I use the digital scales only because I had them before building. It's easy enough to get the exact amount of epoxy and hardener into the cup. I pour epoxy and hardener into separate cups and pour it from there into the cup on the scales. With the scales being accurate down to .01 of a gram, it means that when I am down to scooping the last 1/2 gram in, I just add by slowly dribbling off the end of the popsicle stick. Like I said, I had the digital scales and wanted to use them and from what I hear, the ratios don't need absolutely exact anyway but I am having fun with it.
I'll buy some syringes to do the measuring vs weighing test and post the results. I'm intrigued too. On 5/11/07, Brian Kraut <brian.kr...@engalt.com> wrote: > > Like you describe using the tare weight function of the scale is the way I > do it and I think the most accurate. One thing I do is to clean out old > T-88 bottles (with acetone) and then use them for the laminating > epoxy. It > is a lot easier and less messy than using the syringes which I have also > tried. Be sure to mark them so you don't mix them up with your T-88. I > was > using cheap ketchup and mustard containers at one time, but the lids would > pop off when I was squeezing hard on the thicker epoxies. > > >From what I have read the T-88 is not near as critical on getting the > ratio > just perfect like some other epoxies, but it is cheap and easy enough to > weigh it, especially since you really should be using a scale for your > laminating epoxies anyway. > > Brian Kraut > Engineering Alternatives, Inc. > www.engalt.com > > -----Original Message----- > From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net]On > Behalf Of Harold Woods > Sent: Thursday, May 10, 2007 11:51 AM > To: kr...@mylist.net > Subject: KR> measuring epoxy ratios, > > > Hi Netters. > I do not care whose brand of epoxy you are using but follow their > recommendations for mixing ratios. Either you are going to measure by > volume > or by weight. Personally , I look at the glue job to be done. I want > enough > , never too little but now away too much either. I use plastic syringes > for > this work and measure by volume. > I never measure the epoxy resin in one container and the hardener in > another.That is asking for trouble. You cannot get all of the one into the > other without leaving some on the side walls etc of one of the containers. > If the glue job looks like a 25 ml/cc of resin then it is put into a fresh > container. If the manufacturer wants a 1 to 1 by volume then I know that I > will use 25 ml/cc of hardener . Measure it and add it on top of the resin > then mix. I use a different sized syringe for resin and for hardener. > This > warns me not to mix them up. I have cut off and opened up the ends of the > syringes for easy fluid flow when filling the syringes. When not in use > each > syringe hangs over its own can to catch any drips. > A different mixing ratio of say, 3 to 1 is mathematically easy to do. 30 > ml/cc resin to > 10 ml/cc hardener. > The density of the epoxy and of the hardener is not the same. Thus if you > are going to mix by weight the required ratios might as someone mentioned > be > 100 weights of resin to 83 weights of hardener. Out with the multi beam > balance or nicer yet a digital balance (= or - 0.1gram). You pour enough > resin into container on the left pan with an identical container on the > right pan. Weigh it. It turned out to be 42.8 g. > Out with the calculator and we have 83 x 42.8 divided by 100 =35.5 grams > hardener. > If you have a tare weight adjustment you can zero the scale and add > hardener > to the 35.5 gram weight but what if you over run the 35.5 mark? By the > time > you stopped pouring to weighed 37.1 grams? That is 1.6 grams too much > hardener. So you should add 100 x 1.6 divided by 83 = 1.9 grams more > resin. > Be careful or you will overcontrol and start the yoyo effect again. There > is > nothing wrong with mixing by weight. If you are using the very thick , 3M > product "Scotch Weld", you must do it by weight and the ratio is weird. > You can purchase different sized syringes at a Drug store, a Farm or > Veterinary supply store, hobby shop etc. Cut the ends or drill the end out > to a suitable size. > If you are careful the syringes will last a long time. > Sorry if this got too long. > Regards, > Harold Woods. > Orillia, ON. Canada. > haroldwo...@rogers.com > > > > > > > > > > > > _______________________________________ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > Post photos, introductions, and For Sale items to > http://www.kr2forum.com/phpBB2/index.php > please see other KRnet info at http://www.krnet.org/info.html > > > > > _______________________________________ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > Post photos, introductions, and For Sale items to > http://www.kr2forum.com/phpBB2/index.php > please see other KRnet info at http://www.krnet.org/info.html > -- Darren Crompton AUSTRALIA www.kr-2s.com
