Poly cement expiration

If it hasn't dried out, it should be fine - I am using a bottle of cement (Faller "Expert") which I bought in the mid-late 80's and it's still going strong.

However, if you have any doubt, buy new cement. I'd recommend giving liquid cement a go - Once you get the hang of it, you'll be pleased with the results.

Thanks!

It hasn't dried out, but I have the impression that once applied it dries faster than it used to, so I have to stick the parts quite fast. I'm happy with the results. My only worry is not to fall apart in time or something.

I'll give the liquid cement a try once I can get myself going to the hobby store.

At your recommendation, I have bought a bottle of Mode Master liquid cement for plastics, with a brush on attached to the lid. I never used liquid cement till now. From what I have learned by searching the forum, this should be applied on joints when the parts are fitted together, or to stregthen the existing joints, by touching the brush along the edges. Is this the correct technique ?

Use a separate fine brush.  This will make it much easier to get the glue right where you want it and nowhere else.  The brush that comes with the bottle is kind of like using a cannon to kill a fly, it is clumsy and difficult to keep from getting glue everywhere but the joint that you are working on.  I use an old camel hair brush that is well beyond use for painting.  Now that that one is kind of rough shape for glue now, I will probably buy a cheapie at Hobby Lobby to replace it.  I haven't experimented with synthetic brushes to see if the glue will soften them but I'm fairly certian that a nylon brush will work fine and be cheaper.

My first impression using liquid cement:

The odor is killing my throat, the tube cement was perfume compared to this :)
I applied along edges already glued with cement from the tube, and it fills the very small gaps well. However, it leaves glossy stains in the places the brush touches the plastic, in spots often impossible to sand.

Stay with it man.  It is well worth it in the long run.

The glossy spots are simply melted plastic that have pooled and dried clear with a bit of the solvent mixed in from the glue. Polish it with a wad of 000 steel wool.

I havent touched tube glue in almost twenty five years, and have no interest in starting now....

If the small brush (or the big honkin thing that comes in some of these bottles) doesnt work well, use a cheap student type draftsmans inking pen with the adjustable tip. I paid two dollars for a really cheap one with a cheap plastic handle and it works great for long fueselage seams (like 1/48 jets).

HTH

David

 

I ended up using both the tube and the liquid glue. I first apply the glue on the wider contact areas, then apply the liquid on loose corners or to fill the very small gaps between the parts. For small pieces I use only the glue from the tube. The problem is that if I apply the liquid on the outside (visible) part, it will stain spots impossible to sand, such us around small rivets. Would the paint cover these spots?

And I'm not quite sure what the "000 steel wool" is, I have only sand paper with 300, 400, 600 and 1000 granularity. Since I've taken this hobby seriously only recently, my tools arsenal is quite limited at the present.

Hi Dragos

Steel wool is a very fine spun metal, you may be more familiar with kitchen scouring pads like SOS pads that are laoded with soap, that is a steel wool pad, a pretty rough one. Steel wool is used by woodworkers and some metalsmiths for polishing wood and or metal to a high lustre. It comes in a big wad, we can get it here in the US at any discount store. The "000" part is the grade, the more zeros, the finer the wool, very much like the higher the number of sandpaper, the higher the lustre since it is "cutting" less.  A bag will last you a few years. I use it to remove the fine residue you are finding on top of your seams.

Have a look at Usimutu's head and you see a wad of it, I use it to polish the primer and any rough spots on a prepped figure.

Any hardware store or well stocked grocery stores will even have it for a couple of dollars.

Oh, and it leaves fine metallic shavings, so be ready to sweep/ vaccuum your work area.  

David

 

dragos wrote:

My first impression using liquid cement: The odor is killing my throat, the tube cement was perfume compared to this :) I applied along edges already glued with cement from the tube, and it fills the very small gaps well. However, it leaves glossy stains in the places the brush touches the plastic, in spots often impossible to sand.

Ahh.... I think I know what the problem is.

Not all liquid cements are equal.

There are two broad classes of liquid cements:

• Hot "Thin" full-solvent types, such as Tamiya "Extra thin", the old Testors, Tenax R7, Ambroid ProWeld (and others), which rely on solvent action alone to "melt" the parts together to form a bond. These cements work best with the "touch to the joint" method.

and

• "medium" slower acting cements which are less aggressive and thicker because they rely less on the solvent action and contain a "binder" for added strength. This class includes Tamiya "regular" liquid cement, Revell Contacta, Humbrol Precision Poly, Modelmaster Liquid cement (and others). These cements work best when applied on a similar way to tube cements, as they don't flow along joints as easily as the type described above.

Your Modelmaster liquid cement belongs to the second group and includes a plastic "binder" which solidifies as the cement cures. This is what is leaving the glossy marks.

Now having said all that, there's nothing wrong with the Modelmaster cement that you're using - it will still give you better results than blobby tube glue. All it means is that it doesn't flow along joints as easily as the "hot" cements. 

Phil_H wrote:

dragos wrote: My first impression using liquid cement: The odor is killing my throat, the tube cement was perfume compared to this :) I applied along edges already glued with cement from the tube, and it fills the very small gaps well. However, it leaves glossy stains in the places the brush touches the plastic, in spots often impossible to sand. Ahh.... I think I know what the problem is. Not all liquid cements are equal. There are two broad classes of liquid cements: Hot "Thin" full-solvent types, such as Tamiya "Extra thin", the old Testors, Tenax R7, Ambroid ProWeld (and others), which rely on solvent action alone to "melt" the parts together to form a bond. These cements work best with the "touch to the joint" method. and "medium" slower acting cements which are less aggressive and thicker because they rely less on the solvent action and contain a "binder" for added strength. This class includes Tamiya "regular" liquid cement, Revell Contacta, Humbrol Precision Poly, Modelmaster Liquid cement (and others). These cements work best when applied on a similar way to tube cements, as they don't flow along joints as easily as the type described above. Your Modelmaster liquid cement belongs to the second group and includes a plastic "binder" which solidifies as the cement cures. This is what is leaving the glossy marks. Now having said all that, there's nothing wrong with the Modelmaster cement that you're using - it will still give you better results than blobby tube glue. All it means is that it doesn't flow along joints as easily as the "hot" cements.

 Hi Phil

If I try to apply this glue like the tube cement on a long surface, I either have to apply a thick layer, risking to leak over margins, or to move very fast, because when I reach the end of the surface the point were I started is dry. If the area to be glued is small and can be covered with a single run of the brush, I agree this is far better than the stringy blobs of the tube cement.