Liquid cement questions

[russosborne]

I've been reading lots of info here on this subject. I am more confused than before.

What I am trying to do is get the best bang for the buck, as I am currently unemployed other than helping out my brother for a month or so. Any constructive thoughts or suggestions most welcomed. Looking only for liquid cement information here. And if I have missed any options please feel free to bring them into the mix.

In the past I have used Ambroid Weld (which I think I liked, but it's been a long time and it sounds like it is gone for good ) Tenax, the Plastruct stuff, etc. I honestly don't remember having a preference for any over the others. I would prefer these days for whatever it is to be strong and quick since I generally am using my other hand to hold whatever it is I am gluing and my hands aren't like they used to be. I do want there to be a good bond/weld. I remember some of what I have used in the past not holding well.

So I started thinking about the MEK that I can go buy tomorrow at Lowes very cheap. But I also like to breath, so that may not be the best idea.  I do have a car painting respirator I could use, but this is a closed house with my wife, mother in law, and 5 animals all inside as well.
Someone also mentioned using an MEK substitute, but again I haven't found any real follow up on how that has worked.

Someone about 3 years ago in a thread mentioned using Nail Polish thinner, but I didn't see any real follow up on how that worked.

A couple here at least have mentioned Weld-on 3. So I did a search on Amazon for that, and found that not only it isn't that cheap anymore, but there is also a 4 now. Not sure what the differences are, both are still available. Buying a pint of either now with shipping is more than buying a pint's worth of hobby store cement. Local is an option I haven't been able to check into yet. They also sell syringes made by the same company, but they aren't that cheap(over $5 each) and I think the size is way too big. 25 gauge needles. Might be great for what the glue is intended to be used on, but probably not so great for 1/25th models.

As far as buying model brand cement, I was looking for the Tamiya extra thin today, but the 2 hobby shops I was at didn't have it. Neither one is really well stocked anyway.

At the rate I have been building I do have enough branded "model" type cement around to last a while, if I don't dump another bottle of it like I did earlier this week. But I am hoping that I can start feeling more like building and need to come up with a plan for that. If it ends up being best to buy the hobby store stuff I'll deal with that, but it sounds like at least to many here that buying other ways works better.

I have been using the brush that comes in the bottle to apply the cement up til now, but I just bought another Touch n Flow set since I can't find my first one that I bought years ago but never really used. I am hoping to be able to use that instead.

Being a diabetic doesn't automatically get you syringes either. My wife is one (so am I for that matter, but I have no insurance hence no drugs) but she doesn't use that sort of insulin. Her's is a prefilled plastic syringe with measured doses and I haven't been able to tear one apart and still be able to reuse it.

Thanks,
Russ

 

[SSNJim]

My favorite is Testors Model Master Liquid Cement for Plastic Models (stock number 8872). It comes in a home plate shaped container with a very thin application tube. You can put the cement right where you want it in the amount you want, and it won't spill. It is fairly slow drying without a strong odor. It is supposed to be MEK based and suitable for ABS parts like Plastruct, too. It's all I've used for years, and have been quite happy with it.

[Ace-Garageguy]

Buying MEK in larger containers and decanting it into your little old cement bottles is by far the most cost-effective way to go, and you'll find that the majority of liquid "cements" are MEK-based.

Weld-On (Sci-Grip) 3 is methylene-chloride (dicloromethane) based (or at least used to be), more toxic than MEK.

Weld-On (Sci-Grip) 4 is simply a slightly "slower" version of 3, not so prone to bulshing on clear acrylics.

If you have a plastic fabricator or plastic supply house (try a web search) in your town, you should be able to buy Weld-On or MEK there and save the hazmat shipping fees.

If you decant it outside, don't stick the bottle up your nose, and keep it capped other than when you're actually using it, you shouldn't have any odor or toxicity problems whatsoever.

Nail-polish thinner is simply lacquer thinner with some smell-good added. Some folks say it works very well, though I haven't tried it.

Using solvent with styrene is more akin to welding than gluing. Solvent dissolves the styrene temporarily, dissolved styrene from the two parts flow together, solvent evaporates, styrene returns to a solid. There is no "glue" in the final joint. The two parts have become one styrene part.

Therefore, any solvent that will dissolve styrene will also weld styrene. MEK just happens to be very strong solvent well suited to the task. Many others will work. Lacquer thinners, as noted above, are good suitable replacements because they contain strong solvents for melting lacquer paint. The evaporation rate of the solvent will determine the work and set time.

You can make your own "thick" MEK by dissolving a small amount of styrene into the can prior to using.

 

On solvents

Safety Warning: most of these solvents are toxic. Do not inhale them, especially deliberately. Use in a very well ventilated area. They are also highly volatile and thus flammable. Keep away from open flames. Do not smoke while applying solvents.
 

• 1,2 Dichloroethane: Also known as Ethylene dichloride. Found in paint removers.
• Acetone: Found in small quantities in nail polish remover. Also found in various plastic cements. Also found in acrylic paint thinners and varnishes. Can be bought pure.
• Cyclohexanone: Found in plastic cement, particularly ABS and PVC pipe cement.
• Dichloromethane: Also known as Methylene chloride. Found primarily in paint stripper. Used as an industrial solvent. Banned in Europe.
• Methyl ethyl ketone (MEK): Also known as Butanone. A large component of almost all plastic cements especially ABS and polystyrene cement. Can be bought pure.
• Methyl benzene: Also known as Toluene. Used mostly as a paint thinner or paint remover. Found along with MEK in polystyrene model kit cement.
• Tetrahydrofuran: Found almost exclusively in PVC cement. Can also be in some varnishes.

