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Hi Folks
Awhile back I said I was going to do some research to compare the properties of Jeffco, WEST and Hysol. Here it is, sorry but it was delayed but I was delayed and frustrated by the lack of consistency in the way these were tested and the lack of data in some cases.
First off, these are from the manufacturers published data sheet or from talking to their tech guys so if you really need specific properties, check with the manufacturer. Also, some of these numbers have to be surmised such as Tg by looking at the softening and "working temps" so I have stated these as estimates. Note too that peels are given without stating the type of peel test performed of which there are three common ones, "T" peel, rolling drum and Bell peel. The Bell and rolling drum normally give fairly similar results but "T" peel is more severe possibly and in SOME tests, is lower that the other two but is GENERALLY fairly comparable. So take these as general information only, not gospel.
Note in particular that the laminating epoxies in this group (WEST and Jeffco) do not have peel or lap shear strength. Expect these to be significantly lower that the bonding adhesives like probably around 750-1000 psi but don't hold it against them, they are designed for one type of application so it would be like blaming a Basset hound for not winning a race against a Gray hound. That's not what they were designed to do. But you might gather too, that using Jeffco in place of Hysol if you need high strength bonds is asking for trouble. And look at the Tg (Glass transition Temperature) which is the temperature were the molecules start to move. This is normally about 10 degrees F above the HDT or "Heat Distortion Temperature." HDT is related to Tg but is lower because a load is placed on the specimen during the heating phase.
There are also many other properties I could have added to compare but they tend to get even more weird with less and less comparable data from the manufacturers. In particular elevated temperature properties are often critical to real world performance so look at the Tg of your resins carefully and see if all things being equal, it will outperform other matrix or bonding resins on a hot day. One glaring comparison between the bonding adhesives and the laminating (one of the few fields that actually are shown on most resins) is the bulk properties in tensile. This means the un-reinforced resin cast properties. Note that the bonding adhesives are all inferior to the laminating adhesives in bulk tensile. This is typical.
I'll digress just a bit but I wanted to state that an important thing to note is that the thickness of the bond line drastically affects shear strength. A bond line .1 mm thick is typically about 20% stronger than one 1.0 mm thick. Even a quarter mm bondline (.25mm) losses 4% in strength when compared to the .1 mm bond. These of course will vary but it gives you an idea of what the variables can change. Any area stated as "NG" means "Not Given", however, I hope to have some more data for Applied Poleramic in the next week or so.
I have posted this as an attached MS Excel file and as a copy to the web which is kind of ugly but better than nothing if you don't have Excel.
| Comparison of physical properties of epoxies |
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| Adhesive |
Ten. Shear |
Peel |
Elongation |
Tg |
Pot life |
Bulk tensile |
Hardness |
| Hysol 9380 |
5350 psi |
50 lb/in |
NG |
210 deg F |
NG |
NG |
77 |
| Hysol 9339 |
4500 psi |
20 lb/in |
2.60% |
133 deg F |
120 min/450 gr. |
5000 |
75 |
| Hysol 9360 |
5000 psi |
50 lb/in |
NG |
225 F appr. |
50 min/200 gr |
NG |
NG |
| Hysol 9361 |
3500 psi |
25 lb/in |
40% |
140 F appr |
120 min/450 gr. |
NG |
70 |
| Hysol 9330 |
5500 psi |
46 lb/in |
2.4% |
135 deg F |
60 min/100 gr. |
5600 |
NG |
| Jeffco 1307/3102 |
NG |
NG |
4.50% |
122 deg F |
15 min/150 gr. |
9000 |
84 |
| WEST 105/205 |
NG |
NG |
3.40% |
129 deg F |
12 min/100 gr. |
7850 |
83 |
| AP DR-5/102 |
NG |
NG |
NG |
190 deg F |
15 min/150 gr. |
NG |
NG |
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| Results of testing at 77 degrees F |
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So a brief explanation of the test:
TENSILE SHEAR: A lap bond joint is prepared, cured and pulled apart to ultimate failure, results are given in psi. The typical adherend is 2023-T3 aluminum with a Chromic Acid Anodize etch (CAA).
PEEL: As stated earlier, it is probably "T" peel but there were a couple of rolling drum or Bell peels so these are only roughly comparable. The data are given in pounds per linear inch since all of the stress is placed only along the bond, not the whole coupon.
ELONGATION: Is the percent the base resin elongated before failure.
Tg: Glass transition temperature in degrees F.
POT LIFE: Is a relatively loose term since the size of the pot and amount of resin drastically alters the working time. Figure the ones that show short times with small masses are going to get very hot and need to be mixed in small batches or be spread quickly where they can release heat from the exotherm. Working life when spread thin will be much longer than in a pot.
BULK TENSILE: Means the properties of the adhesive without any resin, sometimes called "neat resin properties".
HARDNESS: is given with the results of a Shore hardness tester.
While you can't always compare these one against the other, what I hope this illustrates are the vast differences that are possible with the very diverse term of "epoxy." I will try and update it again in a bit.
Happy grinding!
Dan Newland
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