styrene cement

The best cement I have ever found for plastic is Tanax 7R. You local hobby shop should stock this.

Thanks.  I have an unopened bottle in my shop.  Guess it's time to open it.

Chuck Sartor posted:

The best cement I have ever found for plastic is Tanax 7R. You local hobby shop should stock this.

Or you can get a quart of M-E-K at Home Depot for not much more than a bottle of Tenax.  I believe Tenax is Methylene Chloride whereas MEK is Methyl Ethyl Ketone.  But both produce the desired effect. Both are relatively "hot" solvents for styrene.  Both are dangerous via inhalation and skin contact if used improperly.  Be careful with thin parts as both solvents are aggressive and can deform parts with thinner cross sections.

Take care, both with yourself and your models, if you use either solvent.  And keep the lid on when possible as it will reduce fumes and evaporation.  And also knocking it over on your desktop and randomly gluing a bunch of styrene parts sitting there into one big mess.  

Jim

Just read that you already have a bottle of Tenax 7R.  By all means use that instead of the MEK.

A word on MEK.  It's the adhesive that keeps on giving.

I built a G scale loco a while back using styrene and MEK.  After about three months I noticed that the whole body was twisted like a barber's pole.

I've got a photo or two on an old drive, if anyone would like to see it; I'll go look for it.

Cheers

big train posted:

Chuck Sartor posted:

The best cement I have ever found for plastic is Tanax 7R. You local hobby shop should stock this.

Or you can get a quart of M-E-K at Home Depot for not much more than a bottle of Tenax.  I believe Tenax is Methylene Chloride whereas MEK is Methyl Ethyl Ketone.  But both produce the desired effect. Both are relatively "hot" solvents for styrene.  Both are dangerous via inhalation and skin contact if used improperly.   

Although neither are particularly benign substances, the dangers of Methylene Chloride are pretty unambiguous (for one thing, it is a suspected carcinogen). There is less evidence that M-E-K has long-term health effects.

M-E-K was outlawed in California about the time I left McDonnell Douglas.  Sure ruins boots in a hurry.

Methylene chloride is something that I use regularly - gallons of it; I have a 1 liter bottle of MEK and it's locked away.  That stuff is nasty smelling, very flammable (Methylene Chloride isn't), and has enough health issues that I won't have it in my labs except for that 1 bottle.

Unfortunately, I'm building a kit that's ABS plastic so I have a small bottle of MEK in my shop for just this kit - then it gets disposed.

BTW, apply either using a small brush that you can sacrifice at the end of the build as it will over time pick up plastic.

Also, if you can, get a better bottle that actually seals for either solvent.

Tom:

I have never used Tenex 7R so don't know if it bonds wood to styrene. You mentioned you need to bond balsa/basswood to styrene.

For styrene to styrene - tenex / plastruct bondene / or just about any plastic cement you are comfortable with. Some are instant stick and some give you a little time.

For wood to styrene I believe only a super glue like Zap-A-Gap / Mike's cement / Loctite etc would work.

For paper to wood or styrene I use Aleene's tacky glue. I would think any white glue like Mod Podge / Elmers would also work.

Joe

Model Structures posted:

Tom:

I have never used Tenex 7R so don't know if it bonds wood to styrene. You mentioned you need to bond balsa/basswood to styrene.

It won't bond wood to styrene.

For styrene to styrene - tenex / plastruct bondene / or just about any plastic cement you are comfortable with. Some are instant stick and some give you a little time.

For wood to styrene I believe only a super glue like Zap-A-Gap / Mike's cement / Loctite etc would work.

For paper to wood or styrene I use Aleene's tacky glue. I would think any white glue like Mod Podge / Elmers would also work.

Joe

For wood to styrene one can also use Goo or CA, or the mix of the 2; Goo on the wood and CA on the styrene.

I built a G scale loco a while back using styrene and MEK.  After about three months I noticed that the whole body was twisted like a barber's pole.

Styrene Cement works by melting the plastic together. That is the reason it won't bond styrene to wood. I suspect that also has something to do with the G scale loco body twisting. back in the day, I had the same thing happen to me with some plastic model kits

In my experience, it needs to be used very sparingly.
When I need to use styrene cement, I use a liquid product that has a brush applicator attached to the cap.
I've been using the same bottle for years (I don't build models any more).

C W Burfle posted:

I suspect that also has something to do with the G scale loco body twisting. back in the day, I had the same thing happen to me with some plastic model kits

 

The solvent plastic glues/adhesives are just that and if any solvent gets trapped it will find a way out eventually warping, twisting, bubbling the plastic as it's boiling point is generally only slightly above room temperature.

In my experience, it needs to be used very sparingly.
When I need to use styrene cement, I use a liquid product that has a brush applicator attached to the cap.
I've been using the same bottle for years (I don't build models any more).

 

Indeed. As I note above, use a brush - the smallest that you can use actually that conveys enough solvent to the surface.  Do allow the excess to evaporate.

CW:

Basically the same problem exists today. I routinely glue thin veneer sheets (diamond floor / brick / siding etc) to a flat pieces of styrene (40-80 mil). If I don't glue the sheet down to a superstructure within a few days it will warp forming a concave shape.

Joe

I'm not sure what you meant by, "wicking up 12""? No cement that I'm aware of will wick over that distant. To apply styrene solvent, I've been relying on a Touch-n-Flo applicator. It enable you to apply a relatively small amount with pretty good control. For the uninitiated, it's a glass tube with a pice of capillary tubing epoxied at one end. The other end is open. I find the only way to consistently load it is by putting the open end in my mouth and apply suction until the liquid moves up about 1/2 up the tube. This is a very bad practice. I have only gotten that stuff into my mouth a couple of times (very small amounts) and will probably get cancer some time in the future. Hopefully, I won't live that long. I've tried their method which relies on capillary attraction. I've also used polypropylene syringes to apply the negative pressure, but the solvent eventually softens the O-ring on the plunger and makes it hard to move. Anyway, the applicator is very effective.

I find the only way to consistently load it is by putting the open end in my mouth and apply suction until the liquid moves up about 1/2 up the tube. This is a very bad practice..

Indeed, it is.  Pipetting by mouth has not been acceptable for decades; could/should use a pipette bulb. 

I should probably get a hold of some of those. I do feel like I'm pressing my luck.