White (woodworking) PVA glue VS Brass

Dear Capt,

Honestly never had longterm success with PVA (Poly Vinyl Acrylate) or "white woodworking glue" on Brass. Once dry, and assuming a _thin_ layer of glue, it will "tack" mechanically rigid, but still peel-away very easily. Almost in opposition to ACC, PVA appears to handle "shear forces" OK, but will let-go under tensile or "pull" forces. (Brass is generally too smooth for the glue to "tooth" into).

If there is any crud or oxidisation on the brass surface, you may also discover greenish oxidisation occuring around and even _between_ the glue and brass over time.

2-part epoxy will work longterm mechanically, but will definitely tear-up the paint you're trying to protect.

Sillicon caulking (shower and glass sealant, always opt for the "neutral cure" option!) may also work,
although if too thick will likely result in a "flexx-y" joint rather than a mechanical-rigid one.
(Applying Sillicon Caulking with a _dry_ piece of card or styrene, slid between the brass and the ties as you described _can_ work. I regularly use such techniques to get various glues into thin-slot situations ).

I would also be concerned about the sticking-capability of PVA against the plastic sleepers.

Personally, the trying-to-preserve-the-paintwork issue is (I _think_) the bit that will keep you awake-at-night in this situation. When it comes to laying track, build it right the first time, and approach it like "once-it's down, it's down for keeps". If some issue occurs which is soooo serious as to require tearing-up and relaying the bridge trackage, then you've obviously got bigger/more-basic issues to resolve...

As such, in similar situation, I'd go with either 2-part 5-min epoxy or sillicon caulking, and comfort myself with the knowledge that a multitude of painting issues can be "resolved" with judicious weathering...

Happy Modelling,
Aim to Improve,
Prof Klyzlr

Thanks Prof.Klyzir I always

Thanks Prof.Klyzir I always appreciate your posts. Very thorough and succinct info./feedback. I'll do a little experimenting.

I'll experiment with some brass stock/track and both materials and see what appeals.  You're right about assuming any job to be permanent but I was hoping to find a happy medium.

 I'll go with an epoxy if the caulk doesn't seem to be a success. At least I can clean off the caulk if I have to go with epoxy later...I'm presuming?

I've had good luck with white glue sticking to non-keyed/toothed styrene shims and track so thought maybe metal would work also, but had my doubts.

Thanks!

Jim

Aleene' Tacky Glue

The Professor never fails to deliver! He provided a great explanation...

I use Aleene's Tacky Glue to bond my track to styrofoam roadbed, and for a host of modeling needs - including at times 'temporary' bonds between styrene or metal. These can be broken, but are a bit more flexible than white glue or carpenter's (yellow) wood glue. It shouldn't harm your finish on the bridges. Any completely rigid bond will bond to the painted surface and risk damaging it.

Might be worth a try...it is my favorite adhesive other than my gap-filling ACC, and could always be put to good use if it doesn't work here. Good luck.

Don't know if this would work or not, but...

If you used ACC to spot weld a few places would a debonding agent be able to penetrate a weld enough to break it free should you want to remove the track?  Not sure how much maneuvering room you'd need to get at the welds or if the design of the bridge would make that possible.  If you do use ACC I'd look at a needle-type applicator to keep away from paint that would show as much as you can.

I'll second the Aleene's Tacky Glue

I originally considered Aleene's Tacky Glue to be just thick PVA glue, and perhaps that is what it is, but it seems to hold much better between dissimilar materials and things with a small mating surfaces. I like the high tack properties. It is nice to stick a piece down and get on with your life. Especially for a man with no patience like myself. That being said, if you are a person with no patience, store the glue bottle upside down, as waiting for the glue to flow down to the nozzle so you can squeeze it out can take enough time to rattle ones nerves and get you seriously thinking about taking up Macrame!!

If you want a more permanent bond I'd go with the Professor's idea of using the silicon caulking. Use the paintable type so you can touch up any blobs that might appear. A good way of applying caulking is to squirt a bit of it into the back of one of those syringes with the curved tips and use it like a tiny caulking gun. This works great for squeezing out small amounts and for filling sloppy joints that have resulted because the builder didn't have the patience to mitre the joint properly.

I'll stop now as I'm starting to lose my patience.

The tacky glue appealed

The tacky glue appealed initially...anyone used it on brass bridges/track?  Is it easily movable for minor realignment before setting up?

I'd love to use something that would release with a dousing of water "on down the road" if it'll work.  One reason I considered this is that I would like to wait to weather the bridges until after the layout is much further along and can see exactly what would look best in the scene but also to allow a repair if it were ever necessary.

Jim

Rubber cement

How about using rubber  cement?  It should bond reasonably well, but still be removable.  Put a thin coat on the bridge and the track, let it dry, and stick the track in place.

As Ken said...

+1 for the rubber cement, sounds a lot like the glue the other guys are describing - but I have no experience with them myself.

Ken & Travis, I thought of

Ken & Travis, I thought of rubber cement but was afraid that the solvent in the glue would cause bridge paint cracking, etc.

Still mulling it all over...a water based adhesive seems less likely to have paint issues.

I may talk myself into what Prof suggested, ruining paint if need be and dealing with it if I had to, down the road, but after paying for spendy painted brass, it's just counter-intuitive to willingly  "attack the paint" if I don't have to.

Walther's goop, barge cement, etc. are commonly used and were all considered but they have the solvent concerns with the paint should I ever need to replace or repair the bridge track.

I've got to cut and glue up all of the abutment/pier shims before I have to make a "final" decision.

Thanks for the feedback guys. I do appreciate it.

Jim

Rubber glue is called . . .

"Contact Cement" made by LePage.  It is basically the same as the  Goodyear Pliabond adhesive we used many years back for patching tire tubes on bicycles and car tires.  Even when dried it does maintains a degree of flexibility.

Read the directions first and it should work fine.  Yes, it is removable.  It can be dissolved with Acetone.  However, Acetone will also dissolve most plastics, so beware.  Or, if you wish to avoid the fumes of Acetone, you may be able to peal it off by hand - but it would take some time and finger nails.

If Contact Cement is in contact with paint you will also be pealing the paint off when removing the adhesive.  Actually, just about any adhesive, in contact with paint, will remove the paint.

Tough call but I would experiment on some junk stock before trying any adhesive if I wanted to remove it later on.

G.T.

My suggestion

If you're concerned about the paint, try painting a piece of brass (treated as you would the bridge) and then putting various glues on it to see:

1. How well it bonds
2. How well it comes off
3. If it damages the paint

Personally, I would not worry too much about the paint.  Touch-up would not be that difficult, and between the nature of the prototypes (which were not always painted in one piece, but as needed) and the fact that any touch-up needed would be practically invisible beneath the track anyway, I just don't think it's worth worrying about.  More important in my opinion would be to make sure that whatever adhesive you use does what you want - holds the track down, but is still removable/adjustable as needed.

How About Walther's Goo?

I mean, how solidly do you need to fasten it down? I would think a drop or two of the Goo at each end and in the middle should hold it solidly, and still have some flexibility, and wouldn't transfer sound as well as epoxy or other mechanically rigid bonding agents....

Perhaps...