Aluminum sides - cut to fit before install?

[uberpixel]

I'm getting ready to skin my 5x10 teardrop using 5x10x.040 5052 aluminum, and I'm curious how people are attaching their sides. I have a general plan, but my main question is - do people pre-cut their side panels to size? That's where my plan is currently breaking down. I could try to place the full 5x10 sheet on the side of my trailer and mark it, rough trim with a power shears (or jigsaw) and then try and follow the steps below. But with the sides rough cut to within 1/4", I'm not sure if the tape method will work...

The example I cite below looks like the sides have already been cut to their final shape (probably using a production template). If I don't pre-cut the sides I don't see how to apply adequate pressure all around the sides. I can create a ledge to set the sides on so at least the bottom edge will be aligned, but it gets a little wishy-washy after that.

Here's the OregonTrailR youtube video https://www.youtube.com/watch?v=u93RJZp648A and would like to generally follow their method which I interpret as:

Roof:
1. Apply Flexible latex adhesive/caulk around perimeter and vent opening
2. Place aluminum sheet on roof, staple one end, then use ratchet straps to hold in place/form the curve (I would probably strap first then staple all around)
3. Secure remaining perimeter with stainless staples
4. Router/trim edges as necessary

Sides:
1. Apply flexible latex adhesive/caulk around perimeter and door/window opening
2. Place PRE-TRIMMED aluminum sheet on side using pins in harness holes or ledge to help position (this is where I get into trouble)
3. Use J-Roller to press edges of aluminum into adhesive/caulk
4. Tape edges to hold aluminum flush to edges of sidewall

I'm hoping to start skinning in the next week or so, so any advice would be greatly appreciated!

-uberpixel

[Lile]

Well this reply is a little late, I hope your process went well,you're probably already done with it, but here are some suggestions maybe others will benefit from.

DON'T use stainless fasteners with aluminum. Zinc plated or galvanized actually has less galvanic action with aluminum than stainless.

Latex caulk isn't a particularly good material for trailer waterproofing under the skin. It'll work pretty good for a while, but a trailer gets a lot of twisting and torqueing forces as it goes down the road. You want a caulking material that flexes and never dries out. Butyl caulks come in a strip like tape, or can also be bought in sheets on a roll about 6" wide. The butyl remains flexible, seals around fasteners, is forgiving as things flex. It remains sticky and gooey.

I would not use staples on aluminum - I would use screws, as I think they will seal better against butyl tape underneath. I have also used roofing screws, with the little rubber washers, but I think they are kinda ugly.

Frank Bear's folks at Vintage Technologies recommend only fastening the aluminum at the edges, letting it float otherwise.

So the edges look like this:

Corners and edges, areas around vent etc use butyl window flashing available from big box hardware stores. It's not a bad idea to cover the whole trailer in this stuff.


At the very edge, under your edge trim, use butyl rubber tape 1" wide. Keep it in the fridge (not the freezer) for a day to make it easier to work with.

Set the sides and fasten the bottom - Butyl rubber tape, then siding, then aluminum trim, screws through the aluminum trim and through the tape. You can also clamp the bottom edge in place, rout it to shape, then do all the butyl tape and flashing.

Use a router with a follower bit to get the sides perfectly aligned with the top edge. Apply butyl rubber tape to the roof edge after you run the router (oops)

Set the top at one end, letting both sides hang over. Clamp the end or fasten it Use a couple of ratchet straps to get the top skin in place. Rout the edges with a follower bit against the sides. Butyl tape is already in place under the edges. Use aluminum trim strip with fasteners drilled directly through the trim strip and the tape3 to hold it in place. I'd use a row of screws and tape underneath the aluminum around any penetrations, vents, etc. Doors and windows should have their own sealant or gasket against the skin and so should not require additional screws.

I don't see a need to use adhesives on aluminum skin, and I'm not sure I would recommend it.

Let us know how your project came out!

I'm getting ready to skin my 5x10 teardrop using 5x10x.040 5052 aluminum, and I'm curious how people are attaching their sides. I have a general plan, but my main question is - do people pre-cut their side panels to size? That's where my plan is currently breaking down. I could try to place the full 5x10 sheet on the side of my trailer and mark it, rough trim with a power shears (or jigsaw) and then try and follow the steps below. But with the sides rough cut to within 1/4", I'm not sure if the tape method will work...

