I think the accepted thinner for generic epoxy is acetone.
You may "think" that, but I "know" that lacquer thinner works with acra-glas....courtesy of Lynton McKenzie.
I don't thin epoxy, never have. I find that warm acra-glas (not the gel) is plenty thin enough if I want runny epoxy. I don't use it for cracked/broken wood in
most cases anyway since its not any stronger than a good wood glue, if as strong, and is messier to clean up and has a longer set time.
I "think" Acetone is an epoxy thinner because its so labeled. But I have no experience with thinning. I don't know what Brownell's thinner is either.
Its possible to use lacquer thinner (and it may be preferred see the quote below) or even denatured alcohol but apparently Acetone leaves the epoxy slightly stronger than lacquer thinner and significantly stronger than denatured alcohol. But thinning is not recommended if the glue is used as a structural adhesive. Acetone can also cause color changes in the epoxy over time.
The red type below was added by me.
Those wanting to get glue deep into cracks may find that a hypodermic needle will work for this.
Dan
From
http://www.seqair.com/skunkworks/Glues/WestSystem/Thinning/Thinning.html"Thinning epoxy with solvent
Adding solvent is a quick, simple method of thinning epoxy, but unlike using heat to thin it, the strength and moisture resistance of the cured epoxy are drastically affected. Below are some of the effects adding solvent has on West System epoxy. While there are a large number of chemicals available to thin epoxy, we selected acetone, lacquer thinner and denatured alcohol for this discussion because they are commonly available and do a good job of reducing viscosity. Additionally, these solvents evaporate quickly and are less likely to be trapped in the cured epoxy-an important characteristic. For a variety of reasons, fast evaporating lacquer thinner appears to be more appropriate for thinning purposes than acetone or alcohol.
· Adding a small amount of one of these solvents has a significant effect on the viscosity of the epoxy. For example, adding 5% lacquer thinner makes about a 60% reduction in viscosity (Figure 3).
· Adding 5% lacquer thinner to epoxy reduces the epoxy's compressive strength by 35%-a big hit in the mechanical properties of West System epoxy (Figure 4). The addition of more than 5% solvent results in an excessively flexible cured-material.
Thinning epoxy with solvent causes enough loss of strength that we (and most other reputable epoxy formulators) cannot recommend using it as a structural adhesive. · Adding a volatile solvent extends the pot life and cure time of epoxy and jeopardizes the reliability and predictability of cure. Additionally, with slow rate of cure, it takes longer before work can be sanded.
· Adding volatile solvent may cause shrinkage of the cured epoxy. Applying thinned epoxy in large, confined areas (like consolidating a large pocket of rotted wood) is likely to trap some of the solvent. In thick applications, the epoxy cures very quickly and not all of the solvent has time to evaporate before the epoxy hardens. Over time, the solvent works its way out and as this happens, the cured epoxy shrinks and in many instances cracks.
Shrinkage also causes print-through. You may have a surface sanded smooth only to have the resin shrink. This shrinkage often reveals the texture of the substrate. Shrinkage can continue to be a problem until all the trapped solvent works its way out of the cured epoxy.
· Adding solvents, especially acetone, alters the color of the cured epoxy. While the effects are not immediate, adding acetone to epoxy causes the color to change from slightly amber to very dark amber.
· Adding solvent results in a temporary reduction in viscosity. Volatile solvents evaporate quickly as they are agitated during brushing or rolling, causing the viscosity to continually change as time passes.
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· Adding volatile solvent to West System epoxy has some adverse health and safety effects. West System epoxy components are nonflammable but the chance of fire or explosion goes up in proportion to the amount of solvent you add. Also, the vapors of many volatile solvents are hazardous to your health and proper ventilation is mandatory to prevent inhaling harmful quantities of them.
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Does thinning epoxy make sense? In some situations, thinning is appropriate. In others, it is not.
We feel that in most circumstances using heat to thin epoxy is preferred to using solvents. As long as the epoxy does not overheat during cure, the full physical characteristics of the cured epoxy remain.
Adding solvent is a quick, simple method of thinning epoxy, but the strength and moisture resistance of the cured epoxy are signiflcantly reduced."
