Project pretty prius grill block

[Otto]

Once the foam expands but before it sets up, can you screed it like concrete, cake icing, or spackle compound? If so, you could use a lot less of the stuff, with less sculpting needed.

Also, since foam insulation board comes in urethane with foil backing (R Max?), perhaps a basic plug in the right shape could be inserted into the bumper gap, then sanded or sculpted. R Max is fairly fine consistency, with smaller bubbles than expanded Great Stuff, so sands and sculpts well. Gorilla Glue is essentially the same stuff (just not foamed), so makes good adhesive.

[Daox]

Originally Posted by Otto

Once the foam expands but before it sets up, can you screed it like concrete, cake icing, or spackle compound? If so, you could use a lot less of the stuff, with less sculpting needed.

I don't think that would work well. You might be able to do it immediately after spraying it, but it gets tacky very quickly.

[CigaR007]

From my experience, it is recommended to fill the opening with more foam than necessary and cut/sand the excess. It should leave a fairly smooth surface with no "air" dimples and it is much easier to work with, not to mention that it is less time-consuming.

[Daox]

I'm looking forward to having this done more and more. Today it was a wonderful 29F out when I left for work. I think my max coolant temp hit 159F on the way in and that includes getting stopped for a train coming through which isn't normal. I may have to look into additional engine compartment sealing for winter.

I also still haven't decided how to attach the grill block yet. I'd love to have something that is easy to just pull out should we have a warm day or we need to go on a longer trip as this is our long trip car. Magnets sound ok, so does some form of plastic clip or rubber banding it from the back side or something like that.

[BamZipPow]

You could try eye hooks, flat bar, and pins to secure it to the backside of the grill if you have easy access/space.

[California98Civic]

Nice. I'm practicing this technique right now to fill the hole left by my passenger mirror delete. Your work looks very clean. I have the bubbly surface too. I'm planning fiberglass too. But I can't work on it now. So I'm happy to live vicariously...

[Daox]

I just got done putting fiberglass over the front. I only used 1-1.5 layers. I'm not sure thats enough, but this thing really doesn't need to be stiff either, it just needs to have that front surface hardened up so I can put some body filler over the top. However, this is only the 2nd time I've ever used fiberglass, so I really don't know what I'm doing!

[Daox]

I checked the fiberglass this morning and it seemed to be solid enough to start putting filler over the top. Its still somewhat flexible which is how I hoped it would be.

[California98Civic]

Originally Posted by Daox

In this image I can see a fleck of silver that indicates the aluminum foil. In my experience Great Stuff adheres to many many surfaces. I think the foil would be one. So your grill block is foil backed? Did you try to peal the foil off? Did it come off?

[Daox]

Yes, the block is foil backed. It adheres quite well to the foil. I did try to peal it away and it is stuck on there good.