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
