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wavy skin

PostPosted: Sat Aug 23, 2008 3:17 pm
by looped
I got the 1/8th glued down on the lil fart the other day. the edges are good with the help of the straps and a few finish nails but in the middle section there is a slight wavy-ness to it. it isnt plain to see but when dragging my hand across it i can fell it just a little. if i go with a high gloss finish it would show its ugly head pretty well.


My question is this. would adding a second layer of 1/8th ply correct this or would it just become a thicker, wavy piece of wood? as far as the strength aspect the one sheet of 1/8th would suffice it seems.

PostPosted: Sat Aug 23, 2008 3:20 pm
by starleen2
How many spar do you have underneath it? are the waves horizontal across the tear? Not sure about the 1/8 most use two layers of 1/8 to make 1/4.

PostPosted: Sat Aug 23, 2008 3:38 pm
by looped
well the spars are as pictured..

Image

the wavy is happening where the top meets the front radius. we did everything we could think of to get it on there tight.

when looking it looks smooth but dragging a hand across it i can feel the ripples a bit, maybe i am asking too much from one layer of 1/8th.

right now i could vinyl it and it would look good but i am also thinking that a high gloss paint job would also be an idea, if i could smooth it out

PostPosted: Sat Aug 23, 2008 4:33 pm
by starleen2
if the budget supports it, I'd put another 1/8 layer on it and see what happens - if it's still wavy use some bondo or other type of filler to smooth it out if your going to paint it (need to do this with a super glossy paintjob any way), but only if the waves are not too deep - more than a 3/16 ? Might want to use a straight edge to measure how deep the waves are. Being an upholster in a former time - MPO is not to put any fabric or vinyl on the outside because eventually it WILL need replacing - vinyl – no matter what the type or grade does not last forever outside – even with cleaning and protectorate – Just my two cents worth ;)

PostPosted: Sat Aug 23, 2008 5:04 pm
by Gage
starleen2 wrote:<snip> Not sure about the 1/8 most use two layers of 1/8 to make 1/4.

Not sure about that statement. Only the unknowing who don't want to listen use 1/4" or two layers of 1/8".

PostPosted: Sat Aug 23, 2008 5:14 pm
by Gage
What's that, 6' wide?

Image

Add a spar in between your existing spars and glue the hell out of it. Don't use Gorilla Glue to attach the skin to the spars. Gorilla Glue foams and you don't want that there. Use either Liquid Nail or Titebond.

PostPosted: Sun Aug 24, 2008 3:00 am
by looped
it is 42.5 wide the spars are between 4 and 6 inches apart the first skin is on there and i will be putting another 1/8 on there. i used titebond 3 to glue it down.


When gluing the second layer on there i am guessing to trowel on some titebond 3 in a good coat and then apply, right? if there is a better way to attach the second sheet of 1/8th i am all ears.

PostPosted: Sun Aug 24, 2008 3:04 am
by looped
starleen2 wrote:....... but only if the waves are not too deep - more than a 3/16 ? Might want to use a straight edge to measure how deep the waves are. ;)



put a straight edge on the top there is about 1/16th gap in the lows,, and the wood has a lot of flex there so i plan to put a second layer of 1/8th on it.

PostPosted: Sun Aug 24, 2008 3:54 am
by Gage
Sounds like your spar may be bowed slightly and the 1/8" ply is just following it. Chances are that the 1/16" won't even be noticed. If you bond two pieces of 1/8" together, your still going to have the dip. Think about it. :thinking:

That's being as nice as I can be.

PostPosted: Sun Aug 24, 2008 4:13 am
by looped
Gage wrote:Sounds like your spar may be bowed slightly and the 1/8" ply is just following it. Chances are that the 1/16" won't even be noticed. If you bond two pieces of 1/8" together, your still going to have the dip. Think about it. :thinking:

That's being as nice as I can be.



its between the spars that it is getting wavy..

Either way i will be putting another layer if just to take away some of the flimsy-ness on the top..

would titebond be the best to glue a large area or would another glue like subfloor adhesive work better?

PostPosted: Sun Aug 24, 2008 5:59 am
by GPW
Loop, you could stagger the seams in the roofing ,with the second layer,or just add a second spar for more support at the transition line ... we had a similar problem at the ply join over a single narrow spar...a thicker roof is always a good thing...since we had a few limbs go through the thin 1/8" roof on our Jayco... :o

PostPosted: Sun Aug 24, 2008 6:07 am
by looped
there is no seam in the skin. it is all one piece.. adding spars is not an option as there is a layer already there and well with the glue and clamping being done and then the excess trimmed off the edges it is fair to say that this layer isnt going anywhere. well unless i want to completely destroy this trailer to replace the skin that is already permanently affixed to it.

PostPosted: Sun Aug 24, 2008 7:33 am
by Hoosier Greg
My first suggestion would have been what Gage said add more spars .Since that is not an option,it might be a good idea to use titebond in the level areas (thinner) and liquid Nail (thicker) in the areas where the dips are. Except lay a heavy bead of liquid nail and trowel it on to fill the the low spot.
Just an Idea ... :thinking:
Greg

PostPosted: Sun Aug 24, 2008 7:37 am
by Mark72
Loop, I haven't used tIII but i did use it on my build. I would think that either one would be a good choice between the layers of ply. I went to the website and the only major difference I see is that the wii has a longer open time than the tII . I would stay away from any of the poly glues as they foam when they are curing and would push the 2 layers apart with more force than you could likely get clamped down. Another thing to consider, Is there any way to make sure the plies are clamped tight together in those low spots? I see your ceiling is already installed. Are there any access points where you can install props against the floor to hold the lower ply up tight against the top one? Maybe you have some openings for dome lights or some other places you can use for that.

Mark

PostPosted: Sun Aug 24, 2008 6:45 pm
by looped
After doing some thinking on it i am considering this as a possible remedy.

ya see the low spots are the spars and the bend of the arch is the same as the bend of the birch and as you can see in the foreground of this pic the birch bends very easily in this direction
Image

So i am thinking to put a second layer on there cross grain. if i start from the back i can put the seam on a spar up front. the total length of the skin that is on there is 5'5-1/2" so that would put the seam on the front well enough to be covered by or butted to the metal that will be the stone guard.

I found a source for some color anodised diamond plate at a fair price so that would make the butting to the second layer a possibility.
link