Help with these Visual Flaws

[Tegmark]

These marks I have circled in my below attached picture have become more obvious as I sand in between coats.
They look like unnatural defects in the appearance of the stain under the clear & stand our more on certain angles.

I started noticing them when sanding 2nd coat, by the time I started sanding the 3rd coat they were obvious as pictured.
now sanding the 4th coat they are have clearly gotten more significant directly from sanding.

My test piece below is pine wood that was sanded with 180grit, dusted off, then stained with spirit based stain, I wiped off excess well & left a day to dry.
Using 7008 2pack polyU, 1st coat thinned 10%, then the others not thinned. Sanding with 400grit paper.


What could be causing this? My guess is it's simple the pressure of sanding on stain & a bad choice in spirit based stain or expired stain?


https://s32.postimg.org/47h0gj1dt/woodwork_stuff_ups.jpg (https://postimg.org/image/47h0gj1dt/)

[Christos]

From what you have circled I don't think it looks too bad. Are these smooth to the touch or a little rough?

[Tahlee]

Hello Tegmark
only a guess but if the spots are becoming more pronounced after each coat then I do suspect that the darkening surround is making the light spots look lighter.

Could be some form of wax or glue on the wood that is rejecting the stains

the fix could be as easy as using a colour filler on those spots

regards

Rob

[Xanthorrhoeas]

What kind of pine is it? Pinus radiata and Pinus ellioti are notorious for having some areas not take stain. It may be due to the resin. I'm sure that you are also aware of the wax/oil/PVA problem mentioned by Tahlee above. Some other pines are also very resinous and suffer from the same problem. Historically the problem seems to have been solved by using very dark pigment stains, butt hat may not be what you are seeking.

I have not bothered to solve the problem myself - I just don't use those pines or else don't stain if I'm using something like Hoop Pine or Huon Pine - but I have read other posters suggest solutions such as pre-sealing the timber with very dilute shellac or sanding sealer (same thing I think).

[Xanthorrhoeas]

I do realise this doesn't solve your problem, but thought it may explain what has occurred.

David

[Tegmark]

From what you have circled I don't think it looks too bad. Are these smooth to the touch or a little rough?

Hi, while they aren't too bad in appearance, they keep getting a little worse with sanding each coat. The are smooth to the touch, I have no doubt it's the stain. The clear coat is fine without any problems.

[Tegmark]

Hello Tegmark
only a guess but if the spots are becoming more pronounced after each coat then I do suspect that the darkening surround is making the light spots look lighter.

Could be some form of wax or glue on the wood that is rejecting the stains

the fix could be as easy as using a colour filler on those spots

regards

Rob

Hi Rob, should I be cleaning the surface with some wax & grease remover before stain? I usually just dust off as I don't want the grain to raise or wait for the wood to dry up. Maybe the wax in the wood will simple come back from within again & again? Perhaps brought on by pressure from sanding.

This also happened once on veneered Particle board. I will have to try wattyl's own brand of stain & clean the wood before staining.

[Tegmark]

What kind of pine is it? Pinus radiata and Pinus ellioti are notorious for having some areas not take stain. It may be due to the resin. I'm sure that you are also aware of the wax/oil/PVA problem mentioned by Tahlee above. Some other pines are also very resinous and suffer from the same problem. Historically the problem seems to have been solved by using very dark pigment stains, butt hat may not be what you are seeking.

I have not bothered to solve the problem myself - I just don't use those pines or else don't stain if I'm using something like Hoop Pine or Huon Pine - but I have read other posters suggest solutions such as pre-sealing the timber with very dilute shellac or sanding sealer (same thing I think).

Not sure what pine it is, just a scrap piece that was on a cheap cloths draws. Thanks for your suggestions, I will try again on some hard wood like Tas Oak.

[Tahlee]

Hi Rob, should I be cleaning the surface with some wax & grease remover before stain? I usually just dust off as I don't want the grain to raise or wait for the wood to dry up. Maybe the wax in the wood will simple come back from within again & again? Perhaps brought on by pressure from sanding.

This also happened once on veneered Particle board. I will have to try wattyl's own brand of stain & clean the wood before staining.

Just use a prestain coditioner before the stain as it helps alleviate blotchiness on soft timbers such as pine

I use the Minwax prestain conditioer and fine it very good indeed

Rob

[Tegmark]

Just use a prestain coditioner before the stain as it helps alleviate blotchiness on soft timbers such as pine

I use the Minwax prestain conditioer and fine it very good indeed

Rob

Hi Rob.


Searching doesn't seem to give much details & I'm just curious what exactly does the conditioner do? Do you usually need it for hard woods like Tas oak?

Thanks