Brian Mahaney wrote:

On Tue, 21 Feb 2006 09:00:56 -0800, David wrote:


Brian Mahaney wrote:


On Tue, 21 Feb 2006 00:50:32 GMT, Rumpty wrote:



What brand poly were you using?



"Brian Mahaney" wrote in message
news:18bo5x3ndz8x7$.17ox3qn6nfub8$.dlg@40tude. net...


Hello,

I've never tried a water-based poly until today, and I have run into a
problem. Admittedly, I am experimenting a bit. The problem is a crackled
finish. Here are the details of what I did.


Ace Brand. From the hardware store, for experimentation.

Brian

Brian, I doubt that it's the reason for your problem but you do know NOT
to use waxy shellac as an undercoat, right? Always used de-waxed
shellac under other finishes. I use a compatible sealer when I spray
waterborne polys and I've never had any issues with cracking, bubbling,
peeling, blushing, or any other surface defect so I'm not too good at
diagnosing problems as I've not had to solve any. (Now with regards to
regular poly...that's another story)

Dave

Dave


The shellac was dewaxed, but it did occur to me that I ran a tack cloth
over the whole thing just before I sprayed. It was one of those ones you
get at the hardware store. I forgot about that. Could that have left
stearates on the surface? Would that have caused the problem. I may never
know, but I'll change a variable next time and see what happens. I'm going
to sand the finish off soon and try again.

Brian
It could leave OIL on the surface. That shouldn't cause the cracking, as
far as I know. Jeff Jewitt and Bob Flexner both have excellent books on
finishing.

I use sterated papers between coats of WB poly and never have a
problem. Now the same paper, when used with Minwhacks poly causes me no
end of problem with cratering. I'm not a fan of using tack cloths and
have abandoned their use altogether. I use a combination of a type of
cloth who's type and composition I can't describe, other to say it's
sort of "waffle" looking, and compressed air. I like blowing out pores
before and between sanded coats of finish. You can wipe a surface all
day long and not remove debris from the pores.

Dave