Sealing Between Sheets of Aluminum before Riveting

WILDEBILL308 said:

You need the two sheets as tightly together as possible. You will never squeeze out all the sealant.
There is no reason not to use a permanent repair in this instance. If needed it can be repaired or replaced as many times as needed.
Bill

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What would be the best method to get the sheets tight?

1. Use Cleckos until sealant cures then rivet.
2. Use Cleckos and then rivet non-clecko'd holes before sealant cures.
3. Use nuts/bolts until sealant cures then rivet.
4. Use nuts/bolts and then rivet  non-clecko'd holes before sealant cures.
5. Some other/better method.

Permanent adhesives such as 5200 are exactly what the name implies. It will literally stick to fiberglass so well that if you pull it apart the fiberglass delaminates before the adhesive fails. Moderate thickness steel is deformed trying to peel two pieces apart after being glued with 5200. How would you propose to take two pieces of aluminum apart after permanent adhesive is applied? Lets say he hits a corner of a sign and one of the wedge shaped pieces needs to be replaced?

Ken

5200 comes apart with heat.  With the aluminum skin a heat gun applied to the aluminum skin will release the 5200.

I'm not using 5200. I'm going to go with Vulkem 116 since it can be removed if needed.

Whalensdad said:

What would be the best method to get the sheets tight?

1. Use Cleckos until sealant cures then rivet.
2. Use Cleckos and then rivet non-clecko'd holes before sealant cures.
3. Use nuts/bolts until sealant cures then rivet.
4. Use nuts/bolts and then rivet  non-clecko'd holes before sealant cures.
5. Some other/better method.

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I was looking at your pictures, in the next to last you have a place where the skin is bent up (looks like you were prying on it) I would take a flat bar and a mallet or smooth faced (planishing) hammer and smooth the edges as well as you can. See what you can do as you want the metal seams to lay as flat as you can.

The method I would use for installation is.
1. Get everything ready when the sealant is mixed is not the time to be looking for stuff.
2. If you have clecos you can do it by your self Olympic Shaveable Rivets are a  "blind" rivet and do not need someone to buck them.. If you use setup bolts you will need two people. one to hold the nut and one to tighten it or vise versa. I would put a setup bolt or cleco in every hole then start installing by taking the ones in the center out and working out.

3. I would save a little of the sealant or you can use some of the squeeze out  to coat the shank rivets before you pull them. This will help make a waterproof seal. So to save money I would do it when the sealant is wet. If you let it dry you would need fresh sealant for the rivets. If you do let it dry you can clean the dry sealant out of the holes using a stiff brisel bottle brush of the right size. I don't recommend using a drill because you will enlarge the holes and the rivets won't pull right.
Bill

I used a DAP product, Side winder advanced polymer caulk. I contacted Dap and told them I was lapping aluminum over aluminum and would this product work. They said yes, it was designed as a bedding sealant and can be used in standing water. It will not wash out. I applied it with a 1/16 notched trowel on a 2 inch over lap. I don't think you will ever get your aluminum flat or smooth enough to get even contact between the two pieces. It might take a lager notched trowel to fill the voids. I did a test piece with the side winder with rivets spaced 2 inches apart. I removed the rivets and was unable to pull the 2 pieces apart. I was able to cut them apart with a snap off type razor blade fully extended. I had full coverage on the bedded area. I used a pressure washed to test my trailer after the exterior siding was complete. There were no leaks. I used a piece of hardwood with a sharp angle cut on one end to remove any caulk that got by the  masking tape and on too the prepainted aluminum. It cleans up with mineral spirits and has a fairly long open time to work with. I was able to do 16 foot lengths in the Florida sun with no problems.

Have fun with your project and Happy camping, Tom 

Thanks for the suggestions. I'm going to go with the Vulkem (it's already on order), but I like how you attacked your project and may use some of your techniques.

bucks2 said:

Good ideas, but don't Clekos hold the pieces tightly together? I think Whalensdad needs to have the sealant stay between the sheets until cured and then the rivets will hold the pieces in place. If it's squeezed out before cured, then the seal may be compromised.

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Nope, do not let the sealant even get tacky, the sealant goes in wet. Rivet while it still squishes into place. There should be even "squeeze-put" all along the seams.

If the sealant is cured before the parts are riveted, the sealant will not "adhere" to the part that was not touching it. This will allow water to seep through.

I work at Lockheed Martin, building the C-130J. Was at Cessna building small jets before this job. Our sealant comes premixed from a vendor and frozen to -20 to -40. When we put two layers of skin together we very thoroughly clean and dry the overlapping areas while the sealant thaws. Also dip more sealant into the holes, or on the rivets before putting them in.

srs713 said:

Nope, do not let the sealant even get tacky, the sealant goes in wet. Rivet while it still squishes into place. There should be even "squeeze-put" all along the seams.

If the sealant is cured before the parts are riveted, the sealant will not "adhere" to the part that was not touching it. This will allow water to seep through.

I work at Lockheed Martin, building the C-130J. Was at Cessna building small jets before this job. Our sealant comes premixed from a vendor and frozen to -20 to -40. When we put two layers of skin together we very thoroughly clean and dry the overlapping areas while the sealant thaws. Also dip more sealant into the holes, or on the rivets before putting them in.