The example I cite below looks like the sides have already been cut to their final shape (probably using a production template). If I don't pre-cut the sides I don't see how to apply adequate pressure all around the sides. I can create a ledge to set the sides on so at least the bottom edge will be aligned, but it gets a little wishy-washy after that.

Here's the OregonTrailR youtube video https://www.youtube.com/watch?v=u93RJZp648A and would like to generally follow their method which I interpret as:

Roof:
1. Apply Flexible latex adhesive/caulk around perimeter and vent opening
2. Place aluminum sheet on roof, staple one end, then use ratchet straps to hold in place/form the curve (I would probably strap first then staple all around)
3. Secure remaining perimeter with stainless staples
4. Router/trim edges as necessary

Sides:
1. Apply flexible latex adhesive/caulk around perimeter and door/window opening
2. Place PRE-TRIMMED aluminum sheet on side using pins in harness holes or ledge to help position (this is where I get into trouble)
3. Use J-Roller to press edges of aluminum into adhesive/caulk
4. Tape edges to hold aluminum flush to edges of sidewall

I'm hoping to start skinning in the next week or so, so any advice would be greatly appreciated!

-uberpixel

[uberpixel]

Thanks for the response. I haven't started skinning yet - probably tomorrow...

Based on your instructions, I don't think I stated my question clearly enough. And realize that I left out my plans for the corner trim and overall sealing strategy.

I mostly wanted to know if people pre-cut the sides to shape before they attach. I think I'm going to prop my sides in place, mark with a sharpie and then cut to within 1/8" of the mark with a jigsaw - then align and clamp the bottom and front edges and router the roof and back to match the side profile.

Also, I intend to use the typical aluminum "insert trim" on the corners, so I'm not sure how I would work around screws.

As far as my plan to seal the perimeter, I'm planning to use 1.5" wide 3M 4411N extreme sealing tape. This will go on and wrap the corners after the aluminum sides and top are trimmed to fit, then I will put the corner insert trim over the top of the tape. Then pre-drill and screw the trim down with a dab of Proflex in each screw hole. The caulk I mentioned would go between the plywood roof/sides and the aluminum skin and is mostly to just hold the perimeter of the aluminum walls in place until the corner trim goes on, not to be relied upon as a key part of the fastening or sealing system.

So, like countless others on this forum, it looks like I'm asking for advice, getting an answer, and then deciding to proceed with my original plans even though I've never done this before.

There's still time to tell me I'm making a huge mistake, but soon it'll be done and after that I'd rather live in ignorant bliss and hope I never have a problem with leaks/etc.

Good tip on the zinc vs. stainless. I didn't realize, but now I know!

-uberpixel

[eLink]

Here's the OregonTrailR youtube video https://www.youtube.com/watch?v=u93RJZp648A and would like to generally follow their method which I interpret as:

Roof:
1. Apply Flexible latex adhesive/caulk around perimeter and vent opening
2. Place aluminum sheet on roof, staple one end, then use ratchet straps to hold in place/form the curve (I would probably strap first then staple all around)
3. Secure remaining perimeter with stainless staples
4. Router/trim edges as necessary

Sides:
1. Apply flexible latex adhesive/caulk around perimeter and door/window opening
2. Place PRE-TRIMMED aluminum sheet on side using pins in harness holes or ledge to help position (this is where I get into trouble)
3. Use J-Roller to press edges of aluminum into adhesive/caulk
4. Tape edges to hold aluminum flush to edges of sidewall

-uberpixel

I am getting ready to skin my camper soon as well. It looks like the Oregon Trail'r team is applying the latex caulk to unfinished plywood. But most people here recommend sealing the plywood with epoxy or polyurethane first. In that case I'm wondering if the caulk will cure properly.

[halfdome, Danny]

I'm not a fan of floating aluminum skins to the teardrop.
I use Contact cement on the walls and skins.
Not one of the 6 teardrops I've made have had any problems with this method.
I don't reccomend using a scroll saw to rough cut the aluminum as the vibration of the saw will scratch up the aluminum.
I use pneumatic shears to rough cut the aluminum.
Make sure you use a 2 flute router bit at the minimum, when routing, or you may run into problems.
I use an Amana Tool 1/4" solid carbide aluminum laminate trim bit # 51430 with twin bottom bearings and spiral cut.
It's a bit pricey , over $60, but is perfect for the job at hand.
Danny

[uberpixel]

I am getting ready to skin my camper soon as well. It looks like the Oregon Trail'r team is applying the latex caulk to unfinished plywood. But most people here recommend sealing the plywood with epoxy or polyurethane first. In that case I'm wondering if the caulk will cure properly.

