Tiny "chunks" in estapol finish

[IRONxMortlock]

Hi folks,

I'm currently making a bed from tassy oak and I'm at the stage of finishing it.

I have stained the timber and applied a single coat of estapol's satin finish. Following the directions on the can, I Iightly sanded the first coat of estapol and then, after wiping away the dust, began to apply the second coat.

To my horror I found tiny particles appearing in some areas in the finish!:o On one area which isn't going to show I tried to pick/rub these out but it just seemed to create even more chunks. This is very disappointing as the finish after applying the first coat looked absolutely beautiful. I'm now wishing I'd just done a single coat only.

I have the following questions:

1. How do I get rid of it?
2. What causes this effect?
3. How can I prevent it in the future?

Thank you very much for your help,

M

EDIT

Here are some pictures.
http://img485.imageshack.us/img485/7306/p2260011nx6.jpg

http://img152.imageshack.us/img152/9885/p2260013og8.jpg

[Harry72]

Was it a fresh can of estipol? Was your brush surgically clean?
The 1st picture looks like a reaction, but the 2nd closer picture there definitely something contaminating it.
Getting rid of it, if the estipol is still soft/green a light heatgun and a scraper will take the majority of it off, then a light sanding. Or sand it off completely, being stained you will probably need to restain it.

[Ashore]

Mate was the stain and estapol the same brand and compatable :?


Rgds

[IRONxMortlock]

Thanks for the replies!

Yep, same brand (wattlyl with "traditional craftsman stain) and no mention of them being incompatible.

What's strange is that this didn't happen when I first applied the estapol. The first coat (directly onto the stained timber) worked like a charm. After it had dried it was lovely and smooth and it felt even better after the light sand.

The second coat went on smoothly but then these chunks started to appear after I had finished applying it. I first opened the tin on Sunday and have taken care to keep it clean. I was using a clean brush.

[DJ’s Timber]

Another thing to think about, what was the temperature and humidity like at the time of application, was it in the recommended range stated on the can

[IRONxMortlock]

Another thing to think about, what was the temperature and humidity like at the time of application, was it in the recommended range stated on the can

Yep, no worries. A lovely day here in Brisbane. Max of 26 and 61% humidity. I did this around 9AM so it was probably about 18 or 20 then. Well within the tolerances.

[Big Shed]

It almost looks like the second coat is lifting the first coat. It also appears to be following the grain pattern, which makes me thinks that the stain is the underlaying problem.

How long between applying stain and first, and between first coat and second coat?
If there was insufficient time between applying the stain and the first coat, or high humidity, then the first coat would not have through dried, the solvent in the second coat then attacked the uncured first coat.

If lifting is the problem, then all is not lost, just let it dry thoroughly, ie a few days as there is trapped solvent in the film, then sand smooth and re-coat.

The surface imperfections are too big to be from contamination in the varnish, you would have noticed them, or rubbish in the brush, you would have seen that when you applied the varnish.

[IRONxMortlock]

It almost looks like the second coat is lifting the first coat. It also appears to be following the grain pattern, which makes me thinks that the stain is the underlaying problem.

How long between applying stain and first, and between first coat and second coat?
If there was insufficient time between applying the stain and the first coat, or high humidity, then the first coat would not have through dried, the solvent in the second coat then attacked the uncured first coat.

If lifting is the problem, then all is not lost, just let it dry thoroughly, ie a few days as there is trapped solvent in the film, then sand smooth and re-coat.

The surface imperfections are too big to be from contamination in the varnish, you would have noticed them, or rubbish in the brush, you would have seen that when you applied the varnish.

I think you maybe right, the second coat is lifting away the first. The chunks seem to be made up of the finish itself.

I waited a full 24 hours after applying the stain before I put on the first coat of estapol. I waited another 24 hours before the second coat but it did rain during that day (Yay for Brisbane!) so it may not have dried properly.

I'll take your advice and let it sit for three days and then sand before I try a third coat. I'll post back here with the conclusion.

Thanks for your help!

M

[Big Shed]

After 3 days test the film by sanding in an inconspicous place, if it isn't cured it'll clog the sand paper, if it is cured you'll be able to sand real easy.

[speedy]

Hi,
Up here in North QLD, in the rainforest I have to let estapol dry for at least a week between coats, otherwise it will lift the previous coat.
I now use lacquer or polyurathane, much less trouble and so much quicker, I can do three coats in a day or two, instead of three weeks.:U

[bitingmidge]

Speedy,

Isn't Estapol polyurethene?

Cheers,
P:cool:

[durwood]

Stating it's estapol doesn't narrow the field enough.

