Polyurethane glue

What is this?

What do you use it for?

What are its brand names in the UK and where do you obtain it?

We are probably behind you this side of the pond but I have not herd of it before I started surfing this Forum

David

Polyurethane glue is for woodworkers, primarily.

It is (in the Colonies) about five times as expensive as ordinary wood glue (Titebond original formula, for example) and offers no real performance advantage to modelers over wood glues.

In some situations polyurethane glues are counter-productive, as in the case of sheeting foam cores with balsa skins : as the glue expands it can force the skins away from the cores resulting in the classic 'starved horse' appearance (washboard). That's probably the major down-side to PU glues - the expansion tends to push the wood bits apart causing if nothing else misalignment of the wood bits.

The only instance where PU glues shine over aliphatic resins (wood glues) is where there is a need to fill gaps, which of course normally result from poorly fitted wood bits anyway.

Check the Titebond or Gorilla Glue web sites - they likely have UK distribution.

works well when gluing coroplast (SPAD's).

i really beg to differ with you on sheeting foam cores with it.it is byfar the best way to sheet foam cores,it goes on with a playing card squeege on the foam and on the wood and set in the shucks with lots of weight and you will have the best foam sheeting job you ever seen.it soaks into the foam about 3/8 inch deep and fills any holes in between the sheets that you might have missed,and is easy to sand,i even use it for all my hindges,small dab of water in the holes ,a small amount of probond and coat the hindge lightly and insert all hindges and line them up,check it every 15 minutes for foaming for the first 45 min and let stand for 4 or 5 hours

Bad for the lungs (tumors) and other body parts!!!! Always use gloves, and even though it doesn't have a strong smell, use a well ventilated area!

Looky here- http://www.elmers.com/msds/mp9401.htm

Titebond II seems to be my favorite of late....sands easily and dries quickly.

Jerry

I agree with 3dd on this one, it works great for sheeting foam. The sheeting won't float if you use enough weight, and don't use too much glue.

Another vote for poly glue and wing sheeting. If done right, it can't be beat. It's also great for TIGHT fitting critical joints, such as firewalls and landing gear plates. It also works well for bonding metal to wood, plastic to wood, and plastic to plastic. It's all I use for building my coroplast creations. It has a bit of a learning curve, ie, you need to experiment with it your area. Heat and moisture play an important role in it's cure. Try pouring a quarter inch of it an 8 oz dixie cup, and then add 1/2 inch of warm water. Mix it with a popsicle stick and walk away for half an hour or so. When you return it should be in it's 'expand' stage. Now take your heat gun and hold it about 2-3 feet away. Watch as the glue expands right before your eyes! Experiments like this will help you figure out its different cure stages. I like to keep the heat in my garage to at least 70 when I'm using it.

Poly glue will not expand in an air tight enviornment. However, if you mist it with water first, it will cure in a nearly airtight enviornment. Just play around with it. Try running beads on scrap wood, and mist each bead with different amounts of water, or at different times in it's cure stages. This method will teach you in a hurry how the glue reacts to moisture and air temperature in your area.

Set in the shucks with lots of weight, check for foam every 15 minutes, and it's cured in 4 or 5 hours.

Yup, that about says it all for sheeting foam cores with polyurethane.

I don't like foam wings and so build as few as possible. When I do build foam wings, I prefer to use an adhesive which does not require "lots of weight", and which cures immediately, not 4 to 5 hours later.

Sorghum is the one adhesive of which I am aware that has those properties, and which is foam-friendly. Haven't tried ordinary contact cement, but it should work as well.

even at that you need to put a load on the shucks for awhile and sourgum haha will release in the heat of day in the summer.to each their own to learn and like or dislike

The only thing I use polyurethane for is [link=http://airfieldmodels.com/information_source/how_to_articles_for_model_builders/construction/make_balsa_wood_plywood/index.htm]laminating parts[/link] under lots of weight. I live in Florida, so I don't have to moisten the wood first. There's enough humidity here that it isn't necessary.

Not if you use the product correctly, but then that's a much larger issue with polyurethane glues.

Using poly is all about technique and as such requires some patience and trail and error. Once you figure it out the stuff is great and has many uses. Of course if you just want to run a bead and stick the parts together use wood glue or epoxy.

I have found it to be great for sheeting foam parts if you use water to moisten the contact areas and use the glue sparingly as a little goes a long way. For wood to wood joints that require strength it has almost replaced epoxy as my adhesive of choice. It's ligher than epoxy and just as strong IMO if applied correctly and it can be sanded pretty easily as well. I have also found that on poorly fitting joints it is far superior to other glues as the glue itself actually is pretty strong and supports the joint rather than just creating a bond between the parts. For ARF's it's great as you can run abead in places that are questionable and have no worries about that joint ever comming loose.

Like many other products that we modelers use most hate it when they first try it but if they take the time to figure the product out it will quicky find a place on their work bench.

Fred,

You are right.... if used properly. And every actor has his own method and so goes the modeling ways too. Poly-u is by far lighter then sourgum. I used to use the sourgum stuff back in the 70's but have since switched to the poly glues for sheeting wings. The poly glue when used with carbon fiber will also produce an extremely strong setup in the wing. My pattern plane has over 525 sq in per panel and they only weight 14.5 oz RTF w/servo.

Either glue works good when the proper application is used. Soooooo sheet away.

Smooth Flying...

Wayne G.