About repair resin bonding strength test

[BrightFastWSR]

I’d like to know which repair resin has the best bonding strength. Here below is a way I test the resin bonding strength, please let me know if you think this way is resonable.

The data of the resin I test are as below:
Film Tensile Strength:2.830 psi.
Adhesion Tensile on Glass of >1,800 psi.

And 1psi=0.07037kg/cm^2, so I change the unit as below:

Film Tensile Strength:199kg/ cm^2.
Adhesion Tensile on Glass of >126kg/ cm^2.



Step1: I tear off one piece of outer layer glass of a windshield: thickness 0.2cm, length 5 cm.

Step2: I use a glass cutter to cut it into 2 piece, the Cross-sectional area is 0.2cm*5cm= 1 cm^2

Step3: I put together 2 pieces again and inject the test resin into the crack. After the crack is full of test resin, then I cure it under the 365nm UV light for over 10 minutes.

Step4: the test resin is fully cured and the split glass are bonded together again.

Step5: Now according the resin data, the repaired area should has the capacity to afford shearing force over 100kg. I clamp one edge of the glass and slowly put down a 15kg stuff on the other edge, However, the glass can not afford it at all and cracked from the repaired area again.

How do you think this way to test resin bonding quality? If you think this way resonable, would you please let me know the testing results of the resin you use? The resin quality is so important for the business. Thank you very much.

[GlassStarz]

I could think of about a million other things to do with my time. The mfg does testing under lab controled conditions and the results are avail to everyone. If you need more work spend some of that time looking for more customers if you have all you can handle try spending that time with your Family or at the Gym me Im heading out the door to Surf a couple hours not cutting and bonding pieces of glass to do some sort of non lab controlled test game Just my 2 cents

[usmc68]

I agree, you are trying to reinvent the wheel.Simply buy Delta's Magnibond and pit filler, and only have to buy 2 resins.

[sunshine wr]

I think this is a waste of time .

[Nomad]

First off I applaud Brightfast for trying to check on the figures that come out on most of the well known resins from well respected companies. Consumer reports does this kind of thing with all sorts of products and I don't think anyone is putting them down for doing it except the companies that make poor products. If the guy wants to spend his free time doing this instead of watching the lobotomy tube, then more power to him.

Getting to the question, I think all pieces of glass need to be EXACTLY the same size, cured for EXACTLY the same time and held in position for testing in EXACTLY the same place. The load put on the piece must also be applied in the same place in each piece of glass. I think you could use regular window glass or plate glass as I don't think there is much difference in formulation. Maybe there is but this might not affect the holding power of the resin either. All variables have to be eliminated except for the holding power of the resin itself.

Each test should be repeated a number of times to make sure you have accurate data.

I would put it in the sun for a day or two to make sure it is thoroughly cured.

Remember that there are a lot of things that are important about resins, including elasticity and viscosity and maybe toxicity to the user. Also does it weather well and not yellow, does it maintain its strength over a long period of time?

For example, a thicker resin might be stronger but can you get it into the chip?

Good luck, if you are going to evaluate a lot of resins it will be a lot of work. Post your results when you have them.

[screenman]

Can I suggest that you buy resin that has been BS AU 1991 242 tested, this involves something like 70 different tests before it is passed. All this testing is carried out by experts in laboratory conditions, using calibrated equipment. I think only about 5 or 6 resins have passed this so far, there could be more I do not know about. Magnibond being one that has passed.

The strength and quality certainly has a standards to measure up to when doing repairs, however the technician can make a huge difference as well, I have seen many a poor job carried out by people using quality equipment and resins.

Are you having troubles with repairs that leads you to test resins, if you are using a certain resin that has been BS AU 1991 242 tested and having problems I would say you are doing something wrong.

PS. I cannot see the curing film, you do realise that repair resins are anaerobic and ultra violet curing I hope.

[BrightFastWSR]

Are you having troubles with repairs that leads you to test resins, if you are using a certain resin that has been BS AU 1991 242 tested and having problems I would say you are doing something wrong.

PS. I cannot see the curing film, you do realise that repair resins are anaerobic and ultra violet curing I hope.

If you look at Step4 picture carefully, you can see curing film on both sides of the glass. To make sure the resin is fully cured, I have cured one side of the glass for 10 minutes under the UV light first, then turn the glass upside down and cured it for anther 10 minutes, so the total curing time is 20 minutes.

Till now I don't have complaints for the cracks I repaired for my customers and I have repaired approx. 10 windshield long cracks already in last 3 months. Since I gurantee lifetime for my repair, I concern the resin bonding strength very much. I had thought the resin would bite off some glass from the opposite side when it cracked again, but the result was not.

Can anyone make a test in this way using Magnibond or other quality resins you believe to see if there's any difference with my result? Thank you.

[screenman]

You can actually buy copies of the tests carried out, however I am sure Delta may be able to let you have the information you require. I may be wrong but I think the cost of having a resin properly tested is about £1500.