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I pumped my first batch of epoxy today!!!!!!


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My friend Gene Knapp came over tonight to help me calibrate my Sticky Stuff adjustable epoxy pump for my MGS 285 and slow hardener. We have it as close as humanly possible +/_ .008 by weight. Anyways, I am very excited. The first practice layup was a 6 layer Bid 18"x12.5". I love that cutting wheel for the fiberglass. I don't have time to wait the 4hrs to trim, so I will wait till full cure and cut it with a coping saw, or bring it to work and use the band saw. The layup went well. No air bubbles and no epoxy ridges with the squeegie. The direction of the cloth stayed straight, no waves. I have to wait to weigh it to see if I am over on the epoxy content or not. My garage is maintaining 72 degrees and the resin box is holding 90 degrees. The garage feels warmer than the house!! : ) I will be posting regularly as I progress. Here are some pics.

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Rob Wiehl

COZY MKIV #1521

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If I only use slow hardener, I find that layups may take days to fully cure, so I always add some amount of fast hardener, depending on what I am doing.

 

If you use a pump - is there any way to mix in some fast hardener?

 

And welcome! :cool:

Phil Kriley

Cozy #1460

Chapter 13 - nose

Right wing done - working on right winglet.

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10:30am this morning when I woke up the layup is still tacky as expected with slow hardener. The garage is holding 72 degrees. I drew out the 10"x12" rectangle per instructions. I will let it finish curing the next day or so and cut the rectangle out and weigh it. I hope I am within weight tollerance. Phil had a great question. Can you accurately add fast hardener to the ratio mixture from the pump, or do you have to mix a batch seperatly on the scale? I am thinking you have to use the scale only. I am having a BLAST already and I haven't even really done anything yet. This is going to be an adventure!!

Rob Wiehl

COZY MKIV #1521

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If I only use slow hardener, I find that layups may take days to fully cure, so I always add some amount of fast hardener, depending on what I am doing.

 

If you use a pump - is there any way to mix in some fast hardener?

 

And welcome! :cool:

Phil,

 

 

Yes, there is a way!!!

 

However, one thing you will learn as you do more of this stuff is that you will find a specific mixture that you will be able to use for virtually all of the layups, except for the extremely long ones. You might have to vary it a little for hot days.

 

I personally use a 50/50 mix of fast to slow for everything and find that good for me.

 

To vary the amount with the pump, keep a minimum of hardener in the reservoir (the base resin can be full) If you want it to cure a little faster, add some fast to the reservoir for a slower setting time add some slow. Make sure that you have added enough harder so that you won't suck air and mix the hardener combination with a chopstick or similar tool before pumping. the mixture of the hardeners is not critical as is the mixture of the hardeners and the other part. Play around with it. You will find a mixture that you like.

 

If you want to go to the dark side, you can always get a scale and use it (as Darth breathes heavily) for faster sets.

I Canardly contain myself!

Rich :D

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The reason I used just the slow hardener only is because I was unsure about the mixing of hardeners. Better safe than sorry. Now that I know how I can go about SAFELY playing with hardener mixtures, I will do just that. I'll need to make another run to AC Spruce East next month and get a bunch of hardener, slow and fast. For now, I'll have to deal with the slow. Thanks for the info!!

Rob Wiehl

COZY MKIV #1521

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Phil,

 

 

Yes, there is a way!!!

 

However, one thing you will learn as you do more of this stuff is that you will find a specific mixture that you will be able to use for virtually all of the layups, except for the extremely long ones. You might have to vary it a little for hot days.

 

I personally use a 50/50 mix of fast to slow for everything and find that good for me.

 

To vary the amount with the pump, keep a minimum of hardener in the reservoir (the base resin can be full) If you want it to cure a little faster, add some fast to the reservoir for a slower setting time add some slow. Make sure that you have added enough harder so that you won't suck air and mix the hardener combination with a chopstick or similar tool before pumping. the mixture of the hardeners is not critical as is the mixture of the hardeners and the other part. Play around with it. You will find a mixture that you like.

 

If you want to go to the dark side, you can always get a scale and use it (as Darth breathes heavily) for faster sets.

But the fast hardener weighs more than the slow hardener. If you do as you suggest, you will not have the proper ratio by weight when pumping - right?

 

That's why I use a scale. MGS is mixed by weight, not by volume. I pour the resin, then add hardener - either fast, slow, or some of each, depending on what I am doing - until it balances.

 

So I still don't see a way to use a pump if you are going to mix hardeners. :confused:

Phil Kriley

Cozy #1460

Chapter 13 - nose

Right wing done - working on right winglet.

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But the fast hardener weighs more than the slow hardener. If you do as you suggest, you will not have the proper ratio by weight when pumping - right?....

If the ratios needed to be different on a volume basis for different hardeners, then you'd be right. But they don't.

 

So I still don't see a way to use a pump if you are going to mix hardeners.

