SPI-Pon™ 812 Epoxy Embedding Kit

The most widely used type of embedding resin kit in the world!

Explanation of hazardous labels

SPI-Pon 812 is a direct substitute for the epoxy resin formulation "EPON^® 812" which at the time of its discontinuation by its manufacturer, Shell Chemical, was the most widely used embedding resin in electron microscopy in the world. With its slightly lower viscosity the SPI-Pon "replacement" kit allows for at least some samples noticeably easier infiltration. The SPI-Pon "Epon replacement" kit can be used as a direct substitute for the original "Epon 812". Users report no differences (except as already noted) in sectioning, staining, or stability in the electron beam. Everything is exactly the same except for the substitution of SPI-Pon 812 for Epon 812.

SPI-Pon 812 can also be the preferred "Epon substitute" resin for samples that have solubilities for the resin monomers (that is, the samples could be dissolved by the monomer or combination of monomers). Special methods have been published for applications with these kinds of samples. Interesting enough, the resin has great versatility, one can find it just as likely to be the resin of choice for embedding biological tissue material as they are, the resin of choice for embedding solid catalyst or other plastic samples. No other resin is known to us that can be used over such a broad range of samples representing such a wide range of hardness. Most users of the SPI-Pon resin kit cure their samples at 60°C. Faster cures are possible at slightly higher temperatures, up to 70°C.

SPI-Pon 812 resin, in the cured state is, relatively speaking, quite inert with respect to exposure to osmium tetroxide and is often times the preferred resin for those staining with osmium tetroxide, both for life science as well as materials science applications.

Note that the DMP-30 in the formulation has a relatively short shelf life, but, there are precautions one can take to lengthen it, thereby mitigating in some respects that one particular and known disadvantage. Also, the user should appreciate that this resin does not work well in the presence of even a slight amount of moisture. So in addition to the obvious (resin does not cure right), any moisture present results in gas bubbles being formed during the polymerization which results in a really terrible embedment.

Note about bubbles in the final cured block:
One of the more common "problems" is the appearance of bubbles in the final cured block. This is usually the result of retained moisture in the sample. Depending on the sample itself, there are obviously different ways one could use to remove residual moisture. But bubbles are usually the result of moisture in the sample. Another source of bubbles of course is mixing that was too vigorous. But no matter the source, pumping on the mixed ingredients for a short time with a mechanical pump vacuum will cause the bubbles to rise and exist the system. The precise amount of time this takes will be determined by how fast the system polymerizes.

Hardness vs. viscosity:
Another one of the trade offs faced regularly by microscopists is that of resin viscosity vs. hardness of the final block. By way of the addition of excess hardener, one can make a block out of SPI-Pon 812 that is as hard as any resin and certainly harder than a lot of resins. Polymerizing under such conditions does result in a higher viscosity of the resin and therefore potentially less effective infiltration. But we always recommend this as the place to start since the alternatives are both more expensive and more complicated to use. For a lower viscosity embedment, we recommend trying SPI-Chem Low Acid GMA, TEM formulation. The GMA monomer has a viscosity slightly less than that of water.

Particle "pull-out":
When embedding hard spherical particles, sometimes the particles themselves are being pulled out by the action of the knife, so that the sections exhibit just the "ghosts" or holes where the particles once were. In order to reduce the tendency for this to happened, we recommend the use of SPI-Chem™ (3-glycidoxypropyl) trimethoxysilane.

BDMA Modified Kit:
Some researchers prefer the formulation with BDMA substituted for DMP-30 because of a lower viscosity, permitting better infiltration of difficult to infiltrate samples.

There are two potential drawbacks to the ordering of the BDMA formulation:

In terms of shipping costs, BDMA is a "dangerous goods" material where as DMP-30 is not. Therefore, under some circumstances, the shipment of BDMA could be a lot more costly than shipment of DMP-30.

When making up the working mixtures, there have been reports that the BDMA mixtures got much more viscous more quickly than DMP-30 mixtures, everything else being equal.

An understated potential safety risk:
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.

Original SPI-Pon 812 Formulation with DMP-30:

Kit Contains (1500 gms):
SPI-Pon 812	450 ml
DDSA	450 ml
NMA	450 ml
DMP-30	2 x 30 ml

		SPI #	Each	10+, Each		In Stock
		02660-AB	$ 53.84	$ 48.46		Yes

Storage conditions: Room temperature
Hazardous from the stand point of shipping

BDMA Modified SPI-Pon 812 Formulation

Lower viscosity

Kit Contains (1375 gms):
SPI-Pon 812	450 ml
DDSA	450 ml
NMA	450 ml
BDMA	30 ml

			SPI #	Each	10+, Each		In Stock
			02663-AB	$ 59.30	$ 53.37		Yes

Storage conditions: Room temperature
Not hazardous from standpoint of shipping

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