Mustang Sheet Fabrication Guide - Curbellplastics.com

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Cutting/Machining• Do not blend paints from different manufacturers• Do not use an overly thick layer of paint to obtainopacity. It is better to use several thin layers toachieve this resultPaint RemovalWhen paint removal is required, remove as soon afterpainting as possible. A paint thinner may be used;however, review the paint manufacturer’srecommendations prior to applying. Always minimizethe time solvents are in contact with plastic sheet.Vinyl FilmsLettering and intricate designs made with vinyladhere well to Mustang sheet. They can be appliedeither wet or dry, depending on the preference ofthe operator. Due to the low temperature requiredto thermoform, the stretching characteristics, andMustang’s overall thermoforming superiority toother plastic materials, a sheet pre-decorated withvinyl can be thermoformed for distortion formingapplications. The unique process of forming apre-applied vinyl on the second surface is anoption with Mustang, with the only limitationbeing the vinyl’s ability to stretch. This processis not done on other sign plastics.Vinyl WeedingMustang sheet is an excellent material for vinyldecoration, both prior to and after thermoforming.As with other plastics, the sheet needs to dryovernight to allow the moisture to escape frombetween the Mustang and the vinyl. If using multiplelayers of vinyl decoration, additional time maybe required.The thermoforming temperatures for Mustang arecompatible with those of vinyl, allowing more evenvinyl stretching characteristics and less chance ofvinyl blistering.Use caution when removing (weeding) the excessvinyl from a pre-decorated, thermoformed sign face.The below steps are suggested when using andweeding vinyl from a formed face:• Apply vinyl per the manufacturer’srecommendations• Generally, it is best to weed vinyl as soon afterforming as possible• Allow Mustang sheet to cool a minimum of 1hour to room temperature prior to weeding• Do not allow the knife used to weed penetratethe surface of Mustang• Once the weeding process has begun, pull thevinyl in smooth, even motions. Removing toorapidly could cause the vinyl to tear• Use both hands to pull the vinyl from Mustang atan approximate 70-80 degree angle. Pulling ata 45 degree angle is more difficult and increasesthe chance of vinyl tearingSecond Surface Vinyl Weeding• When applying and thermoforming second surfacevinyl (applied to the non UV side of the sheet), thevinyl must be weeded before it cools completely.Complete cooling generally occurs within 5-10minutes after forming. Ideally, weeding shouldtake place as soon as the vinyl has the integrityto do so.• If weeding the second surface vinyl isn’t possibleprior to complete cooling, reheat the area ofvinyl where weeding is necessary using a smallhand-held propane torch, using the “fanning”attachment. Take care not to burn or blister thevinyl during this process.FormingCold BendingAlthough no plastic sheet should be cold bent toany severity, a bend in Mustang can be achievedwithout applying heat. A minimum radius of atleast 100 times the initial thickness of the sheetis required.Brake BendingBrake bending is not recommended whenfabricating plastic sheet. However, if this typeof fabrication is necessary, do not perform onMustang sheet >0.100" (2.5mm) thickness.Heat bending should be used on thicker gauges.Brake bending creates high levels of stress in thebend area, and could result in cracks and breakageduring this process, or at a later time.9
FormingLine BendingLine bending, also known as strip heating, is atechnique used for forming sharp bends in theplastic sheet. When heated properly, Mustang lendsitself well to this type of fabrication. The radius ofthe bend can be controlled by the width of theheated area. The temperature of the side oppositeof the heat source should be heated to ≥250° Fprior to bending. This will assist in eliminating theresidual stress that can form when bending at atemperature that is too cold. Thicker sheets shouldbe heated from both sides to achieve a uniformheating through the sheet. Heat perpendicular tothe manufacturer’s extrusion direction to reduce thepossibility of warpage in the heated areas. Alwaysstabilize the sheet by clamping during the heatingand cooling processes.Oven HeatingMustang sheet should be heated in a horizontaloven. It is not conducive to use with vertical ovens.ThermoformingThe term thermoforming refers to the processof heating a plastic sheet to sufficient temperature toform a shaped article. Mustang sheet excels in thisarea, offering a unique combination unmatched bypolycarbonate. Mustang sheet can be thermoformedwithout pre-drying, forms at lower temperatures,has faster heating and cooling cycles, has excellentmaterial distribution characteristics and processesconsistently. Deep draws and intricate part definitionsare achievable with Mustang by using simple vacuumforming techniques.The entire cut to size sheet is typically heated toforming temperature inside an oven. The formingtemperature depends on the thickness of the sheetand the shape or complexity of the mold (See Table2). For less intricate molds, heat Mustang sheet onthe lower side of the temperature range. For deeperdraws and more complicated mold designs, heat tothe middle to upper side of the temperature range.Because Mustang sheet exhibits great detail, careshould be taken when manufacturing the mold. Itneeds to be smooth. Mustang sheet will form to thedetails of a rough mold (mold mark-off).The radii of the finished part should be greater thanor equal to the initial sheet thickness. This willgreatly reduce stress molded into the part due tosharp radii (See Figure 5). Sharper corners increasethe localized stress, which could lead to micro cracks,and then to possible part failure.During the cooling process, a thermoformed partshould be fully supported as additional shrinkagemay occur. The extrusion direction of the sheet is themost susceptible to shrinkage. Supporting will reducethe possibility of warping of the final part, especiallyin the flange area.Thermoforming Temperature vs Sheet ThicknessMustang Thermoforming Conditions: 0.118 to 0.177 thicknessPropertyOptimal Forming Temperature Range (ºF)Optimal Forming Temperature (ºF)Heating Time with One Sided Heating OvenMolded Part Release Temperature (ºF)Optimal Mold Temperature (ºF)Typical shrinkage factorsMDTD0.118310-3403254-5 minutes180-185180
Page 1 and 2: Fabrication GuidebyCurbell Plastics
Page 4: Mustang FeaturesTemperature Resista
Page 7 and 8: Cutting/MachiningBlade Diameter (in
Page 9: Cutting/MachiningAdhering Mustang t
Page 14 and 15: Chemical ResistanceChemical Resista
Page 16 and 17: Troubleshooting GuideMustang Circul
Page 18 and 19: DisclaimerThis manual is a general

Mustang Sheet Fabrication Guide - Curbellplastics.com

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