Procedure for splicing viton

[kevlar49]

I am reviewing a procedure for splicing viton and don't know if the manufacturer is doing this properly. Can someone guide me. It sounds like they are taking uncured viton and pressing it against roughened kevlar-reinforced viton sheet (this is for an air duct) and heating to 350 F while maintaining pressure.

Are there any good resources to explain how to splice this properly?

 

[unclesyd]

Is their process working or are you having failures?

Vulcanizing is a very common way to join Viton parts.
When you say uncured Viton are you referring to a Viton adhesive?

Here is just one company that uses vulcanizing in fabrication.
Most companies are pretty tight lipped about their specific process.

http://www.reissmfg.com/rubber_fabricating.asp

You call always ask Dupont. I have always found them to be quite helpful.

http://wwwm.dupontelastomers.com/On.../ScrptPub.dll?ESPW=ENT_EXTV2&ESPJNP=ContactUs

 

[kevlar49]

Thank you, unclesyd. Here is what I got from Dupont:
"Recommend you contact the supplier of the expansion joint - they should be experienced in making field splices such as the one they are going to attempt, and should know the best way to make the splice.

The splice CAN be made using uncured FKM compound, sandwiched between two sheets of cured FKM, but the surfaces of the belting to be spliced need to be very clean (wiped clean with a solvent-soaked rag) and the splice needs to be clamped under pressure (ideally, >50psi) during the application of heat to the splice area. Sufficient time must be allowed for the 350F heat to fully penetrate the belting, to the uncured FKM sandwiched between the layers. If the belting is 3/16" thick, and is reinforced with fabric (the Kevlar you mentioned), it might well require at least 4-5 hours, for the temperature to penetrate into the center of the splice and cure the layer of uncured FKM.

Another option is for them to use a FKM adhesive (like Pelmor Laboratories PLV-2000). PLV-2000 is a 2-part adhesive, and will vulcanize at room temperature.
Clean both belt surfaces that are to be spliced together, by wiping surface with a solvent-soaked rag (acetone or toluene)
Apply a thin coat of the mixed, two-part adhesive to both belt surfaces that are to be spliced together and allow to air-dry (they should experiment with the adhesive, to determine how long a time is necessary, to allow the solvent to evaporate, but without allowing the accelerated cement to cure)
Clamp the coated surfaces together and allow the cement to cure (at least 2 hours)."

 

[unclesyd]

I hope there reply helped.
Here is the information on PLV 2000. I have used Pelmor products numerous times with great success.

http://www.pelseal.com/adhes.html

 

[mesadave]

We used to but viton spliced o-rings from a company in AZ. They always had great delivery time until I called one day to expedite an order. They told me it would be at least 4 weeks. I asked why the long delivery and they replied "It rained".
Humidity is a factor in bonding viton.

 

[MintJulep]

You might also ask the folks that make the sheet. One such company is

http://www.salem-republic.com/calendered-products.htm

They probably have a need to splice on occasion.