Viton o rings

[HBF]

Hey all..I’m trying to find a metric Viton o ring for a Mastercraft roofing nail gun that was sold in Canada but was made in china and now parts are obsolete.. it seems that over in your neck of the woods they are common but not so much here without taking a second mortgage out on my house…Can any one of you fine gents or lasses point me in the right direction? 38 x 4.5 Viton metric o ring 70 or 80 D hardness scale..

 

[Erie Fred]

Does it have to be Viton ?

 

[zzr1200]

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The above company is based in Holland....

 

[Agroshield]

38 x 4.5 is not so far from 1 1/2" x 3/16" so an imperial one from across the border might be an option.

 

[HBF]

Does it have to be Viton ?

Well it’s in an air nailer and when the piston reaches the end of its stroke it lets the air pressure out through a series of small bleed holes. I have tried NBR and silicone o rings and they shred when they pass the bleed holes so it’s got to a harder o ring to slip past them, but I’m open to suggestions

38 x 4.5 is not so far from 1 1/2" x 3/16" so an imperial one from across the border might be an option.

Well I’m going by the size of the o ring in the parts schematic, I have tried the imperial size but it is slightly larger and when installed in the piston the WD of the o ring is slightly squished which in turn makes it a larger OD and it won’t slip into the cylinder bore.

 

[hotponyshoes]

Is 38mm the ID or the OD?

 

[bricol]

Well it’s in an air nailer and when the piston reaches the end of its stroke it lets the air pressure out through a series of small bleed holes. I have tried NBR and silicone o rings and they shred when they pass the bleed holes so it’s got to a harder o ring to slip past them, but I’m open to suggestions


Well I’m going by the size of the o ring in the parts schematic, I have tried the imperial size but it is slightly larger and when installed in the piston the WD of the o ring is slightly squished which in turn makes it a larger OD and it won’t slip into the cylinder bore.

I'd measure the groove and work from that to select the nearest imperial size suitable for the groove, rather than an imperial equivalent of the metric o-ring.

 

[HBF]

Is 38mm the ID or the OD?

It’s the ID…the way you figure out the size of o rings (metric ) is .. 38 mm ID plus the WD plus the WD which will give you the OD. 38+4.5+4.5 =47 OD..which is the size I need 38 ID by 47 OD but you order it 38 x 4.5
Go figure..

 

[HBF]

I'd measure the groove and work from that to select the nearest imperial size suitable for the groove, rather than an imperial equivalent of the metric o-ring.

I know what your saying but it has anywhere from 80psi to 110 psi on the piston when fired and any thinner on the WD it will bypass the o ring, but in saying that I still need something like viton or Teflon to slip past the bleed holes and won’t be shredded

 

[Guzrik]

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They also have nbr 90 shore, but not sure if they would send it to you.

Techniparts.nl will also sell them, seems a standard o-ring.

 

[bricol]

I know what your saying but it has anywhere from 80psi to 110 psi on the piston when fired and any thinner on the WD it will bypass the o ring, but in saying that I still need something like viton or Teflon to slip past the bleed holes and won’t be shredded

I really can't imagine a viton one would be any more resistant to being torn that what you've tried. I've run o-rings past bleed holes with no noticeable issues in my designs before - no damage to the holes?

 

[HBF]

I really can't imagine a viton one would be any more resistant to being torn that what you've tried. I've run o-rings past bleed holes with no noticeable issues in my designs before - no damage to the holes?

The bleed holes are fine, the problem I’m having is the size of the o ring,it seems that the WD is an oddball size.
I need the exact size,if it’s to thick it will expand the OD which will push out in the bleed holes and shreds the o ring..if it’s to thin it won’t seal under high pressures…I need 4.5 WD ..47mm OD and 38 mm ID…and the old o ring looks like viton.

 

[Guzrik]

The bleed holes are fine, the problem I’m having is the size of the o ring,it seems that the WD is an oddball size.
I need the exact size,if it’s to thick it will expand the OD which will push out in the bleed holes and shreds the o ring..if it’s to thin it won’t seal under high pressures…I need 4.5 WD ..47mm OD and 38 mm ID…and the old o ring looks like viton.

AFAIK it takes electronmicroscopy to distinguish nbr/viton?
How do you know it is viton?
I would send an email to techniparts.nl and just ask for a quote incuding shipping for a few different ones. They normally don't charge small order cost to me, so I try to make my orders a bit bigger by ordering a few of each.
Maybe a 90shore nbr is better in respect to the bleedholes.

 

[HBF]

AFAIK it takes electronmicroscopy to distinguish nbr/viton?
How do you know it is viton?
I would send an email to techniparts.nl and just ask for a quote incuding shipping for a few different ones. They normally don't charge small order cost to me, so I try to make my orders a bit bigger by ordering a few of each.
Maybe a 90shore nbr is better in respect to the bleedholes.

Yes I will check into it.. thanks