Large Scale Central

PVA Glue--What is it?

General Discussion
#1

I was reading an article by the late Peter Jones in the June 2008 issue of Garden Railways in which he recommends the use of PVA glue as a preservative for wood used in outdoor models. He assumes that the reader knows what PVA glue is and doesn’t describe said product.

A search of the internet is less than revealing, because the entering “PVA GLUE” into my favorite search engine yields this:

PVA (Polyvinyl acetates) are probably the most common adhesive on the market. They come in a variety of formulas, all ever so slightly different, and specific to what they are designed to glue. Here are some tips for using Polyvinyl acetates.

  • All PVAs are designed to work on porous materials only
  • PVAs are water based, and clean up with warm soapy water.
  • PVA is only toxic to ingest, it does not emit any harmful fumes, and is not hazardous to touch
  • PVA sets best in good air circulation, at room temperature.
  • PVAs need pressure to adhere, see our info on clamping.
  • Most PVAs are not water proof. The yellow PVAs have a higher moisture resistance than the white ones, but neither are completely water proof.
  • Never allow your PVAs to freeze. This breaks down the polymers and your glue will be rendered useless!
  • Yellow PVAs have a shorter shelf life than white PVAs.
  • Be wary of over priced PVAs that claim to be for a specific use. There is very little difference from one PVA to the other, and nothing that should increase the cost.
  • Although PVA is not a gap filler, in some cases you can add sawdust to it to increase its gap filling ability.

I don’t think this is what Peter was refering to.

Any ideas?

#2

Steve, I think that you are correct in assuming that he wasn’t referring to standard PVA glue.

Standard PVA glue is what we consider typical white wood glue. Also as the generic white school glue and by a 1000 other brands. We all know that this type of glue is NOT water proof, and in fact will dissolve when wet, even after well dried and cured.

#3

Dave Taylor said:

Steve, I think that you are correct in assuming that he wasn’t referring to standard PVA glue.

Standard PVA glue is what we consider typical white wood glue. Also as the generic white school glue and by a 1000 other brands. We all know that this type of glue is NOT water proof, and in fact will dissolve when wet, even after well dried and cured.

Ok, so what was Peter referring to? He used the product to resurrect a long abandoned, rotten, plywood model house. He restored it from derelict to pristine. Are we talking about something like Titebond III?

#4

Steve Featherkile said:

I was reading an article by the late Peter Jones in the June 2008 issue of Garden Railways in which he recommends the use of PVA glue as a preservative for wood used in outdoor models. He assumes that the reader knows what PVA glue is and doesn’t describe said product.

A search of the internet is less than revealing, because the entering “PVA GLUE” into my favorite search engine yields this:

PVA (Polyvinyl acetates) are probably the most common adhesive on the market. They come in a variety of formulas, all ever so slightly different, and specific to what they are designed to glue. Here are some tips for using Polyvinyl acetates.

  • All PVAs are designed to work on porous materials only
  • Most PVAs are not water proof. The yellow PVAs have a higher moisture resistance than the white ones, but neither are completely water proof.
  • Never allow your PVAs to freeze. This breaks down the polymers and your glue will be rendered useless!
  • Yellow PVAs have a shorter shelf life than white PVAs.
  • Be wary of over priced PVAs that claim to be for a specific use. There is very little difference from one PVA to the other, and nothing that should increase the cost.
  • Although PVA is not a gap filler, in some cases you can add sawdust to it to increase its gap filling ability.

I don’t think this is what Peter was refering to.

Any ideas?

Note that the above has been snipped to remove excess info.

If we read here, we see that PVCs are both white and yellow but neither is fully waterproof.But, they are moisture resistant.

We can also see that they can be used as a gap filler if SAW dust is added.

You are asking how it can be a preservative for wood outdoors. I would say that I have often smeared Titebond III over the entire surface of wood I have used in both structures and railcars, I use a brush and also occasionally thin it with a bit of water. When dry it seals the pores of the wood therefore stopping moisture from getting into the wood.

NO, I do not believe this would keep out the moisture if said building were to sit in a puddle, but it will help keep the wood from sucking the moisture out of the air on a humid day.

I also use it as a surface prep before sanding. It helps rid the surface of the fine wood fibers but doesn’t stop the paint from adhering to the surface.

So I’m not brand specific I have done the same with Elmers wood glues for years, both the white and yellow wood glues.

Hope this helps

#5

Thanks, Dave

#6

Exactly what Dave said. But remember wood “stain” will not penetrate PVA glue so if you want to stain keep the glue off of the surface.

#7

So, stain first, then glue to preserve? Or, glue, then paint?

#8

Guys. I don’t think that he was referring to what we have now days… Tightbond lll has only been around for a limited number of years. The MSDS on it lists it as “Crosslink Polyvinyl Acetate”. And that cross linking is what I think makes it waterproof. The MSDS also makes it out to be perty darn inert across the board. You can get it to ignite if you work really hard at it.

I too have used it as a general sealer/waterproofer on my working water tank build. Primer and paint adhere to it well, as did other silicon based adhesives (roof shingles)

(http://i1234.photobucket.com/albums/ff403/dave2-8-0/WT-83.jpg)

(http://i1234.photobucket.com/albums/ff403/dave2-8-0/WT-80.jpg)

(http://i1234.photobucket.com/albums/ff403/dave2-8-0/WT-94.jpg)

#9

A word of caution when using typical PVA glue is that it is alkaline. In smaller scales many use it as a filler with lead to secure weights in their models. Over time the alkaline PVA reacts with the lead causing gases to be released and the PVA to expand in volume. This inevitably results in a disaster if the weight is retained inside a cavity with no room for expansion.

The effect on cast iron weights or other metals is unknown.

#10

hehe

Kids often taste it in school. Must not be THAT toxic. Or maybe we’ve just discovered the real cause of ADHD.

#11

The waterproof feature is an essential for those looking for this feature.

I found – be careful to read – the 3M silicone sealer/glue comes in a waterproof clear version. The print “waterproof” is not large. The sealer has “glue” qualities and adheres plastics, tiles, wood, etc., as long as there is not a stress load. Say, buildings for the layout and track down on a trestle.

Wendell