Thinning Contact Cement

[Chuck Seiler]

    I'm not sure if I am posting in the correct forum, but I can't find one for glue.

 

    What is the best way to thin contact cement.  I am using Weldwood DAP contact cement on my card model.  I am down to a third of the bottle and it is getting a bit thick... coming out in gobs.  I want to thin it down a bit so I can continue to use it.  I see nowhere on the bottle the recommended "clean up" material.

[Jaager]

I found the MDS 

 

the solvent seems to be:

Section 3 - Composition /

Information On IngredientsChemical NameCASRN  

                                                                          Wt%
Toluene   108-88- 3                                         15-40
Acetone   67-64-1                                            15-40
Light aliphatic solvent naphtha   64742-89-8   7-13
n-Heptane   142-82- 5                                      5-10
Methylcyclohexane   108-87- 2                       0.5-1.5

 

They do not even have a fixed ratio,  just a range

It is a proprietary mixture (?) so no off the shelf solvent.  Reads like some nasty stuff to breathe.

 

The adhesive is a rubber derivative

I have a home made thickness sander from very old NRJ plans - 11" Maple  drum and used this stuff to fix the 11x9 sheet of abrasive medium.  It is a job the remove and clean.  Naphtha will cause it to unstick and roll into balls but still a lot of work to remove.   Mineral spirits will loosen it -- eventually.  No solvent have I found. 

My Byrnes replacement, although 6" instead of 11",  is magnitudes faster and easier to replace the media on.

 

If you must use it,  it looks to me as though you are limited to buying the smallest size container and pitching it when it evaporates too much carrier solvent.

 

With straight up Best Test or Elmer's rubber cement, you can buy Bestine - n-Heptane - in pints or quarts -  but this stuff looks no go.

 

 

[mgdawson]

Hi Chuck,

 

On leatherworker.net they talk about acetone, MEK (MEKP is not the same), toluene and even general purpose thinners, it depends on the brand of contact. One poster specifically mentions he'd had success with Toluene for thinning DAP weldwood, Acetone for cleanup and less success for thinning.

 

Let us know how you fare.

 

Mark

[Bob Cleek]

On 6/21/2020 at 10:19 PM, Jaager said:

have a home made thickness sander from very old NRJ plans - 11" Maple  drum and used this stuff to fix the 11x9 sheet of abrasive medium.  It is a job the remove and clean.  Naphtha will cause it to unstick and roll into balls but still a lot of work to remove. 

If you haven't already, try 3M disk adhesive, sold in auto body and fender supply houses. (If they still make it. Every time I try to buy something useful her in CA, it seems they've outlawed it!) It comes in applicator bottles, "toothpaste" tubes, and aerosol cans. It's made to easily clean off sanding pads with acetone. It does get a bit tenacious when it's been sitting for a long time, though. It may be hard to come by these days, though. Everybody seems to have gone to adhesive-backed pre-cut disks and hook and loop. Cutting your own out of sandpaper bought by the 100 sheet sleeve is way cheaper than hoop and loop!

[Chuck Seiler]

All,

 

    Many thanks.  I have no idea what toluene is, but a check of AMAZON says it is more expensive than I want to pay.  Better to toss the bottle and get new.

 

    I will get some 100% acetone and try it out without burning down the house or asphyxiating myself.

 

Bob,  I get my Cali banned stuff from Arizona. 

[Bob Cleek]

25 minutes ago, Chuck Seiler said:

Bob,  I get my Cali banned stuff from Arizona. 

Shssss! Keep that under yer hat, will ya? We don't want to blow a good thing.

 

BTW, if you are in San Diego, you can run across the border and get lots of really good stuff you can't buy in California. Guys used to run down there and buy tributyl tin oxide to add to their boat bottom paint in CA. It was banned everywhere years ago because it killed marine organisms... which is exactly what it was supposed to do!  

[Chuck Seiler]

I used to go to TJ alot in the 90s.  Not anymore.  Too dangerous for me.

[Chuck Seiler]

    Experiment complete.  Aware of the risks posed in post #5, I took my experiment outside with adequate ventilation.  I still ended up with a slight headache and mild buzz.

 

    I took a gob of contact cement and placed it in a shallow container, mixed in some acetone.  It thinned a little on the surface but the result was not great.  At this point the bottle is nearly unusable, so I will put some acetone in the bottle and see how that works...give it some time to work.

[Chazz]

Hi Chuck,

 

I don't make paper models so I don't know whether my 2 cents will apply, but...

 

There are (at least) two possible alternatives you might consider.  One is Fabri-tak, a hard-drying rubber cement sort of stuff sold in fabric stores for doing seams, attaching decorations and such work.  I have used it to lay down the hems of sails and attach cords for stitching on bolt ropes; and some tacking jobs for further gluing.  It does not stain, even dress fabrics, it dries very fast..30 seconds or so,   and it dries hard, not sticky like rubber cement, and it is claimed to be washable.  It is easily thinned with acetone (needed quite often).

 

When thinning with a solvent as volatile as acetone, don't use a vessel with a relatively large surface area.  You'll probably lose as much to evaporation as you get into the glue.

 

Here's a tip.  When pouring a flowable liquid like water or acetone from one container to another hold a thin dowel or piece of heavy wire or such, say about 1/16" in diameter (long enough to reach the lower container) across the opening you're pouring from.  The liquid will cling to the dowel and run down nicely  into the vessel below.

 

The second possibility is Liquid PSA, available from Micromark.  It's a water based glue you apply to your joint, allow to dry a few minutes, when it dries to a transparent tacky film, easy to handle.  When dry, press the two pieces together, like contact cement.  Much easier to handle and no odor Dries hard after a couple of days. 

 

Good luck;

 

Chazz

 

 

 

 

[Chuck Seiler]

Chazz,

 

    Thanks for the info.  I will check them out.