Gluing Plastic outdoors

[john passek]

Lately I've had some customers come back complaining that their plaques are ruined,
I ask what glue they used and they answer, I don't know.
I tried a search but didn't really find a satisfying answer.
What's happening is the glue is eating the back coating off the reverse engraved plastic, not the color fill but the coating.
What is the recommended glue for gluing plastic to cement and or wood in exterior applications..
Thanks for any advice.

[Rodne Gold]

I would use marine silicon caulking , the same stuff used to construct fish tanks etc. We use that often and it works a charm. Only problem is you have to hold the plaque in place a long time before it is set enough to hold on its own (we use masking tape or just put a piece of double sided adhesive tape on the back and put the blobs of silicon around it , strip the tape , put on wall , tape holds the plaque while silicon solidifies)

I don't think it's the glue that's being used that's causing damage , the coating would come off almost immediately if it were that , some solvent type glues do emit solvent fumes for a while , but this sounds like a material fault to me , especially if diverse customers are complaining.
Most of the engraving plastics are NOT suitable for exterior usage , I have seen some of the interior stuff a few months on looking terrible. The cap (the part you engrave thru) tends to almost tarnish and crack etc. You can apply a piece of sign vinyl to the back of the plaque as well , which would act as a barrier to any glue/tape etc you use.

What I would suggest you use is this:

Acrylic sheet (1/8th) and spray paint the gold/silver/background finish and then laser and then colour , put a sign vinyl piece on the back to protect everything.

If you don't want to use the silicon and want to supply the plaques with your own method of adhering , I would use a Very high bond (VHB) tape , use the thicker "cushioned" stuff for irregular surfaces like cement and the thinner stuff for flat surfaces.

[Mike Null]

You can use two part epoxy that you buy at the home improvement store. I use Loctite. There is also a tape you can use.

[Joe Pelonio]

For that kind of job I apply vinyl to the back first, it protects it from the weather and adhesives. Then I use a few pieces of double-sided vhb foam tape and silicone. The tape holds it in place while the silicone sets up.

[Wes Mitchell]

John, what kind of plastic are you using? That might help to narrow the issue.

[john passek]

Thanks for all the replies guys.
Wes - I use Encore smooh gold/clear rated for outdoor use.
Mike - I have used the epoxy and it ate through the back, I can only assume there are some 2 part epoxy out there that work and others that don't.

The plaques I make are memorials that are glued to cement park benches, I thought about using the VHB tape but I think the plaque would stick out too for.
I will keep trying the suggestion you all gave me.
Thank You , Much appreciated.

[Don Williams Michigan]

I have used VHB tape to mount heavy plaques on outdoor cement walls. 3 + years of four season weather and no issues.

[Joe Pelonio]

Thanks for all the replies guys.
I thought about using the VHB tape but I think the plaque would stick out too for.
I will keep trying the suggestion you all gave me.
Thank You , Much appreciated.
There are many widths and thicknesses, the stuff I use is about 1/32" and would not cause a problem with sticking out.

[Rodne Gold]

I would never use anything barring perspex (acrylic) for outdoor use , non of the "outdoor" rated engraving lams we have used (and we used a lot of different brands) has stood up well over an extended period. In fact we only use acrylic if the customer INSISTS , as these labels (on benches , memorial walls etc) really need to last for decades. I normally always use brass/stainless/anodised aluminium/bronze for this stuff.

Worst thing is someone coming in 1-3 yrs down the line with a messed up plastic plaque/label , ruins your reputation as an expert, especially if you knew it was for a rough application outdoors , generally you have to do a freebie replacement on something else other than the plastic.
Apart from anything else , you can charge a LOT more for a "real metal" plaque. It's more difficult to do with a laser tho.. Anodised can be lasered , but you really need to do black to get readable (white) text,

Stainless can be marked with Cerdec but is a bear to cut and drill , brass needs to be etched and paint filled (which you can do on the laser..using the laser to ablate a resist and then using a ferric chloride etchant...same with bronze.

.We do bronze by using brass , filling lettering with white and then chemically making the surface like bronze - dark chocolate brown with white lettering
Brass will tarnish tho (chemical bronze wont) so you need to advise the customer of this or to tell em to polish with brasso to maintain a nice shiny finish.
Acrylic stuff we have done with the lasers and quality paint (we use automotive duco type paint) looks pretty good even 12 years down the line , and prior to lasers , I have seen acrylic reverse engraved signs I did over 20 years back and they still look as good as new.

[john passek]

Thanks Rodne
I would really like to use corian but I can't find it in my area.
I never thought of acrylic, do you paint the back completly and laser trough like reverse or do you engrave and paint fill. I guess either way would work.

[Rodne Gold]

Depends on the application , with odd colours I tend to spray the acrylic first , laser thru and then paint fill , but we also often laser unpainted , paint fill and then stick a piece of sign vinyl over it for the background colour (adhesive side down , you cant see the adhesive if you do it properly)

[Jimmy Phillips]

Marine Adhesive 5200.......

[Carrie Vasquez]

Hi John!
In regards to your comment "I would really like to use corian but I can't find it in my area", I wanted to share with you a great online source: SolidSurface.com has a huge selection of overstock materials in most major brands, including full and partial sheets.
Hope this helps,
:-) Carrie