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  #1  
Old 07-02-2018, 08:01 PM
TASEsq TASEsq is offline
 
Join Date: Aug 2017
Location: Melbourne, Australia
Posts: 100
Default Priming Experience - Stewart Systems Eko-Poxy

Hi all,

Just thought i would share my experiences on my trial of Stewart System's Ekopoxy through a DeVilbiss Starting Line gun at 30psi.

It went pretty well i thought, however the main issue was the thickness of the paint (see the below blog post for images and a description of the issue).

My response was to thin it with distilled water until it looked about right for spraying, and i then emailed Stewart Systems to get their take on the issue, with the following response:
Quote:
With EkoPoxy, it is normal for it to get thick like that when it sits for a while. We have noted that on the info sheet. You should not thin it to correct for that though. It just needs stirred with a drill stir for a few minutes and it will come back to a thick liquid form. Then follow the directions for mixing it and it should be about the right viscosity. You can thin it a little more than the published ratio, but don’t go too much.
For those using the Eko-Poxy, how is everyone mixing it?

Blog post link: https://tasrv14.blogspot.com/2018/07...t-priming.html
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  #2  
Old 07-02-2018, 09:29 PM
rockwoodrv9 rockwoodrv9 is offline
 
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Location: Meridian ID, Aspen CO
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I have used a kitchen egg type beater on a drill to mix paint before. If you can find a milkshake mixer rod, that would work too. If not, a piece of #3 rebar could be bent in the shape needed to mix. Even a 1" flat drill bit would work.
https://www.oster.com/parts-and-acce...000-adType^PLA
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Last edited by rockwoodrv9 : 07-02-2018 at 09:31 PM.
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  #3  
Old 07-03-2018, 01:06 AM
TASEsq TASEsq is offline
 
Join Date: Aug 2017
Location: Melbourne, Australia
Posts: 100
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Good idea thanks - maybe I’ll grind the point of one of my
Spade bits. Hadn’t thought of that.
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  #4  
Old 07-03-2018, 04:45 AM
Reflex Reflex is offline
 
Join Date: Jan 2015
Location: Kansas
Posts: 96
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I've had/have the same issue. I'm far enough into the build that I've become used to what has to be done before the paint is used. There's been multiple discussions about the the consistency of the paint while it is still in the can. One of the discussions is here.

When I open the can, I find the consistency to be about like cookie dough before it's mixed. After it's mixed it's still to thick to spray. At least that's been my experience.

What I've ended up doing is:
  • Going to the paint store, getting a clean and unused gallon paint can
  • I've been buying my primer by the quart. It's a little expensive, but I don't need that much for the project. I buy two quarts at a time. (still on my third quart and have a bunch left)
  • Take a dog food can opener and cut the bottom out of each can and pour the contents equally into each gallon can I got from the paint store. I cut the bottom out of the can to avoid leaving contents caught under the lid band at the top of the can.

The paint is so thick it comes out much like canned dog food. The liquid portion will be separated so you need to make sure that ALL the contents from the quart paint cans go into the gallon paint can. I use a spatula to get every thing I can out of the original container.

When complete, you'll have a half gallon of paint in a gallon can. At that point it's easy to mix each time and there's very little waste. Sounds like a lot of work, but probably took more time to write this than to do.

I've also found that EkoPoxy takes more reducing with water than the 5:1:1 ratio on the can. This stuff is pretty thick. I'm using the 3M PPS priming system at 25 psi or so. I find that I need to mix about 10-15% more distilled water into the paint than is called for.

In the end, I think the finished product is worth it. I like the idea of a waterborne paint and lowering the risk of heath factors. It's tough, cleans up well, and I don't feel like I have to wear a mask into the shop for the rest of the day.
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  #5  
Old 07-03-2018, 04:53 AM
TASEsq TASEsq is offline
 
Join Date: Aug 2017
Location: Melbourne, Australia
Posts: 100
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Thank you - that makes sense.

How do you do the mixing? Thinking about the metal spade bit I was worried if I scratched the inside of the can, being waterborne, it may rust the can which is bad news.