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I think you are wasting your breath. They know more than a couple of old sheet metal mechanics that actually did the job. Now I only have 35 years experience on F-16 F-22 and F-35 but what do we know.
Bill

WILDEBILL308 said:

I think you are wasting your breath. They know more than a couple of old sheet metal mechanics that actually did the job. Now I only have 35 years experience on F-16 F-22 and F-35 but what do we know.
Bill

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I didn't know you built new planes or repaired old ones with 40 year old bent used metal. That's some pretty good experience to have. What did you do with a piece of metal that came to you with a bend at the wrong place at the factory? Did you put that onto the plane?

PS, How much used sheet metal did you put on the F22's?

Ken

bucks2 said:

I didn't know you built new planes or repaired old ones with 40 year old bent used metal. That's some pretty good experience to have. What did you do with a piece of metal that came to you with a bend at the wrong place at the factory? Did you put that onto the plane?

PS, How much used sheet metal did you put on the F22's?

Ken

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Well Ken at the factory you just send it back to who made it. Not many used/recycled beer cans in the F-22 or the F-35. When I was working on B-52s and KC-135s in the AF you would take the broken part or parts off the plane take them to the shop and fabricate a new part then take it back and install it.
I might be wrong but I think I have a pretty good idea on how to re do the joint in a travel trailer.
Bill

Exactly Bill. You said: "Quote from: WILDEBILL308 on September 20, 2015, 08:13:00 PM
I think you are wasting your breath. They know more than a couple of old sheet metal mechanics that actually did the job. Now I only have 35 years experience on F-16 F-22 and F-35 but what do we know.
Bill"

My point is, your experience you quoted is with new parts. The OP is working with old pieces. He's not fabricating new. Look at the pictures again. Not even close to nice new clean sheet metal. He's trying to do a job that is not at all like factory work. He has warped, bent metal, elongated holes, corrosion, things you wouldn't think of trying to make do with on a new plane or even an old plane. You may also know very well how to work with old as do many others of us.

I spent last week watching 70 year old planes fly 400+ MPH. Their sheet metal doesn't look at all like the OP's trailer.

Ken

bucks2 said:

Exactly Bill. You said: "Quote from: WILDEBILL308 on September 20, 2015, 08:13:00 PM
I think you are wasting your breath. They know more than a couple of old sheet metal mechanics that actually did the job. Now I only have 35 years experience on F-16 F-22 and F-35 but what do we know.
Bill"

My point is, your experience you quoted is with new parts. The OP is working with old pieces. He's not fabricating new. Look at the pictures again. Not even close to nice new clean sheet metal. He's trying to do a job that is not at all like factory work. He has warped, bent metal, elongated holes, corrosion, things you wouldn't think of trying to make do with on a new plane or even an old plane. You may also know very well how to work with old as do many others of us.

I spent last week watching 70 year old planes fly 400+ MPH. Their sheet metal doesn't look at all like the OP's trailer.

Ken

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Can you please show me what part of my advise wouldn't work? Perhaps you can share with us what you have as experience that makes you such an expert on my knowledge and experience. Yes please tell us about your skill level and experience please. You apparently choose not to understand that working on B-52 and KC135 aircraft will give you lots of experience working on old corroded bent damaged sheet metal.
Stephen S. and I have had Both formal training and a great amount of experience in the field. You will note I recommended to the OP how to smooth out some of the dings and dents Because I have done that before. Now if It was my trailer I would have repaired it so you wouldn't be able to tell it had ben repaired but I was trying to help the OP get as good of job as he could with what he was working with.
Bill

Can you please show me where I said your advice wouldn't work? Can you please show me where I said I was an expert?

Here's what you said you were an expert on, "Now I only have 35 years experience on F-16 F-22 and F-35" Did you forget to add the B52 and KC135 experience in there? Or perhaps you just got that experience since you wrote the post? Because it says you have experience on only 3 specific aircraft. That is your direct quote of your stated experience, isn't it?

Ken

bucks2 said:

Can you please show me where I said your advice wouldn't work? Can you please show me where I said I was an expert?

Here's what you said you were an expert on, "Now I only have 35 years experience on F-16 F-22 and F-35" Did you forget to add the B52 and KC135 experience in there? Or perhaps you just got that experience since you wrote the post? Because it says you have experience on only 3 specific aircraft. That is your direct quote of your stated experience, isn't it?

Ken

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I did not know I had to submit a complete resume of my job experience to you before offering advise to the OP. I did mention in ? Reply #30 on: September 20, 2015, 09:21:30 PM ? outer experience. The 3 specific aircraft that I mentioned are 3 of the most sophisticated aircraft to ever fly. This would lead an intelligent person to understand that perhaps I might have some skill and training.
Now what training do you have? All I see is an attempt to be the winey snarky blowhard who tries to pick someone else's post apart. 
Bill

I just re-read the entire thread. Here's the first "Snarky" comment.

"I think you are wasting your breath. They know more than a couple of old sheet metal mechanics that actually did the job. Now I only have 35 years experience on F-16 F-22 and F-35 but what do we know.
Bill"

It was your comment, as everyone that bothers to read the thread can see. You get the last word, I'm done with you. And everyone will notice whose blood pressure is up and needs their medication.

Ken