friendly plastic not that friendly

[Mike Ryan]

Well, I have made a run at friendly plastic for the 4th time, got it to work this time.
I am making a caul for back veneer on a parlor guitar headstock and it curves slightly at the neck. .
The temperature of this product is very critical to its use. So many videos etc. on the net "just add some hot water" and the beads are supposed to turn clean then you can mold this stuff.
WRONG.
This time I had a double boiler water bath, went to almost exactly 150 degrees F to get the stuff to melt uniformly.
THEN, it took at least 20 minutes to melt uniformly.
THEN, I took it off the heat and waited until it became turbid again. Took a while.
Then, at just the right time, (the temp difference between sticky and perfectly mold-able isn't much) I was able to actually mold it and it seems to have worked, not perfectly but well enough.
OK,
earlier today, I did as video instructions recommend and I had the most sticky substance in the world, the friendly plastic, all over my kitchen, my hands and everywhere else. Fortunately , I can recover most of it by waiting till it hardens.
Another example of someone who is used to using a material making a video with almost no guidelines about using complicated, thermoplastic substance in a comprehensive, mission critical way in this instance.
This stuff is a God send to the luthier if you can actually use it.

[David King]

Mike, thanks for posting this. I really enjoyed your description. It might need to be copied over to the review section at some later date.
It's a problem with so many "instructional videos" these days. They always seem to forget that the folks searching for their video are coming to it to learn something. I couldn't help thinking you could probably have band-sawed that caul from scrap wood and lined it with cork in the time it took you to stage one with the "friendly" plastic.
Whenever someone names a product "friendly" anything it's a given you need to show up with a hazmat suit and a supplied air hood at the ready.

[Michael Lewis]

Mike, your description made me think about when I was learning how to work with CA in it's various viscosities. Probably entertaining to onlookers.

[Stephen Neal Saqui]

Does anyone know how to handle this stuff? It would be nice to know!

[Mike Ryan]

Maybe, I was not clear above.
Once I got the temp right for melting and waited long enough for the stuff to get to its actually malleable (not over-sticky) state, it has worked and I was able to use it to glue the curved headstock back veneer in. It is the waiting until I can actually mold it that is the key I guess. That part is not easy and goes by fairly quickly and the temp in the room I was in was in the mid 70's.
Also, don't heat it in water in a well used steel pan. It sticks and won't come off. It does not stick much to a corning-ware small piece of bake-ware. Comes off easily. Also, if re using cut up in as small a pieces as you can. (not that easy to cut and band saw can make the cut lines "dirty").
I think it is worth learning to use but need MUCH BETTER documentation.
Kind of like learning to sharpen and put a hook on cabinet scrapers.
I would like to hear from the friendly plastic gurus out there, though. That certainly isn't me.

[Randy Roberts]

Mike,
You had me laughing for quite a while, not at you but because you brought back the first dozen or so times I tried to use it.
It's definitely got a learning curve to it, but once you kinda get the hang of working with it, there's a ton of things it's awful handy for.

I found heating it on the stove in a shallow Teflon frying pan until it's clear works pretty well. I usually just grab it out of the hot water with my hands (as fast as possible!) because sticks etc. seem to just stick to it and make a mess.

If you can keep from touching it for very long in any one place ( kind of "hot potato" game) you can get it where you want it without incorporating yourself into the caul or whatever you are doing. I've tried spritzing cold water on the surface to just get the outside slightly whitish and not so sticky and that has worked (sometimes).

Best advice is to have waxed paper in between the surfaces it would contact, gloop a bunch of it on, lay another layer of waxed paper over it, softly press down until the glob extends out over whatever you need, and then just leave it alone.

The leave it alone part is the key. The more you try to fine tune the fit the more it gets screwed up, at least for me. Go have a cup of coffee or something.

Once it's hard, you can double stick tape it to the backing you want to use. If you glop it onto a piece of wood first thing, you cant get it off again to re-use.

Maybe I'm just too cheap. I can't bear to just throw it away, so I keep trying to rescue every last little piece.

[Mike Ryan]

actually I found the luthiers friend, packing tape, works as a non stick surface very well.
I have a system now that I can repeat so I will try that next time. My caul from friendly plastic with plywood pressed to the non-contact surface for clamp pressure worked just fine to get the curve for my headstock back veneer.
I think this is the kind of friendly stuff that needs tricky approaches to no get it everywhere. I had it all over the kitchen the first attempt yesterday but then did my temperature and color approach which did work.
I agree it could be very useful stuff for luthiers.

[Barry Daniels]

Similar to my most recent adventure: welding breakage in a HDPE canoe. I watched a bunch of YouTube videos where everyone, except for one experienced geezer, made a big mess of things. I tried a hot air gun and an electric stick shellac knife, but I had the best luck using a soldering iron hooked up to my heat blanket controller set to about 525* F. Once the right temperature is established, everything worked fairly well. I just hope it floats.

[Mike Ryan]

I wonder how many have given up on friendly plastic or just put it on the back shelf and plan to try again like me.
I remember when this type plastic came out in the 90's for medical applications such as splints. Supposedly, you could heat it and mold it to any shape for a splint. I actually tried it a couple of times but it was not very "friendly" and I quit using it. Funny, I don't see it used anymore. Back to the plain old aluminum and foam ones for fingers etc.

[Bryan Bear]

I've never used "friendly plastic" before and am surprised to hear that it is so problematic. Years ago I had some research projects that involved brain imaging. We used to have the thermoplastic masks that we would heat in a hot water bath and form them to the subjects face and clamp it down. It would quickly cool and harden helping to remind the subject to keep his/her head still. I rescued several of them and wish I had gotten more! It is great for making bridge cluing cauls and such.

I always assumed that friendly plastic was just about the same stuff. I don't remember the temperature it softened at but it was low enough to not be unduly uncomfortable on your face and had enough open time that you could pull it out of the water bath, dry it off and walk it into the MRI room and position the subject and still have time to get it formed.

[Mario Proulx]

You might be heating it too much? The few times I've used it I simply dropped some into a cup of hot water, waited for it to soften, squished it together to form a ball, then pressed it against whatever I was making a caul for. Seemed to work fine... No, it wasn't dead-smooth and void-free, but as a caul, it worked.

Perhaps you're expecting it to do something it isn't meant to do?

[Mike Ryan]

the problem here is defining what is he heating too much. I think if I could be defined in a meaningful way that friendly plastic actually be a little more friendly