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Old Feb 19, 2013, 09:54 AM
rip
ripacheco's Avatar
United States, FL, Niceville
Joined Jan 2013
1,659 Posts
Help!
Epoxy help!

Did I just ruined my gliders wing?

It be a shame.

I used PARBOND 300 B epoxy to join the two halves.

It was over 70F on the shop and after 4 hours the epoxy had 'cured' but I would still leave a nail mark on it.

Left it overnight over night it was in the 40s

This morning I could still leave nail mark!

Took it inside last hope... If it is still on the same condition wing is ruined
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Last edited by ripacheco; Feb 19, 2013 at 10:36 AM.
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Old Feb 19, 2013, 10:10 AM
The Prez....... again
kenh3497's Avatar
United States, IA, Rockwell
Joined Jul 2011
4,167 Posts
If you can get in someplace where the temp is 80+ you might be able to save it. What is the normal cure time? I'm not familiar with the parbond product. Maybe someone will come along smarter than I am to help out.
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Old Feb 19, 2013, 10:30 AM
25+ years of RC flying
BigIron357's Avatar
United States, FL
Joined Aug 2012
1,493 Posts
I ran into a similar situation using Parbond 329. The Heads Up RC ad said it's a 30 minute epoxy so I expected it to fully cure in about 30 minutes. Didn't happen. It was still very gooey and sticky even after an hour. Turns out that 30 minutes is the working time and 50-60 minutes is the fixing time. No info about a full cure time. But mine was fully cured the next morning.

I found the manufacturers website and it states that Parbond 329 is a low odor version of Parbond 300. http://www.parsonadhesives.com/parti...industries.htm

Having run into the issue, I decided that the next time I use the epoxy that I will heat it with my heat gun after mixing in order to speed up the curing process. This will also thin the mix for application. I've done this successfully with other slow-cure epoxies many times in the past. My current project will include the 329 epoxy this week. I'll report back with results.

So my recommendation is to apply some heat to your epoxy to see if you can get it to kick and cure.
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Old Feb 19, 2013, 10:37 AM
rip
ripacheco's Avatar
United States, FL, Niceville
Joined Jan 2013
1,659 Posts
Quote:
Originally Posted by BigIron357 View Post
I ran into a similar situation using Parbond 329. The Heads Up RC ad said it's a 30 minute epoxy so I expected it to fully cure in about 30 minutes. Didn't happen. It was still very gooey and sticky even after an hour. Turns out that 30 minutes is the working time and 50-60 minutes is the fixing time. No info about a full cure time. But mine was fully cured the next morning.

I found the manufacturers website and it states that Parbond 329 is a low odor version of Parbond 300. http://www.parsonadhesives.com/parti...industries.htm

Having run into the issue, I decided that the next time I use the epoxy that I will heat it with my heat gun after mixing in order to speed up the curing process. This will also thin the mix for application. I've done this successfully with other slow-cure epoxies many times in the past. My current project will include the 329 epoxy this week. I'll report back with results.

So my recommendation is to apply some heat to your epoxy to see if you can get it to kick and cure.
It is now inside the house at 75F... when I get home i will check on it and if necesarry put heat to it. At least there is hope...
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Old Feb 19, 2013, 11:49 AM
KNS
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Switzerland, SO, Olten
Joined Dec 2012
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40 F/ 5C definitely isn't going to help with letting the epoxy harden out quickly. Having things in the house for a while will help. Problem is augmented if components aren't mixed well/long enough and or if the quantities are (slightly) off.Long enough for me is long: 30sec/5min epoxy, couple of minutes for 30min epoxy.
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Old Feb 19, 2013, 11:59 AM
rip
ripacheco's Avatar
United States, FL, Niceville
Joined Jan 2013
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Quote:
Originally Posted by BigIron357 View Post
My current project will include the 329 epoxy this week. I'll report back with results...
Please do ... This is the first time I've had an issue with Epoxy. Granted this is my first build in the Florida "Winter"

--Robert
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Old Feb 19, 2013, 12:08 PM
25+ years of RC flying
BigIron357's Avatar
United States, FL
Joined Aug 2012
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Quote:
Originally Posted by ripacheco View Post
Please do ... This is the first time I've had an issue with Epoxy. Granted this is my first build in the Florida "Winter"

