double strings

[rap138]

Hiya
I want to adapt a cheap bass I have to 4 double strings, as in one extra an octave or two higher, I just need to know how do I get the higher strings? aren't guitar strings too short for purpose?
are there special sets?
please excuse my ignorance if the answer too obvious
thanks

[Phalex]

Look into an 8 string set. They make an 8 string bass, so there must be 8 string strings out there somewhere.

[rap138]

i know, i can find 8 single courses easy, the trouble is that i don't know if they are the same for double courses. it could be. i just need to know the gauges. or where to find proper double ones.

[JimmyM]

I wouldn't do it. That's a lot of tension to add to a neck built for 4 strings. The neck's liable to warp.

[rap138]

I thought the same, but is a REAL cheap bass, I finally did add the extra 4 strings, but i'm just using guitar lowest four.
so far the neck is taking the pressure, time will tell. at least the sound is much better than before.
thanx for the advice though, i wouldn't do this to my main bass