System Three Frequently Asked Questions - Part 1
Questions and Answers
I made a large batch and found a few areas that are still sticky after most of the surface is cured hard. What happened?
The material was probably not thoroughly mixed and unmixed material was scraped from the container onto the surface. When mixing always be sure to mix from the bottom to the top and scrape the sides of the container and the stick. Experienced users dump and scrape the mixed material from the first container into a second and then mix again. This totally avoids the problem described above.
Can I fix it?
Yes. First, scrape off what you can. Then pour or wipe a suitable solvent on the surface. Wear a respirator or provide proper ventilation when working with solvents. Wipe or scrub the resin surface. This will remove residual uncured resin but won't harm any cured resin. Sand the underlying cured resin and apply a fresh coat properly measured and thoroughly mixed. Note: Over bare wood the fresh coat of resin will need to be worked into the wood with a stiff-bristle brush to mix any residual uncured material into the fresh material. This will ensure that the fresh coat will adhere properly to the wood.
I have material that hasn't cured after four days in a warm room. Can I apply fresh resin over the top and have the whole thing cure hard?
No. If the older material has stopped curing, applying more epoxy won't start it up again. The uncured resin must be removed and new material applied to that surface.
Can I use the hardener from one of your epoxy systems with the resin from another?
No. Epoxy resin systems are two-part products where each part is designed to go with the other.
Can I apply mixed epoxy to a piece of wood and then bend it without cracking the epoxy?
Yes, while the cured epoxy may be stiffer than an equal thickness of wood, the epoxy coating is much thinner and can be bent further than the wood it coats without cracking.
I laminated some bent wood strips with epoxy adhesive and clamped them overnight. When I found them the next day the adhesive had cured hard but several strips had sprung open. How can I keep them together?
Leave the clamps on a full 24 hours. The epoxy had not adequately cured when the clamps were removed. The force caused by the bent wood trying to straighten was sufficient to cause the uncured epoxy to fail. It opened up some time after you removed the clamps, but the epoxy continued to cure between the time the clamps were removed and when you saw the lamination's the next day.
To avoid the above problem I left the clamps on for three days but the epoxy adhesive still failed at the interface between the strips. The surface appeared grainy or sugary. Why?
Likely you used too much clamping pressure. The clamps squeezed most of the epoxy out of the joints and the wood absorbed what was left leaving a starved joint. A grainy feel at the interface is symptomatic of a starved epoxy glue joint.
How much clamping pressure do I use for an epoxy glue joint?
Epoxy adhesives, being gap-filling glues, need only enough clamping to close the joint. Unlike other glues epoxy does not require high pressure to make a proper glue joint.
Will epoxy resin adhesives bond all materials together?
Epoxy resin adhesives will bond all woods, aluminum and glass well. It does not bond to Teflon, polyethylene, polypropylene, nylon, or Mylar. It bonds poorly to polyvinyl chloride, acrylic and polycarbonate plastics. The only way to tell if an epoxy will bond to a material is to try it. Generally, epoxy adhesives are the best choice for bonding dissimilar materials together. If epoxy bonds to Material A and to Material B it will bond the two materials to each other. The best thing to do is to try it and see for yourself.
What materials can I put over your epoxy products? What materials will your epoxy go over?
Since epoxy resin system vary in compatibility with materials, there is no single list. In general, if a material is not listed in the product directions or application instructions, the best thing to do is to try it and see for yourself.
Can I use your epoxy products to build or repair a gas tank?
System Three epoxies, when properly cured, are resistant to diesel fuel and aviation fuel, but not gasoline. There are gasoline-resistant epoxy products available, but System Three does not make one.
Paint Products FAQS
What is the coverage of WR-LPU Topcoat?
We recommend a spreading rate approximately 400 square feet per gallon. This will give a coating of 2.5 mils(0.0025") dry film thickness.
What is the coverage of WR-155 Primer?
We recommend a spreading rate of approximately 250 square feet per gallon. This will allow for some coating removal from sanding, and still leaving a 2.5 mil dry film thickness.
How long after I finish my wood/epoxy boat can I apply System Three Spar Varnish?
You should wait a minimum of two weeks for the resin to cure, then sand it, wash it to remove the dust, and apply the varnish.
More System Three FAQ - Part II
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