TheSamba.com :: View topic - Vapor Barrier Replacement How-To

Fri Nov 08, 2013 10:14 pm

I tried a few different glues to see what would duplicate the kind of "grab" that I felt removing my original vapor barriers. VW seemed to use a very thin adhesive - nothing like caulk or putty, and one that seemed to allow the vapor barrier to be removed and re-attached for servicing, at least in part.

After trying 3M Super 77 spray glue (way too aggressive), brush on rubber cement (not enough adhesion), Aleene's Repositionable Tacky Spray (not bad, but still a little too aggressive), I tried Krylon Easy-Tack Repositionable Adhesive 7020.

The Krylon Easy-Tack sprays nice and thin but also seems to hold the new polyethylene vapor barrier plastic real well, and 6 hours after sticking it down I could remove the plastic with a reasonable effort. As importantly, I could also stick it right back down and get similar adhesion. It's hardly a long-term test, but subjectively it just seems about right compromise between adhesion, removal and potential re-application.

Fri Nov 08, 2013 10:21 pm

Thanks, good info.

Sat Nov 09, 2013 12:56 am

Spray adhesives have there place....as does contact cement. In my opinion this is not a place for either.

Sat Nov 09, 2013 8:13 am

Hoody wrote: Spray adhesives have there place....as does contact cement. In my opinion this is not a place for either.

Then what would you use?

Sat Nov 09, 2013 8:20 am

eche_bus wrote: I tried a few different glues to see what would duplicate the kind of "grab" that I felt removing my original vapor barriers. VW seemed to use a very thin adhesive - nothing like caulk or putty, and one that seemed to allow the vapor barrier to be removed and re-attached for servicing, at least in part.

After trying 3M Super 77 spray glue (way too aggressive), brush on rubber cement (not enough adhesion), Aleene's Repositionable Tacky Spray (not bad, but still a little too aggressive), I tried Krylon Easy-Tack Repositionable Adhesive 7020.

The Krylon Easy-Tack sprays nice and thin but also seems to hold the new polyethylene vapor barrier plastic real well, and 6 hours after sticking it down I could remove the plastic with a reasonable effort. As importantly, I could also stick it right back down and get similar adhesion. It's hardly a long-term test, but subjectively it just seems about right compromise between adhesion, removal and potential re-application.

I like this suggestion. My next vapor barrier will get this to test its holding power over time. The only question I have is will it hold over the long term. Heat and moisture over time may or may not affect this. Im interested to see the result as this would solve the issue of having to redo the barrier anytime a service is required of the inner door mechanism. Having a project in the wings needing me to tare into a newer vapor barrier this could be a time saver.

Sat Nov 09, 2013 8:53 am

curtis4085 wrote: eche_bus wrote: Krylon Easy-Tack Repositionable Adhesive 7020.[/b][/i]

I like this suggestion.

I am desperately hopeful . . .
Colin

Sat Nov 09, 2013 8:57 am

I've got almost 12 years on the 3M #75 in mine, so far so good.

Sat Nov 09, 2013 10:59 am

I used a thin bead of auto body caulk. You can also use the 3m black body caulk and roll it into a thin line to adhere.

Sat Nov 09, 2013 11:56 am

Hoody wrote: Spray adhesives have there place....as does contact cement. In my opinion this is not a place for either.
Believe me, a spray adhesive wasn't my first choice, because of all the masking for overspray required. But I noticed that VW applied their adhesive over fairly wide areas of the door frame and as such it wasn't any kind of strip caulk. That's what led me to try a brushable rubber cement (using a test panel, not the actual door). It was simply too easy to remove the plastic. The brushable DAP contact cement I have would gaurantee the plastic would never come off, so that's no good. So I did a wide internet search on removable adhesives and pretty much just found glue stick -type things. The search led to repositionable glues (cause you definitely want that characteristic), where I only found spray glues, no brushable ones.

I don't see evidence of brush strokes in the glue residue on my RH door (plastic removed but not otherwise disturbed), and it appears the adhesive was sprayed on the door frame and not a part of the plastic itself - I could be wrong, but I don't see a consistent stickiness to the original plastic that would suggest it was self-adhesive.

To be clear, I don't care to reproduce the appearance of the glue (I'm not insane, ok? :wink: ), just trying to duplicate the general adhesion and wide-area application. I think the Krylon product is about right, but yeah ... a pain-in-the-a** to have to do all the tape-off for overspray.

Sat Nov 09, 2013 12:01 pm

I use double sided carpet tape. just pulled my door skin on my ghia to adjust my window , after 4 years, it pulled clean and sealed back just as tight.

http://www.amazon.com/Duck-1-41-Inch---42-Feet-Fib...arpet+tape

Sat Nov 09, 2013 12:49 pm

busdaddy wrote: I've got almost 12 years on the 3M #75 in mine, so far so good.
Oh - that's good to hear. I just bought a can of that, and will be doing six doors in the near future. It was pricey! One can for nearly $30. But if it does the job, it is worth it.

Now I need to decide on an adhesive for the plastic sheeting - to - plastic sheeting bond, for the flap.

Sat Nov 09, 2013 2:24 pm

eche_bus wrote: Believe me, a spray adhesive wasn't my first choice, because of all the masking for overspray required. .
A quick wipe with mineral spirits takes off the overspray (if any), get it while it's fresh and it's easy to remove.

