What is the difference between PU4ii and PU4ii-L?

We use the PU4ii for smaller animals like mice and rats. The processing time is about 10 to 30 min, which is perfect for the casting of smaller animals. Longer processing time maybe needed when casting larger objects, e.g. human cadaver. The processing time for such objects is typically much longer (40 to 60 min) and we then advise to use PU4ii-L.

What does processing time mean?

Time needed to mix the PU4ii including the injection/perfusion. Best is when the resin is mixed
with the solvent (EMK) and the pigment in advance. This mixture may be kept for minutes or hours
if sealed tightly. Immediately before casting the hardener is added to this mixture, stirred briefly
and then injected with a syringe. To remove small air bubbles in the resin, the final mixture is set
under vacuum for 2-3 minutes using a standard vacuum chamber.

How many animals (e.g. mouse, rat, rabbit etc.) can I cast with one kit?

On average, we use 5 g of resin for one mouse. Under optimal working conditions, the
kit will be allow to cast 100 mice.
For a rat we use 15 g of resin. For hole animal/organ a rule of thumb could be triple the
average blood volume. And, for larger animals a local intra-arterial casting may be
sufficient and render superior casts than complete-animal-casts.

Are there any modifications for microCT procedures?

For microCT you need to introduce radio opacity. No radio opaque material has been
found to mix to the resin without impairing its viscosity. Immersing the casts in osmium
solution are still the only solution. See Krucker et al 2006.

What do I need besides the polyurethane resin kit to be able to do perfect casts?

The PU resin needs to be mixed whit a solvent to obtain low viscosity. Best results where obtained when adding 30% Ethylmethlketone [EMK from MERCK: # 106014 (2-Butanon) puriss. or 2-Butanone from ACROS Organics #149670010]
The hardener has shortest shelf life and should be covered with dry gas XTEND-IT from SMOOTH-ON after each opening.