--Robert
Yah. Florida winter can be tricky. Got down to 24 here yesterday morning. 79 outside right now.
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Old Feb 19, 2013, 12:46 PM
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United States, PA, Beaver
Joined Sep 2001
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May be a bad batch or bad mix/ratio, or even contamination of some sort, but I don't think it is the temp. When we have a few days in a row sub 0, my shop is in the lower 60s, and the epoxy takes forever to cure, but it does finally cure fully.
I am less than careful when it comes to ratios (I have had quite a bit left on one part when the other part is gone) , and try to mix thoroughly, but have to admit I am not as careful as I should be at times, but I have yet to have a batch not fully cure.
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Old Feb 19, 2013, 01:25 PM
rip
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United States, FL, Niceville
Joined Jan 2013
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Quote:
Originally Posted by BigIron357 View Post
Yah. Florida winter can be tricky. Got down to 24 here yesterday morning. 79 outside right now.
I know how it is... I went to the university in Dayton , Ohio ... I remember walking in the snow from the bus to campus.... BRRRRR
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Old Feb 19, 2013, 11:43 PM
rip
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United States, FL, Niceville
Joined Jan 2013
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After work I checked on my wing. The epoxy looks the same... It's like a hard rubber.... Not like a hard solid plastic. Forget about trying to sand that.

I'm so disappointed at that epoxy brand ... I will never ever use PARBOND again.

I found the mixing cup in the garbage and I was able to pull out the left over epoxy and I could bend it with my fingers. I blasted that with my heat gun and let it rest until tomorrow...

What a shame for my wing
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Old Feb 20, 2013, 07:10 AM
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Joined May 2005
241 Posts
You can fix it!

Don't give up. You can fix it.
Cut apart the wing with a razor saw and remove the old epoxy with a knife or whatever works. Then try again.

I have found a couple of things that really help when using epoxy.

Pre-warm the epoxy to over 80 degrees F.
Carefully measure the correct ratio of the two parts. e.g equal parts of each.
Count to at least 100 while you are mixing. Meaning, mix thoroughly.
Allow to cure in a warm environment.

I have had rubbery epoxy joints in the past, no more now.
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Old Feb 20, 2013, 09:24 AM
The Prez....... again
kenh3497's Avatar
United States, IA, Rockwell
Joined Jul 2011
4,167 Posts
Quote:
Originally Posted by ripacheco View Post
After work I checked on my wing. The epoxy looks the same... It's like a hard rubber.... Not like a hard solid plastic. Forget about trying to sand that.

I'm so disappointed at that epoxy brand ... I will never ever use PARBOND again.

I found the mixing cup in the garbage and I was able to pull out the left over epoxy and I could bend it with my fingers. I blasted that with my heat gun and let it rest until tomorrow...

What a shame for my wing
If the epoxy is still soft after you let it set, you can still save the wing. Carefully heat the joint with your heat gun and when it is nice and toasty warm VERY CAREFULLY start to pry the joint apart. Try a thin putty knife to start and work in in the joint. The heat will soften the epoxy to allow this to happen. Even well cured epoxy will respond to this treatment. Be patient though, as it does take some time.

Ken
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Old Feb 20, 2013, 09:31 AM
25+ years of RC flying
BigIron357's Avatar
United States, FL
Joined Aug 2012
1,493 Posts
Quote:
Originally Posted by ripacheco View Post
After work I checked on my wing. The epoxy looks the same... It's like a hard rubber.... Not like a hard solid plastic. Forget about trying to sand that.

I'm so disappointed at that epoxy brand ... I will never ever use PARBOND again.

I found the mixing cup in the garbage and I was able to pull out the left over epoxy and I could bend it with my fingers. I blasted that with my heat gun and let it rest until tomorrow...

What a shame for my wing
Hmmm.... I guess I'd better do a test of my epoxy before I glass the center section of the wing I'm working on. I've been using epoxy like this for over 40 years and have never had an issue like this before.
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Old Feb 20, 2013, 10:26 AM
rip
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United States, FL, Niceville
Joined Jan 2013
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Quote:
Originally Posted by BigIron357 View Post
Hmmm.... I guess I'd better do a test of my epoxy before I glass the center section of the wing I'm working on. I've been using epoxy like this for over 40 years and have never had an issue like this before.
YES test before commiting to something that is "do-right or ruin" Like glassing or joining the middle of the wing

I think the concensus of the people I've explained my problem is:
  1. Didn't Mix it long enough
  2. Temperature didn't help
  3. May have been slightly off on the mix.

From now on i'm measuring by weight my epoxy and i'm mixing it counting to 100!
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Old Feb 20, 2013, 12:22 PM
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Florida
Joined Aug 2004
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If the container you mixed it in had a wax coating or finish, this would cause just such a problem. Be careful of what you mix the epoxy in.
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