Went through this process this summer (with lots of helpful advice from members).
You will want some construction adhesive such as PL or liquid nails to glue the wood to the metal frame, it seals the water out as well as providing some adhesive.
On my 77
Scamp 13 there is a small piece of plywood that extends from the frame cross member to the shell at the bottom hinge side of the door. Tabbed in to the shell this piece is important to holding the door frame square.
As Eddie points out you have to get the shell and door frame in position before you make your floor template.
First picture:
- You can see the plywood replacement for that door brace in the top frame of this picture. Mine was rotted and broken free of the tabbing. I left much of the original tabbing in place as a guide to alignment.
- Middle picture note that a small amount of the original floor tabbing is still in place to give something to align the new floor with.
- Third frame shows wood floor propped up so I could apply construction adhesive with caulk gun and drop floor into place.
Second picture shows how I rigged up a tourniquet "winch" to pull the door frame back into square. Essentially a loop of rope that has a stick of wood through it, the more times you twist the rope the shorter it gets. Pulling the bottom side of the door frame in. I could see the original tabbing and there was a screw through the wall into this piece of plywood showing original location before it all came loose. I also used a carpenters square off of the floor as a guide to how much I needed to move things to get the hinge side square again.
- C clamp on the wood around the wall that supports the top of the couch.
- Rope runs over upright block cut to same height (or slightly higher) as couch support lip. Block turns the downward pull of rope anchored at floor into horizontal pull on wall to bring bottom of door back into place. Held in place by clamping to frame.
- C clamp at floor to anchor the other end of the rope loop.
- Small rusty C clamp holding the replacement plywood piece running out to the shell at bottom of door.
Once everything was positioned so that door frame was square I then tabbed in the wood piece at the bottom, once a couple or three coats of FG resin and mat had cured I could remove all the clamps and braces and make a template for the floor.
Also has a better view of the old tab left in place, I put thickened resin into that gap when I inserted the new floor wood, others have suggested adhesives, or leave it as an air gap.
Last but not least a YouTube video on how to make "Peanut Butter" which is thickened FG resin, lot easier to work with overhead when doing the bottom of the floor. Your FG supplier should have these items available.
I used the approach suggested by Eddie Longest of propping the shell up using the belly band. Two props on the front off of the frame, plus one on each side. Cut just a little long so that they could be wedged under the belly band at a slight angle out.
Wire brushed and painted the frame also while I had good access.
Things that gave me problems:
Rivets from couch that go into cabinet - the heads I would normally drill out to remove were inside cabinet blocked by
fridge. I used a dermal to cut those off and/or drill them out from under the couch but it was difficult due to the cramped space under the seat.
The wood floor seam where the kitchen cabinet ends and the front floor piece begins was a little tough to cut back in the corner and not "true" to the frame. Alignment with straight edge of new piece took some tweaking.
I used a rubber hose (from air compressor) to lay along the wall and trace the curve onto my cardboard template. Trimmed and repeated until my template matched wall. Then used a straight edge (or chalk line) to mark the line of the frame for the inner part of that floor.
This picture is of doing the bunk brace but shows how I got a matching template using a hose.
Used an oscillating tool with a saw blade to cut the old
fiberglass out. Needed two curved 180 degree blades and two straight 1 1/2 inch blades. Bought the better quality ones because the cheap ones that come with the saw are not very sharp and don't hold an edge.
Two types of FG resin one has wax additive to "seal" the resin by rising to the top, one does not and tends to remain slightly tacky on the surface. Ask your FG shop about which you should use but essentially a second coat of FG resin won't stick well to the wax surface of the first coat so you have to clean (really well) between coats or use an additive type only on the final coat.
Epoxy vs. Poly resin is something that hopefully some others with more knowledge of the pro and con of these will post on. I used poly because it matched original but epoxy is an option.
It takes a lot of resin, I bought quarts and should have just purchased a gallon up front. Would have saved hassle and money.
Used mostly mat but did use cloth at a few points for my original connections and on some straight places.