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        Discussion Mercury M100F Foam Safe CA Will Not Dry

#1 AndyManxx Jun 12, 2012 07:19 PM

Mercury M100F Foam Safe CA Will Not Dry
 
I recently cracked the leading 3 inches right next to the fuse on the left wing of my PZ P47 Thunderbolt. I have successfully used this same bottle of foam safe CA in the past in similar circumstances.

This time, however, the glue simply won't dry. It has been 3 days now, and the exposed CA is mostly dry, but when i press the crack together, tacky CA still squishes out.

I did not use any sort of activator (i hadn't in the past either) and I'm guessing that's where I went wrong as this CA relies on moisture to set.

Hindsight is good and all, but is there anything I can do to get this CA to dry? Would applying activator or water to the exposed CA do anything? It's not looking like any moisture is getting in there, so will this stuff ever dry?

Aside from buying a new wing, does anyone have any suggestions?

Thanks in advance,

Andy

#2 fnlrun Jun 12, 2012 07:20 PM

6 min epoxy

#3 AndyManxx Jun 12, 2012 07:55 PM

There's still wet CA in there. It's impossible to get it out as it's only a crack and not a break. I don't think adding new epoxy on top of wet CA will work.

#4 AndyManxx Jun 12, 2012 11:59 PM

Any other ideas?

#5 FieldofDreamsFlyer Jun 13, 2012 12:13 AM

Hair dryer

#6 AndyManxx Jun 13, 2012 08:39 AM

Do you think the heat from the hair dryer will melt the Z-Foam?

#7 lebl468 Jun 13, 2012 10:10 AM

What ever you do, do not add epoxy to still wet CA...I had it chemicaly react and get VERY hot. I had a similar problem to yours, on my HK mustang, a crack in the wing right from new, tried CA, and it would not set, so the next day fired some 5 min epoxy into the crack, and it got hot enough to melt the beer cooler foam in some spots. As for CA not setting I find the same tube will not set and then 3 months later set as it should, I chalk it up to humidity (or lack of it).

#8 lebl468 Jun 13, 2012 10:13 AM

For repairs that can sit over night I use a product called "Hold The Foam". It is a tube of what I suspect is white glue, but when it dries fully (24hrs) it is almost see through and hard a concrete. For stuff that has to fly now....5 min epoxy all the way.

#9 lebl468 Jun 13, 2012 10:14 AM

Quote:

Originally Posted by AndyManxx (Post 21885031)
Do you think the heat from the hair dryer will melt the Z-Foam?

I think you should be OK, just keep an eye on it.

#10 desmo Jun 13, 2012 12:22 PM

try putting saliva over it - that normally helps. it's natures activator

CA needs an anaerobic environment to set

#11 DaveA Jun 13, 2012 01:38 PM

Don't know which foam your P-47 is made of. If it is EPP or one of the rubbery foams, CA kicker should be OK and it ought to catalyze it even down in the crack. What I can't remember is if kicker damages polystyrene foam. If your bird is polystyrene, shoot some kicker on some scrap foam from a cooler or something. If it survives, you are all set. If not, you can try dripping water on it, not sure how well it will penetrate but should certainly catalyze what is near the surface.

I think humidity is much more important than anaerobic conditions, it ought to be plenty anaerobic down in a crack in plastic sitting overnight.

- - Dave

#12 atlav8r Jun 25, 2012 05:44 PM

Hi,
CA is an acrylic resin the only trigger, or catalyst, it requires are the hydroxyl ions in water. Since almost any substrate you may want to glue will at least have trace amounts of water on it's surface CA will adhere to most anything.
However, as most balsa has some moisture in it the CA sets up quick. Foam on the other hand has no moisture and as such an accelerator needs to be used in most cases.

Lots of help here
http://mercuryadhesives.com/MercuryFAQ.htm
Hope this helps



Quote:

Originally Posted by AndyManxx (Post 21880349)
I recently cracked the leading 3 inches right next to the fuse on the left wing of my PZ P47 Thunderbolt. I have successfully used this same bottle of foam safe CA in the past in similar circumstances.

This time, however, the glue simply won't dry. It has been 3 days now, and the exposed CA is mostly dry, but when i press the crack together, tacky CA still squishes out.

I did not use any sort of activator (i hadn't in the past either) and I'm guessing that's where I went wrong as this CA relies on moisture to set.

Hindsight is good and all, but is there anything I can do to get this CA to dry? Would applying activator or water to the exposed CA do anything? It's not looking like any moisture is getting in there, so will this stuff ever dry?

Aside from buying a new wing, does anyone have any suggestions?

Thanks in advance,

Andy



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