Question about wipe on poly

[sailor55330]

Hi,

I'm finishing up a bandsaw stand I built and am in the process of finishing it. I used birch plywood for the construction (wish I had used oak in retrospect). I have applied 2 coats of Minwax wipe on poly so far, sanding with 220 after the first and fine steel wool after the second. I really haven't seen much difference between the 1st and 2nd coats. Given that this is built for the shop, does anyone have any advice for adding a 3rd coat? I'm leaning towards it for added durability (or am I just spinning my wheels).

Thank you.

[cabinetman]

What results are you looking for? You may want to add another coat or two depending on how much shine and finish you're after.

.

[Joe DeFazio]

Hi,

I'm finishing up a bandsaw stand I built and am in the process of finishing it. I used birch plywood for the construction (wish I had used oak in retrospect). I have applied 2 coats of Minwax wipe on poly so far, sanding with 220 after the first and fine steel wool after the second. I really haven't seen much difference between the 1st and 2nd coats. Given that this is built for the shop, does anyone have any advice for adding a 3rd coat? I'm leaning towards it for added durability (or am I just spinning my wheels).

Thank you.

Minwax Wipe-On Poly builds really slowly, by design. It is a little bit of poly in a lot of mineral spirits. The first coat will sink into your birch ply pretty well, leaving little on the surface. It may take 5-6 coats or more to equal two coats of a regular brushable poly.

So, go ahead and put on a third coat, or even a fourth if you want a bit of extra protection for shop stands.

I "hot-coat" with Wipe-On Poly, meaning that I try to get the next coat on when the last coat is still curing, so that the molecules in the coats crosslink. If you do this, wait for almost all of the solvent to evaporate but with the poly still pretty flexible and not completely cured, and then promptly re-coat.

This creates one thick coat, instead of several distinct layers of polymers with nothing but mechanical adhesion holding them together (which is why you must scuff-sand if you let each coat fully cure between coats). For shop furniture, this also goes faster because you don't have to sand between coats (that is assuming that you are not terribly picky about creating an absolutely flawless finish, of course).

[sailor55330]

Thanks for the quick response. I just added the 3rd coat. Given the size of the stand, it really doesn't take long to scuff sand and apply. It's starting to get the "deep" look to it. I'm thinking one more and then mount the saw. Pics to follow when it's finished.

[cabinetman]

I "hot-coat" with Wipe-On Poly, meaning that I try to get the next coat on when the last coat is still curing, so that the molecules in the coats crosslink. If you do this, wait for almost all of the solvent to evaporate but with the poly still pretty flexible and not completely cured, and then promptly re-coat.

This creates one thick coat, instead of several distinct layers of polymers with nothing but mechanical adhesion holding them together (which is why you must scuff-sand if you let each coat fully cure between coats). For shop furniture, this also goes faster because you don't have to sand between coats (that is assuming that you are not terribly picky about creating an absolutely flawless finish, of course).

In theory that seems like what you would get. You don't wind up with one thick coat. In actuality, without allowing each application to "dry" completely, adding another coat will just delay the curing of the previous application. Once dry, a scuff sanding with 320x (I use open coat sandpaper), another coat can be applied.

.

[chopnhack]

Sailor, did the birch blotch? Why did you say you would have preferred oak?

[sailor55330]

I didn't have any issues with the birch blotching, I think I just realized I like the look of oak better with the more pronounced grain pattern. Maybe I thought the poly would make the birch warm up a little (and it is somewhat). I think it's mostly a learning lesson of personal preference.

[cabinetman]

I didn't have any issues with the birch blotching, I think I just realized I like the look of oak better with the more pronounced grain pattern. Maybe I thought the poly would make the birch warm up a little (and it is somewhat). I think it's mostly a learning lesson of personal preference.

Try experimenting with a scrap of the Birch. Take some BLO (boiled linseed oil), and dilute half and half with naptha. Wipe on, and let dry. Then try your wipe on poly.

.

[herb fellows]

I've used a number of different brands of wipe on poly and they all build agonizingly slowly.
A friend told me to put on a brush on coat of gloss poly as the base, no matter what you were going to do after that.
He says if you properly sand it out with 220, the hand applied coats will have the same look (no brush marks etc.) but will work much quicker, maybe 2-3 coats instead of 5-6. I haven't tried it yet, so only 2nd hand info.