Sheet metal to sheet metal glue/sealant recommendations?

[JDecker-SKO]

Hi all,

Getting lined out to start buttoning up my roof raise, and need some advice.

As the title says, Im looking for a good glue/sealant for sheet metal to sheet metal use. Sheets are 20 GA galvanized, and will be screwed together every couple inches as well.

I had hoped to use PL premium or the like (polyurethane construction adhesive), but further research indicates it needs at least one side to be porous, as it is cured by moisture. I don't think the middle inch would ever completely cure on a joint with 2" of overlap.

Our mechanic at work suggested 3M body panel adhesive, which is recommended for van bodies and the like, but I have three issues with it:
1. Two part epoxy is a PITA
2. Cost is $40/200ml. Yikes!
3. I worry an epoxy will be brittle and eventually cracked from vibration.

So, what have you had success with?

Jdecker

 

[jazty]

If you're planning on skipping mechanical fasteners and going an adhesive-only route then you might want to look into 3M VHB tape.

If you're planning on riveting, screwing or bolting the metal together then just get some automotive seam sealer. I actually used a black butyl vapour barrier caulking (Acousti-Seal by LePage) which has the same ingredients as seam sealer, but it's a bit goopier. I tried another brand of vapour barrier caulking which was completely different and unusable.

 

[Tango-SKO]

Contact Sika Corporation for a recommendation. They make some of the most advanced adhesives on the planet and have several lines specifically for metal to metal. A couple are rated stronger than welding or riveting. Most cars, trucks, trains and airplanes today use these types of adhesives in place of mechanical attachment in many situations.

 

[SR2K]

I'd say grab a little mig welder and lay a bead the whole length of it.

 

[Peasant Racing]

I'd say grab a little mig welder and lay a bead the whole length of it.

That's what I would do. No worries about it falling apart and given the price of MIG wire it might also be the cheapest method.

 

[aaronsb]

I'd go with sikaflex or the vhb tape. Is the original chassis riveted? Try to copy the techniques the factory used to join the panels.

 

[slaughridge85]

I'd go with sikaflex or the vhb tape. Is the original chassis riveted? Try to copy the techniques the factory used to join the panels.

This, also if he's not an experienced welder, trying to lay a bead on 20 ga sheet is gonna warp and oilcan the piss out of it...

 

[2kool4skool]

This to That (Glue Advice)

 

[Jolly Roger-SKO]

I have been around sheetmetal for a long time and I prefer sonolastic master seal NP-1 if it is for something you might want to take apart and re-use later just seal the seam outside and or inside or you will waste the edges getting it apart. Run a bead between the two pieces and water to wet your fingers or putty knife to spread out what whatever squishes out when you screw/rivet the pieces together and also cover the screws/rivets I like a small bucket of water and to use my finger but to each his own. Every exterior seam on my bus was caulked before painted.
I am only primered and only because of the neighborhood HOA and the county but its in my driveway and I can work on it when I have time. With almost any sealer exposed .try to keep the exposed beads adequate but small because no matter what brand is used the paint on the sealant is going to crack and expose the caulking regardless. Are as suggested you could go more money and get the tape because it will fit your seams and not squish out for the paint to cover.
I do recommend looking at your manufacterer's web site and or calling them to see what was originally used? The panels I took off were because of rust and the sealant was completely dried up and came off with a fingernail or small scraper and no residue left on the panel's so I sealed everything I didn't remove.
I used NP-1 because it was free from the company I worked for (many a partial tube left at the end of the day ) and they bought 20-30 cases at a time and I know what it is like to take something apart with just the way it was used in my work much less the stuff I have used it for personally. Temporary fixes that worked and had to get back to the pieces? Sonolastic has been around as long as sikaflex and both probably owned by the main provider for all BASF the chemical company.

 

[2kool4skool]

This is very good info. and from a person that actually knows and has made a living doing this, not from some self proclaimed expert.

 

[paulnack]

Reviving an old thread-

So, OP, what did you end up using and how did you like it?

 

[Brewerbob]

Reviving an old thread-

So, OP, what did you end up using and how did you like it?

