ratio pumps

[velocity dreamer]

It seems the measuring of resin and hardner described in the Long-Ez plans would be very time consuming and messy. Has anyone here used ratio pumps and if so which ones do you prefer and why.

 

Lynn

[Jon Matcho]

Many use Ratio Pumps, available at Wicks or Aircraft Spruce. Just make sure you get the right pump (mix ratio) for your epoxy system.

 

Personally, I don't use a pump and prefer the scale so far. I would suggest going through the first building chapter before making up your mind as well.

[Jerry Schneider]

Personally, I don't use a pump and prefer the scale so far. I would suggest going through the first building chapter before making up your mind as well.

Jon, don't you mean an electronic scale, and NOT the balance scale mentioned in the Plans?

Just want to keep things clear.

[Jon Matcho]

Jon, don't you mean an electronic scale, and NOT the balance scale mentioned in the Plans?

OH YEAH! Specifically, I use a Tanita brand kitchen scale, but others are fine -- just make sure you get one that does 1-gram increments instead of 2-gram.

 

It was you Jerry that convinced me that this route was AOK. I just haven't found the perfect squeeze bottles just yet; I'm still pouring directly out of the containers (hardener into a temporary mouthwash cup, then carefully into the mixing cup on the scale).

[Jerry Schneider]

Jon wrote:

"It was you Jerry that convinced me that this route was AOK. I just haven't found the perfect squeeze bottles just yet; I'm still pouring directly out of the containers (hardener into a temporary mouthwash cup, then carefully into the mixing cup on the scale)."

 

Stop looking.

I've since taken to pouring directly from the cans as well.

(Ah so.... the student has become the master. )

[Jon Matcho]

I hope to run out of 5-min epoxy this next decade (I'm actually using the 5-min epoxy from my prior decade's hobby, RC modeling), so maybe I could use one of those containers for the hardener. Ooo -- BOTH for hardener, one fast, and one slow.

 

For the resin, I just need to remember to go grocery shopping one of these days to get a liquid laundry detergent bottle -- one with the no-drip spout and translucent gradient window on the side -- use it up, and clean w/boiling water a couple times. I hear they're perfect for holding and pouring resin.

[jprock]

I bought the ratio pump from Velocity and have been very happy with it. It makes mixing odd ratio epoxy very easy. The EZpoxy that comes with the Velocity kit gets mixed in a 100:44 ratio. It would be a pain to use a scale to measure this since in the course of building I will go through many gallons of EZpoxy. The Velocity also comes with another epoxy that is mixed in a 2:1 ratio. I use a scale for this and it is fairly easy to get that ratio right, but even that simple ratio takes longer using a scale.

 

The pump is expensive, and I understand people not wanting to lay out $250 to simplify a task that can be done with a $20 scale... but the ratio pump works great and saves a lot of time. Just as any other high priced tool, you can spend time working without the tool, but it costs you time...how much is your time worth?

[velocity dreamer]

Thank you for your input. It just seems to me from my reading that there is alot of resin to mix and it seems that the scale would be very time consuming, especially on the large jobs like the wing. Am I just thinking on to small a scale or is it just not as much resin to mix.

 

Lynn

[filipo]

I found some plastic water bottles for 99 cents each to use as resin and hardener dispensing bottles. They are the kind with the a stopper you pull out to drink, and push back in to close, and they hold about a pint.

 

Omar

[Kent Ashton]

Thank you for your input. It just seems to me from my reading that there is alot of resin to mix and it seems that the scale would be very time consuming, especially on the large jobs like the wing. Am I just thinking on to small a scale or is it just not as much resin to mix.

 

Lynn

You're not thinking balancing scale, are you? By 'scale', I think most folks mean a postal scale. If you dispense right out of the can (punch a hole in the top, seal with a screw) or squeeze bottle to the postal scale with a spreadsheet to give you the resin-to-hardener values, it goes very quickly. The pumps are great but expensive and you gotta keep 'em clean, keep CO2 out of the hardener, etc.

-Kent

[Jerry Schneider]

Lynn,

 

You may want to try searching the Cozy Archives. There are a plethora of opinions for you to evaluate.

 

Here's my take: Most who start with the pump, like the pump. Most who start with the scale (digital), like the scale. And rarely the twain shall meet.

It's hard to beleive, but there is no clear winner when you look at the group of bulders as a whole.

Some feel the the scale is more cumbersome due to the odd mixing ratios of the various epoxies. I post an excel spreadsheet nearby to get around that.

Some feel the pump needs to be cleaned out periodically due to hardener crystalization, so they prefer the scale, (me). Some don't.

 

The large mixing cups can hold at least 200g of resin plus the needed hardener, which is about the largest batch I feel comfortable with considering exotherm issues. So, the large batch thing doesn't come into play.... for me. Others will disagree. Oh well.

 

What it really comes down to is personal preference. Flip a coin and use the time you saved ruminating over which is best to make a few extra parts. Or, (my reccomendation), peruse the Archives for the pros/cons/issues to determine what YOU are most comfortable with, because this issue has been explored extensively, and some of the more "experienced" builders might not feel like going over it again, (which might limit the number of data points for you to consider.). Damn, THAT was a long sentence.