The MGS datasheet (for 285) explicitly calls out mixing ratios either by weight OR volume, and they're the same for all the hardeners. If the pump is calibrated correctly to a ratio of 100:50 (+/-2) by volume, then everything will be fine.
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Hey Rich.

I object. :bad: Us scale users have not gone to the dark side. In fact I think we saw the light.;)

I change my ratios on the fly...I often want some small part to go 'off' sooner than another lay-up[and use like 3/4 to 1/4], and then I decide I can conserve some Fast hardener and go with more slow in the mix say reverse that 1/3 to 2/3 and all it is is looking at the grams I am adding as the digital scale ticks upwards as I am adding the different hardeners. I just have to get the hardener #'s to add up to 40...on a 100gram resin batch. [MGS335]

Its just to dang easy. The art is getting a feel for what a particular layup is going to use, and how much time it is going to take to do it, and getting the best variable mix [since its variable with a scale] so that it cures in a decent time. [i don't like having the garage at 80 degrees longer than an hour before a layup and longer than its set time].

The 80 degree mark is the minimum I have arrived at from everybody describing good cure environment temps.

Self confessed Wingnut.

Now think about it...wouldn't you rather LIVE your life, rather than watch someone else's, on Reality T.V.?

Get up off that couch!!! =)

 

Progress; Fuselage on all three, with outside and inside nearly complete. 8 inch extended nose. FHC done. Canard finished. ERacer wings done with blended winglets. IO540 starting rebuild. Mounting Spar. Starting strake ribs.

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I used a scale for a couple weeks until my pump rebuild kit arrived. Personally I didn't care for it. I found it I wasn't extremely careful it was easy to overshoot the ratio, then I had to add in more resin. Also in just the couple weeks I was using the the bottles were completely covered in epoxy from my gloves. The problem was that this would flake off into the cup occasionally as I squeezed the bottle.

 

My hardener is almost out in the pump. It's been 50/50, but I'll be filling it up with mostly slow in preparation for the large CH5 layup next week. In the meantime, I'll probably make the small electrical channel layup. For that I may use all fast and use the scale. IMHO, The pump is just so much easier that I'll probably just it.

 

I have a

Drew Chaplin (aka the Foam Whisperer)

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www.Cozy1200.com - I'm a builder now! :cool:

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Brace for impact...

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The reason I used just the slow hardener only is because I was unsure about the mixing of hardeners. Better safe than sorry.

I run 2 pumps. 1 fast and 1 slow. It works real well.

T Mann - Loooong-EZ/20B Infinity R/G Chpts 18

Velocity/RG N951TM

Mann's Airplane Factory

We add rocket's to everything!

4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done

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if only we all were so fortunate! :) Sorry for the sarcasim. It's not a bad idea if you don't mind the $$$.

Yeah ....... it is pricey. I must say that when it comes to working efficiently ...... I value my second pump as much as my Fein Multimaster.

T Mann - Loooong-EZ/20B Infinity R/G Chpts 18

Velocity/RG N951TM

Mann's Airplane Factory

We add rocket's to everything!

4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done

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If the ratios needed to be different on a volume basis for different hardeners, then you'd be right. But they don't.

 

The MGS datasheet (for 285) explicitly calls out mixing ratios either by weight OR volume, and they're the same for all the hardeners. If the pump is calibrated correctly to a ratio of 100:50 (+/-2) by volume, then everything will be fine.

Marc,

 

I just want to clarify with you on the ratio. I have mine calibrated by weight for the slow hardener. If the fast hardener is the same weight than I should be ok to mix hardeners in the pump? I just want to be sure about this before I mess something up.

 

Thanks

Rob Wiehl

COZY MKIV #1521

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I bet I could use a scale to do all my mixing and not lose much time compared to when I use my pump. I do this all the time when I want to use any combination of fast hardner. (My pump is full of 100% slow.) But I will use the pump on all my large layups because it is so convenient.

 

I really don't see the big deal with either way, to each his own I guess. I like both pumping and scaling, no biggy one way or the other.

 

Kraig

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Ok, I went on the MGS web page and printed out the technical data on the L285 system. It turns out that "The hardeners have the same mixing ratio and can be mixed among themselves in any ratio." It also states that the the L285 resin with any combination of mixing 285, 286, or 287 hardeners is acceptable with EITHER the 100 : 40 (+/_ 2) weight ratio OR the 100 : 50 (+/_ 2) by volume ratio. That pretty much sums it up. And its comming right from MGS. So I should be safe to add fast to my reservoir of my pump without throwing off the ratio. The one thing I still question is that my label on my slow hardener says 100 : 38 by weight, but the web site says 100 : 40. My pump is adjusted for 38 not 40 like the web page says. Am I ok or should I re-calibrate? Anyone else run into this?

Rob Wiehl

COZY MKIV #1521

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get the hardener #'s to add up to 40...on a 100gram resin batch. [MGS335]

 

That's for 285, 100:40 by weight, 100:50 by volume

MGS335 is 100:38 by weight, 100:45 by volume.

