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Seeking remedies for this...

PostPosted: Mon Nov 09, 2020 10:58 am
by TimC
I am not sure how to proceed and am open to suggestions. First, the photo is the front corner of our current build. 1 1/2" foam roof panels, 2" wall panels. The roof panels were glued down slightly over on one side, thus short on the other side. About 3/16" at the most. We're hoping to round over the edge. Haven't decided on a radius yet. It will be PMFd after filling/shaping.

Is it as simple as filling the kerfs with GS then Surfoaming the edge to the profile we hope to end with? We have to deal with the canvas seam as well. Probably about a two inch overlap of the wall.

Thanks, Tim

Image

Re: Seeking remedies for this...

PostPosted: Mon Nov 09, 2020 2:06 pm
by RJ Howell
A curve on a curve, cool idea, yet hard to achieve. Forming it is easy enough but covering with PMF (cloth) could be tricky (to say the least). I had a hard time with just the main curve, yet just me hopefully. I looked into using some drywall moldings that I liked, but again opt'ed out as I couldn't work out a clean seam.. :(

I can see how it could be done in fiberglass (sanding in seams and layers), yet with PMF.. :thinking:

Good challenge! I'll be watching what you do.

After-thought: Maybe a strip (4-6") to cover the curve and then roll the side/roff over? I'm thinking layers again. :roll:

Re: Seeking remedies for this...

PostPosted: Mon Nov 09, 2020 7:08 pm
by Pmullen503
Shaping GS to foam will be difficult because they sand so differently. It's hard to control but you can scrape it off or push it back as it foams up.

I would sand in your radius and see how much filling you need. Maybe you can get away with spackle or slivers of foam. Worst case I would section in some new foam. That will be easier to sand than GS.

Is that canvas in the photo from covering the inside roof?

Re: Seeking remedies for this...

PostPosted: Tue Nov 10, 2020 7:27 am
by TimC
Pmullen503 wrote:Is that canvas in the photo from covering the inside roof?


Thanks. No, the canvas in that photo is extra from the outside wall.

Re: Seeking remedies for this...

PostPosted: Tue Nov 10, 2020 9:45 am
by OP827
I used GS to fill some void and to fair surface. GS does not create uniform foam, it would create big bubbles inside that will open up once I start sanding deeper than 2mm. If you could restrict GS foam from expansion by putting scotch taped wood strip against that gap once filled with GS, then the foam will not have large voids in it. It is important to let GS to fully cure before fairing as it can expand further even after a week as I learned. GS works, but if possible, I prefer glued foam strips of same material to correct shape, it gives better control over the results. I used TB2, epoxy with micro balloons, PLP to glue foam. I prefer a thin layer of epoxy to other methods, as it faired the best for me. Hope it helps.

Re: Seeking remedies for this...

PostPosted: Tue Nov 10, 2020 11:14 am
by KCStudly
I used several techniques for filling kerfs. Also, some pretty simple layout techniques for applying sanding guidelines for radius corners on curved roof. Also a sanding block with details on technique. I don't have time at this moment to go back and quote a particular page in my build, but will try to circle back around to get you closer. My outside finish is epoxy/FG, but as long as you don't overdo the overlaps too much it should pretty much lay down okay.

Re: Seeking remedies for this...

PostPosted: Tue Nov 10, 2020 2:48 pm
by aggie79
This may be a possible method to help get a consistent radius edge (although any technique will be a challenge on a curved profile.) Find the appropriate size PVC with the approximate inner diameter you want to achieve as an outer radius. Rip/cut the PVC in half. Use temporary spray adhesive to adhere sandpaper to the inner radius. Use this "tool" to sand down the edge to the radius.

Re: Seeking remedies for this...

PostPosted: Tue Nov 10, 2020 3:31 pm
by OP827
I used a radius router bit to make the sanding block for roof line radius. I have combined curves and it worked well.
http://tnttt.com/gallery/image.php?image_id=138794

Re: Seeking remedies for this...

PostPosted: Tue Nov 10, 2020 3:33 pm
by TimC
aggie79 wrote:This may be a possible method to help get a consistent radius edge (although any technique will be a challenge on a curved profile.) Find the appropriate size PVC with the approximate inner diameter you want to achieve as an outer radius. Rip/cut the PVC in half. Use temporary spray adhesive to adhere sandpaper to the inner radius. Use this "tool" to sand down the edge to the radius.


That is just brilliant!

Re: Seeking remedies for this...

PostPosted: Tue Nov 10, 2020 8:20 pm
by Wolfgang92025
My solution is a lot like aggie 79.
I used a piece of wood about 2x6x12"
Marked my radius I wanted and cut it on a bandsaw, Jig saw would also work.
Glued in a piece of 40 grid sandpaper.
Foam doesn't stand a chance and you have a nice radius in no time.
I use the same method to create a 15° chamfer on my roof line.
Lay it out in wood, add sandpaper and you re on your way.

Re: Seeking remedies for this...

PostPosted: Thu Nov 12, 2020 7:50 pm
by KCStudly
Hope this helps!

Here's the post where I started experimenting with kerf filling options (clicky).

This post shows how I laid out guide lines (clicky) for the roof edge radius where there were no spars (that I had previously rounded over with a 3/4 radius bit in the router) to guide off of.

And here is the post where I show how I rounded over the corners of my roof profile (clicky).