Does liquid cement go bad?

Solvents in anything, paints and adhesives, tend to evaporate over time, no matter how tight the apparent seal on the bottle.

Can't say as to the Plastruct glue, but I recently had a bottle of Testors liquid glue that was thickening up (and turning slightly yellow, as yours is) to the point of being unusable. After testing a small quantity for compatibility, I added some Goof-off (a xylene-based solvent that I just happened to have handy), and it's as good as new.

If you can figure out what the Plastruct's active ingredient is, you might be able to "juice it" a little. Or it might be cheaper and easier just to replace it.

I definitely believe over time that key components in liquid glues evaporate. I've had some 'sketchy' bottles of Testors or Tamiya liquid that was just 'not right' anymore. Discared and got new bottles and all was fine.

Sounds like the good stuff is gone and you're just left with the smell.

"Sounds like the good stuff is gone and you're just left with the smell."

This also happens with ex-girlfriends.

Don - I also have noticed liquid cement losing it's aggressive melting nature, although I build frequently enough that I usually empty a bottle before that happens.

A thought: I believe some cements contain MEK, and that is highly evaporative in my experience with it. I suppose it could be possible to replenish that ingredient, but at what ratio? Likely better and less costly to just buy a new bottle of cement.

Patrick

patrick206

A thought: I believe some cements contain MEK, and that is highly evaporative in my experience with it. I suppose it could be possible to replenish that ingredient, but at what ratio? Likely better and less costly to just buy a new bottle of cement.

Patrick

I've noticed that straight MEK does about as good for joining styrene.  You might give it a try?

Gary

Yes- but the environmental fanatics have banned MEK here in Colorado- they would rather be riding bikes and smoking pot, than building models.

I was warned that MEK was going to disappear from the shelves, and tried to buy some before it was gone. I was too late!  All that is available in Minnesota are "MEK substitute".

If a liquid glue were a single chemical, like MEK or acetone or whatever, then the volume of the stuff that is in the bottle would decrease, but stay at the same concentration.  If the boil-off of the volatiles is causing the problem, then there must be fillers, inactive ingredients in the stuff we buy.  Since I can't seem to find MEK in the stores any more, I am going to try acetone, which I can still get.

Don,

MEK seems to be harder to find everywhere. It doesn't seem to be 'banned' here (Delaware) as yet but the VOC police are watching I fear. Anyway, have a look on Amazon:

www.amazon.com/.../ref=sr_1_1

Don't think there are restrictions on shipping but don't know for sure. The local 'DoItBest' hardware store carries it in gallons and quarts but Home Depot and Lowes do not - only substitute (which it isn't by far).

Edit: Or if you want a gallon: http://www.cqconcepts.com/chem_methylethylketone.php for $60.00

Can't believe I'm reading this. I also have a bottle of Plastruct that still smells strong, but does nothing. No clue when I got it. Just tried it recently.

I also recently tried an old bottle of Tenax. Smelled like water. Inquired at the LHS, was told it is famous for evaporating with the lid closed. Have to assume the Plastruct did the same.

Neither of either in my future. I don't want that stuff evaporating into my house! I'm assuming the active ingredient is MEK, but that's a guess.

PS, I realise the OP is a bit old.

If the volume of the stuff in the bottle is staying the same, then it likely is not evaporating, unless the active ingredient is a very small percentage of the liquid in the bottle.  That doesn't seem right to me.

Don Stauffer

If the volume of the stuff in the bottle is staying the same, then it likely is not evaporating, unless the active ingredient is a very small percentage of the liquid in the bottle.  That doesn't seem right to me.

Don, you made me realize that I heard one person's opinion then preached it here as gospel. You make a good point.

In my case, no idea if the volume in the bottles have stayed the same or not.

I have two bottles of Plastruct.  One is really new and one is a few years old.  There is a noticeable difference in their effectiveness.  The old one just doesn't work as well.  I have no idea why.

The last several times I've checked Lowes they only had the gallon size in stock.

Has anyone ever found if an unopened tube of Testors glue  can go bad over time? The reason I ask is that recently I bought an old Testors model on eBay and when it arrived, it turned out to be a complete "set".

It had all of the paints needed, brushes, dropcloth, cheapo knife AND a tube of the old Testors glue (the "good" kind with all the BAD stuff in it).

The tube was never pierced at the top and is still squishy when squeezed. I'm gonna estimate the model is at least 20 years old.

My thinking is that it should still be good after all this time, considering it's still sealed.....but I'd love to hear if anyone has had experience with something similar to this.

Matt

"Sounds like the good stuff is gone and you're just left with the smell."

This also happens with ex-girlfriends.

I laughed so hard I spilled my tea.

Matt OBrien

Has anyone ever found if an unopened tube of Testors glue  can go bad over time? The reason I ask is that recently I bought an old Testors model on eBay and when it arrived, it turned out to be a complete "set".

It had all of the paints needed, brushes, dropcloth, cheapo knife AND a tube of the old Testors glue (the "good" kind with all the BAD stuff in it).

The tube was never pierced at the top and is still squishy when squeezed. I'm gonna estimate the model is at least 20 years old.

My thinking is that it should still be good after all this time, considering it's still sealed.....but I'd love to hear if anyone has had experience with something similar to this.

Matt

Not sure but I know a few very old unopened tubes of cement basically became hardened logs after a while. I bought some of these old kits long ago and the tubes are normally bad.

I had a bottle of Plastruct Bondene that was fine, until I got down to the last quarter-inch in the bottle or so.  Then it started to get a little cloudy, but it still formed a good bond.  Still, that took about 10 years or so.

I also noticed the that cloudiness seemed to include little dissolved bits of styrene, and I wondered if it picked up some plastic, every time I applied glue with the brush.

I picked up a bottle of their Weldene liquid glue in the meantime, to compare how it works.  I've had it for over a year, and it's working fine.