 

And actually, there is a density difference between hardeners for 335 (it's negligible for 285), but it's not that big, and while theoretically that should mean differing ratios for fast and slow, practically because these things have an allowable range, the upshot is it's really not worth worrying about, so MGS doesn't. One or both are slightly off optimal to compromise on a value you can use for both - the difference between them isn't that much more than the nominal variation in density anyhow.

 

 

The one thing I still question is that my label on my slow hardener says 100 : 38 by weight, but the web site says 100 : 40. My pump is adjusted for 38 not 40 like the web page says. Am I ok or should I re-calibrate? Anyone else run into this?

Are you really sure you have 285?

 

Reason I ask is you say your bottles state 100:38, which is 335, and from the picture in the opening post, your mix looks decidedly light green, which as I recall from the bottles in the store is the tint of 335 hardener. 285 hardener is rather vibrant medium blue, and the mixed resin is very much a pale blue colour.

 

Any chance what you have is 335 not 285?

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Craig K.

Cozy IV #1457

building chapter seven!

http://www.maddyhome.com/canardpages/pages/chasingmars/index.html

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... I am having a BLAST already and I haven't even really done anything yet....

(he's hooked :cool: )

Wait till you complete the IP, and envision yout feet in the openings :D

Wait untill you glue the IP to the sides, and envision the (soon to be) zoom-zoom noises you can make when you install and glass the bottom (I am!)

 

Epoxy will be mostly hard in 24-48 hours, depending on temp, but not fully cured for about a week (or more, depending on ambient temp). A fan forced free-air heat tent will accelerate this, so will covering it with a heat blanket of some sort. (talking like I'm some sort of pro ;) )

 

Rick

Rick Hall; MK-IV plans #1477; cozy.zggtr.org

Build status: 1-7, bits of 8-9, 10, 14 done! Working on engine/prop/avionics.
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Are you really sure you have 285?

 

Reason I ask is you say your bottles state 100:38, which is 335, and from the picture in the opening post, your mix looks decidedly light green, which as I recall from the bottles in the store is the tint of 335 hardener. 285 hardener is rather vibrant medium blue, and the mixed resin is very much a pale blue colour.

 

Any chance what you have is 335 not 285?

 

I am not 100% sure about that, but I told the clerk at AC spruce that I wanted the H287s slow hardener. That is what I was billed for on my recipt. I will check the container lable closely when I get home and post back. I dont remember seeing the numbers H287S or H340S on the container anywhre, but it does say slow hardener. I hope I have the right stuff here, otherwise someone at AC spruce is going to get an earfull. I already have this in my pump and if it is wrong, I have to take it all apart and flush it out, not to mention drive all the way back there to return these and get the proper ones (and hope they accept the opened container given the circumstances), and loose a day of work on saturday, and pay the gas. I will be EXTREMELY pissed off if they gave me the wrong one. If the ratio is confirmable, i believe they did. I'll post back when I get home and confirm.

Rob Wiehl

COZY MKIV #1521

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Are you really sure you have 285?

 

Reason I ask is you say your bottles state 100:38, which is 335, and from the picture in the opening post, your mix looks decidedly light green, which as I recall from the bottles in the store is the tint of 335 hardener. 285 hardener is rather vibrant medium blue, and the mixed resin is very much a pale blue colour.

 

Any chance what you have is 335 not 285?

I am not 100% sure about that, but I told the clerk at AC spruce that I wanted the H287s slow hardener. That is what I was billed for on my recipt. I will check the container lable closely when I get home and post back. I dont remember seeing the numbers H287S or H340S on the container anywhre, but it does say slow hardener. I hope I have the right stuff here, otherwise someone at AC spruce is going to get an earfull. I already have this in my pump and if it is wrong, I have to take it all apart and flush it out, not to mention drive all the way back there to return these and get the proper ones (and hope they accept the opened container given the circumstances), and loose a day of work on saturday, and pay the gas. I will be EXTREMELY pissed off if they gave me the wrong one. If the ratio is confirmable, i believe they did. I'll post back when I get home and confirm.[/quote

 

 

@&!#@!!!!!! THEY GAVE ME THE WRONG STUFF!!!!! My recipt says 01-41006 H287S but they gave me the H340!!!! Now I have a 300mi round trip and a lost day of work to look forward to. The problem is I looked right at the container and read off the ratios, but didn't look right above the ratio to see the H340 starring me in the face. I'm glad I only opened on can. But now the OTHER problem is my pump. What the heck am I supposed to do to flush the pump out so my PROPER hardener is not contaminated? I'm not off to a good start here.

Rob Wiehl

COZY MKIV #1521

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one word....

 

VINEGAR.

 

or how our Sri Lankan product manger would pronounce "wineger" :)

 

I clean up my everything with it. Squeegee, brushes, scissors, etc. I think I read somewhere that it breaks down the hardener.

Drew Chaplin (aka the Foam Whisperer)

---

www.Cozy1200.com - I'm a builder now! :cool:

---

Brace for impact...

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