Might have to make up some kind of plastic or wooden mixing stick I can chuck into my drill.
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  #6  
Old 07-03-2018, 07:55 AM
Michael Burbidge Michael Burbidge is offline
 
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Location: Sammamish, WA
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Default Paint mixer

This for my drill worked great.

https://www.amazon.com/Allway-10031-...80014858&psc=1
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  #7  
Old 07-03-2018, 08:13 AM
nilberg nilberg is offline
 
Join Date: Dec 2012
Location: Katy, TX
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Quote:
Originally Posted by Michael Burbidge View Post
That exactly what I used, but only for stirring the paint in the can.

For the mixing:
- Mix with weight ratio 1:5.6
- For fresh paint (which is thinner), I add 15% water which happens to be nearly as much as the white stuff (1/5.6 is around 18%)
- For old paint (which is pretty thick) I add as much water as needed to get it back to how it was fresh. Sometimes I have to go up to 20-25%.

HVLP setting:20 psi.
If I go higher and the weather is hot I get sandpaper instead of primed surface. I try to avoid priming at hot and humid days.
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  #8  
Old 07-03-2018, 08:58 AM
tims88 tims88 is offline
 
Join Date: Jul 2016
Location: Arvada, CO
Posts: 50
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Quote:
Originally Posted by Michael Burbidge View Post
I use the same attachment but I found it at Home Depot. I find that only a minute or two of mixing Part A with that attachment is needed to return it to the same consistency it was when I first got the primer. However, I don't think my Part A has ever looked quite as thick as it does in your blog post.

I also noticed you were wondering about how quickly you could rivet after priming. I've found that when I prime I need to give it at least 48 hours to cure before I'm satisfied with how durable the primer is. If I don't give it that long then I'm able to scrape the primer off of the parts with a fingernail. After 48 hours it's pretty tough.
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  #9  
Old 07-03-2018, 05:47 PM
TASEsq TASEsq is offline
 
Join Date: Aug 2017
Location: Melbourne, Australia
Posts: 100
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Great - thanks for the replies.

I didn't seem to have any issues with the spraying despite the amount of water i added (against the recommendation in the email from Stewart's). Good to hear someone else is doing that.

24 hours later and the paint is hard as a rock - i can scratch it with my fingernail and it leaves a small mark on the paint, but nothing comes off. Pretty impressive - i managed to rivet the stiffners, skins to the spar and ribs to the skins (on the practice kit) all in under 24 hours with no issues.

@michael - that is the exact mixer Stewart's say they use to to mix the paint. I might try and find one here locally or amazon.

The local hardware store has this one which i might also try: https://www.bunnings.com.au/uni-pro-...hment_p1670460
Looks like a little boat propeller on the end.

Thanks for all the replies. I think i will try a combination of all the methods - decant into a larger container, then use the mixer to try and mix it back to a decent consistency. If this doesn't work, i'll add water until it is correct. It just simply won't go through the gun if i don't.
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  #10  
Old 07-04-2018, 06:56 AM
Reflex Reflex is offline
 
Join Date: Jan 2015
Location: Kansas
Posts: 96
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Trent,

Not sure if you were asking about how to mix it in the can, or the ratio being used.

If you're asking about mixing it in the can, if you're going the larger container route (1/2 gallon in a gallon can), I find that a simple wooden paint stick works very well. I've tried other devices, but so much primer sticks to the mixer, that I found I was wasting what I thought was a large amount.

Using the wooden paint stick, I just take a piece of scrap aluminum and run the excess that stuck to the mixing stick back into the can. You can get be quite vigorous when the gallon can is only half full.

If you're asking about the mix ratio, I don't add any water until I'm mixing a batch to spray.

Lastly, I'm not sure how long I should be waiting before riveting. I dimple AFTER I prime. I figure that if the primer can take a dimple, it should have little problem with a rivet. I'm waiting about 3 days before dimpling with no issues. Not sure how much sooner would work...haven't tried it.

Fred
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