Repair Class C Cab to Coach Seal?

[edog1973]

The cab to coach seal on on the sides of my Holiday Rambler Class C needs a little help.  It looks like it is is a foam gasket that that was sandwiched during construction.  The outside edge of the gasket where it was exposed to the elements is completely dried up and cracked.  Fortunately the interior portion that is actually making the seal seems to be in decent shape, it not leaking.  So the problem appears to be mostly cosmetic.

I'm thinking that I can remove the old cracked foam, trim back as far as possible with a razor, and fill in the gap with a high quality sealant.   I just hate the idea of slapping calk on the problem.

Has anyone else ran up against this issue?  Do you have any recommendations on how to fix it?

[Gearhead88]

Mine is sealed with some kind of urethane calking , I believe it was built that way.


It's thirty one years old now .


I'm taking care of maintenance items like that on an on going basis , the cab/coach seal needs attention this year , my plan is to buy some high quality sealant , clean out the seam and apply sealant .


Your description , removal of the weathered old seal and applying new caulking sounds fine to me.

[TerryH]

Based on your photo and a fair amount of experience with sealants and caulking I suggest the following:
Trim the 'foam gasket' approx. 3/8" deep into the void. Personally, I would use an 'Olfa Knife'. A razor blade, given it's size, is very difficult to control.

Balance of the foam serves as both a coach to coach gasket and will serve as a backing and bond breaker for the new sealant. Bond breaker prevents 3 sided adhesion.

Caution - if you do use an Olfa or similar knife with segregated blades PLEASE use eye protection. A colleague of mine had the blade snap and deflate his cornea. Not nice.

Vacuum out any foam trimmings that remain.
Use a 3M Scotch Brite dipped in Naptha (old school Ronson Lighter Fluid) to clean any residue. Use only enough naptha as needed and only where needed.
Mask off both sides of the coach, approx. 1/8" from the curve. 2" masking tape would be best. Run the tape a few inches beyond and fold the top and bottom of the tape over to make it easier to remove.

Choose your sealant carefully.
You may want to read this:

http://www.finehomebuilding.com/2004/05/01/making-sense-of-caulks-a...

Link may not work - here is an alternative:

http://www.finehomebuilding.com/2004/05/01/making-sense-of-caulks-and-sealants

What I do not agree with is Polyurethane cautions:
It is no more dangerous to you than any other sealant you may use. Standard precautions, yes.
Stringy - depends entirely on the product and intended use. Some, such as those used for major joints such as tilt up buildings actually have that built into the manufacture for adhesion and cohesion.
As for butyl caulk, yes it is very water resistant and extremely viable - provided (which is not stated) - it is shielded from constant UV exposure. It is EXTREMELY messy to apply.

General: Personally, I would avoid any inexpensive caulking that does not tell you it's composition. There are a lot of them in the big box stores.
No offence intended to those involved, but advice you receive from an associate at a big box store or local hardware store is difficult to accept as expert. My advice would be to look for a sealant supplier in your area and talk to them. They will likely be wholesale only, but if you pick a time when they are not busy they should be willing to suggest products. They also can direct you to a retailer for the appropriate product.

My recommendation would be a polyurethane.

. Two suppliers of polyurethane I would recommend are Sika and NP-1.

Caulking: Cut the nozzle of the tube slightly smaller than the width of the void you are filling.
Hold your gun about 45 degrees from the joint. If you are caulking down, raise the back of the gun a couple of inches. If caulking up, lower it. Run the caulk ahead of the nozzle. You want to see it coming out of the tip. This forces it into the void and forces out air.
Dry tool first, forcing the caulk into the void and taking excess away from the edge of the tape. I find a bare finger best, or based on your photo and the probable size of the joint the side of your thumb, but I'm too old to worry about precautions. You will have to stop every so often to clean your finger and may have to go over some areas again.

If you do not tool the caulking you have wasted your time and money.

Remove the tape, pulling it slightly towards the bead. This helps any feather or strings left on the tape to stay on the bead. Fold the tape into itself every foot or so to keep it manageable. Have a garbage bag open and ready and lots of paper towels - you will need them.
Final tooling: Slightly soapy water in a container, use your finger/thumb with light pressure and short quick strokes. This smoothes out the taped edge and gives it it's final appearance.

Finished job should look like a vinyl gasket that was originally installed.
Or better.

Hope this helps.

[Gearhead88]

Great advice , the link is a good read too .

[edog1973]

Another quick follow up.  I ended up using 3M 5200 calk.  After doing quite a bit of research I found that it was the strongest, would not peal off, remained flexible and is paintable.  I trimmed the old foam off, with a plastic scrapper and a razor blade. It did not come off easy.


My wife takes pride in her ability to use calk (quick your snickering guys, remember, that's my wife) so she did the application.  The is 5200 is very thick and gooey.  She said it was like working with taffy.  Even with the difficulty she ended up doing a very nice job. After letting it dry for a week I painted it to match.


Special bonus fact: The 1983 Holiday Rambler, and I'd suspect several years before and after, uses stock Ford Wimbledon White.  Dupli-Color sells touch up paint that's available in almost every parts store around.  The Dupli-Color part number is BFM0041. I would't want to paint the whole thing with it, but for a little touch up it works very well and matches perfectly. 

[Rickf1985]

More power to your wife, I have worked with 5200 a lot in marine use and it is nasty stuff! It is beyond tenacious when it gets on something, like your hands. Forget getting it off, it will wear off in a couple months. When that camper is rotted into the ground 100 years from now there will be a strip of 5200 standing tall and proud!

