Sanding pigtails in epoxy, will they disappear with more epoxy?

BigandSmall

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Leave the 80 grit pigtails and epoxy fill right over top, will they disappear?

Or should I sand them all to 120 grit but slightly deeper into the weave? (I'd like to avoid this)

I'd like to add a thin top coat of epoxy after level sanding the kayak. Just starting to show the weave in a few too many locations for my liking, not into the weave but just appearing. My mouse sander left some deeper pigtails with the 80 grit I was using to level everything out. Since the boat is starting to look good I don't want to save time and ruin the finish. Thinking I'll heat the shop up for the top coat and after tipping off go over it with the heat gun to help get in in there.
 

mick_allen

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I think that whatever the 'pigtails' are [epoxy sanding marks or cloth weave] a fill coat in one less obscure area to double check what happens is safer [finish wise] than immediately doing more sanding removal and possibly more cloth exposure.
 

JohnAbercrombie

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By 'pigtails' you mean the circular swirls that are left when an orbital sander gets a small 'lump' stuck to the paper?
If you clean the surface well (with water), dry, and apply epoxy, I don't think those scratches will show through -certainly not as much as if you sand into the fabric.

Your idea about heating up the shop is the right one for epoxy work. Get the boat warm, apply warm epoxy, then you can turn off the heat and let things cool down as the epoxy gets hard. Turn the heat back on at that point if you want to make the final curing (which actually takes weeks) go faster.
I've found that I get lumps of sanding residue on the paper when the epoxy isn't cured fully hard. Wet sanding (by hand or with a 'safe' sander - not a regular 120volt electric one) helps.

Take all my sugestions 'with a grain of salt' as I have been putting painted finishes on my projects for years, so I have probably developed a lot of bad habits which would show with a clear finish. :)
 

JohnAbercrombie

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I think that whatever the 'pigtails' are [epoxy sanding marks or cloth weave] a fill coat in one less obscure area to double check what happens is safer [finish wise] than immediately doing more sanding removal and possibly more cloth exposure.
:thumbsup::thumbsup:
Yes - experiments on small areas are definitely worth the time they take. Pick a hull area which will get scratched up anyway, once the boat is in use.
 

BigandSmall

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Thank you guys. Yes the pigtails are from a low end sander with bad sand paper. I made the mistake of grabbing some CDN tire sand paper instead of the Black and Decker brand I had been using for my mouse. The holes didn't line up with either but the CDN tire brand clogged instantly. I was brushing with one hand and sanding with the other outside in decent wind. When I switched back to B&D no more clogging but I ran out of B&D and finished the 80 grit with CDN tire brand. Perhaps it was the wrong type of general purpose paper, I only checked grit. Definitely going to order a new sander and dust extraction system soon but that's a whole different topic.
 

JohnAbercrombie

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Sanding is more 'technical' than it seems. LIke a lot of power tools, I think of sanders as 'power assisted hand tools'.
For levelling and fairing, I try to use the longest sanding block that's practical, with hand sanding.
I think of it as a fitness activity. :) Like the KarateKid:"Wax on, wax off.."
A foam block with stick-on paper is a good tool.
For rough sanding I use a 5" random orbital disk sander.
The larger/longer the block the better it will level/'fair' the surface.

Also, did you wash the surface before you started sanding? Amine blush on the surface can help to clog sandpaper. And, you don't want to be sanding blush into the surface where it could interfere with the fill coat adhesion.
 

JohnAbercrombie

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Definitely going to order a new sander and dust extraction system soon but that's a whole different topic.
Once I got a (very) good sander and dust extractor ($$$) it was a matter of "Why didn't I do this years ago?". But it did seem like a lot of money at the time.
Using mesh sanding disks helps a lot, too.
 

BigandSmall

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Too funny, I had just sent you an email for an opinion a sander John. No I didn't wash before I started sanding, whoops. Good tip for future readers. There didn't appear to be any on the surface but I certainly could see the other fill coat appear as I sanded lower.
Great video on sanding by Nick Schade here for others looking for sanding tips.
 

BigandSmall

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So the epoxy was very forgiving and made all the scratches disappear in case anyone was wondering. I did heat up my shop with space heaters and the baseboard heater. When I turned on the heat gun too I tripped the breaker. Plugs and lights on the same circuit, total darkness.

When finish sanding the final fill coat again I could lightly see cloth again in a few spots. Hopefully the varnish will be as forgiving as the epoxy for making the cloth disappear.
 
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