Inlayind Formica

[jteneyck]

I would glue the Formica to a piece of 1/4" Baltic birch plywood or MDF.  Then create your inlay hole.  I don't see the need to route a hole, just a recess, because I would glue it in with TB glue so there would be no increase in thickness from the glue.  But if you feel more comfortable making a hole and then routing a rabbet to glue in a support from the back, sure, go to it.  

John

I might drill a couple of holes to daylight through the bottom of the recess for air to vent out as the inlay goes in.

[K. L. McReynolds]

What about using underlayment(1/8") under the Formica? Then make the hole with a router just a tiny bit deeper than the thickness of the Formica/wood. Drill holes for glue to escape and fit the piece in the cutout. The glue squeeze out could be used to level the insert.

[mike4244]

I need to inlay an odd-shaped piece of Formica, about 13” x 21” into a piece of 1/2” Baltic Birch.  This is the counter in my van, and will need to support as much as a gallon of milk or a full Instant Pot.  The back side is irrelevant.

I’m not concerned about my ability to create the crevice, but I question my ability to anticipate the exact depth of the crevice, given that neither the inlay nor the substrate could withstand any finish sanding afterward.  I’m also a bit squeamish about laying that large an inlay exactly right, even with dowels.  The ply is matched grain with another piece, so I have one chance to get it right.

Please critique my plan, better ideas welcome.

Plane some scrap ply to 1/4”, adhere the Formica, and trim to final dimension.  

Create the crevice, then carry it all the way through the ply—IOW, make a hole.  

Dry-fit the Formica piece into the hole.  Rabbet the back side of the hole with a rabbeting bit to the depth of the back side of the Formica piece.

Mount the Formica into the hole with TBIII, making sure the front side is exactly level.  Let this dry.  

Make a “back plate” that fits into the rabbetted crevice.  Glue into place.

Thanks in advance.

Carolyn, use hot hide glue , it is reversible if needed. Adjust the cutter depth on a scrap, glue a scrap to the recess. When satisfied with the result, rout your plywood. Why 1/4" plywood substrate? Bad idea in my opinion. The 1/4" plywood has to be oriented so it is perpendicular to the Baltic birch. Not only that but routing 5/16" into 1/2" plywood leaves 3/16" thick . With hot hide glue you can fit the Formica dry, install over the routed area , then adhere the Formica with a heat gun and laminate roller. 
The glue is applied to the substrate , let it cool. Then install ,no dowels needed. When positioned you heat the center area and roll it towards the edges. This is much easier job than you have envisioned.
mike

[fredhargis]

Could you get a uniform depth using a router bridge to cut out the hole?

[MsNomer]

I’m thinking cutting a hole will be a lot easier than routing out 13” x 21” (yes, I’d have to make a bridge).

Wouldn’t hot hide glue tend to reverse itself if I put something hot on the counter?

I’m liking these ideas. Even if I eventually stick with my original plan, it’s always good to think it through carefully.

I can’t do anything til I either work the warp out of this sh**ty Baltic birch wannabe or start over with another sheet that may be just as warped.

[jteneyck]

I’m thinking cutting a hole will be a lot easier than routing out 13” x 21” (yes, I’d have to make a bridge).

Wouldn’t hot hide glue tend to reverse itself if I put something hot on the counter?

I’m liking these ideas.  Even if I eventually stick with my original plan, it’s always good to think it through carefully.

I can’t do anything til I either work the warp out of this sh**ty Baltic birch wannabe or start over with another sheet that may be just as warped.

You don't need a router bridge.  Start in the center and work your way to the edges.  You can do any size recess needed.  

Then don't use the lousy Baltic birch. Use MDF.  It's dead flat and very consistent in thickness.  

As long as you clamp the inlay in the recess TB glues will add no thickness.  


If you are really worried about heat, then you shouldn't use contact cement or TB to glue the Formica to the substrate.  That would be a bigger worry than what the inlay is glued into the main substrate with.  Epoxy would be the better choice.  

John

[MsNomer]

OK, I may give the recess a try. I can drill holes for glue escape and maybe I can even try a dry fit. Can’t use MDF, though, or won’t, because this lid with a two-inch rim around the Formica is one of the most-seen pieces of the van. That rim needs to flow with the rest of the counter.

[jteneyck]

OK, I may give the recess a try.  I can drill holes for glue escape and maybe I can even try a dry fit.  Can’t use MDF, though, or won’t, because this lid with a two-inch rim around the Formica is one of the most-seen pieces of the van.  That rim needs to flow with the rest of the counter.

I don't understand.  The MDF will be hidden between the Formica and substrate.  How does that present a problem?

[MsNomer]

The formica will be inset into a 17” x 25” opening plywood lid in the counter. That lid is warped in an area removed from the inset area. You can see the lid in this photo.



I’m remaking the counter primarily to extend it on both ends.

[CLETUS]

Instead of having a plain plywood countertop with an overly complicated formica inlay. I'd formica the whole thing. But I'm easy like that.