Radiator shroud repair, what works? Glue? Custom mix or ?

I have a near perfect 1970 26" radiator shroud with one damaged mounting point & a larger, perfect broken donor part for the same section.

What type of glue / bonding agent have you used that works with this type of plastic?

Thanks!

The same type of plastic ground into small chunks and mixed with acetone to make a paste with. A Scott Harms trick from way back.

Also glued a tab on plastic grill back together before knowing of the above method with pvc cement. Seems pretty strong.

I knew that about grilles, are the shrouds the same type of plastic?

Thanks.

I want to say they are same material.

I'd ask Scott as he would know for sure.

You know Scott, he will see this thread sooner or later...... ;-)

Thanks again.

It's made of a Polyethylene blend (grills are ABS, an entirely different material with different properties). Problem is that the Polyethylene/Polypropylene family of plastics are very "slick" and HIGHLY chemical resistant (they make containers for acids, paint stripper, etc. from a similar material due this fact). So, it's rather like gluing a broken candle together, glues, fiberglass and such don't adhere to it well, they just sit on top and eventually peel off. Therefore, pretty much impossible to "glue it" with anything. When they make repairs to large industrial containers they use heat and weld it together but this leaves visual melted plastic scaring which don't look good on our car parts. If you have light scratches or cosmetic imperfections you can use plastic epoxies as a filler and finish paint the shroud black with SEMS interior paint and get a nice finish, but as you know, O.E. correct is bare plastic.

.02

Thanks for the info Scott.

I heard from a pal that has used this for shrouds with good results - https://www.amazon.com/3M-08115-Panel-Bonding-Adhesive/dp/B000PEW4MI

Here is a photo of the torn hole in the shroud & the donor part.

I've never tried panel bonding adhesive but it might be aggressive enough to work. One thing though, that stuff is expensive, weigh the costs of that vs a better shroud .02

I used J-B Weld in the past with great results. After everything cured, I used SEM Trim Black to hide the repair.

Could you use one of the JB Weld putty style epoxy sticks? I know they make them in several varieties. Pick up a stick and mix it up on something and test it out, then paint to match maybe? Early morning, so not sure if the brain is working at 100% yet with this idea.

i used the clear jb weld and painted it over with sem paint came out nice and very sturdy.

stop by a body shop that has a polyvance plastic welder.
if they have any skills that's a 5 min repair after the welder warms up. if they use the black fiberflex rods, https://www.polyvance.com/FiberFlex-1/, it will be the same color as the shroud. a little detail sanding it will be as good as new.

plastic welding demo, https://www.youtube.com/watch?v=cMT_DHYbsYE

Mr T2U shows the proper way to bond PP materials. The cosmetic detailing to hide the weld will be the trickiest part.

superglue and baking soda. Simple, cheap.

https://www.youtube.com/watch?v=A-XEG57RX4Y

if the person doing the repair knows what he is doing it's a 30min undetectable repair.

both ridges are still present on the shroud so the repair is easy. i do bumper repairs like this a LOT at work. if you use the welding rod i have listed the weld will be the same color as the shroud.
just take a SMOOTH piece of metal, the foil tape wrinkles when you use it as a backer filling holes and embeds itself in the weld.
put the metal on the front side and attach securely.
fill the hole with rod from the back side and smooth the weld with the iron.
after the weld is cool pull the metal from the weld.
the surface should be smooth. just a little detail sanding and quick paint blend and you are done.


the sanding will be the same as filling it with adhesive.
the biggest problem will be the repair area will look to good compared to the rest of the shroud.

Plastic welding is the way to go.
But I just repaired one using 3M panel bond, shroud was broken clean through. Needed to V-groove both sides but it’s a very strong repair.
In either case the shroud will have to be painted.