Well, I called the Whiffle Ball folks in Connecticut and the 4x4 folks at Alltech Motorsports. The Whiffle balls are made of low-density polyethylene (LDPE) and the Alltech hollow cylindrical baffles are made of high-density polyethylene (HDPE). Chinese Whiffle balls are mostly ABS (Acrylonitrile Butadiene Styrene) plastic and should not be used. Further research ‘suggests’ that HPDE would be the preferred baffling material, when compared with using LDPE, due to its superior resistance to gasoline. However, Whiffle is sending me some balls for testing. I’ve included a couple of photo excerpts from a chemical resistance chart regarding LDPE’s resistance to gasoline. Other sources are:
http://www.calpaclab.com/chemical-chart-containers/
http://www.thermoscientific.com/content/dam/tfs/LPG/LCD/LCD%20Documents/Product%20Manuals%20%26%20Specifications/Filtration%20Products/Filter%20Units%20and%20Bottletop%20Filters/Filter%20Units/D20480~.pdf
http://www.newpig.com/wcsstore/NewPigUSCatalogAssetStore/Attachment/documents/ccg/LDPE.pdf
http://www.professionalplastics.com/professionalplastics/HDPE-LDPEChemicalResistanceChart.pdf
http://www.nationalscientific.com/support/pdf/NS-ChemicalResistanceReferenceCharts.pdf
http://www.dynalabcorp.com/files/Physical%20Properties.pdf
http://www.premierplastics.com/Adobe/Chemical%20Resistance%20of%20Polyethylene.pdf
http://www.tedpella.com/company_html/chem-resistance.htm
http://sevierlab.vet.cornell.edu/resources/Chemical-Resistance-Chart-Detail.pdf
My conclusion is that I'll end up giving the Whiffle balls to the kids. If I do anything other than foam, it'll be the Alltech baffles. I'll leave the 'wife' ball jokes for Croc. :cheers: