dust Posted January 30, 2004 Share Posted January 30, 2004 My way is the only way and it is best I just gave terribly slanted advice on the use of a pump and i gave it over the phone so no one could correct me! I use an epoxy ratio pump and i love it, but, many use and love thier scales, weighing each batch, effeciently and quickly. Soooooo could someone here give thier advice and experience on using a scale for measurment. Thought there was a thread, but, i couldn't find it enjoy the build Dust Quote maker wood dust and shavings - foam and fiberglass dust and one day a cozy will pop out, enjoying the build i can be reached at http://www.canardcommunity.com/ Link to comment Share on other sites More sharing options...
CBarber Posted January 30, 2004 Share Posted January 30, 2004 I use the pump and love it. Howeverk, the SportAir workshops now sponsored by EAA teaches the scale method. They use digital postage scales that cost about $100.00 or so. I found one by Weight Wathers for about $30.00. One of the things the workshop suggested is keeping a ratio chart handy so you can messure out the amount you need. If it is 100 grams to 44 grams the math is pretty easy <g>, however, if you only need 73 grams, it is nice to have a ready chart to glance at. To use the scale, you literally weigh the cup on the scale (or zero out the scale with the cup on it) then add the the resin to the correct reading, then add the hardener in the correct amount. Mix for at least two minutes (something I still do even with the pump). If memory serves, the workshop taught you to use two cups, one for each mixture and then add the two to a single cup. However, after we became comfortable with the process, we got pretty god, oh, I mean good (sorry dust <g>) at adding the second to the first without using two cups (may not be as pure, but it worked). I still use the wheel chock I made. It was not all that bad using the scale while at the workshop, but, IMHO, the pump is sweeeeeeet. FWIW. All the best, Chris Quote Christopher Barber Velocity SE/FG w/yoke. Zoom, zoom, zoom. www.LoneStarVelocity.com Live with Passion... Link to comment Share on other sites More sharing options...
ekisbey Posted January 30, 2004 Share Posted January 30, 2004 For the few layups I've done so far, I used the scale, and found it straightforward and intuitive once I had it working right. I haven't done any of the really big layups so I'm not certain whether this will hold true or not down the road. I've also not yet purchased a pump, though I fully intend to do so. It'll be interesting to see which I prefer, since at this point I'm perfectly content to continue to use the scales. Quote Evan Kisbey Cozy Mk IV plans # 1114 "There may not be any stupid questions, but I've seen LOTS of curious idiots..." Link to comment Share on other sites More sharing options...
macleodm3 Posted January 30, 2004 Share Posted January 30, 2004 The West System Epoxy kits have "Mini Pumps" available for use with their system. I will follow most builders' advice and go with the MGS, but I was wondering if any pumps similar to the West system have been used among us for MGS or ohter epoxies. The west system pump kit is $9.25 in AS&S... vs $250 for the "good" pump. I have no experience with this "building" thing YET, so no advice is available from me on the scale method. Quote Andrew Anunson I work underground and I play in the sky... no problem Link to comment Share on other sites More sharing options...
dust Posted January 30, 2004 Author Share Posted January 30, 2004 I have the west system pumps and they wear out, for me they last a gallon or two. On another point, if you want to vary the fast to slow hardener, for diferent pot life and cure times, it may be allot easier to use the scale method. enjoy the build Quote maker wood dust and shavings - foam and fiberglass dust and one day a cozy will pop out, enjoying the build i can be reached at http://www.canardcommunity.com/ Link to comment Share on other sites More sharing options...
John Slade Posted January 30, 2004 Share Posted January 30, 2004 I have no experience of using scales. The whole idea of the pump appealed to me and I used it for the entire build. I think it comes down to convienience and speed of operation. How long (in seconds) does it take from deciding you need more epoxy during a layup to continuing the wetout with a new batch? Using the pump and mgs I'd guess at 30 seconds. What???? you say - what about the 2 minute mix time? The 30 seconds includes mixing. Burts original 2 minute mix was for the old smelly thick stuff. Mgs hardener is slightly colored and you can SEE when it's mixed. Also, when the stuff is hot it's like water and mixes very very easily. Call me a heretic if you like, but a good 20 second mix on the way back from the hot box, scrapping the sides and mixing it well, has never failed me. Scratch tests have always been good, everything has cured just fine. I hate to imagine weighing little bits of epoxy on scales, then pouring them into a cup (leaving different amounts in the original cups because of different viscosity.) I often use 1 pump of the handle. Most commonly 2 pumps. Occasionally 1/2 a pump. Scales might be ok when mixing a good amount of epoxy, but with the new low viscosity stuff you dont tend to do it that way. You mix 2 squirts, wet it out, then go back for another 2 squirts. This way the epxy is always hot out of the box and wetting out is more like painting than squeeging. As for mixing fast and slow - I would tend to keep the hardener level fairly low and just dump a bit more fast in if it was a cool evening, or slow if it was a big job or a warn day. You loearn to judge where the ration is and how much to add to get what you want. You only really need all slow for maybe 4 or 5 big layups. Most of the time it doesnt matter much what ratio you're using. I vote PUMP Quote I can be reached on the "other" forum http://canardaviationforum.dmt.net Link to comment Share on other sites More sharing options...
George Sychrovsky Posted January 30, 2004 Share Posted January 30, 2004 When I worked on the Lancair project we had a pump, It was quick on small batches but it took a lot of pumping on big ones. And the amount was always a guess. In my shop where I fabricate parts I use a 5lb scale from office Depot (staples) for about 65 bucks and I have no intention to buy a pump, its faster for bigger batches I mostly use and amount is known automatically. You also need a cheap calculator which I set conveniently next to the scale, The measuring process is very simple. Set it on grams, Weigh the precut cloth first (example 300 g) and you will need the same in the weight of the resin. I use Aeropoxy which mixes 100:27 so its 300:1.27= 236 Zero the scale with the cup on it, Put in 236 grams of resin then fill the rest with the hardener to get 300 grams total and you are done. Oh yeah ,and not to forget the best trick to handle the epoxy, transfer it into those laundry detergent plastic bottles with the no drip spouts, works like a charm and you don’t have the epoxy dripping and running down the side. George Quote Link to comment Share on other sites More sharing options...
John DiStefano Posted January 30, 2004 Share Posted January 30, 2004 I use a gram scale (O haus is the mfg...$60 online)WITH West epoxy pumps. I have never used the pump which is probably marginally faster. But here is why I decided scale over pump: 1 - The thought of cleaning it is a BIG turn off. Even if it is only once in a while. 2 - IIRC, you need to check it every so often to make sure it is calibrated correctly, so you need a scale anyway.. I was afraid that after doing a large or very important lay-up I would find out that the pump is off calibration. It seems as though you should probably use a scale if you use a pump. 3 - I am using the MGS 285 with fast and slow hardener and I seldom use JUST fast OR slow...usually some combo of them both.. How do you use a pump when you are using 2 different hardeners? I am sure some one who uses the pump could answer this though. The West system pumps seem to work fine. For the resin, Every full shot is 22grams. For the hardener, I use a smaller pump, 9 grams per full shot. They do however require ocasional maintenance (once so far). Quote Link to comment Share on other sites More sharing options...
Cozy1200 Posted January 30, 2004 Share Posted January 30, 2004 How do you use a pump when you are using 2 different hardeners? That is a good question. What do you do when you want to change ratio of fast and slow harders? Quote Drew Chaplin (aka the Foam Whisperer) --- www.Cozy1200.com - I'm a builder now! --- Brace for impact... Link to comment Share on other sites More sharing options...
John DiStefano Posted January 30, 2004 Share Posted January 30, 2004 I though I would also post how I measure the epoxy. It is not really different from how C Barber mentioned earlier but here goes. 1- take a paper cup could be new, or one with cured epoxy or alittle left over from a previous batch. 2 - put cup on scale, and "Zero it out"... Tare function IIRC 3 - Pump the desired amount resin in the cup. Usually 2-4 shots from the west pump and weigh it. Lets say its 65 grams. 4 - "Zero it out" again, which is just pressing a button. look up on my handy mixing ratio spreadsheet that hangs on the outside of my hot box. Find 65 grams in the resin column, look over at the hardener column and it says X grams of hardener. 5 - in a small plastic cup I put in a few pumps of fast/slow/both hardeners depending on my cure time I want.. This I do not weigh, but swirl it around a bit 6 - pour the hardener mixture into the resin cup which is still on the scale, and stop when the scale reads X. Elapsed time, for steps 1 - 6, 30 seconds guaranteed accurate mix with no clean up ever. The excel spreadsheet is not hard to do and I would say it is essential if using a scale. If anyone is interested, fire me an EMail or just post here and I'll send it. Quote Link to comment Share on other sites More sharing options...
John DiStefano Posted January 30, 2004 Share Posted January 30, 2004 Sorry George, did not see your post.. What he said!! Quote Link to comment Share on other sites More sharing options...
