Unit 3 M&M

3D printer

Printing

Casting

Stretcher bars

- Tim Johnson

Jacksons Stretcher Bars

Professional Stretcher Bar Range:

The Jackson’s Professional Stretcher Bar Range comes in three depths of wood (the amount the stretcher bar comes out from the wall). These depths are 18mm, 21mm and 43mm. Stretcher bars are sold in pairs.

For the 18mm and 21mm depths the stretcher bar lengths are measured in inches. The 18mm deep bars come in 2 inch increments from 12 inches up to 40 inches in length. For the 21mm deep bars the lengths come in 1 inch increments from 9 inches up to 54 inches in length. These stretchers can only accommodate one center bar (if required) and this center bar would be parallel to the shortest side of the stretcher. Center bars slots come in the stretcher bars of 30 inches and over. The stretcher bars in both the 18mm and 21mm depths are chamfered so that the canvas does not sit flat on the wood.

The stretcher bar lengths with a depth of 43mm are measured in centimeters (cms), with 10 cms increments from 30cms up to 200cms in length. These stretcher bars are made so that a raised beading is incorporated into the profile of the wood. Center bars are definitely recommended when any side of the stretcher exceeds 100cms (please note that in fact the stretcher bars with slots for center bars actually start at 80cms). If the stretcher is 100 x 100cms or larger (at least) two center bars – or cross bars - should be used, and in this ranged these crossbars pass over one another.

Please note that for any single stretcher in the Professional Range that the stretcher bars and center / cross bars should be in either the 18mm, 21mm or 43mm depths – meaning that the three depths cannot be combined in one stretcher.

Jacksons Stretcher Bar Museum Range.

The Museum Stretcher Bar Range comes in two depths of wood (the amount the stretcher comes out from the wall). These depths are 20mm and 35mm. Stretcher bars are sold in pairs.

The stretcher bar lengths in this range are measured in centimeters (cms) with 5cms increments up to 200cms in length. These stretcher bars are made so that a raised beading is incorporated into the profile of the wood. Stretcher bars of 60 cms and over have a slot for a center bar. Center bars of 100cms and over have a central half lap joint allowing cross center bars (on the same plane) giving the stretcher added strength required for larger paintings.

Please note that for any stretcher in the Museum Range that the stretcher bars and cross bars should be in either 20mm or 35cms depths – meaning that the two depths cannot be combined in a single stretcher.

Jackson’s Alu-Pro – Aluminium and wood – Stretcher Bar Range.

This range of stretcher bars, center bar, crossbars and required accessories (see below), although expensive, are excellent quality and, due to the aluminium and wood construction very strong, durable and true. Once bought the only tool necessary to put the stretcher together is a 4mm Alu-Pro Allen Key. This Allen Key is essential.

The Alu-Pro stretcher bars come in three depths (the amount the stretcher protrudes from the wall) that are 25mm (slim profile), 35mm and 45mm (deep profile). Alu-Pro stretcher bars are sold in pairs, so two pairs of desired lengths are required, all being of the same depth).

The stretcher bars in the Alu-Pro range are measured in centimeters, with 10cms increments, from 40cms up to 200cms.

4 x Corner Connectors (attach the stretcher bars together at the corners) for each stretcher are required.

If a single Primary Center Bar is used 2 x Support Connectors (these attach the primary center bar to the stretcher bars) are required. Primary Center Bars can be bought from 40cms, with 10 cms increments, up to 200cms. Please note that when you buy the primary center bar it will be denoted as the same length as the shortest side of the stretcher (the primary center bar braces between the two longer stretcher sides and therefore runs parallel to the shorter stretcher sides). The actual length of the primary center bar will, however, in actuality be less as it will be as long as the inside face of the shorter stretcher bars – but for clarity this center bar is sold as the same length as the shortest stretcher bars as it has been specifically designed to work with the length of those bars.

If your Alu-Pro stretcher is large enough to require a Secondary Cross Bar Set (comes in two pieces) – these are available from 120cms, in 10cms increments, up to 200cms. To fix the Secondary Cross Bar Set a further 2 x Support Connectors plus 2 x Cross Connectors (these attach the secondary and primary cross bars) are required per secondary cross bar installation.

Alu-Pro Calstretch Spanners are also available and I would advise buying these. They are the equivalent to stretcher wedges and can be used to gently expand the corners of the stretcher to tighten the canvas. 2 are required for each corner of the stretcher meaning 8 are required for the four corners. If a primary center bar or primary and secondary bars are used then an addition spanner is required at each point where a center bar (primary or secondary) attaches to the stretcher bars (ie. A stretcher with just one primary center bar will require 10 spanners. A stretcher with both a primary center bar and a secondary bar set would require 12 spanners).

Other Alu-Pro accessories (not essential):

‘Alu-Pro Screw Eyelets’. 2 are required per stretcher and can be attached to the stretcher and picture wire connected between the eyelets to hang the work. If the work is large and heavy use ‘Alu-Pro Heavy Duty Hangers’ instead.

Alu Pro Frame Stabilisers. These are ‘L’ shaped metal brackets that are assembled inside the corners of the stretcher bars to add stability for very large stretchers. (8 are required for the four corners).

‘Alu-Pro Extenders’. These can be used to connect two stretcher bars, of the same depth, thereby extending their length.

TJ