Widely popular, world wide, these kits polymerize overnight for easy sectioning and staining the next day. The kits are based on "Lufts formula". We are told that Araldite 502, which is manufactured in the USA, is the same as Araldite 753 which is made in Europe. For many years, the Araldite 502 kits (which we call the "classic" formulation) was widely used world wide for EM procedures. However, for some users, this has been changed slightly, when it was shown that BDMA has a lower viscosity and therefore, more quickly infiltrates tissue samples. Other advantages include a much longer shelf life relative to DMP-30. Also according to Glauert one can add a small amount of DBP in some instances, thereby permitting easier sectioning, since DBP acts as a plasticizer and reduces the hardness of the cured block. On the other hand, there are precautions one can take to lengthen the shelf life of DMP-30, thereby mitigating in some respects that one particular disadvantage.
SPI will continue to supply the widely used SPI-Chem Araldite 502 Kit "original" formulation. We find that this is the formulation requested by most persons. Furthermore, substitution of BDMA for the DMP-30 makes, what would otherwise being a kit not containing a hazardous component, into one that did, resulting in higher shipping charges. But we did want to point out the possibility of using BDMA in place of the DMP-30.
However, for the convenience of those customers who prefer the newer approach using BDMA, we also offer a second version of this popular embedding system. Hence, you can select from the "Original" or the "BDMA enhanced" Araldite 502 kits.
The formulation offered by SPI Supplies for Araldite 502 is identical to that originally published by M. A. Hayat and which was optimized for the following:
The key is that if one uses 45° C for 24 hours and 60° C for another 24-36 hours, the formulation should work. For heat sensitive samples, one can use only 45°C, but we can not predict how long should be the curing time. We would estimate 72 hours minimum but it could be longer, perhaps as long as 96 hours.
We are addressing now the cured block, something that to most people is about as inert of a material as one will find. But the standard practice in many laboratories is to use a small jeweler's (or even a small hack) saw to cut the block down to the right size, sometimes even to shape it. We want to address the dust that is generated and how its exposure can and should be minimized.
Polymerization is typically carried out by heating filled capsules to 60°C for at least 16 hours. An alternative procedure is to heat to 35°C for 24 hours, followed by heating to 45°C for a second 24 hours, then to 60°C for 16 hours.
Produces blocks that are slightly harder than those made with the Araldite 502. Kit formula is based on method of Glauert, A.M. & Glauert, R.H..
Typical protocols call for an "overnight" cure of 8-16 hours at 80°C.
Same as above kits except BDMA and DBP are shipped as 9x30 ml bottles instead of two 250 ml bottles.
