Acrylic vs. Epoxy

[GlassStarz]

Maybe someone at delta can tell me the advantages for one over the other I recently ordered a product from one of thier compettors who pitch the acrylic as being the way to go im no chemist and being a salesman for 20 yrs im an easy touch. What is the dif and what are the plus and minus? price is important to me but not enough that i would give the customer less quality I do have some morals :roll:

[glassdoctor]

I didn't know epoxy was still being used in windshield repair. I thought it was just an old wives tale.

Do they mean acrylic vs. acrylic with acid added. Some resin has acids added to it. They claim this to improve the bonding strength... "etch" the glass. It sounds good. But I was told several years ago by someone in the buisness I trust, that the real reason that acid is added is create resins with a shelf life. Acid-free resins don't have the one year shelf life like "regular" (hint: acid) resins.

This may not be true. Elvis may not be dead either. And, maybe this isn't what you meant anyway. Did you really mean epoxy, like a resin and catalyst additive?

OT: This just made me wonder... has anyone ever actually tried to use CA glue? (aka superglue) I am sure there are many reasons why it isn't used, but now I am curious what those reasons are...

[GlassStarz]

again im not a chemist but I guess what matters most is does it work well? Does it give the customer a quality repair? as it gets slower and colder (sposed to be -20 friday) I start to wonder about lame stuff

[Repair1]

I think I know about the stuff your talking about (yellow label) they claim it is an epoxy base whatever it is it’s junk in my opinion, stay far away from that stuff!!! I thought wow what a deal $20.00 an ounce well let me tell you after 30 days or so almost every repair I did with it opened right back up like nothing was ever put into it. Cost me a bunch in redo’s and god only knows how many customers didn’t call me back. Bottom line is I through away a couple hundred dollars of that CRAP!!!
As usual just my opinion….


Happy Repairing

Brian

[Brent Deines]

Let me start with a disclaimer: I do not claim to be an expert on epoxy based resins, as we have never sold them at Delta Kits. However I have done a bit of research on the subject, and I have spoken to chemists who make epoxy resins for other applications. I have also talked to a number of windshield repair technicians that were quite unhappy with epoxy based resins currently being marketed to the windshield repair industry. These technicians now use acrylic acid based resins.

First you need to understand that no single ingredient is solely responsible for the effectiveness, or lack of effectiveness of any windshield repair resin product. The secret behind all leading resin products is in the specific formulation of the ingredients. Just because a resin has an acrylic acid base, does not mean it will not yellow, shrink, cure, or flow properly. Elasticity is also a very important factor in formulating a high quality windshield repair resin, and many resins fail to achieve the proper mix of elasticity and hardness. It’s not just shore hardness, tensile strength, sheer strength, lap strength, viscosity, low shrinkage, non-yellowing, wetting, cure rate, or clarity that make a great resin; it’s a combination of all these things.

It is also important to understand that not all epoxy based resins are 2-part resins. While in the 80’s several windshield repair companies used 2-part resins, today you are likely to find 2-part resins only in the $10 windshield repair kits that you find in the auto parts stores, and most of these are yellow before you use them. Most modern day manufacturers of epoxy based resins for windshield repair use a one part formula, although even those are few and far between.

Today most windshield repair resin manufacturers choose acrylic acid based resins due to the fact that when properly formulated, they tend to perform better than epoxy based resin products. There are a variety of reasons for the preference of acrylic acid based resins, one of which, according to a reputable chemist, is that the acid actually etches the glass, although not visibly, creating a better bonding surface. On the other hand, acrylic acid can irritate the skin, so the key is to use just enough to maximize the bonding strength, and no more. Rarely does Delta Kits receive complaints about skin irritation from any of our resins; however we do receive many complaints about skin irritation from other products containing very high concentrations of acrylic acid, or other acids that improve bonding strength. Many windshield repair technicians have the same complaint about epoxy based resins. The epoxy based resins that we have tested not only have a very offensive odor, but they also did not meet our high standards for adhesion, consistency, and elasticity.

One of the latest trends is water based resin. We have researched this idea as well, and while we can see the benefit in principle, our chemists assure us that water based resins cannot possibly achieve the same bonding strength as acid based resins. In my humble opinion, one of the most compelling reasons for companies to sell water based resin, or epoxy based resin, is cost. High quality resins are very expensive to manufacture, and are therefore not the cheapest resin to buy. On the other hand, one failed repair is worth more than one bottle of resin, so saving a few cents per repair is not worth sacrificing even a little quality. Whatever resin you choose, you should do so based on the quality, not on price only.

[desertstars]

Well-stated, Brent.

Lots of food for thought there.