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Building Tips and technical articles. => Paint and finishing => Topic started by: Lauri Malila on May 12, 2012, 01:12:08 AM

Title: O-ring material for an airbrush..?
Post by: Lauri Malila on May 12, 2012, 01:12:08 AM

 Hi.

 I have some Harder & Steenbeck airbrushes. They are quite good, maybe just not so sophisticated as Iwata's but good enough for painting my airplanes. And certainly easier to clean than an Iwata of same size (I also have HP-C's).
 But there is one problem. Both the paint cup and nozzle body are sealed with an ordinary (Neoprene, I guess) O-ring. I have not measured them but they look something like 6x1mm.
 These O-rings don't like my paints & thinners. I've noticed the biggest problems with 2-component polyurethane paint and universal nitro thinner. The rings swell and eventually break. Usually they last as long as I paint but break in the dismantling/assembly of the cleaning process.
 I'm about to order replacement rings. What material do you recommend? Viton?

 Lauri

Title: Re: O-ring material for an airbrush..?
Post by: Tim Wescott on May 12, 2012, 09:12:16 AM

Without thinking about it, yes, Viton.

If you want to spend the $$, get some Viton and some of whatever else is listed as chemical resistant (McMaster-Carr has a pretty long list of what their O-rings resist and what they don't.  I don't know if it's accurate or thorough, but it is long).  Then try each one out in turn so you know what to settle on.

Title: Re: O-ring material for an airbrush..?
Post by: Lauri Malila on May 12, 2012, 09:30:50 AM

 Thanks, Tim.

 Yep, I've been looking at Mcmaster-Carr site. It's good for such information but unfortunately they are unwilling to send stuff to Europe. But smallparts.com has quite good selection too.

 Lauri

Title: Re: O-ring material for an airbrush..?
Post by: RandySmith on May 12, 2012, 11:11:29 AM

Hi Lauri

I would try the red silicone rings first before Viton. They are more the same hardness and Viton may have a problem with being harder than neoprene

Randy

Title: Re: O-ring material for an airbrush..?
Post by: Rob Killick on May 12, 2012, 02:22:18 PM

Lauri ,

What Randy said is a good start . The only problem with the silicone o-rings , is that they may turn to "snot" (pardon the reference), if exposed to petroleum based solvents .

If you can find teflon based o-rings with a durometer of around 75 , they might work the best.

Just my 2 cents worth.

Rob Killick

Title: Re: O-ring material for an airbrush..?
Post by: Lauri Malila on May 12, 2012, 03:34:04 PM

 Thanks again for tips.

 Randy is right, I use Viton rings in my mufflers and at least the ones I've got are indeed harder than neoprene. In the airbrush, the ring needs to be soft. I'll see what I can find and then do some tests.

 Lauri