For attaching the inner flap I've used the tape for house vapor barriers with sucess.

Sat Nov 09, 2013 4:17 pm

I've also used clear 3m packing tape. It hold well and peels off too.

Mon Sep 22, 2014 12:54 pm

I apologize in advance.

I'm in the process of making vapor barriers for my 72 Westy, and I don't quite understand what the flap is for. It was on the barrier of a parts bus I have, but I don't know if I need it.

Is it to protect water from coming in the air vent on the door?

Mon Sep 22, 2014 1:30 pm

Just watching this one over time. I have made numerous sets of panels for other cars.

A couple details. Other than a spray adhesive, contact cement...thinned with proper contact cement thinner like this one...there are many others

http://www.dap.com/docs/tech/00030535.pdf

To about starting with 90/10 and ending at 80/20 contact cement to thinner...you can apply it very evenly and cleanly from a pan with a hard rubber roller.

Also....and this goes back to a couple of posts from about 2010 or so.....DO NOT...use vinyl or shower curtain material. Yes... some of those are fine for UV...but UV is not the issue here.

Vinyl continues outgassing and shrinking daily for the rest of its life. That solvent that outgasses will turn the contact cement to a gooey mess. And eventually the vinyl will get crispy. Wrong stuff.

The Low density polyethylene film most are using should be fine....but if you are wondering why factory film feels thicker when its not.....its because its High density Polyethylene film. You can get this in many stores by the roll but you need to be specific about what you are buying. Read the label.
Ray

Mon Sep 22, 2014 4:48 pm

reservoirdubs wrote: I don't quite understand what the flap is for.

Without the flap, drips (either directly or by splashing) can get on the outer face of the plastic sheet, and
run down to where they are trapped between the plastic and the door metal. Rust and mildew result.

With the flap, the water will run down to the "drainage channel" (hah!) at the bottom of the door.

Tue May 03, 2016 1:11 am

curtis4085 wrote: eche_bus wrote: I tried Krylon Easy-Tack Repositionable Adhesive 7020.

The Krylon Easy-Tack sprays nice and thin but also seems to hold the new polyethylene vapor barrier plastic real well, and 6 hours after sticking it down I could remove the plastic with a reasonable effort. As importantly, I could also stick it right back down and get similar adhesion. It's hardly a long-term test, but subjectively it just seems about right compromise between adhesion, removal and potential re-application.

I like this suggestion. My next vapor barrier will get this to test its holding power over time. The only question I have is will it hold over the long term. Heat and moisture over time may or may not affect this.

Anyone who used this way back when care to comment on longevity? It's the only repisitionable adhesive I could find, it'd be great to get feedback before I proceed.

I tried the double-sided carpet tape but wasn't convinced the coverage was adequate and it was even more of a pain than just masking for spray. I considered using Dap Draft Attack Removable Caulk as I know it's easy to apply and subsequently remove, but it would require re-application if I ever need access.

Tue May 03, 2016 8:58 am

Himejii wrote: curtis4085 wrote: eche_bus wrote: I tried Krylon Easy-Tack Repositionable Adhesive 7020.

The Krylon Easy-Tack sprays nice and thin but also seems to hold the new polyethylene vapor barrier plastic real well, and 6 hours after sticking it down I could remove the plastic with a reasonable effort. As importantly, I could also stick it right back down and get similar adhesion. It's hardly a long-term test, but subjectively it just seems about right compromise between adhesion, removal and potential re-application.

I like this suggestion. My next vapor barrier will get this to test its holding power over time. The only question I have is will it hold over the long term. Heat and moisture over time may or may not affect this.

Anyone who used this way back when care to comment on longevity? It's the only repisitionable adhesive I could find, it'd be great to get feedback before I proceed.

I tried the double-sided carpet tape but wasn't convinced the coverage was adequate and it was even more of a pain than just masking for spray. I considered using Dap Draft Attack Removable Caulk as I know it's easy to apply and subsequently remove, but it would require re-application if I ever need access.

I just did mine, I used 3m spray adhesive. For a plastic liner it should last for quite a while.

Tue May 03, 2016 9:09 am

khalimadeath wrote: I just did mine, I used 3m spray adhesive. For a plastic liner it should last for quite a while.

The 77 or the 75?

I can't find the 75 (repositionable) locally. I have no doubt that the 77 will hold...forever. My concern is that if I want to clean & re-lube the door mechanisms in a year, I probably won't do it if it means cleaning off all the adhesive and applying new vapour barrier. I just want to peel back enough to access the mechanism and then stick it back on.

People have said the 75 is perfect for that but I can't find it for less than $90 on Amazon, so I'm just wondering if the Krylon is comparable long-term.

Tue May 03, 2016 9:34 am

Himejii wrote:
People have said the 75 is perfect for that but I can't find it for less than $90 on Amazon, so I'm just wondering if the Krylon is comparable long-term.

http://www.amazon.com/3M-Repositionable-Clear-Adhesive-10-25-Ounce/dp/B000BKQD82

https://www.zoro.com/3m-spray-adhesive-size-16-oz-...lsrc=aw.ds

Grainger also stocks it.

Robbie