[TerryH]

That is very impressive. No evidence of air bubbling, excellent tooling.
Great job.
Visible caulking, like yours, should appear to be a 'vinyl filler', like yours.
I am always happy to see a caulking job that was not done with the aid of a putty knife.
Kudos to your wife. Based on the photo she should be teaching caulking application.

[legomybago]

nice

[Gearhead88]

well done

[WrigleysBraveWin]

Based on your photo and a fair amount of experience with sealants and caulking I suggest the following:
Trim the 'foam gasket' approx. 3/8" deep into the void. Personally, I would use an 'Olfa Knife'. A razor blade, given it's size, is very difficult to control.

Balance of the foam serves as both a coach to coach gasket and will serve as a backing and bond breaker for the new sealant. Bond breaker prevents 3 sided adhesion.

Caution - if you do use an Olfa or similar knife with segregated blades PLEASE use eye protection. A colleague of mine had the blade snap and deflate his cornea. Not nice.

Vacuum out any foam trimmings that remain.
Use a 3M Scotch Brite dipped in Naptha (old school Ronson Lighter Fluid) to clean any residue. Use only enough naptha as needed and only where needed.
Mask off both sides of the coach, approx. 1/8" from the curve. 2" masking tape would be best. Run the tape a few inches beyond and fold the top and bottom of the tape over to make it easier to remove.

Choose your sealant carefully.
You may want to read this:

http://www.finehomebuilding.com/2004/05/01/making-sense-of-caulks-a...

Link may not work - here is an alternative:

http://www.finehomebuilding.com/2004/05/01/making-sense-of-caulks-and-sealants

What I do not agree with is Polyurethane cautions:
It is no more dangerous to you than any other sealant you may use. Standard precautions, yes.
Stringy - depends entirely on the product and intended use. Some, such as those used for major joints such as tilt up buildings actually have that built into the manufacture for adhesion and cohesion.
As for butyl caulk, yes it is very water resistant and extremely viable - provided (which is not stated) - it is shielded from constant UV exposure. It is EXTREMELY messy to apply.

General: Personally, I would avoid any inexpensive caulking that does not tell you it's composition. There are a lot of them in the big box stores.
No offence intended to those involved, but advice you receive from an associate at a big box store or local hardware store is difficult to accept as expert. My advice would be to look for a sealant supplier in your area and talk to them. They will likely be wholesale only, but if you pick a time when they are not busy they should be willing to suggest products. They also can direct you to a retailer for the appropriate product.

My recommendation would be a polyurethane.

. Two suppliers of polyurethane I would recommend are Sika and NP-1.

Caulking: Cut the nozzle of the tube slightly smaller than the width of the void you are filling.
Hold your gun about 45 degrees from the joint. If you are caulking down, raise the back of the gun a couple of inches. If caulking up, lower it. Run the caulk ahead of the nozzle. You want to see it coming out of the tip. This forces it into the void and forces out air.
Dry tool first, forcing the caulk into the void and taking excess away from the edge of the tape. I find a bare finger best, or based on your photo and the probable size of the joint the side of your thumb, but I'm too old to worry about precautions. You will have to stop every so often to clean your finger and may have to go over some areas again.

If you do not tool the caulking you have wasted your time and money.

Remove the tape, pulling it slightly towards the bead. This helps any feather or strings left on the tape to stay on the bead. Fold the tape into itself every foot or so to keep it manageable. Have a garbage bag open and ready and lots of paper towels - you will need them.
Final tooling: Slightly soapy water in a container, use your finger/thumb with light pressure and short quick strokes. This smoothes out the taped edge and gives it it's final appearance.

Finished job should look like a vinyl gasket that was originally installed.
Or better.

Hope this helps.

Excellent Post .....  One Sealant I almost exclusively used in the Roofing Business was a Structural Sealnt made by ChemLink called M1 ......


M1 is a Structural Sealant that remains very flexible and sticks extremely well to almost everything and is actually rated to hold steel decking to steel bar joists WITHOUT Screws for Hurricane Force Winds .....


Check Out BigRock Supply for more info including data sheets, etc


https://www.bigrocksupply.com/store/p/7061-ChemLink-M-1-Structural-Adhesive-Sealant-10-1-oz-Cartridge.aspx

[Winnebago Warrior 94]

looks awesome ..great job to both of you ..teamwork 

[Rickf1985]

Excellent Post .....  One Sealant I almost exclusively used in the Roofing Business was a Structural Sealnt made by ChemLink called M1 ......


M1 is a Structural Sealant that remains very flexible and sticks extremely well to almost everything and is actually rated to hold steel decking to steel bar joists WITHOUT Screws for Hurricane Force Winds .....


Check Out BigRock Supply for more info including data sheets, etc


https://www.bigrocksupply.com/store/p/7061-ChemLink-M-1-Structural-Adhesive-Sealant-10-1-oz-Cartridge.aspx

That looks like some really promising stuff or use on RV's! It looks to me like it would be perfect to use to glue down mounts for solar panels instead of screwing through the roof. And the price is very good compared to what else is out there.

[WrigleysBraveWin]

That looks like some really promising stuff or use on RV's! It looks to me like it would be perfect to use to glue down mounts for solar panels instead of screwing through the roof. And the price is very good compared to what else is out there.

M1 would have no issues holding down anything, if applied correctly and the substrate didn't give away. Big Rock Supply are good folks to deal with as well.