Help! "Bubbles" forming under styrene plastic streets?

[Bart1701]

I used thin styrene sheets for the streets and parking lots on my layout. I don't remember what thickness, but it was pretty thin so that it would adapt to any fluctuations in the streets. In most cases, they were glued directly to foam insulation board using latex adhesive caulk (such as the DAP squeeze tubes of caulk from Home Depot).

I noticed recently that I have "bubbles" starting to appear in some sections of my streets. It's almost as if an air bubble has formed under the plastic. The "bubbles" are usually  1" to 1-1/2" diameter in size. The curious thing is that this is happening on the most recently completed section of my layout (which has been complete for about 1 year now) . The streets on the other two sections of the layout that were completed a year or two before the last section are not exhibiting this symptom anywhere that I can see.

It looks like the street department is going to have their work cut out for them. Does anyone have any idea what might have caused this so that I don't have this happen again?

Thanks,
Bart

[rogergperkins]

If you have used a liquid adhesive, it may have dried unevenly creating this problem.
I like double stick tape or one of 3M's transfer adhesive to fix any thin sheet styrene in place.
Also good option to adhere sheet brick or stone to thicker styrene sheet for buildings.
  You may have some great pot-holes created.

[DKS]

Note that you are bonding a non-porous material to another non-porous material, so it takes much longer for things to cure; you may need to be patient as the bubbles may subside. Or... they may not; knowing the thickness of the street material you used is helpful to diagnose the problem--it may be too thin. As for corrective action, you might consider drilling holes in the bubbles to see if they flatten out; then plug the drill holes with manhole covers. Failing that, well... you may need to call the road crew for a resurface job.

FWIW, I don't use caulk to bond streets in place; I use Loctite PowerGrab. It still takes longer to cure than normal, but I've never had any street bubble or otherwise warp. I also use minimum .030 styrene for streets, in general, and I find it flexes enough to follow contours as needed, without flexing too much and looking unnatural.

[davefoxx]

Note that you are bonding a non-porous material to another non-porous material, so it takes much longer for things to cure; you may need to be patient as the bubbles may subside. Or... they may not; knowing the thickness of the street material you used is helpful to diagnose the problem--it may be too thin. As for corrective action, you might consider drilling holes in the bubbles to see if they flatten out; then plug the drill holes with manhole covers. Failing that, well... you may need to call the road crew for a resurface job.

FWIW, I don't use caulk to bond streets in place; I use Loctite PowerGrab. It still takes longer to cure than normal, but I've never had any street bubble or otherwise warp. I also use minimum .030 styrene for streets, in general, and I find it flexes enough to follow contours as needed, without flexing too much and looking unnatural.

I like Loctite Power Grab, too.  I'm using 0.060" black styrene for my roads at the suggestion of Chris333, which is working very well for me so far.  Because it's thick enough to bridge small gaps without deformation, if there's any delamination or bubbles under the 0.060" styrene, it really would be no cause for concern.

DFF

[Bart1701]

The thickness was either .015 or .030 styrene - not sure which one since I have some of each on hand in my closet at the moment.

It was installed almost a year ago, so I think I have given enough time for everything to cure.

I may end up pulling up the section of street and the parking lot that has the issue. It would be about 10 inches of street and would be a bit of a pain to do, but not impossible. I'd probably use the .030 styrene this time. If the adjoining sections (which are not showing this problem at the moment and I am keeping my fingers crossed that they never do!) are thinner styrene, I would think that I could sand the .030 down at the joint to smooth the transition between the varying heights.

Off to the hobby shop now for some other stuff. I'll take look at Home Depot for the Loctite Powergrab that was mentioned!

Thanks,
Bart

[Ian MacMillan]

I use PowerGrab and PL adhesive. I found that with the .015 styrene that I had been using for streets that they did not take kindly to climate changes her in northern New England, let alone when I had it put into the travel trailer for shows. I had several roads that would bubble. I am going to be using the black .060 on the new layout, which is in a much more climate controlled room as well.

[sizemore]

Be careful it might turn into a sink hole!


The S.

[nkalanaga]

I've had that problem, but only with petroleum-derivative solvents.  On the other hand, I never did get a sheet of 0.06 inch styrene, used as a road, to stick well to plywood.  Latex adhesives didn't work.  Epoxy didn't work.  I finally nailed it down -with real nails.  Drill a hole for the wire brad, countersink the head so it's even with the surface, drive it in, and put a stick-on manhole cover over the head!

One edge had a sidewalk, so that edge could be pinned down with streetlights, signs, etc, and the other was spiked with ME track spikes, with notches to hid the heads, before the gravel shoulder was added.

