Talk Composites - The Forum for Advanced Composites

Skinning resin viscosity

http://www.talkcomposites.com/Topic34752.aspx

By idcomp - 2/4/2020 1:44:46 PM

Hi all,

Having problems with resin being too runny. I put two coats then light sand with 240grit then one more coat. And still resin is too thin on some places like curves it just runs off even if I put thicker coat. 

I mix resin and hardener and wait for about 5-10 min for it to degas

Had this problem before. You can see it in the pic where on such a little slope it just wont stay in place just runs off.

How to deal with this problem?
By Hanaldo - 2/5/2020 1:19:36 AM

 
idcomp - 2/4/2020 5:21:39 PM
 
Warren (Staff) - 2/4/2020 5:02:18 PM
The resin is advertised as a low viscosity resin.  Might be worth looking up the TDS to check and compare.  A low viscosity resin may well be the cause of your issues.

For example, the XCR coating resin is slightly thicker than our own laminating resins, which is what makes it more suitable for skinning that our laminating resins.

What am I looking for exactly?

Left resin mixed for about 35-40mins at about 20c its thicker but not sure will it help. Will see and report back.

Also is it good idea to spray acetone to get rid of the bubbles?

Look for the Viscosity properties in centipoise. Laminating resins tend to have a viscosity of around 350-600cps. Coating resins like the XCR resin are normally thicker, around 800-1000cps. 

No,  or a good idea to use acetone, it can effect the properties of the resin and hurt the surface finish. Use a hot air gun or a blow torch and quickly run it back and forth over the surface to pop any bubbles. Beware the getting the resin too hot can burn it and cause issues, so only do enough to pop the bubbles. Heat will also lower the viscosity again and potentially lead to more running issues.