MEK

I have used MEK for cementing plastic parts together for years.   The only difference is the the MEK evaporates a lot faster.  Strength and durability is the same as far as I have been able to determine over the past 15 years that I have been using it

Don

Alternatives to MEK

I asked about this on another forum post... 

http://model-railroad-hobbyist.com/node/7063

My local hobby shop has just informed me that all the standard plastic solvents (Ambroid, Tenax-7R and similar) are now not readily available in canada, due to a change in customs regulations between Canada and the US.

Living in Canada, that creates a problem.  However, I discovered that good old Lacquer Thinner contains Toluene, Methyl Alcohol and MEK, and you can buy liter cans from any big box store for less than $10.

Other than being VERY liquid, it works great. This is where a syringe comes in handy.  You can get those form Hobby Lobby...

John

If it melts it, it welds it

Plastics cover the whole range from very resistant to organic solvents all the way to highly sensitive to organic solvents. Styrene happens to be on the far end of the highly sensitive to organic solvents scale. Hence, many solvents will easily melt styrene.

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.

Broken record

I may sound like a broken record (remember those?) but make sure that you use any solvent with proper ventilation!  Sniffing this stuff can turn your brain to mush - which will really reduce your enjoyment of your model railroad.

Rick

Another happy MEK user

I've used MEK, lacquer thinner, and a variety of commercial glues and solvents.  MEK is by far my favorite.  As has already been noted, it is very thin - I use a long handled paint brush to apply it (glue a straw to the side of the can to hold the brush).  Unlike any of the commercial glues (except perhaps Testors) that I have tried, MEK leaves absolutely no residue.  I have even used it on painted models to attach detail parts (anybody try to assemble a painted P2K Mather stock car kit?) and had no paint damage at all.  It is quite "hot" however, so you have to take care when gluing thin parts.  The flip side of that is that laminating thin styrene onto a thicker car side gives something very close to "oil canning" seen in many prototype cars.

MEK

If you read the label on a bottle of Testor's liquid cement, that's exactly what it is. MEK with a little styrene dissolved in.

MEK and a safety note

Don

A few years back, Well really a lot of years back, I worked for an aviation fixed based operator. They used  MEK to strip the paint on aircraft. The Mek solvent not only is a breathing hazard, but can be absorbed through the skin. I have used it for a solvent myself, but I try to avoid skin contact.

Regards,

John

MEK Dangerous Try Weldon 3

Weldon 3 is a great alternative to MEK or Plastic Cement.

Here is a link to read more...
http://www.delviesplastics.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=DPI&Category_Code=Acrylic_Cement

Jimmy Simmons

MEK & Barge cement

I've got a little glass jar of MEK mixed up with Barge Cement. Makes a nice "instant gummy/adjustable hold" liquid cement.

I got the idea from Les Halmos, not sure where he found it at.

Safety

Agreed, MEK is dangerous however Weldon 3 is methylene chloride (dichloromethane) which is arguably a more hazardous solvent.

Neither should be used carelessly. Little drop of either in an eye would be a very very bad thing. Safety first!

MEK

I've used MEK as a cement on styrene plastic structure kits with good success.  I bought 1 qt. cans of it at my local Lowes store for about $9.00.  Since very little needs to be used to accomplish the task, a quart of MEK will last you along time.

As stated above you should take precautions with MEK, i.e., avoid skin contact and breathing it.

Since very little is necessary to stick two pieces of styrene together, I would suggest that you consider using the Touch-N-Flow Applicator sold by Micro-Mark, Item #81778 at $7.60.  This applicator consists of a glass capillary tube with a very fine steel needle at its tip.  All you have to do is touch the steel tip to the joint you want to glue and the MEK will flow out of the applicator into the joint by capillary action.   This reduces the chance of exposure to the liquid or vapor.

Bob

MEK & Barge

Types of solvents

I have a bottle of Plastruct Plastic Weld cement, and the bottle says it contains trichloromethane.

I hate that stuff. It leaves a nasty residue on the surface of the model. I much prefer the Testor's cement (which is MEK based) which leaves no surface residue. It's thin, wicks right into the joint and is perfect for styrene-to-styrene joints, especially when scratchbuilding a car side.

If you mix it 50/50 with

If you mix it 50/50 with methylated spirits it will remove paint from plastic without harming the plastic.

Also make great airbrush and paintbrush cleaner.

MEK is sold in the UK as a

MEK is sold in the UK as a plastic cement. It used to be a stronger blend called MEK Pac but they had to change the recipe. Excellent bonding properties and I apply with a small brush that has passed its useful painting days. That said, MEK is also useful for revitalising brushes that have been stuck up with paint

Jon 

Menards

Was at a Menards in Michigan buying some fence stain when I noticed they have a nice selection of basic solvents in quarts and gallons. Quarts of MEK were on the shelf.

Haven't given up on using MEK

I'm still going to try it at some point but since I was ordering track and drill bits and other supplies the other day , I broke down and included a bottle of Tenax 7R  on the order.  All this stuff, MEK included, is nasty but it's a necessary evil to get clean god looking joints with plastic.

Michael

MEK to bond SAN plastic

I have a cup article that is made up of two halves that are to be joined together. They have a tongue and groove that fit into each other and I am using MEK to bond the SAN (Styrene Acrylonitrile) articles. I then put water into the cup about 2 hour after welding the two halves together and the article started to get a bit of an oily feel to it. Is this common? How long should MEK be left to set for before it can come into contact with water?

Plastruct Plastic Weld verses Tenax

I've used both of these, and I found the Tenax stuff to be more effective,   a bit quicker acting, and maybe a bit stronger bond,...it appeared to me.
 

But I bought a 'case of bottles' a number of years ago, and never opened most of the bottles. When I recently sought them out from storage, I found almost all the bottles EMPTY ! Since the bottles were glass I have to think the liquid evaporated out of the tightly closed plastic caps.    disappointed

Tenax

Same experiences here. Love using it....hate not being able to find it at dealers and really hate that you either get partially filled bottles or lose it during storage. I’ve had a little more success when I tighten the caps on the bottles when I ever find some. Very frustrating.

I might be wrong, but....

IF Tenax 7R was methylene chloride, and indications are that it was.  It might still be found in a plastics fabrication shop.  It works very well for welding plexiglass to itself.  It is very volatile (close the bottle as tight as possible) and should be used in a well ventilated area just as MEK should.

If I was home I’d give you the name of the company packaging it, but...

Fortuitously, today I got to smell a bottle of Tenax 7R  and it did not smell like pure methylene chloride.  Maybe a methanol mixture with the methylene chloride...  Not sure.

MEK is my go to styrene solvent.

Nick

Bottle Closed TIGHT

I had those Tenax bottles closed tightly, but it still managed to escape

Has anybody tried a rubber

Has anybody tried a rubber washer or maybe an o-ring under the bottle cap to prevent evaporation?

Rubber & MEK

@John - I’d do a little test first as MEK is brutal on a lot of materials. Maybe a fiber washer?