Jim Sower Posted January 30, 2004 Share Posted January 30, 2004 Originally posted by CBarber ... However, the SportAir workshops now sponsored by EAA teaches the scale method ... the workshop taught you to use two cups, one for each mixture and then add the two to a single cup ... IIRC Burt started the two-cup method so as to enable us to build a (balance) scale out of a stick, a couple of small boards and a nail. That made the airplane $80 cheaper to build. Balance scales require two cups and thence the bit about wetting the cups with what you recon will not pour out when you're done. A real PITA, not to mention the errors it can introduce. No reason at all for more than one cup if you're not using a balance scale. More better use a postage scale with a "metering table" and a West pump (or, like I have, a mustard/ketsup pump from local food service store for a couple of bucks). Pouring from the can/bottle sucks in my experience - I invariably over- or under-pour. I use postage scale and mustard pumps and a single cup for the 10-year old EZ-Poxy on my workbench, but when it gets to the actual airplane I'll be switching to MGS 285 and a calibrated pump. Quote ...Destiny's Plaything... Link to comment Share on other sites More sharing options...
John Slade Posted January 30, 2004 Share Posted January 30, 2004 How do you use a pump when you are using 2 different hardeners? Easy. You keep the hardener level fairly low, then dump a bit more of one in when you want to change the ratio. Sounds haphazard, but it works fine. You get the nang of it quickly. As for calibration - the pump is not capable of being out of calibration. Calibration is fixed and cannot be changed. It's always right. The only way it can be out is if air is pumped in one side - this is obvious when it happens. Pump v scale is one of the issues which will never be settled. I'd suggest trying both methods and decide for yourself which to use. Quote I can be reached on the "other" forum http://canardaviationforum.dmt.net Link to comment Share on other sites More sharing options...
marbleturtle Posted February 9, 2004 Share Posted February 9, 2004 Whoops... sorry about performing CPR on a dead post! There is alot of flack on one of the mail groups about pumps springing leaks at inoportune moments and soaking cloths, water heaters, garages, neighbor's kitty with large amounts of sticky stuff enraging spouse, family, fire departments, CDC, and neighbors. This has come up just as I am getting ready to place my first order. I for one don't want to pony up the 200 big ones if a scale and old tupperware bowls are more reliable. Anyone have a problem with leaks? Quote This ain't rocket surgery! Link to comment Share on other sites More sharing options...
Joe Patterson Posted February 9, 2004 Share Posted February 9, 2004 Mr. Marble Turtle I have been watching posts here and there......I Kinda already thought I would never be able to fully trust a pump............Every other Mix/batch, I would want to put it on a scale..... What with all the leaks............I have started leaning back towards "Scale"......... Love to you Brothers all , Joe Chapters 4-26 Quote Joseph@TheNativeSpirit.Net I am Building a Jo-Z IV StarShip. What Do YOU Want? Link to comment Share on other sites More sharing options...
John Slade Posted February 9, 2004 Share Posted February 9, 2004 My "sticky stuff" pump is a few days short of 5 years old. It HAS NEVER LEAKED. I trust it totally. You'd have to kill me to get it out of my cold sticky hands. But then, that's just my opinion..... Quote I can be reached on the "other" forum http://canardaviationforum.dmt.net Link to comment Share on other sites More sharing options...
dust Posted February 9, 2004 Author Share Posted February 9, 2004 5 1/2 years no leaks, every two or so years, check calibration, perfecto. reliability is not a problem with our pump enjoy the mixing Dust, not the imposter, building spirit, he he he Quote maker wood dust and shavings - foam and fiberglass dust and one day a cozy will pop out, enjoying the build i can be reached at http://www.canardcommunity.com/ Link to comment Share on other sites More sharing options...
macleodm3 Posted February 9, 2004 Share Posted February 9, 2004 Pump reliability seems to be measured in extremes. Some builders say its the only way to go and they've never had any problems while others say they leak, clog up, on and on. I checked out what seemed to be the most common scale offered on ebay, and read some amazon reviews about how awful the scale is. Its unreliable, gives faulty readings, and has to be "cycled" to obtain true readings. So... I'll save some startup money with a scale, but lets all be careful choosing which scale we get. My wife might really like a scale that reads 10% low somedays, but not me! Quote Andrew Anunson I work underground and I play in the sky... no problem Link to comment Share on other sites More sharing options...
