I'm planning on replacing a 4x12 foot section of skin.
My plan is to drill out the rivets, remove the old skin, take the old and new skin to a sheet metal shop and have them make an exact duplicate - rivet holes and all.
As many of you know Peter H replaced a large section of skin on his motorhome - he and I have been discussing this, and his view is not to pre-drill the rivet holes.
Soooo what do all you skin experts think? If I don't predrill, then I'm not sure how should I drill the rivet holes - especially where the new skin overlaps the old skin (therefore cannot see where to drill the holes).
Do as you please, but I would not pre drill rivet holes.
Before removing old skin, I mark reference points for the new AND old skin by superimposing new over old.
When new is in place, use old to find hidden holes in the frame.
Dick
I would use the method Dick recommends, but rather than try to hit a new hole on top of a hidden hole, I would move the hole about 3/16" to the left, right, up or down so that you completely miss the old hole underneath. Otherwise, you will always be off by just a little, and that will cause wrinkles. So I would use the old hole pattern as a guide where NOT to put the new holes.
I would first remove the section to be replaced, and trace it on the new metal. Cut out the shape you require afterwards, with an air shear for the straight cuts, or a nibbler for tight curves, if necessary.
Then use a grid of wide strips of masking tape to protect the new panel, lay the old panel on the new panel and mark the old hols on the masking tape.
This way you know where the ribs are, and where the old holes are, in approximation.
I would take markdoane's idea from here, using new holes.
One thing I am not sure of, is whether to go long rivet lines first, or short ones, to avoid wrinkles.
I guess down the center one on each rib would work, then up or down.
Good luck - this will be one of my projects in the future.
So do I then take the masking tape off then put back on again away from the old holes?
I thought drilling out the old rivets would be the toughest part.
I still wonder if would make swiss cheese out of the frame.
I have worked with the inside skin of my 59 - removing old panels and reassembling - also worked with the belly. Guess this is much more involved............
Just a guess on my part on the rivet installation pattern but here goes.
Install all the top row rivets first starting at the center and working toward either side on the horizontal. I would then start down the ribs installing the rivets the same way, working horizontal across the ribs.
This of course assumes you have the trailer parked, chocked, and the stabilizers down. I would be sure it is level for good measure.
Working the rivet lines in this manner should eliminate the chance for wrinkles. The top row will need to be in the old holes so the repair looks right.
I would bet Andy from Inland could tell you for sure if you send him an email
__________________
Brett G
WBCCI #5501 AIR # 49
"Stop worrying about the potholes in the road and celebrate the journey." -- Fitzhugh Mullan
Wise men talk because they have someting to say; fools, because they have to say something. -- Plato
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Dont move the tape, just drill the new holes a little to the side of the holes as marked on the tape. The entire set of holes in one dirction are all offset in the same direction.
You could even move each hole a little bit closer to the start point, so that at the other end of the row you would end up with one extra rivet hole.
Where you have vertical and horizontal rows intersecting, use the original hole location so that the rows line up.
The extra holes in the floor channel is not going to compromise the integrity. I would be more worried about loose rivets if you tried to match up the old holes and ended up being 1/16" off center.
Also, I would use Cleco temporary fasteners so that the sheet lies flat without wrinkles, then I would start in the center and work out.
I replaced my interior skin so had a bunch of holes to drill and wanted some uniformity in spacing of the rivets. I drilled 1/8" holes in 3/16" thick aluminum strip to use for a template, then used a spring loaded center punch to dimple the panels before I installed them.
I think I understand what your saying except where the new goes underneath the old - should I use the holes in the old skin and drill into the new skin?
Well, I would likely not move the tape, but rather drill next to the rivet mark from the old sheet. This way you are not likely to hit the same old rivet hole again, which might be elongated by now or too large. Make new, tight, accurate holes, in both the new sheet, and the rib.
All the suggestions so far have been good ones, in my opinion.
I like the temporary fastener idea to affix the panel before securing it permanently. I wonder if one cold use double sided carpet tape on the ribs to hold the panel while drilling and riveting.
I own an air rivet gun, which is a huge improvement over a hand riveter.
Also, I purchased a rivet drill set from Andy at InlandRV. The drills he sold me are the best I have ever used for this purpose. I am still only on the second drill bit for the 1/8in rivets, broke one when I hit a frame section while removing a belly pan section.
My air riveter came from Sears a few years ago. It appears to be better quality than the ones available from harbor Freight etc. having the right tools makes a huge difference, even if you have to learn how to use them first.
Sometimes the panels are very tightly bonded with sealer. It feels like you missed a rivet, but the panel is actually glued in place..
Good luck!
Ken,
(regarding where the old skin goes over the new)
Yes, definitely. Just make sure to hold the drill nice and square. I assumed from your first post that where the old skin was on top of the new, you would drill straight through. The problem is where the new skin is on top of the old, it's almost impossible to get good alignment.
There are hole guides that will tranfer hole locations from underneath, but they only work for sheets that are less than about 12" from the edge.
Uwe, now that I'm the new expert on skin replacement
what I plan to do is use Cleco's to hold the skin, get everythink lined up before I start riveting.
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