Well - 20 minutes ago I finished coating the exterior of my plywood with poly... Hadn't really considered if the caulk would cure.

I was planning to use this stuff (Big Stretch) https://www.lowes.com/pd/Big-Stretch-10-5-fl-oz-Clear-Paintable-Latex-Caulk/1000327793 since it was recommended by Oregon Trail'R but it's water based - so as you point out it may never cure... Maybe I'll just skip it or look for a non-water based option since I'm not really sure what it's accomplishing. I have some Proflex - maybe I'll use that instead.

-uberpixel

[uberpixel]

I'm not a fan of floating aluminum skins to the teardrop.
I use Contact cement on the walls and skins.

What contact cement do you use?

I don't reccomend using a scroll saw to rough cut the aluminum as the vibration of the saw will scratch up the aluminum.
I use pneumatic shears to rough cut the aluminum.

Looks like a trip to Harbor Freight is in order...

Make sure you use a 2 flute router bit at the minimum, when routing, or you may run into problems.
I use an Amana Tool 1/4" solid carbide aluminum laminate trim bit # 51430 with twin bottom bearings and spiral cut.
It's a bit pricey , over $60, but is perfect for the job at hand.
Danny

I have a down cutting trim bit I used on Formica that I could probably sacrifice for this job.

Thanks for the suggestions!

-uberpixel

[halfdome, Danny]

I use Wilsonart 951 contact cement spray grade in 5 gallon size which isn't a consumer product but you can get the consumer brush/roller gallons from Home Depot.
I've used the gallons many times before and it works great.
Danny

[uberpixel]

I use Wilsonart 951 contact cement spray grade in 5 gallon size which isn't a consumer product but you can get the consumer brush/roller gallons from Home Depot.
I've used the gallons many times before and it works great.
Danny

After reading several recommendations on the contact cement approach, I ended up going this direction instead of the "floating skin method" I described in my first post in this thread.

Here's what I ended up doing:

For adhesive, I used the classic DAP Weldwood solvent based stuff since I have had good experience with Formica countertops in the past (wear a mask and open the garage door). I started with the front wall and the roof panel. Just rolled it on both sides - placed wood spacers to prevent premature adhesion - lined up one edge - pressed in place - then remove wood spacers one by one and press in place. Hit it with a J-roller and done - just needed a little edge trimming with a router then on to the sidewalls. Dry fit sidewall panels with bottom and front edges lined up, traced the shape, pre-cut with 1/4" buffer. Tried using an electric shears from Harbor Freight, but it was not working well at all - probably would work fine with a decent shears but the $42 Harbor Freight option was garbage. Ended up using a jigsaw instead. Definitely need to protect the aluminum from scuffing or make sure you are running the saw on the backside of the aluminum sheet. Followed same application process for the sidewalls, lined up the bottom and front, put wood buffer pieces to prevent premature adhesion, then progressively press it in place.

One trick I found that worked really well... To locate and accurately pre-drill the porch light hole (or other holes) in the aluminum skin, I made my porch light hole (in the plywood) big enough that I could stuff the wires back into the hole, then placed a magnet on a piece of masking tape and basically tape the magnet into the hole. Then when you dry fit the aluminum panel, use another magnet to find the taped magnet. Trace a circle around the outside magnet, remove the dry fit panel and drill away. Then when you stick the drilled panel in place, you just need to use a hook tool to fish the wires out through the hole. Worked great!

First impression on the contact adhesive method is that it worked great and I have no complaints. Time will tell if the fabled thermal expansion issue arises, but the more I thought about it, it just seemed like floating would almost guarantee rippling as a result of thermal expansion whereas contact cement might help prevent or manage it to a certain extent. Even with the "floating" approach, the skin would still be locked in enough places (doors/windows/trim) that I think it would still ripple. We'll see... I'm certainly no expert as this is only my first build.

-uberpixel

[tony.latham]

...then placed a magnet on a piece of masking tape and basically tape the magnet into the hole.

Well... I'd call that brilliant.

Tony