CBarber Posted February 9, 2004 Share Posted February 9, 2004 I think y'all are creating problems where none really exist. Sure a tool may fail, but to pressume that it will or not work as designed seems hyper sensitive. To focus on the times they have failed and kinda ignore the vast majority that work fine seems akin to the media focusing on the one plane crash that month and ignoring all the safe flights that consistantly occur. My eyes tend to roll over when I continue to hear "considering the concequences" argument. We all know them and I think most of us always keep them formost in our minds, but the argument seems so self evident that hearing it mentioned continuously.....well, isn't my favorite thing. The scales are not a huge hassel (and I use them on occasion) until you compare them to the ease and reliablity of a pump. YMMV. Oh, and btw, I cut my arilons(sp?) out tonight. My 2 cents. All the best, Chris Quote Christopher Barber Velocity SE/FG w/yoke. Zoom, zoom, zoom. www.LoneStarVelocity.com Live with Passion... Link to comment Share on other sites More sharing options...
John Slade Posted February 9, 2004 Share Posted February 9, 2004 >I'll save some startup money with a scale The epoxy pump is probably the second most used tool during the entire project. (The first is my belt sander belt on a piece of plywood). IMHO its the wrong place to save a few $ during start-up. Chris: My eyes tend to roll over when I continue to hear "considering the concequences" argument. We all know them and I think most of us always keep them formost in our minds, but the argument seems so self evident that hearing it mentioned continuously.....well, isn't my favorite thing. I know EXACTLY what you mean and often wondered if this bothered anyone else. The one that gets me the most is "remember - the lives of you, your family and friends are dependant on this" Well... Duh! Another one is "Be careful out there!". Both comments infer that you're stupid and don't care about the lives of you're loved ones. I'm offended every time I read this [insert Jim's favorite word].End of rant. Quote I can be reached on the "other" forum http://canardaviationforum.dmt.net Link to comment Share on other sites More sharing options...
Joe Patterson Posted February 9, 2004 Share Posted February 9, 2004 John Slade and Dust, Why have you pumps not leaked..that is scary. What do you do different, Do you keep the warmth up, Do you clean them regularly????????? Y'all ain't been sniffin varnish have ya? enjoy the build , dust...... woops.I mean Peace My Brothers, Joe:cool: Quote Joseph@TheNativeSpirit.Net I am Building a Jo-Z IV StarShip. What Do YOU Want? Link to comment Share on other sites More sharing options...
macleodm3 Posted February 9, 2004 Share Posted February 9, 2004 CBarber and John Slade, What are you two refering to when you mention "consider the consequences"... I didn't see anything like that here. We're just discussing measurement techniques and not the sanity of homebuilding (Although I don't like to hear those comments either ). Quote Andrew Anunson I work underground and I play in the sky... no problem Link to comment Share on other sites More sharing options...
CBarber Posted February 9, 2004 Share Posted February 9, 2004 Of course, all that being said, now that I have defended the pumps, mine is surely due for a failure. It is that "Murphy was an optomist" thing Quote Christopher Barber Velocity SE/FG w/yoke. Zoom, zoom, zoom. www.LoneStarVelocity.com Live with Passion... Link to comment Share on other sites More sharing options...
John Slade Posted February 9, 2004 Share Posted February 9, 2004 What do you do different, Do you keep the warmth up, Do you clean them regularly????????? Nope. I'm probably the roughest user of tools on the planet. I cleaned it twice or three times, usually after it had been left idle for a while. I left the tops off many times. I overheated it (too big a bulb - got to about 140f), I've left it off (cold) for months, then started using it again without problems. As Chris said, I think it's like airplane accidents. The uninitiated read about one, and they extrapolate this to include all airplanes. Same with pumps and house air conditioners. There's a better than average chance that they'll serve you well for years without a problem. Mine failed last week. Does the failure rate of house AC units make me want to cool my house with a bunch of fridges with the door open? Nope. Having said that, I can imagine that the hole at the bottom of the jug is a bit fragile - so dont lift the pump by the jug. Not that I really treated it very gently. Joe - you sound like a gentle kind of person. Your pump will be fine. Quote I can be reached on the "other" forum http://canardaviationforum.dmt.net Link to comment Share on other sites More sharing options...
John Slade Posted February 9, 2004 Share Posted February 9, 2004 What are you two refering to when you mention "consider the consequences"... I was just reacting to Chris's comment. I'm not sure what fired him off. Quote I can be reached on the "other" forum http://canardaviationforum.dmt.net Link to comment Share on other sites More sharing options...
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