Hi all,
I would like to reseal the outside seam where the fiberglass overcab meets the steel van body. Whatever Chinook used has become brittle and is now cracking.
What caulk would you recommend?
sealant suggestion request
sealant suggestion request
1994 Premier
Re: sealant suggestion request
Hi.
Do you mean the joint above the windshield?
Just checking
Do you mean the joint above the windshield?
Just checking
1994 Concourse dinette, Ford 7.5L (460 V8)
Re: sealant suggestion request
Yup, above the windshield gasket, and around both sides above the doors. Sorry if I was unclear...
1994 Premier
Re: sealant suggestion request
Before potentially offering a suggestion, I'd like to ask how you are going about it and what the pieces look like. (Partly to offer a logical suggestion and partly because I've always been curious what is in there!).
Usually when sealing (i.e. "bedding") two things together (that are also mechanically fastened), it depends on how much faying surface you have (i.e. the two, typically flattish, pieces that will be meeting and where the sealant will live), and what the two pieces are made of. In this case I'd guess flattish fiberglass surface to steel (painted?) Ford body surface?
I'm interested in ..... can you pry the two pieces apart enough to get in there with, say, a caulk gun tip? Can you get the old sealant out? What was it? Will you be able to clean in there at all? (solvent soaked rag).
On a fiberglass boat you'd often have a "hull to deck" joint that is two lips held together by various shaped joints plus fastener. Since it's supposed to be a permanent joint, people often use a very very strong polyurethane (e.g. 3M 5200). That is very very adhesive, and is great as long as you never have to get it apart again. In the past, some builders have used good butyl tape, which has proven over time to work very well (as long as there is adequate mechanical fastening as it is purely a sealant). There is also a less adhesive polyurethane (e.g. 3M4200).
I can't think of any other sealant I'd want to use off-hand. But then maybe if I hear more about the joint details and your process for re-sealing it, something else would come to mind. For example, how much are you able to get them apart (I'm not visualizing this part at all), what's in there now, how clean can you get it? Also, are you getting a feeling for how much the screws through the vinyl insert trim extrusion are being counted on as mechanical fasteners? (Presuming yours is constructed that way.) How well are they doing?
(I note that sometime in the early 2000's the shell-to-cab-wings joint had the extrusion and insert trim part eliminated. I'd love to know how that joint goes together and is held (presumably from the inside? Or maybe by adhesive sealant only? But there is so little/no inside access to that area through the Ford B-pillars...)
Usually when sealing (i.e. "bedding") two things together (that are also mechanically fastened), it depends on how much faying surface you have (i.e. the two, typically flattish, pieces that will be meeting and where the sealant will live), and what the two pieces are made of. In this case I'd guess flattish fiberglass surface to steel (painted?) Ford body surface?
I'm interested in ..... can you pry the two pieces apart enough to get in there with, say, a caulk gun tip? Can you get the old sealant out? What was it? Will you be able to clean in there at all? (solvent soaked rag).
On a fiberglass boat you'd often have a "hull to deck" joint that is two lips held together by various shaped joints plus fastener. Since it's supposed to be a permanent joint, people often use a very very strong polyurethane (e.g. 3M 5200). That is very very adhesive, and is great as long as you never have to get it apart again. In the past, some builders have used good butyl tape, which has proven over time to work very well (as long as there is adequate mechanical fastening as it is purely a sealant). There is also a less adhesive polyurethane (e.g. 3M4200).
I can't think of any other sealant I'd want to use off-hand. But then maybe if I hear more about the joint details and your process for re-sealing it, something else would come to mind. For example, how much are you able to get them apart (I'm not visualizing this part at all), what's in there now, how clean can you get it? Also, are you getting a feeling for how much the screws through the vinyl insert trim extrusion are being counted on as mechanical fasteners? (Presuming yours is constructed that way.) How well are they doing?
(I note that sometime in the early 2000's the shell-to-cab-wings joint had the extrusion and insert trim part eliminated. I'd love to know how that joint goes together and is held (presumably from the inside? Or maybe by adhesive sealant only? But there is so little/no inside access to that area through the Ford B-pillars...)
1999 Concourse
Re: sealant suggestion request
That's correct. They're in full contact along the center of the joint, but there's a gap at both driver and passenger edges close to the doors. I'd guesstimate about 1/8", but can't confirm because the joint compound is still in there; it's cracked and unsightly, and probably no longer doing it's job.Blue~Go wrote:Usually when sealing (i.e. "bedding") two things together (that are also mechanically fastened), it depends on how much faying surface you have (i.e. the two, typically flattish, pieces that will be meeting and where the sealant will live), and what the two pieces are made of. In this case I'd guess flattish fiberglass surface to steel (painted?) Ford body surface?
When I get a chance, I'm going to carefully clean it out, and hopefully I'll learn more.
Wish it was an easier problem to solve.
1994 Premier