Secrets to nice canvas seams?

[KCStudly]

I think it might have been Desert Mouse that gave us the "glue the cut line" trick. A really nice canvas over ply trailer.

This is what I was thinking, too, on both counts.

[GPW]

Speaking of ... KC, you have your covering sequence sorted yet ??? With as much as you have “invested" , I figured you’d have some skinning secrets up your sleeve for TPCS

[KCStudly]

I've thought about it a lot, but haven't done any experimenting yet. Seems like a big leap to take based on other peoples experiences, but so is the whole project if you look at it that way!

My thought is to "jamb" the doors, door window, hatch seal area, vent fan cut out, and around the front locker bump out with more compliant bed sheet; then using canvas do the side walls wrapping into these areas with darts/triangle cuts as needed; then the roof/front wall overlapping the side walls.

Areas of concern are at the top corners of the hatch going from the side wall seal area to the hinge spar rear face; where the side wall meets the floor at the back edge of the galley; and how the canvas might build up in the door openings (I will cover the doors last so that if I need to I can trim them down as needed to set the gap correctly, making sure the doors can swing).

My windows are flush mount into the doors, so there is a concern there getting the canvas to wrap into the rabbet and lay down nice and crisply around the edge of the glass (have considered making a mold plug to press the canvas into the window recess while it dries).

Also, I haven't figured out what the transition will be between the edges of the doors and the inner ply skin. At one point I thought about leaving the inner skins off of the doors until after they were wrapped in canvas, then overlapping the canvas edges with the inner skin, but decided to laminate the doors with the walls so that the grain would match. In hindsight, I should have just used the doors as a plug while vacuum bagging the walls, then glued the cutout skin back onto the doors later, after canvas. My concern now is that if I end the canvas on the inside edge corner of the doors, it may try to lift with any abrasion in use, and it will leave the inner plywood skin edges exposed to moisture outside of the door seal. So I may end up wrapping the canvas in over the inner skin just enough to be under the seal, but not show inside of the cabin. the door edges, jambs and hatch seal areas will all be "jambed out" with black paint, so if I paint this inner wrap of canvas to match it will disappear next to the door seal trim when closed, and hopefully just look like trim around the door when open.

[GPW]

KC, how about this ... terminate the canvas skin on the inner door edge with a shallow slot (tuck in the end edges ) and then stuff in a bit of plastic piping to finish ...That would look Good ... easy to do ... for you ...

[GPW]

Just a thought ... We may want to cover the sides and wrap the fabric over the top by several inches , then cover the top over that so the seams are on the roof ... Much less noticeable and Nice smooth sides to look at ...

[atahoekid]

[rowerwet]

having learned to do dope and fabric airplane covering in air plane mechanic school, I like the look of pinked edges, there is a real reason for them as well, to help stop peeling and fraying.
On my tear I didn't have pinking shears, but I found putting the canvas on with paint is much easier than with TBII, since paint takes much longer to dry, you get much more time to pull up edges and trim them to the shape you want.

[KCStudly]

I had thought of the tuck and spline method, like a cane chair seat, but then I also liked the idea of the canvas covering the edge of the inner plywood skin (which is a compromise because I don't like the idea of the canvas showing on the inside).

I'll have to think about that idea; having the roof to wall overlap seam on top of the roof. I think my roof height will be at or below eye level, though, so maybe not as beneficial visually.

Speaking of airplanes, Rover Mike brought a couple of pieces from his over yesterday, the air box that mixes hot air to keep the intake from icing, for Karl to repair. Someone had added a framed screen to it that did not fit properly and was causing it to stress crack (also was interfering with the oil cooler causing that to fail repeatedly). They cut back the bad and replaced with better fitting new.

[GPW]

Pinking shears have to be Really SHARP to cut canvas ... I had two pair , neither would cut the canvas ... but worked great on thinner materials ...

[kudzu]

GPW, please remind us. What weight fabric did you use? It was one of the numbered ducks, IIRC. Maybe #8?

[GPW]

K’, I forget what number, but it was the very Thick 18 oz. canvas... The only thing ... there was no stretching it , and once it got wet and decided to shrink , there was no stopping it .... mine shrunk ~5” over 10’ ... I quickly learned to leave a little extra on each end , then trim when it was mostly dry ... and the shrinking had stopped ... It did cut without fraying... yet we occasionally got a loose thread to remove ... Once it got a couple good coats of paint (+ gripper underneath) and allowed to cure for a couple weeks , the surface got very hard and tight ... Worked out well for me ... The only reason for the much Heavier canvas was for use over the beaded foam ... I thought that would add some extra strength , and it did !!!

[tac422]

Awww... Thanks for the compliments everybody... you're gonna make me blush

Mike bought a really nice 7oz canvas in 72" wide for the Big Pink. IT has a nice almost linen finish, and looks great when finished. With 2 coats of paint on top of the gripper, it's almost texture free on the sides. If I sanded lightly and painted another coat, it would certainly be smooth.(but I'm happy the way it is.)
There is a nice texture on my Roof where I used the aluminum paint.
Plus at 6' wide, there are no visible seams on the sides .
See it here in his thread....

viewtopic.php?f=55&t=44091&start=135

[GPW]

Just a note: When laying out seams , a chalk line is your Friend, giving you an immediate reference for trimming the skin ... Works for laying out paint lines/stripes too...before masking ... just brush off the excess before you paint ...

[Mary C]

I put my canvas on in a hurry an I was not so careful cutting all the straight lines and such I used vinyl spackling to ease out the edges kinda filling them in it worked great after you paint NO Seams..........

Mary C.

Grits builder