As part of Heat-On product development, Radleys have evaluated flasks from a variety of glass manufacturers to ensure that Heat-On blocks will accept the widest possible range of sizes and styles. However, because the tolerances on mass produced glassware can vary greatly, it is not possible to guarantee that all brands will fit. Indeed, experience shows us that glassware from a single manufacturer may vary considerably in size and shape from batch to batch and also from item to item. We therefore advise that customers pre-select appropriate sized glassware to use with Heat-On.
Heat-On has a slightly narrower diameter at the top of the block well, to help stop oversized flasks from fitting through. Of flasks that can be inserted into the Heat-On block, suitable flasks should sit at the bottom of the well, and be a loose fit in the well – able to spin freely in the Heat-On well, without catching or sticking on the sides of the well. If the flask is catching or sticking, it may be misshapen, and may result in jamming or even cracking of the flask when the Heat-On block is cooling. If the flask does not spin freely then it is unsuitable for use in the Heat-On and an alternative flask should be used.We can provide maximum flask outer diameter dimensions for specific Heat-On blocks; please contact us.