Mustang Cutting/Machining

Cutting

Because of its excellent strength and flexibility, MUSTANG sheet cannot be broken using a scribe and break technique. It must be cut completely through. Cutting can be done with a variety of devices such as table and panel saws, circular saws, jig or saber saws, band saws, table and hand routers, CNC routers, and roto-zip tools. If MUSTANG sheet chips or cracks during the cutting and trimming process, it is most likely due to worn, dull blades and bits. Always use clean, sharp cutting equipment and make sure the sheet being cut is adequately secured to prevent vibrations of the sheet during the cutting process.

Table and panel saws are the best options for high volume straight cuts. MUSTANG sheet can be stacked to cut several sheets at one time, but the stack must be held securely to prevent movement. When cutting, the saw blade should protrude through the top of the sheet 1/8"-1/4" (See Fig. 1). Saw blades specifically designed for cutting plastic sheet are commercially available. Those with triple chip grind teeth are preferred.

Blade Diameter (in/mm)	RPM
6 (152)	6400
7.25 (180)	5000
8 (200)	4300
10 (250)	3400
12 (300)	2900
14 (350)	2500

Circular Saw Blade Specifications
Number of teeth	3-4/inch (25mm) >1/8" (3mm) thickness
	8-10/inch (25mm) < 1/8" (3mm) thickness

Routing is a versatile method for cutting and trimming MUSTANG sheet. Bit selection is important and those specifically designed for plastics are commercially available. Carbide bits with sharp one to two fluted designs work very well. The number of flutes depends on the diameter of the bit and the speed (rpm) of the router. In general, use single fluted carbide tipped bits for bit diameters ≤ 3/8" and double fluted carbide tipped bits for larger bit diameters.

Chipping and cracking of the sheet edges can occur if the correct router settings are not observed. This may be detrimental to the physical properties of the sheet. Please see the Troubleshooting Guide on page 15 for additional information.

Other Types Of Saws

Band Saws: Use blades with 8-14 teeth/inch for general cutting: 18-25 teeth/inch when smoother cuts are necessary.

Saber or Jig Saws: Use blades with 8-10 teeth/ inch. Ensure that your sheet material is securely fastened to prevent vibration during the cutting process.

Kett Saws: Blade #157-66, 2.5" diameter, 60 teeth. Rate of cut will determine quality of cut.

Roto-Zip Type: ZB10 bit for small trim of &quo'; 0.150" sheet. For thicker sheet, use Onsrud #52-624.

Drilling

Drilling holes is performed best on a drill press with commercially available plastic cutting drill bits. The bit diameter should be used to determine the appropriate drill speed.

Place a scrap piece of plastic sheet or plywood under the sheet that is being drilled. This will eliminate the possibility of chipping as the bit passes through the other end. Standard twist drills can be used, provided modifications to the drill bit are made. These modifications will allow the bit to scrape rather than cut through the sheet (See Fig. 4).

Regulate the speed of drilling to obtain a continuous spiraling chip. Use air or a cool water mist spray if needed. Avoid cutting oils as they may cause crazing around the drilling area. Refrain from creating notches in the drilled areas as notches and crazing may cause premature failure of the sheet or fabricated part.

Cutting And Drilling Tips: For optimum cutting and drilling quality, the below guidelines should be observed:

• Use sharp blades/bits/tools reserved for cutting plastic sheet • Use proper and constant feed rates and RPMs
• Prolong tool life by using the fastest rate of cut to achieve the desired edge or cut quality
• Always clamp the sheet being fabricated to eliminate vibration which could possibly cause chipping or cracking during cutting/drilling
• Compressed air or a fine water mist may be used if necessary to minimize heat buildup during the cutting and trimming processes

Edge Finishing

When edge finishing is required, mechanical edge finishing with diamond cutting wheels provide excellent results. If further edge quality is required, flame polishing may be the preferred technique (remove masking prior to flame polishing).

Bonding MUSTANG to Itself

Two-part adhesives are recommended when bonding MUSTANG to MUSTANG. Solvent bonding similar to the technique used when bonding acrylic parts is not recommended. There are several adhesives that have been found to work well with MUSTANG sheet. The following have been evaluated and work well with MUSTANG sheet. In order of effectiveness:

• Weld-On #55
• Lord Adhesives #7542 A/B
• Flex Welder 14345
• Lord Adhesives #403/19
• Lord Adhesives #406/19
• Lord Adhesives #406/17
• Plastic Welder II #14340
• Cybercryl #812
• Weld-On #58

Two-sided pressure sensitive tapes such as 3M VHB bonds well to MUSTANG.

Bit Diameter (inches)	Speed (RPM)
1/8	3500
3/16	2500
1/4	1800
3/8	1200
1/2	900
5/8	700

Adhering MUSTANG to Other Materials

Care should be taken when bonding MUSTANG to other materials. Slight differences in thermal expansion and contraction characteristics could place a large concentrated stress on the bonded area. If MUSTANG must be bonded to dissimilar materials, bond as small an area as possible using adhesives that remain flexible after curing.

Below are recommended adhesives for bonding MUSTANG to other materials. In order of effectiveness:

MUSTANG to Polycarbonate	MUSTANG to Acrylic
Lord 7542 A/B	Lord 403/19
Weld-on #58	Lord 406/19
Loctite 3922	Loctite 3922
Loctite 3321	Loctite 3106
Loctite 3106	Loctite 3321
Dymax 3094	Dymax 3094
Lord 406/19	Lord 7542 A/B
Dymax 3015	Bondmaster V5004
Plastic Welder II #14340

The adhesives listed for MUSTANG to MUSTANG, and for bonding MUSTANG to other materials, have been evaluated and are recommended. For best results, please follow the guidelines for use from the adhesive manufacturers.

Mechanical Fastening

Attaching MUSTANG sheet to itself and other substrates can be accomplished with various types of mechanical fasteners. However, when exposed to fluctuating temperatures, allowances for expansion and contraction must be included. Drilling oversized holes, using rubber-coated washers and spacers to distribute localized stress and to act as a cushion to the fastener, as well as not overtightening the fasteners, will allow the sheet to move and assist in the prevention of premature failure at the bonded area. Use only non-rusting fasteners, such as aluminum pop rivets, and space the mechanical fasteners far enough apart to avoid localized overstressing in the attached area, but still close enough to carry the expected load.

Decorating

MUSTANG sheet can easily be decorated using sign paints manufactured for use on plastics. Follow the paint manufacturer's guidelines for optimum results. Always use proper fabrication guidelines prior to painting and make sure that the MUSTANG sheet is clean of dust, dirt, grease, oily residues, and grime. All of these will affect the level of paint adhesion and the performance of the finished product. A 1:1 mixture of water and isopropyl alcohol works well for the oily residues that are resistant to mild soapy water. Use a soft cotton cloth to rub lightly and dry.

MUSTANG sheet works exceptionally well in pre-decorated applications where thermoforming is necessary. Because pre-drying isn't required, the lower thermoforming temperatures, improved material distribution and stretching characteristics, MUSTANG sheet is fully compatible with vinyl and screen inks that are designed for themoformed signs.

When using the spray and cut masking technique, care should be taken not to cut the MUSTANG sheet surface when cutting through the masking. This could cause notches, which may result in premature failure of the sheet or fabricated part. It is suggested that the blade tip of the cutting instrument be rounded to prevent accidental notching.

Paint typically reduces the impact strength of all plastics. Design considerations should be taken into account to minimize the potential for cracking and possible breakage of the finished part.

General guidelines include:

• Avoid too wet a mist when spraying
• Allow proper drying time between coats of paint (refer to paint manufacturer's recommendations)
• Avoid application of heavy wet coats of paint during each application
• Use dry air during the spraying process as water can affect the adhesion and strength of the paint film
• Avoid high humidity areas during the paint curing process
• Do not blend paints from different manufacturers
• Do not use an overly thick layer of paint to obtain opacity. It is better to use several thin layers to achieve this result

Paint Removal

When paint removal is required, remove as soon after painting as possible. A paint thinner may be used; however, review the paint manufacturer's recommendations prior to applying. Always minimize the time solvents are in contact with plastic sheet.

Vinyl Films

Lettering and intricate designs made with vinyl adhere well to MUSTANG sheet. They can be applied either wet or dry, depending on the preference of the operator. Due to the low temperature required to thermoform, the stretching characteristics, and MUSTANG's overall thermoforming superiority to other plastic materials, a sheet pre-decorated with vinyl can be thermoformed for distortion forming applications. The unique process of forming a pre-applied vinyl on the second surface is an option with MUSTANG, with the only limitation being the vinyl's ability to stretch. This process is not done on other sign plastics.

Vinyl Weeding

MUSTANG sheet is an excellent material for vinyl decoration, both prior to and after thermoforming. As with other plastics, the sheet needs to dry overnight to allow the moisture to escape from between the MUSTANG and the vinyl. If using multiple layers of vinyl decoration, additional time may be required.

The thermoforming temperatures for MUSTANG are compatible with those of vinyl, allowing more even vinyl stretching characteristics and less chance of vinyl blistering.

Use caution when removing (weeding) the excess vinyl from a pre-decorated, thermoformed sign face. The below steps are suggested when using and weeding vinyl from a formed face:

• Apply vinyl per the manufacturer's recommendations
• Generally, it is best to weed vinyl as soon after forming as possible
• Allow MUSTANG sheet to cool a minimum of 1 hour to room temperature prior to weeding
• Do not allow the knife used to weed penetrate the surface of MUSTANG
• Once the weeding process has begun, pull the vinyl in smooth, even motions. Removing too rapidly could cause the vinyl to tear
• Use both hands to pull the vinyl from MUSTANG at an approximate 70-80 degree angle. Pulling at a 45 degree angle is more difficult and increases the chance of vinyl tearing

Second Surface Vinyl Weeding

• When applying and thermoforming second surface vinyl (applied to the non UV side of the sheet), the vinyl must be weeded before it cools completely. Complete cooling generally occurs within 5-10 minutes after forming. Ideally, weeding should take place as soon as the vinyl has the integrity to do so.
• If weeding the second surface vinyl isn't possible prior to complete cooling, reheat the area of vinyl where weeding is necessary using a small hand-held propane torch, using the "fanning" attachment. Take care not to burn or blister the vinyl during this process.