SPAR Masters: To round or not to round is the ?

[Guy]

Dear Spar Masters?

If you are putting straight spars across the width of the tear, do you round the part of the spar that comes into contact with the curve of the roof?

[Nitetimes]

I didn't round off any of mine, others may have but I didn't find it nesessary. Everything rolled over just fine. Maybe if you were using a very tight short radius it would help a little.

[TomS]

I kept mine straight.

[toypusher]

I agree with Nitetimes. I did not round over the spars and had no problems with the interior or exterior skins. My spars were only 3/4" in width (1 1/4" x 3/4") with the exception of each side of the vent and where the hatch attaches. These were doubled to 1 1/4" by 1 1/2" for extra strength and attaching surface.

[Steve_Cox]

Hi Guy,

My spars are 2X2 yellow pine. I rounded the spars in the tighter radii. I didn't want gaps between the spar and the 1/4 plywood. I didn't use any screws, nails or staples. Epoxy thickened with wood flour was all I used as adheasive to hold the top on. There are more ways to skin a TD than you can shake a stick at...

Steve

[Hardin Valley Magic]

I left mine square 2x2's. The front of mine is a 28" radius and the rear is a 60" radius. Seems to work, no real flat spots to speak of.

[TonyCooper]

I used 1" x 2" oak spars and left them squared.

[luluyug]

you guys are reading my mind! please stop before i go see a doctor...
i am using an 18 inch radius so i may have to round a few ones (i will use 2x2 off pin on that.

[doug hodder]

I would think that if you are concerned, just draw out the profile on a piece of paper and check the distance that a 2x2 spar or whatever size you are going to work with is compared to the curve...I'm willing to bet that you'll find it isn't that big of a deal....just my opinion...but I might be wrong... .doug

[Chris C]

I agree, Doug. It'll only make a significant difference on tight radii. I'd think most of the glue surface which holds the roof down is on the walls anyway.

[madjack]

...if you're worried about the gap, then use a good pl contruction adhesive...it'll fill the gap, making up any difference...FWIW, we used 4/4x6/4, rectangular, oak ribs on a 24" radius and the gap was extemely minimal
madjack

[Steve_Cox]

I confess, the reason I rounded the corners off my 2X2 spars is because when I glued and screwed the spars in place I put the center of the flat side of the spar flush with the edge of my plywood and the spar corners were sticking up in the radii. Took only seconds to knock off the corners with the belt sander and a 60 grit belt. Also, in any joinery work I do, I don't believe in gap filling unless it is to cover mistakes I made and chose not to go back and do over, and I have quite a few, even a couple in structural areas. When using the table saw, planer and measuring where to drill holes in trim etc, I use dial calipers and measure in thousandths, my accuracy with tools isn't close tolerance however,(can't see like I could when I was 30) but when you are measuring in thousandths of an inch, you can miss your mark quite a bit and still be pretty close..

JMMFO

Steve