How to get a decent finish on 2 part Poly-U

[silentC]

I've used Estapol 7008 2-pack on a benchtop. Had a bugger of a time getting a decent finish on it and I'm still not happy with it. There's a few brush marks and a definite line where the last brush stroke meets the first. The stuff goes off pretty quick and you can't brush over it again - the brush marks disappear OK when you first apply it but if you touch it again, they don't.

Does anyone have any tips for applying this stuff so that you get a decent finish, or is it a waste of time trying?

BTW It can't be sprayed. The finishes I came across that could be sprayed all say "Not suitable for Benchtops" :rolleyes:

[ozwinner]

Couldnt you spray part A, then spray part B on top?
Its only a thin layer after all.
Al

[Shane Watson]

What finish's are you looking at that arn't suitable for bench tops? If ya want something thats easy to use, stay clear of the DIY targeted brands! All the 2 part poly-u's I have used are all more than suitable for bench top application and are all sprayable.

One thing you could try is thinning the stuff before application, probably with a retarder to slow the drying a little, this will allow the fluid to flow more freely for a longer period which should in theory reduce the amount of brush marks or the need to re-hash.

[RETIRED]

One trick used by hand car finishers is to stand the pot in hot water. Don't know if it will work with this or not.

[silentC]

Shane,

I suppose part of the problem is that there isn't a lot of choice at the Pambula Mitre 10. I had a look at the Wattyl stuff and the only one that said 'recommended for benchtops' was the 7008. I looked them up on their website and all the other stuff Mitre 10 had was 'not recommended for benchtops'. There is a Floor Gloss that can be used for this application but they didn't have it on the shelf - not sure if it can be sprayed either.

Mick recommened Mirotone and I checked it out but it's not available locally and in any case the only one that's suitable for bathroom vanity tops is the polyurethane, so I figured if I had to wait for that to be delivered, I might as well go with the Wattyl.

Probably a mistake, I don't know.

With the 7008 they say you can add reducer but only to the first coat. I might try 's suggestion and see if that helps. It hasn't been overly cold down here but not as hot as it was a couple of weeks ago.

Can you give me the name of one or two that you've used so I can be prepared for next time?

Cheers

[Shane Watson]

Well I wouldn't go far past Mirotone. I forget the 'model' (if you can them models! ;) ) numbers. But the likes of croda and wattyl's commercial stuff is also fine.
I know a lot of DIY'ers use floor finish's, what success they have, I don't know.
But give 's suggestion a go and see where ya end up. Don't over heat or you'll loose everything, including the shed! ;)

[bitingmidge]

One trick used by hand car finishers is to stand the pot in hot water. Don't know if it will work with this or not.

Just to take a contrary view for a change:D :D .

I don't know too much about the chemical reactions with polyurethene's (or anything else for that matter) but I would have thought that heating a two pack would in fact speed up the reaction. Certainly that is what happens with epoxy.

Heating does work to a point in thinning the material in traditional varnishes.

I think Shane is on the money; the answer is probably in finding a suitable thinner and/or retarder (preferably a reactive diluent which won't affect the final gloss?) and will give the clear time to self-level. Or you could wait till winter!

A lot of boat guys have had success with foam brushes, try rolling with a thin foam roller and brushing out with a disposable foam brush. I have seen glass-like epoxy finishes produced this way, but haven't had quite the same success myself!

If all else fails, you could try the finesand, finer sand, buff, polishing compound trick, but you'd want to try a sample first, and don't generate too much heat while you are doing it.

Please let us know how you end up!

Cheers,


P

[silentC]

P,

You mean those open cell foam tapered 'brushes' that you can get in the hardware shop? I looked at them but decided I couldn't see how they'd give a better finish than a good brush. Maybe I should give one a go and see what happens.

I suppose I should order some triple E as well and see where that gets me.

I never was a good finisher - much better at starting things...

[bitingmidge]

You mean those open cell foam tapered 'brushes' that you can get in the hardware shop?

Yep! They are interesting to use, I guess if you have a REALLY good paint brush and years of experience you can get a glass finish anyway, but for the rest of us, they probably work because they make it impossible to "scrub" the finish.

I don't like them all that much, but begrudgingly admit that in some clear finish situations (including epoxy) I can do a much better job with them.

BTW, a friend of mine who worked for some years varnishing bright work on boats (and who could get a perfect finish using a straw broom I reckon) used to thin traditional varnish ever so slightly with kerosine, which seemed to retard the drying and also make it better at levelling - dont' try that with two pack though!

Cheers,

P

[q9]

You can in fact thin 7008. I don't thin the first couple of coats, but I do the last, some times 60%. Works much better.

[Dusty]

Firstly, I've found with 7008, you have to apply it fairly thickly so that there is enough material for it to level out after you have finished mucking about with the brush.

Secondly, cut the edges in with a brush and then roll the rest on with a small foam roller.

Thirdly, I can recommend the Sabco brand swiffer pads as a tack rag prior to applying the plastic.

[Sprog]

Use a good quality brush with synthetic bristles. They cost around $25.
Pure bristle brushes are hopeless for Poly finishes.
Put on a thin coat and brush out reasonably quickly. Do not over brush. If the brush starts to drag then stop brushing. Do not go back and try to remove brush marks or thin spots. Leave to dry the recomended time then lightly sand with at least 400 grit. Repeat as required/recommended.

I have found the Oldfields Utra range of synthetic brushes to be very good.

Oldfields Brushes (http://www.oldfields.com.au/brushes.shtml)

Also for large surfaces have a look at this method of applying the finish

Finishing Large Surfaces (http://www.woodworkingtips.com/woodtips/wstip17.html)

[silentC]

Thanks for the further tips guys. I've finished the bench top now - still not overly happy with the result, so maybe I'll rub it back and apply another coat later on.

I used a Rota-cota 'Spirit' brush - guaranteed no bristle loss!

[mannonic]

I have just finished a tas oak kitchen benchtop with 7008 and used a lambswool applicator. Come up great. Only regret is I wish I had bought a new applicator for the last coat. The applicators are $15 each and the stuff to clean them is $20 for 500ml. Cheaper to buy a new applicator.
And I also did the job late at night when it was quite cold.

[silentC]

mannonic,

I read about the lambswool applicators on the tin but my local hardware doesn't stock them. If they're worth it, I might try getting them to order some in. I'm just wondering how much was soaked up by the pad? I guess you'd need to mix up a bit more than you need to allow for that?

I also found that brushes were useless after one application anyway. The reducer just doesn't clean them up well enough and they were like rock the next day.

[rcrosser]

I have a method for cleaning brushes used for 7008 (and other things).
1. Paint the varnish out onto scrap material as far as possible.
2. Rinse the brush quite a few times in as small amount of reducer or thinner as possible. Each time use just enough to wet the brush well. The brush should appear clean after this stage.
3. Wet the brush again with reducer. Wrap the wet brush in a couple of layers of old cotton sheet, in such a way that the layers of sheet are in close contact with the brush.
4. Leave to dry 24 hours. The brush may be slightly stiff, but softens with flexing it a few times before use. It is then good enough to use for further coats, though repeated coats will eventually stiffen it too much.