > 1000$ and of cross-sectional dimater $5mm$ and you carefully wind awg 38 wire on it, your loop's radius will be $ 2.5 × 10^{-3} m$ : 1. Rssistance of device : $ R = 34.4 \Omega$.
2. Required current : $ I = B/1.25A $.
3. Required voltage : $ V = IR = 27.52 B$.
4. Required power : $ P = 22 B^2 J$

All of the above are easily achievable in the comfort of your home, BUT this field would be obtained only at the heart of your solenoid, although their will be appreciable field near the end points, the field would reduce by {$10^{-3} $} outside. Also if you operate it using either AC/DC the wires would be extremely hot and untouchable, if you try to increase the field by increasing applied voltage it may even burn down.

PS : check $Ahr$ of battery it will give you an estimate of how long your device will run before draining your battery of everything, I suppose it would be short.

This was also made In home :