Plastic cement is generally comprised of a solvent (or mixture of solvents) along with dissolved plastic resin of the plastic in question. Thus PVC cement will contain dissolved PVC along with the solvents.
Examples:

Testors is MEK with a little dissolved styrene.
Genova ABS cement is around 20% Acetone, 60% MEK, and 20% ABS resin.
Oatey Green Transition cement is around 40% Tetrahydrofuran, 35% Acetone and MEK, 10% Cyclohexanone, and 15% PVC resin.

Look either on the can or search for Material Safety Data Sheets for the ingredients and quantities, and then look up which plastics these will work with. 

 

Edited October 17, 2015 by Ace-Garageguy

[Snake45]

What Ace said.

Testor liquid cement is basically straight-up MEK with maybe a couple little additives, so if you've used Testors, MLK should cause you no problems.

I think Ambroid is still around--I buy it at a local model railroad shop. It seems to be based on methylene chloride, which is REAL nasty stuff in large quantities but I've never had any problems with it in hobby-size bottles. I think Tenax and Plastruct Weld are pretty much the same thing.

Is there a plastic supply house in your area? Go see them and tell them what you need. They might be able to whip up something suitable in small bottles for a very reasonable price. They deal with plastic welding all the time.

[Bernard Kron]

I use hardware store MEK. The detailed discussion provided so far should provide you with all the facts including an excellent reference to the composition of some of the popular hobby liquid cements that I can't recall seeing before. In any case I like MEK. It's very cheap and very effective. The hardware store variety isn't too aggressive on plastic surfaces (although it will for sure mar clear plastic) so it works extremely well for second penetrating applications to ensure very strong final bonds. I'm very allergic to super-glue so finding appropriate alternatives has been mission critical for me. For styrene MEK is my "weapon of choice".

Because hardware store MEK is so cheap (a quart sells for around $8.00 and lasts me a couple of years), I can make sure that my supply is always fresh. One thing that happens with liquid cements is that they become contaminated with dissolved styrene over time. You can see it cloud up in the jar. As this happens it becomes much weaker. So, because MEK is so very cheap, I can keep a nice clean supply in my applicator jar without worrying about the (very high) cost of the hobby store variety.

One thing I absolutely HATED about many of the popular brands of liquid cement was the tall, tippy bottles - for example Tenax and Plastruct. I constantly was spilling the stuff. I love the solid, squat Tamiya bottles, so as I transitioned to plain old MEK I made sure to set some of those aside as my workbench container - it even comes with an excellent applicator brush.

Edited October 17, 2015 by Bernard Kron

[russosborne]

Thanks, all.

Sounds like the MEK might be the way to go. I am not in a huge hurry, so I will see if any one else posts other ideas and do some more research. Being in the Phoenix metro area I have to believe that there are plastic supply shops around, I just haven't had a chance to research yet. Only thought of this last night.

Might have to buy a bottle of the Tamiya stuff just for the bottle.  I haven't used those yet, but I agree the others are way too top heavy and unstable. I imagine those bottles are cheaper for the manufacturer though. Or they like the idea of the customer spilling the glue so the customer has to buy it more often. Just have to remember not to use any plastic bottles for the MEK.

Russ

[russosborne]

OT For SSNJim,

I am a former submariner also. I only served on one, the USS John C Calhoun, SSBN 630. 1979 to 1983. I was a missile fire control technician. FT(b). Poseidon C3 originally and then the Trident 1 C4 backfit missiles. Did my 6 and got out. Liked the job, hated the boss.

Russ

[Brett Barrow]

Thanks, all.

Sounds like the MEK might be the way to go. I am not in a huge hurry, so I will see if any one else posts other ideas and do some more research. Being in the Phoenix metro area I have to believe that there are plastic supply shops around, I just haven't had a chance to research yet. Only thought of this last night.

Might have to buy a bottle of the Tamiya stuff just for the bottle.  I haven't used those yet, but I agree the others are way too top heavy and unstable. I imagine those bottles are cheaper for the manufacturer though. Or they like the idea of the customer spilling the glue so the customer has to buy it more often. Just have to remember not to use any plastic bottles for the MEK.

Russ

Yes, buy a bottle of Tamiya just for the bottle.  I use it as my cement of choice but I put other stuff in the empty bottles, like other cements and C/A accelerator.  I highly recommend it for the bottle alone.

[Harry Joy]

Tamiya Extra Thin is one thing I will not build without, although I probably use CA glue more. My modeling improved by leaps at certain set points in the past 15 years, and the first thing that moved my modeling past beginner level was discovering Tamiya Extra Thin. (The next step was starting to go to shows and joining a club. The third level was broached when I finally bought an airbrush and compressor.)

[Ace-Garageguy]

Tamiya Extra Thin is one thing I will not build without..., and the first thing that moved my modeling past beginner level was discovering Tamiya Extra Thin.

According to the MSDS for the product (available here):    http://www.stanbridges.com/files/pdf/MSDS87038.pdf

          Tamiya Extra-Thin is 50% acetone, and 50% butyl acetate.

[SSNJim]

OT For SSNJim,

I am a former submariner also. I only served on one, the USS John C Calhoun, SSBN 630. 1979 to 1983. I was a missile fire control technician. FT(b). Poseidon C3 originally and then the Trident 1 C4 backfit missiles. Did my 6 and got out. Liked the job, hated the boss.

Russ

Very cool. I was in 1976-1992, permanently attached to Greenling (614), Birmingham (695) and Finback (670). I also rode Batfish (681), Tinosa (606), and Sunfish (649) for various lengths of time. I was an STS. Best job I ever had.