[pnolan48]

I'll bet you used .015 styrene. .020 will still bubble; .030 is getting thick enough so that it won't bubble unless you use a lot of plastic solvents. My latest batch of twenty (20) 4' x 8' sheets of .015 styrene is miserable stuff: it has little surface gloss, so it "pills" when cutting, and it's brittle, so it won't bend around moderate corners without snapping. I wanted to use .015 styrene for Z scale versions of N scale plans, as Z scale is 72.7% of N scale, so I wouldn't have to adjust thicknesses (75% is close enough to 72.7% that slots and tabs did not have to be re-toleranced).

Ain't working. .020 and thicker has one very pronounced glossy side, which cuts like a dream: .015 (or at least this batch of it) does not have that pronounced side.

I've found styrene sheets vary much more than I expected from batch to batch.

[rogergperkins]

Okay, my point earlier is DO NOT USE LIGUID ADHESIVES TO BOND TO DIFFERENT MATERIALS.
I am not an adhesive specialist, HOWEVER I worked for 3M who make lots of adhesive and picked up a lot of very practical
information during those 28 years.
I use double stick tapes or transfer adhesives to avoid this problem.

I also learned from experience when I ruined a nice scratch built structure by using liquid adhesive to bond the corrugated
metal sheeting to it.
 

[Bart1701]

A few updates, and some questions...

In comparing the section of styrene street that now has bubbles appearing after about 1 year to the other streets on my layout, I have determined:

- One of the other areas on my layout (which has no bubbles appearing) had Woodland Scenics plaster cloth beneath the styrene streets.
- Another section of the layout (without bubbles) had cork roadbed under the styrene.
- The styrene that has the bubbles was glued directly to the underlying foam using latex caulk/adhesive.

So, the earlier comment about issues with gluing two non-porous materials together does seem to be the root cause of my problem.

I did pick up some of the Loctite Power Grab that was mentioned. I wanted to confirm that this adhesive will not experience the same issue gluing two non-porous materials together?

I am also intrigued by the notion of using double-stick tape to secure the styrene to the layout. Is there a particular brand of double-stick tape that people have used with success? I am hoping that it would be fairly thin. Any other thoughts on the merits and disadvantages of using double-stick tape?

Finally, the new roads will be .030" thick. I am pretty sure I used .010" thick styrene before which also aggravated the issue. The replaced section will have to butt up to some .010" styrene (these sections were glued to areas that ascended/descended to different elevations and which had plaster under them so I don't expect any bubbles to be appearing ever). I'll have to sand the joints to make the roads even - so I don't really want to use anything thicker than .030" for the new section.

Thanks,
Bart

[DKS]

Is there a particular brand of double-stick tape that people have used with success? I am hoping that it would be fairly thin. Any other thoughts on the merits and disadvantages of using double-stick tape?

I stay with 3M products. I've tried others and found that some dry up and release, and others turn to goo. 3M makes a very wide range of double-stick tape types, from paper-thin to 1/8-inch thick foam-lined. Each have their advantages: the thinner tape requires that both surfaces be smooth and clean, and flexible enough that good contact can be made across the entire surface in order to make the bond work. Foam-lined tape, on the other hand, is very forgiving, and can accommodate a range of surface irregularity (although anything that is granular or very porous will have problems, which is where the Power Grab comes into play). Always be sure to clean the surfaces to which you apply the tape (rubbing alcohol works) to be sure they're free of dirt, skin oils and other contaminants.

I'm using both the thin and foam-lined tapes on my current layout for attaching streets, and so far both are working well. http://www.jerseycityindustrial.net/streets.htm

[peteski]

Roger mentioned "adhesive transfer" tape and I think that is what I often use for fastening many things.

It is a roll of waxy paper coated with a pressure-sensitive adhesive.  It is like double sided tape but it is adhesive only - no carrier tape.  Since it only adhesive, it is very thin and sticky on both sides. I don't know what brand it is and where to buy it - I god bunch of spools at a surplus store.  Normally you would load it in a special tape gun, but I just unroll it, stick it to one surface, then peel off the backing paper, then stick the item to its final resting place.

[DKS]

It is a roll of waxy paper coated with a pressure-sensitive adhesive.  It is like double sided tape but it is adhesive only - no carrier tape.  Since it only adhesive, it is very thin and sticky on both sides. I don't know what brand it is and where to buy it - I god bunch of spools at a surplus store.  Normally you would load it in a special tape gun, but I just unroll it, stick it to one surface, then peel off the backing paper, then stick the item to its final resting place.

I have some of this stuff as well (it's 3M), although I don't find the adhesive to be quite as aggressive as that on their double-sided products. Incidentally, this is how laser kit manufacturers make peel-and-stick parts.

[peteski]

I have some of this stuff as well (it's 3M), although I don't find the adhesive to be quite as aggressive as that on their double-sided products. Incidentally, this is how laser kit manufacturers make peel-and-stick parts.

The most aggressive adhesive double-sided tape I ever found was a carpet tape.  IIRC, it is 3M and it is white in color.