Plastic cement - what am I doing wrong?

Are LEDs made of styrene? If not, the Testor's plastic cement might be ineffective in bonding it to the styrene engine shell. Certain adhesives, glues and solvents can only be used for certain applications.

I agree, testors plastic cement is likely not suitable for the materials involved. Testors is designed for ABS or polystyrene, it in a sense 'welds' the pieces together. You may be better off with cyanoacrylate (ie super glue) or Gorilla glue that are more multi material oriented.

Silicon is another option to hold them in place.  

I don't know the chemical makeup difference.

The OP in NOT using styrene cement which "melts" the plastic together and can-do harm to clear parts, it was stated that Clear Part Cement and Window Maker is being used.  Clear Part Cement and Window Maker does not harm clear parts.  There is a BIG difference.

Maybe the hole for the LED was drilled too large and the CPC isn't able to fill the large gap securely? I don't know what to tell him, but I would have likely used clear epoxy in this situation if it had to be permanent, or Arlene's Tacky Glue if it had to be flexible.

I've used Elmer's White Glue for LED placement, dries clear and sticks to about everything moderately well in the model locomotive headlight area.

Good old Walther's Goo

I would agree with Ben Maggi...tacky glue.  It will be benign to both LED and body shell materials.  When it dries it will sufficiently hold the LED in place, but will not be so permanent to present a more difficult problem should the LED need replacing down the road.  Just be sure to let the tacky glue thoroughly dry to a clear state before judging it's hold. 

I'd be cautious about CA with the clear LED body.  CA has a tendency to fog/craze some clear plastics...not what you'd want in a headlight.  Further, CA is more forever, anyway...you'll do some real damage in trying to get those items apart in the future if need be.

A touch of clear silicone calk (Steims, above) might work, also...never tried it myself, though.

Just MHO...

KD

@dkdkrd posted:

I'd be cautious about CA with the clear LED body.  CA has a tendency to fog/craze some clear plastics...not what you'd want in a headlight.

Probably best to give that some thought using any chemical and/or solvent based adhesive/glue......plastic, what kind and how compatible.

Use Microscale Micro Crystal Clear. Its the consistency of elmers white glue and can fill a gap, unlike Testors clear canopy glue, which is very thin on purpose. It does dry clear. If its piled on thick, it can take a bit for the cloudiness to dissipate. Whatever resin an LED is made of is probably not reactive to canopy glue, so the canopy glue has no effect aside from making a mess.

Alternatives would be hot glue or walthers goo. I would avoid silicone caulk, as it sometimes can react and degrade wire insulation.

The Testor's Clear Part Cement and Window Maker glue is for polysterene plastic only, if the LED is not the right material it may not work (the body of the train may be ABS, not poly).

Lets make it simple.  Use clear E6000 craft glue, which is not a solvent plastic glue and not dependent on what kind of plastic the parts are.  It will stick to any smooth surface that is not waxy.  Sold every where say Walmart for lowest price.

CCC

I use hot glue to install LED's, many glue types don't stick to them.

@Tom Dempsey posted:

I've used Elmer's White Glue for LED placement, dries clear and sticks to about everything moderately well in the model locomotive headlight area.

Yes. Not everything needs to be welded for millennia. White glue is best on porous wood/paper, etc., of course, but it does a good job on casual jobs - and it is not damaging if you ever want to remove/replace something (like an LED).

I use SOBO (sp?) glue for such things, too. It is a fabric glue, I believe. Dries clear and flexible. I have also used it to make porthole and headlight lenses.

Well, thank you all for the suggestions. I have used silicone adhesive in the past, but I always seemed to get it everywhere, that's really why I wanted to give the Testor's a shot.

I think for my next trick, I will try the E6000 glue, mostly cuz I have a tube sitting in front of me, but I would like to do a separate test to see if it will fog up the LED or the lens.

The quick set time of hot glue is also appealing, so I may give that a shot on the LED strip lights I will apply to the number boards - the spacing on two lights on a strip is just perfect for my number boards

Thanks ya'll!

George

This works for many applications and super quick with the blue light cure.

I thought E6000 was for porous materials not non-porous materials like plastic?

John

I’m for a dab of hot glue. Can be removed down the road if needed.

Alan Graziano on the scenery forum will be able to answer that for you

@Soo Line posted:

This works for many applications and super quick with the blue light cure.

Optical cement is a good option for sure. Also I found Canopy glue to work on substances like this. I works on glass so it should work on LED plastic plus it dries clear. Better than tacky glue.

Pete

Just a dab of silicone adhesive/caulk will hold it in place. Plus it's easily removable.