Finishing wood and plastic together

[NGLJ]

For the first time I find myself pondering on how to finish a combination of wood and plastic. By combination I don't mean a mixture. I am trying to make a pen which has plastic end pieces on the barrel and cap for decoration. I am well versed in how to tackle wood and plastic separately, but not where finishing one may affect finishing the other, and vice versa. The only common way that I can think of is to use CA on the wood, and then I only have plastic, but how to do it without "contaminating" the plastic, or do we care. Since some of the plastic is at the open ends of the barrel and cap, how do I finish the end face without causing a problem on the inside where it is threaded? Hope this all makes sense! Or am I making this more complicated than it really is! Perhaps masking is the answer.

 

[JohnU]

I think I would treat it like a hybrid and just use CA (Gluboost in my shop). Not only will it fill cracks and smooth transitions between materials, but it will also enhance the colors in the materials. Also, the ca finish is usually harder than the plastic material adding durability to the finished surface against dings and dents, along with helping keep a longer shine.

 

[keithlong]

I agree, CA finish all the way.

 

[BHuij]

I have done several composite pens that have various combinations of wood/plastic/resin/acrylic/metal/other materials that need to be turned and finished together. My go-to is regular old CA finish. I won't generally bother with CA if I'm turning a 100% acrylic blank since it doesn't really need it. But when you have multiple materials like that, there's not really any downside to covering everything in CA, then polishing up to a super high gloss.

 

[bugradx2]

I agree that CA (also a GluBoost shop) is what I use for hybrids, all my pens actually. It works like a charm

 

[d_bondi]

+1 for GluBoost CA on everything (except for the threads of course).

IF you are looking for an alternative, for some tropical high density and oily woods, I like to leave them natural.

Here is an example. The wood is old growth true Brazilian Rosewood (Dalbergia Nigra). It is very hard with a Janka Hardness of 2,790. The cap and barrel are completely lined with Black Nikko Ebonite. The section is also Nikko Ebonite. There is no finish on this pen. The ebonite and wood is sanded to 800 and then with a 1500 Mirka MirlonTotal pad. IF the wood looks dry in some places, I will use a very small amount of walnut oil, like single small drop, on a microfiber cloth and rub it into the wood and then wipe it off.



I realize that these two pictures don't give you much of a look at the ebonite in matte finish. So to give you a better idea what your finials might look like, here is another pen that is all ebonite and all in matte finish.

 

[Alchemist]

If sanded above 600 grit, you can use sanding sealer to fill the pores of the wood. Then hit it with a buffing system. You can also use plastX by meguiars. The sanding sealer will not penetrate the plastic parts and you will get a shine either way.

Just make sure your wood part is sealed so the pores are filled.

And yea, you can use CA. Routinely, tobacco pipes are buffed with stem and wood with no CA glue. It's all about surface prep. If you have the pores open or pits that are sanded down the compounds will fill in.

Also, you can tape off the wood parts of the plastic is on the ends. Buff gently and accordingly to your shine.