Not modelling in OO (1:76) or N (1:148) scales?

As long as your printer has the ability scale pages up or down there is no reason why you can't build any of the kits other scales. Your printer's 'Scaling' options is usually found in the 'Advanced', 'Properties' or 'Page Setup' section of your Adobe Reader print window. Please consult your printer's 'Help Index' for more details.

If you are modelling in HO (1:87) or N (International 1:160) all products on can be resized down using table below.

For HO (1:87) or International N (1:160) the card thicknesses can remain as recommended in the instructions, for other scales it is a good idea to adjust the recommended card thicknesses accordingly.

HO scale (1:87 ) - reduce Scalescenes OO to 87%

N scale (International  1:160) - reduce Scalescenes N to 93%

O scale (British 1:43 ) - enlarge Scalescenes OO to 176%

O scale (International  1:48) - enlarge Scalescenes OO to 158%

28mm scale (1:56) - enlarge Scalescenes OO to 135%

TT scale (1:120) - reduce Scalescenes OO to 63%

TT scale (3mm) - reduce Scalescenes OO to 75%

S scale (1:64) - enlarge Scalescenes OO to 118%

Z scale (1:220) - reduce Scalescenes N to 67%

T scale (1:450) - reduce Scalescenes N to 33%

Reducing Scalescenes OO kits down to TT120

As long as your printer has the ability scale pages down there is no reason why you can't build any Scalescenes kits in TT120 scale. 
Your printer's 'Scaling' options is usually found in the Adobe Reader print window. Please consult your printer's 'Help' for more details, search for ‘page scaling'. 

In order for the TT 1:120 scale kits to assemble correctly you will also need to convert the card thickness as follows:
Heavy card - 2mm in OO works out at 1.25mm 
Medium card - 1mm in OO works out at about .5mm
Light card - 200gsm in OO equates to about 110gsm

Most card types are fine, 'mountboard' or 'pasteboard' are good, although cheaper 'grey board' is ideal for Scalescenes models.All those card thicknesses or similar are fairly easy to source. Breakfast cereal box card is almost a perfect match for the Medium card (.5mm) and if glued together (as two ply) then you have something pretty close to 1.25mm.

O scale notes

Apologies, no plans at this stage for O scale kits. To avoid tiling the enlarged sheets, O scale modellers may find access to a large format colour printer useful (scaled up the sheets are actually closer to A2 594x420mm).

You'll also need to roughly double the recommended card thickness which may require you to print some of the base layers twice. Another alternative would be to use foam core board which is usually available in about 4mm and would be much easier to cut out.