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Cyano adhesive vs lead/brass reaction.

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  • Member since
    March, 2013
Cyano adhesive vs lead/brass reaction.
Posted by patrick206 on Saturday, April 21, 2018 6:11 PM

I read a couple of items about cyano creating a reaction, causing swelling and rupturing seams of ballasted models. On an Academy 72nd B-29 I used both lead weights and brass BB's, used cyano to secure, all in the concealed frontal bays. Fuselage assembled, can't go back and remove weights.

I sidelined the model for about two years, to see if anything bad happened, all looks good. Anyone have input about experiencing the swelling? If so, I'd like to know how soon it may have shown up for you. Hopefully, if waiting two years had no problems show up, maybe I'm safe to continue the build.

I'd appreciate any input. Thanks.

Patrick

  • Member since
    July, 2004
  • From: Sunny So. Cal... The OC
Posted by stikpusher on Saturday, April 21, 2018 6:30 PM

Never had it happen myself. And I’ve been using CA with lead shot as my preferred weights for many years. 

 

F is for FIRE, That burns down the whole town!

U is for URANIUM... BOMBS!

N is for NO SURVIVORS...

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LSM

 

  • Member since
    September, 2012
Posted by GMorrison on Saturday, April 21, 2018 6:46 PM

There are at least two types of CA, and lots of casting metals that get called lead.

I did a little research because I'm about to put together a 54mm figure and was curious to know what the hot set up is. Most writers like Gorilla Glue CA or Loctite CA.

I don't use lead for weight, as it does end up in the environment. If I had a bunch around, I might.

I like to use steel nuts and bolts. Not as dense but they do the job.

fox
  • Member since
    January, 2007
  • From: Narvon, Pa.
Posted by fox on Saturday, April 21, 2018 6:52 PM

I've mixed all types of metals in models, separately and mixed, for weights and used CA to keep it there with no problems. If possible I usually use nuts/n/bolts with fine brass shot as a filler for the spaces. Have never had any type of reactions.

Jim  Captain 

Photobucket Main WIP: Rebuild of Monogram 1/8 "Big Deuce" with 1/8 Pocher V-12 in rear - 10%

   On the Bench:   Revell 1/48 Ju 52/3m - 50%;  Revell 1/96 USS Kearsarge - 20% 

I keep hitting "escape", but I'm still here.

  • Member since
    July, 2004
  • From: Sunny So. Cal... The OC
Posted by stikpusher on Saturday, April 21, 2018 7:31 PM

I just don’t see CA swelling. If anything it tends to contract as it dries and cures. And metals only expand or contract due to major heating and cooling. The styrene would be softened long before the metal heated enough to expand. 

 

F is for FIRE, That burns down the whole town!

U is for URANIUM... BOMBS!

N is for NO SURVIVORS...

       - Plankton

LSM

 

  • Member since
    August, 2005
  • From: Sydney, Australia
Posted by Phil_H on Saturday, April 21, 2018 8:06 PM

I wonder if it might be something like a sulfate reaction, like that crystalline growth that happens on car batty terminals. Sufficient growth of this substance in an enclosed space could force seams apart.

  • Member since
    April, 2013
Posted by KnightTemplar5150 on Saturday, April 21, 2018 10:11 PM

Metal can be a funny thing. Most "lead" and white metal are compound alloys with formulas which vary dramatically from manufacturer to manufacturer. If you go heavy on the zinc (Zn) in your process, you can develop Mazak rot as it reacts to the presence of contaminants in the lead (Pb). Muzak rot causes some degree of expansion, but it usually makes the metal crumble to dust when handled. If you go too heavy on the tin (Sn), your metal becomes susceptible to moisture and humidity, which causes expansion and tin pest ("tin soldiers' disease", tin rot, tin bloom, etc.), which leaves something resembling crystals and almost algae-looking blemishes to crop up, even under layers of paint.

Fortunately, metallurgy has come a long ways in this hobby, so it isn't as prevalent a problem as in the past. Most commercially available white metals, BBs, shot, fishing weights, and so on are pretty reliable over time.

  • Member since
    March, 2013
Posted by patrick206 on Sunday, April 22, 2018 2:39 PM

Hi all -

Thanks so much for all of the replies, much appreciated. I checked closely at the full length of the seams where the ballast was placed, all is good.

For a short time I've used stainless nuts in a variety of sizes, agreed, they do work well. I also switched to the thick contact cements, like 3M and Weldon, it secures everything well so nothing will break loose and rattle around.

Nice of you all to chip in with advice, thanks again.

Patrick

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