Some people like sedans, some like trucks, and some crazy idiots even like to fly. It's all good.

 

FWIW,

[Jon Matcho]

It just seems to me from my reading that there is alot of resin to mix and it seems that the scale would be very time consuming, especially on the large jobs like the wing. Am I just thinking on to small a scale or is it just not as much resin to mix.

Until you get to the fuselage sides, there's really not a lot of resin to mix. Also, MIXING is where most of the time is, NOT pouring. You still have to mix by hand after you pump or pour.

 

I do want a pump, but I don't want to worry about the MGS resin crystalizing inside it, and having to clean it often. I'm convinced that MGS is not a good system to use in a pump because the hardener crystalizes so easily in open air. If I ever went to a pump, I'd want to switch to a different epoxy system, such as EZpoxy. I'd want to try ProSet as well.

[jprock]

I agree with the others here... it is a personal preference thing. Some say tomato, some say anoying little red fruit!!

 

Since my experience is with EZpoxy, I didn't realize some of the other epoxy's have crytalization issues. I would probably be a "scale" user if I had to deal with cleaning the pump over and over. I guess it depends on the epoxy.

 

When doing the wings of the Velocity, it was real nice to go to the pump, hit the handle 30 or 40 times, and just start the hand mixing mombo. Large layups like this take a bit over half a gallon of epoxy. I'm sure if you do a bit of pre-setup, such as the excel chart, the extra time could be cut to a minimum. I was a nervous novice when I started, and the added security of having a machine do the ratios, just made sense to me.

[argoldman]

I agree and don't agree with everybody, (and anybody)

 

I have used pumps, I have used scales, I have used balances. They all work.

 

(been doing epoxy stuff for about 20 years).

 

I started with the pump using Saf-t Poxy, switching to aeropoxy. I loved it. It is a real time saver and you don't have to think much about it. Occasionally I would porportion my epoxy by scales.

 

After finishing my first plane, and being too lazy to clean my pump, I decided to fabricate an Aux tank. Because of the aforementioned laziness, I used the weight method. It worked, but took longer, was infinately messier (don't forget you need two cups, one which will remain with uncured goo and always seemed to be knocked over, expelling it's remaining contents (sticky) on the area, needed greater concentration for a good mix.

 

Enter the Cozy.

 

I needed a different pump for MGS (different ratios), and because of my prior experiences, immediately got a new variable ratio pump, and have been happy ever since. Dispensing wpoxy takes a matter of seconds, can be done on the fly. I made a heating cabinet of masonite with a 75W bulb. No thermostat or insulation ( I keep my hanger at a minimum of 45 degrees year round)

 

The only difficulty I find with MGS crystilazing is at the tip of the Part B side of the pump. Very easy to remove with a screw or broken tongue blade.

 

When I did my strake baffles and bulkheads, I decided to use EZ poxy.

 

NO TANKS.

 

I couldn't wait to stop that foolishness and get back to my pump. When I made my fuselage parts (at Aerocad, in their molds) I used the pump. It probably saved multiple hours.

 

Having used both, (and sitll occasionally using both), I can say, without the question, the pump is the way to go.

 

If you are old enough to remember the TR-3 (triumph sports car) They used to advertise it by saying, "If you see a car in back of you that looks like a bull dog, pull over, because it is going to pass you anyway.

 

You will get a pump eventually. You will spend the same amount of $ for it, (perhaps get one that needs a little TLC at a good price). Why not have the pleasure and convienence right from the get-go.

 

That's my idea of ratioing A&B, and I am stickying to it!

[Jerry Schneider]

You will get a pump eventually. You will spend the same amount of $ for it, (perhaps get one that needs a little TLC at a good price).

You may not, and you won't. A good electronic scale is <$100. I've been doing it for 7 years. No desire to switch. I prefer the scale for a number of reasons already posted. Like I said, each to his own.

After finishing my first plane, and being too lazy to clean my pump, I decided to fabricate an Aux tank..

Never had to do clean ANYTHING. I'm lazy too.

Because of the aforementioned laziness, I used the weight method. It worked, but took longer, was infinately messier don't forget you need two cups, one which will remain with uncured goo and always seemed to be knocked over, expelling it's remaining contents (sticky) on the area, needed greater concentration for a good mix..

Not if you use an electronic scale. I use one cup. If the cup doesn't cure, the layup I did with that batch needs to be trashed. (Safety check?)

I couldn't wait to stop that foolishness and get back to my pump. When I made my fuselage parts (at Aerocad, in their molds) I used the pump. It probably saved multiple hours.

Foolishness? A little harsh/critical, but once again, maybe argoldman has never used an electronic scale. Mutiple hours saved? I really doubt it. I feel I can pour a 276gm batch of heated MGS epoxy as fast as a pump.

 

Lastly, and again, peruse the Archives. Make the choice for yourself. They are both good ways to do it. (Tomaytoes vs. Tomahtows)

[Jon Matcho]

Rich, we're referring to using an electronic scale -- nobody is suggesting the caveman balance.

