Building sandwich walls then cutting out the door

[EZ]

While building walls using the stick and 3/4" foam sandwich method for my tiny standie, I was thinking how great it would be to build the door right into the side and then cut it out afterwards. Could frame the door with maybe 1 X 4" then cut it out in the middle of the framing with plunge cuts. There would be no issue of a separate door warping or not matching the level of the side (past experience) and it would be the right size automatically. Have to take into consideration the blade kerf; might be the perfect gap for a door fit. On the negative side, you get only one chance to cut out the door correctly......

Anyone ever tried that or seen it done?

Ed

[John61CT]

Look at the process of building nesting dinghies, exactly what you're talking about, you build one long hull, then chop the boat in half.

[Aguyfromohio]

We did exactly that on the two we built. We glued the door frames into the walls with clearance gaps (fixed side around wall opening, moving side around door, 1/4 inch gap between them), covered the whole thing with skins interior and exterior, and cut the whole thing apart. We used a 1/4 inch router bit with a plain nose like a bearing. It's a Freud 64-100 cutter. That plain end works fine but be warned it heats up fast and smokes like a chimney. But it followed the gap around the curves and did a good job.



We purchased 1/4 inch router bits with a ball bearing end for this but the two we tried failed almost immediately. Seems like those teeny tiny balls and races just cant handle the loads.
Maybe somebody sells a good one but I couldn't find it. So we used the Freud with a plain end.

I found the technique nerve wracking. We had so much time invested into the wall panels with the embedded door parts it was a bit terrifying to think about losing it all and starting over.
But we did it and it worked. Twice. Notice the perfect grain match between door and wall, it's the same piece of wood. Notice that funny little squiggle at upper right, the door frames had that corner shape and the router bit followed it . Also notice the small defect at the 1 o'clock position. The fixed side of the door frame had a little gap between pieces of oak, and the router bit went into the gap and back out as we cut. We added angle trim later, that little notch is now hidden. The second trailer was skinned with prepainted aluminum, the router cut right trough it giving the same results as for the marine plywood.

[redbicycle]

I did something similar. I cut my door out after I had the outside 1/4" skin bonded to the interior skeleton. I did not attach the interior 1/4" skin to my door. Now my door is 1/4" thinner than the walls. This provides the gap I need between the door and the framing of the opening to apply weather stripping for a tight seal.

[EZ]

That round cut certainly looks nerve wracking!

My door will not be quite as difficult. It will be rectanguar, maybe rounded corners on the top. I was thinking about not leaving gaps in the framing, just cutting along the middle of the imbedded 1 X 4 (or maybe 1 X 6) allowing half of it to be the door frame and the other half to be the ....ummm....framing for the door? The straight cuts could be done with a clamped strait edge. I hope to use a plunge-cut mini circular saw for the straigt cuts and sabre saw for rounded corners. Other than the pressure of doing it right the first time I see this as a time saving way to make a door that matches well.

But I have been wrong before.......

[Aguyfromohio]

... Other than the pressure of doing it right the first time I see this as a time saving way to make a door that matches well......

That was the real motivator for us doing it this way. We had no confidence we could make a rounded door to exactly match a rounded doorway if we built the parts separately. We wanted them to come out square and true when we assembled it - same plane, even concentric gap all around. Any time savings was minimal, we took a lot of trouble assembling the two oak door frame rings precisely when we glued up the panel. But cutting the door out of the wall did go quick and easy, the router bit following right down the gap we left between the door rings. We cut matching stair step profiles into the door frame rings so the inside door skin came out smaller than the outside door ring. That gave us a mid thickness step surface to mount a gasket. Here's the outside frame ring, the fixed side.



Here's milling the inner profile of that ring using a router and trammel (compass). We screwed the oak pieces right onto a full size template we made first. Made the moving inner ring same way, milling the outer edge and step.


and the whole outer door frame ring still screwed onto the template

[aggie79]

I did a hybrid version of what you're thinking about doing.

I used 3/4" MDO plywood for the framing. In the "framing" I routed a 1/4" clearance for the door leaving "tabs" to keep the door located.



Then I applied the interior wall finish (5/16" pre-finished engineered/plywood flooring). Here's the interior side showing the "flooring" used as siding:



Here's the street side showing the framing and back side of the flooring. You can see the "tabs":



Then I used a jig saw to cut down the middle of the clearance to "free up" the door:





Then I used a router to clean up the edges of the doors and the door openings. At this point, I had not applied the outside plywood skin, so I clamped the doors together. The doors actually sat for over a year but did not warp.

[Aguyfromohio]

That prefinished flooring as a wall looks great.

[Aguyfromohio]

Here's the door side of our second trailer with white aluminum skins . The gloss black angle trim is installed around the door.

[tony.latham]

That prefinished flooring as a wall looks great.

I challenge you to find one thing in Aggie's build that doesn't.



T

[Aguyfromohio]

That prefinished flooring as a wall looks great.

I challenge you to find one thing in Aggie's build that doesn't.



T

Amen.

[Tom&Shelly]

That prefinished flooring as a wall looks great.

I challenge you to find one thing in Aggie's build that doesn't.



T

Amen.

Agree!