which caulk is best (silicone or polyurethane) for trim?

[LDK]

I'm looking for a caulk that I can get locally (lowes or home depot) that I can use for under the aluminum trim that covers where the roof and sidewall meet. I'm making my own trim that I bought at lowes and it lays flat on the surface and it doesn't look like it would have much room for butyl tape. The cubby manual says poly caulk. Whats the difference between that and silicone?
Thanks

[aggie79]

Larry,

I haven't used it, but in the BORG, over by the roofing materials and gutters, they usually have a sealant (in a caulk gun type tube) used for the seams and caps for metal gutters. The one I'm thinking of is made by OSI - don't know what type of sealant it is though. I think others on the forum have used it.

Take care,
Tom

[nevadatear]

don't know your skin material, but if you are using any kind of finsh-varnish, polyurethane, etc, stay AWAY from the silicone. Silicone resists any kind of finish, and will pock mark a finished surface. If you try to recoat in the future, you will have a mess, the finish will be pocky or will not stick at all.

[LDK]

I'm gonna have white aluminum skin for the top and sides. I just now bought the loctite pl polyurethane sealant. It's a window, door, and siding sealant. Don't know if thats the right choice but I won't open it until I learn more. I can always take it back.

[Shadow Catcher]

Used almost exclusively in the industry is Silicone. I was just out sealing seams today on Compass Rose using a DuPont product picked up at Lowe's.

[kinto]

I'm making my own trim that I bought at lowes

what type of material and in which department is the trim you found at lowes? i've looked around there but haven't spotted anything that seems like it would work.

thanks,
kent

[LDK]

I'm making my own trim that I bought at lowes

what type of material and in which department is the trim you found at lowes? i've looked around there but haven't spotted anything that seems like it would work.

thanks,
kent

Hey Kent

I'm using 1" wide angle aluminum that is 1/16" thick that comes in 8 ft lengths. It's in the same isle that the fasteners are in. It has to be annealed before you can bend it. The reason I'm goin 1" wide is because I'm tryin to hide a little boo boo I made when I cut my aluminum sides out.

[kinto]

ah, ok... i'll check it out. thanks!

[S. Heisley]

I was told to use 3M's 5200. They have the white 7 day cure at Home Depot (found it on the bottom shelf in the paint area) and both that and the 24 hour cure are sold at West Marine. West Marine also has the clear 5200, in squeeze tube or the type of tube used with a caulking gun. It's a little pricey. They use it on boats to seal out moisture wherever they attach things.

[doug hodder]

Yup 3M 5200...best stuff out there..I've sealed tears with it and also glued in brass tubes in wood transoms on boats with it. Made for underwater use, remains flexible. Doug

[48Rob]

Polyurethane is a moisture cure product.
Slicone is an air cure product.

If the surfaces are VERY clean, dry, and properly prepared for the silicone, it can be a very good long lasting sealer.
If not, it is prone to peeling/failing.
As mentioned, it is not a good product to use if paint, varnish, or clear coat will EVER be applied.
Years ago, it was THE choice for sealants.
It still holds much value for specific uses, but has been surpassed for "home" use by other products.

Polyurethane is a good/great glue/construction adhesive, but if you ever wish to separate the parts, don't use it.

I've had very good luck with OSI gutter seal.
It is a clear sealer/caulk that is a rubber product in a very strong solvent base.
It will flow very thin if warmed in the tube, is clear, does not attract dirt like silicone, can be varnished/painted over, and best of all, with a little effort, can be completely removed if needed without leaving any residue, such as for removing metal trim, a roof vent, etc.

I'm on year 6 of use on my wood trailer with no failures or issues.

I'm not familiar with 3-M's 5200, but it may be a good option too.

Rob

[LDK]

Polyurethane is a moisture cure product.
Slicone is an air cure product.

If the surfaces are VERY clean, dry, and properly prepared for the silicone, it can be a very good long lasting sealer.
If not, it is prone to peeling/failing.
As mentioned, it is not a good product to use if paint, varnish, or clear coat will EVER be applied.
Years ago, it was THE choice for sealants.
It still holds much value for specific uses, but has been surpassed for "home" use by other products.

Polyurethane is a good/great glue/construction adhesive, but if you ever wish to separate the parts, don't use it.

I've had very good luck with OSI gutter seal.
It is a clear sealer/caulk that is a rubber product in a very strong solvent base.
It will flow very thin if warmed in the tube, is clear, does not attract dirt like silicone, can be varnished/painted over, and best of all, with a little effort, can be completely removed if needed without leaving any residue, such as for removing metal trim, a roof vent, etc.

I'm on year 6 of use on my wood trailer with no failures or issues.

I'm not familiar with 3-M's 5200, but it may be a good option too.

Rob

Tom (aggie 79) mentioned something about the OSI sealant. I was at the home depot earlier and saw several different kinds of the OSI product. I may give that a try. I bought a tube of loctite polyurethane sealant at lowes but I can return it. I'm afraid the loctite might really lock tight!

[48Rob]

This is what I use.

<img src="http://www.osipro.com/img/products/big/micro.jpg">

[LDK]

This is what I use.

<img src="http://www.osipro.com/img/products/big/micro.jpg">

Hey Rob

I was just at the OSI site earlier and I was thinking that was the one. There were a few other ones too. Thanks for your help.

[LDK]

Just my luck, I returned the loctite sealant because I was going to get the OSI brand but now I can't find the particular one I need. I wanted to get something locally but I guess thats out of the question now. If I'm gonna order some I might as well splurge and get the 3m marine brand. Which kind should I use the 4200 or the 5200?? Should I get one tube or two?? Would that work good under flat trim or would it all squish out?? Questions, questions, questions.