 

Playing Devil's Advocate, I can imagine "multiple hours" wasted with NOT using a pump, but that can mean anything above 2 or more hours. Spread that out over the 3,000 plus you need to complete (3,500?) and it becomes insignificant to me.

 

Using an electronic scale is simple:

 

1) Put cup on scale

2) Tare

3) Pour resin, note weight

4) Tare

5) Pour hardener (using weight from a simple spreadsheet)

6) Mix (I prefer clockwise, but pump users seem to prefer counter-clockwise )

 

One last thought. Even if you have a pump, it's still prudent to verify its ratios by weighing pumped resin and hardener separately on a SCALE. My point is that since you should have a scale anyway, to calibrate your pump, you can do the first chapter without a pump to confirm:

• You like composites
• You'll get beyond the first chapter
• You're willing to spend more $ for a pump

In any event, mix away!

[argoldman]

Rich, we're referring to using an electronic scale -- nobody is suggesting the caveman balance.

 

Playing Devil's Advocate,

One last thought. Even if you have a pump, it's still prudent to verify its ratios by weighing pumped resin and hardener separately on a SCALE. My point is that since you should have a scale anyway, to calibrate your pump, you can do the first chapter without a pump to confirm:

• You like composites
• You'll get beyond the first chapter
• You're willing to spend more $ for a pump

In any event, mix away!

Greetings Devil, thanks for advocating.

 

I guess it all boils down to what fits your style.

 

I agree with the above. Initially the pump must be calibrated, subsequently, the remainder of each mix should be tested after hardened, before disarding the mixing cup-- no matter what the porportioning method is. (I believe that in certain conuntries, production of these cups is necessary for certification.)

 

The method with the electronic scale vs the pterydactylic balance is good. I personally would have problems keeping the ratio sheet around, visible, free from notes and measurements written all over it. I'm the kind of builder that only cleans the hanger floor when it disappears under the by-products of the building process. After the cleaning, I can not find my tools etc. Sometimes I want to take a handfull of them and scatter them on the floor so I can find them.

 

Although there might be some hyperoblie in the "multiple hours" statement, every hour that is spent doing something which does not move me forward, or using what is left of my gray matter, that doesn't have to be used, is wasted. (unless I enjoy it)

 

The end result is the important thing, not necessarily how we get there. The important thing is that when a question is posed, answers from all different viewpoitns are profered and the ultimate decision is an "informed one":confused:

[Jon Matcho]

Right... I'm a fan of buying time and happiness whenever possible (assuming I have the $). I remember actually trying to buy the MBT Proportionator Jr., but AS&S was out of stock at the time. Talk about an expensive pump! In hindsight, I'm not sure how much happiness it would have bought me, especially with the MGS epoxy system which I selected for its supposed superior qualities.

 

For the spreadsheet, you laminate it with packing tape and put it on the wall near the scale.

 

As far as "multiple hours", I'm not so sure it is more time consuming in the long run. Assuming 15 seconds to do the pouring of 1,000 cups of epoxy, you get just over 4.2 hours of pouring. Assuming it takes 5 seconds to do the same with a pump, you get 1.4 hours of pouring -- 2.8 wasted with pouring 1,000 cups. HOWEVER, how long does it take to clean and calibrate the thing every how-often? They do sell rebuilding kits for the things, and I'm sure it takes time to do it right. Assuming an hour total for all that is 1.8 hours wasted, or 6/100ths of a percent of the time required to build from plans (3,000 hours).

 

Messy shop floor?! Now that's telling. Any advice from you now needs to be qualified. Personally, I like to keep the surface of my table tops hidden with tools, papers, and supplies.

 

I feel like mixing epoxy now... but wait, the horse is still breathing. Somebody quick, beat it!

 

[velocity dreamer]

Sorry guys for Stiring things up. I wish I had seen the previous thread on pumps and saved everyones time.

 

Honestly I have been wanting to to do this for so long and it seems always something comes up. I feel I have already wasted to much time and I want to get started. I fear that when I do I will rush to make up for lost time, thats seems to be the way I am. so anything I can do to help myself and make it easier I will try.

 

After reading all you all have said I think I will go with the scale. Reason being I dont want to have to clean the pump. Cleaning up after myself is another weak point of mine. Also John you made it sound so much easier than what I had invisioned in my head.

 

once again I do appreaciate all your thoughts.

[Jon Matcho]

Just take it one step at a time. It was pointed out to me that I should NOT buy anything I don't need right now. I can tell you definitely do not need a pump for your first layups, but you're not going to die if you do -- you might LOVE it.

 

There are other things you can spend your early-chapter-money on, such as the Fein tool. Others, such as the "carpenters level", aren't necessary immediately.

 

I just remembered your name here "velocity dreamer". Does that mean you're after a Velocity? Which plane are you looking at? Your named can be changed if you like -- just not to RV_dreamer.

[velocity dreamer]

As far as my name goes refer to the intros. I will put a post there to describe me since this is the wrong topic thread.

 

Lynn