Varnishing after sanding fiberglass
Varnishing after sanding fiberglass
I have just finished sanding the fiberglassed hull, next step is to varnish. My question is, do I need to buff up the glass before applying varnish? As the book says, the glass has lost its shine and is now cloudy. Will this clear when I apply the varnish or should I do something else before varnishing? Thanks.
Re: Varnishing after sanding fiberglass
Hi BogW,
The hull gets sanded to 220 and as you observe will be typically of a sanded finish (white/cloudy).
When you apply the varnish, it will be like magic and the glory of the wood will shine through.
Hopefully you fully cured that epoxy (manufacturers site) and washed the hull with soap and water before you sanded .... this is an important step in the process, as depending on curing conditions, any epoxy can throw amine blush and this will inhibit the varnish drying. I don't mention this to scare you, just making sure you were aware ... if you failed to do this and the varnish stays tacky, you know what the issue is now. If it dries normally, you have a note for the next time you epoxy.
Also, if your varnish has a thinning schedule, you can skip into the mid range of the schedule, as the application is now on a sealed surface.
Brian
The hull gets sanded to 220 and as you observe will be typically of a sanded finish (white/cloudy).
When you apply the varnish, it will be like magic and the glory of the wood will shine through.
Hopefully you fully cured that epoxy (manufacturers site) and washed the hull with soap and water before you sanded .... this is an important step in the process, as depending on curing conditions, any epoxy can throw amine blush and this will inhibit the varnish drying. I don't mention this to scare you, just making sure you were aware ... if you failed to do this and the varnish stays tacky, you know what the issue is now. If it dries normally, you have a note for the next time you epoxy.
Also, if your varnish has a thinning schedule, you can skip into the mid range of the schedule, as the application is now on a sealed surface.
Brian
Re: Varnishing after sanding fiberglass
Thanks Brian,
That's very helpful. I left the epoxy for two weeks before sanding. I didn't wash the hull though, didn't know about that. Glad to hear that all will be fine when I varnish.
Pete.
That's very helpful. I left the epoxy for two weeks before sanding. I didn't wash the hull though, didn't know about that. Glad to hear that all will be fine when I varnish.
Pete.
Re: Varnishing after sanding fiberglass
BW,
I included the washing step as a warning for the future. It isn't a problem all the time ...but what a mess when it happens, the wash is a simple step to add to prevent.
Most times I figured, well I sand it anyway ... but apparently the blush sands and then gets ground into the surface, so remains an issue. I just completed number 5 and i had a slight issue with this and it was a pita, sanding sticky varnish back off and doing a cleanup.
Hence the warning,
Maybe post a few pics, we do like to see what folks are up to.
Brian
I included the washing step as a warning for the future. It isn't a problem all the time ...but what a mess when it happens, the wash is a simple step to add to prevent.
Most times I figured, well I sand it anyway ... but apparently the blush sands and then gets ground into the surface, so remains an issue. I just completed number 5 and i had a slight issue with this and it was a pita, sanding sticky varnish back off and doing a cleanup.
Hence the warning,
Maybe post a few pics, we do like to see what folks are up to.
Brian
Re: Varnishing after sanding fiberglass
Some epoxies still have the Amine blush.
I use RAKA's resin, and 350 non blush hardener. I've never washed or had any problems with varnish.
Jim
I use RAKA's resin, and 350 non blush hardener. I've never washed or had any problems with varnish.
Jim
Keep your paddle wet and your seat dry!
Re: Varnishing after sanding fiberglass
Just a clarification Jim, "non blush hardener" is just a name, it doesn't mean that it is actually going to yield a final amine blush free finish. Even the description on Raka's site says it "resists" blush, that leaves some room for blush under some conditions.
Depending on the area and weather in the location the product is used, it is my understanding that any epoxy can throw some amine blush ... the fact that you haven't seen any, suggests you have a good area for epoxy use or have been lucky.
I think the wash step is a lot less work than just taking the chance.
Brian
Depending on the area and weather in the location the product is used, it is my understanding that any epoxy can throw some amine blush ... the fact that you haven't seen any, suggests you have a good area for epoxy use or have been lucky.
I think the wash step is a lot less work than just taking the chance.
Brian