Scott Dunsworth Posted December 16, 2014 Report Share Posted December 16, 2014 Has anyone used Raka 425 hardener? Its their cold weather hardener , they say it will cure in the 40's. It mixes at 4 parts to one part hardener. Quote Link to comment Share on other sites More sharing options...
PeterP Posted December 17, 2014 Report Share Posted December 17, 2014 Hey Scott, I tried some of it. I bought the 16oz (?) bottle and I just about used it up. At 4:1 that makes about 1/2 gallon. I remember buying it because of unusually cold weather ( for NC) that year and me wanting to keep the momentum going. It worked well enough but things were a little bit confusing what with me mixing stuff at 4:1, 2:1, 1:1 and 5:1! I was glad when it warmed up enough for me to go back to single mix (2:1). I like using food warmer lamps for smaller jobs and I often wondered if getting an old electric blanket would work. Of course Indiana gets much much colder than NC. Glad to hear you are moving again. PeterP Quote Link to comment Share on other sites More sharing options...
Wile E. Coyote Posted December 17, 2014 Report Share Posted December 17, 2014 As an alternative, I used Cold Cure on my cedar strip canoe in 2002, for the whole thing. Back then it was made by industrial formulators, now System 3 sells it. Cold cure worked fine for me, I still have the canoe and it's in great shape in spite of some rough use. I didn't have to use it in the cold, but it was good to me. If left for a long time the hardener will darken, this doesn't matter if you're painting, but for the canoe I had to make sure I had all the same colour stuff. Quote Link to comment Share on other sites More sharing options...
Scott Dunsworth Posted December 18, 2014 Author Report Share Posted December 18, 2014 Thanks for the info. I have more keel laminations to lay up and would like to get going on them. Quote Link to comment Share on other sites More sharing options...
Howard Posted December 18, 2014 Report Share Posted December 18, 2014 Scott: My take on this is if the temps are too cold to use normal 2:1 Fast cure, you probably don't want to be doing them anyway. Even if you warm the epoxy so it will flow, the wood won't be and will cool off and thicken your epoxy before it gets a chance to get very far into the wood fibers. I'd worry about how strong my eventual joint would be. I'm told that even the medium and slow cures, if used when colder than ideal, are not harmed, and will just sit there in their gelled state until temps do warm enough for them to activate and cure. I was at the shed yesterday with ambient temps in the 30's. It has been colder.......in the teens and 20's at night, so the concrete floor is really cold. It is an icebox in there and slow to warm even when it does warm up outside. Not much happening for me again until March. At least in that shed. Quote Link to comment Share on other sites More sharing options...
Scott Dunsworth Posted December 19, 2014 Author Report Share Posted December 19, 2014 I'm not to worried about the resin saturation, I am using Raka 127 resin which is pretty thin to start with. I also have a feeling that the 425 cold weather hardener is only a bit faster than the 610 fast. Raka says that the 610 will cure if it has 24 hours at 50 degrees, the 625 they claim in the 40's, I don't know if that means 49 or 41 degrees. Quote Link to comment Share on other sites More sharing options...
Hirilonde Posted December 19, 2014 Report Share Posted December 19, 2014 I think there is too much concern about how far into the wood epoxy soaks. As long as it is worked into the grain a little the bond will be sound. And build up is what makes epoxy a great material for waterproofing. That being said it can be too cold to work the epoxy properly. Quote Link to comment Share on other sites More sharing options...
PeterP Posted December 19, 2014 Report Share Posted December 19, 2014 I started using heat gun to make epoxy flow out better when coating- about year - year and half ago. What a difference! My guess it should work equally well for filleting to make sure you get some soak-in. As for Scott's problem - my suggestion would be to build a plastic tent over the keel and run a kero torpedo heater over night. Naturally, you wouldn't want to burn $10 worth of kero to cure $2 worth of epoxy. PeterP Quote Link to comment Share on other sites More sharing options...
Howard Posted December 20, 2014 Report Share Posted December 20, 2014 Wondering about the chemistry of the 425 hardener. Is this simply a faster than fast product, such that if you mixed it at 70 degrees it might go off on you before you could finish mixing it (I found Raka's fast to be pretty fast anyway), or does it give you reasonable working time, plus it will cure at low temps? As i recall when working with Raka's fast cure, if I mixed as much as a half pint or so batch at something like 60 degrees, by the time I got it mixed and the thickener in there, it would already be heating up and would be a real fire drill getting it out of the tub and in place before it went off on me. Quote Link to comment Share on other sites More sharing options...
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