Revived again.


And how much was needed? I've got 48" wide sheets with the 2" overlap. 5 sheets per side.

 

[peterbylt]

When I covered the windows on the MCI I used Sikaflex 252, No screws or rivets, I used 18 Gauge paint grip steel, which is a form of galvanized primer coated steel.

The sheets are approx. 10 foot by 4 foot and weigh at least 100 lbs.
Do not use Sikaflex 252 if you plan on removing it at some time, this stuff bonds good.

It has been on there for 2 years at this time and it does not show any sign of coming loose, I am sure you would bend the metal before the Sikaflex failed.

Peter

 

[Brewerbob]

When I covered the windows on the MCI I used Sikaflex 252, No screws or rivets, I used 18 Gauge paint grip steel, which is a form of galvanized primer coated steel.

The sheets are approx. 10 foot by 4 foot and weigh at least 100 lbs.
Do not use Sikaflex 252 if you plan on removing it at some time, this stuff bonds good.

Peter

Thx Peter. Sounds like fancy steel. My steel is NOT fancy. It's plain cold rolled. Will that make a difference? Probably not if yours is still good with no mechanical fasteners. I don't need it to "glue" the metal together. I have the rivets for that. I just want it waterproof-ish. The ish is on the end because I plan on spray foaming so that'll stop whatever water from coming into the real interior of the bus. I still don't want puddles between the exterior and the insulation tho.



P.S. You're getting old. Your sheet metal wasn't at least 100 lbs. It was only 80 lbs. 18 gauge is 2.0 lbs per sq foot. It certainly feels like more than that especially if you are trying to carry/hang a 10' sheet by yourself. The 8' sheet that was cut down to 6' was a breeze with the suction cups.

 

[peterbylt]

The Sikaflex is definitely waterproof, no leaks at all.

I also ended up welding in cross supports on the covered windows to prevent any oil canning of the large expanses of the Sheet metal, then I had the inside of the windows Spray foamed (along with the rest of the bus), we are very pleased with the result.

If using Sikaflex 252, make sure both surfaces are extremely clean for a good bond.

Try not to get it on anything, almost impossible to clean off with any type of solvent, especially skin, I used a scotch brite pad to sand it off my skin, my friend who helped me left his finger prints permanently displayed on the outside of the sheet metal.

P.S. Yes, I am getting old, Its better than the alternative.

Peter

 

[Brewerbob]

I also ended up welding in cross supports on the covered windows to prevent any oil canning of the large expanses of the Sheet metal, then I had the inside of the windows Spray foamed (along with the rest of the bus), we are very pleased with the result.

Peter

You glued along the new horizontal too right? I've got plenty of window frames because skoolie but with those long bead lines you probably used the same or more. How many tubes did you go thru?

 

[EastCoastCB]

Revived again.


And how much was needed? I've got 48" wide sheets with the 2" overlap. 5 sheets per side.

I'd think 3 or 4 tubes of the 550 would be enough but I've not done a whole bus up with the stuff yet.
It stays flexible.

 

[Brewerbob]

I'd think 3 or 4 tubes of the 550 would be enough but I've not done a whole bus up with the stuff yet.
It stays flexible.

I'd like to buy online wherever it is cheapest. If I run out, it needs to be something the box store carries.

 

[Brewerbob]

I'd think 3 or 4 tubes of the 550 would be enough but I've not done a whole bus up with the stuff yet.
It stays flexible.

P.S. I was thinking like 12 for a double bead.

 

[peterbylt]

Yes I glued the cross bars as well.
(I glued everything, including myself)

If I remember correctly (I might not, because I am old ) I used a tube per window,but they are big windows.

I purchased the Sikaflex 252 at AIM supply.
https://epartners.aimsupply.com/sto...r-uom=EA&warehouse-id=2&item-number=SIK 252-W

The first tube I bought to experiment with before using it on the bus was from Amazon and it was old, I did not like the looks of it, It worked good, but looked like it was already starting to cure.

AIM supply had it on hand locally, recently made and the best price.

Peter