Estapol is just the brand name as there are many different Estapol clears knowing which one would be of some help.

The singly pack ones although polyurethane by name are really only enamel products.

Usually true polurethane would signify a 2 pack product. I think these are the ones Speedy is refering to. Put in hardener and the drying process alters dramatically, it will dry rock hard real quick. Even if the temperature drops below 15 C it will still go off though cold slows it down.

The one pack products can need far more than 24 hours, Bigsheds observation of it following the grain appears to be on the right track.

The stain in the dark grain areas has probably not dried as much as the other areas, as it may have soaked up more stain. If it was oil stain the stain will mix in with the one pack clear (same solvent) and altering the drying time.

Once the single pack enamel sets its Ok but if it hasn't dried out properly any strong solvent coating will attack it and it will turn into a jelly. swelling up and then not drying properly.( like the photo's. ) It doesn't dry like lacquers it forms a skin by mixing with oxygen in the air. Thats why you get a skin on the top of the paint left in the tin.

If after a few days its still not hard it will never be, strip it of and start again. I don't think the end result of your labours rubbed back and finished will ever be a good durable surface for a bed.

Can you post the type of Estapol clear and stain?

[IRONxMortlock]

I'm using this finish (http://www.wattyl.com.au/Applicators/PT/Products/ProductSearch/Product_Details.htm?Id=455) and I used this stain. (http://www.wattyl.com.au/Applicators/PT/Products/ProductSearch/Product_Details.htm?Id=436)

[Frank&Earnest]

Had a similar experience with Wattil gloss Estapol (the old white can with the picture of a horse). My post-mortem, FWIW, was that it was an old can and it had started to polymerase. The brush was collecting, breaking and spreading the little hard bits. Hard to see while wet but the hard bits would protrude when the rest flattened out.

Luckily it was reasonably easy to remove: it created a thick hard coat that peeled off when carefully lifted with a blade.

Good luck.

[speedy]

Speedy,

Isn't Estapol polyurethene?

Cheers,
P:cool:

Estapol is the brand name for Wattyl clear finish paint, some are 2 pack poly, some are single pack poly , some are enamel and some are water based acrylic. I personally won't use wattyl clear finishes again, I now only use cabots clear finishes.

[IRONxMortlock]

It's official - the cause of the problem is due to not allowing the first coat of finish to adequately cure.

This morning I put on a second coat onto the other side of the plank. This side has been drying for more than 48 hours and it worked like a charm. No chunks, just a lovely satin finish.:2tsup:
So much for the "recoat in 8 hours" direction on the can! :doh:

I'm going to let this lot sit until Friday morning and then I am going to sand again. This time I'll wait another 24 hours after sanding before I apply the third coat just in case the sanding exposes some surfaces which haven't properly dried beneath the chunks.

If this doesn't sound right, then please let me know.

Thanks,

M

[durwood]

That should be OK, just keep an eye on the areas that played up before if they act up you would be better off cleaning off the finish and doing it again, especially if the surfaces are the face side of your bed.

The stain states it is suitable for hard surfaces, the grain must have been soft where it acted up and absorbed a fair bit of the stain and was still not completely dry so when you put on the clear it messed up its drying time.

Its always a good idea to allow extra time for drying if you want a god job and you are not in a hurry to get the job done. I was once told "The paint can't be too dry but it can be too wet" which is right most of the time.

I use the satin Estapol like you used often and it is a good durable finish.

(If it goes on properly.)

[les88]

I'm using this finish (http://www.wattyl.com.au/Applicators/PT/Products/ProductSearch/Product_Details.htm?Id=455) and I used this stain. (http://www.wattyl.com.au/Applicators/PT/Products/ProductSearch/Product_Details.htm?Id=436)

I am in the process of applying the same products to my project, so please keep posting.
What I intended to do was to stain all the individual pieces and give them one coat of estapol then glue it together and finally on more coat on the finished job
I previously used shellac and couldn't get an even finish. I sprayed it, used a $70.00 brush and rubbed it on with a singlet. I have made scrap out of 5 projects so far. I am using meranti come maple.

regards
les

[soundman]

I agree that the problem is caused by the previous coat not being off but the detail... ah the detail.

I recon the following.
the wood looks like it has porous sections.
the stain was applied, some portions would hold more stain than others,
the stain looked dry... hmmm
but some solvent probaly remained in the porus depths.
the first coat was applied
some portions absorbed more solvent than others
more solvent remained in the porus depths... now retained by the curing film
the first coat wasn't completey off in some parts
the second coat went on.... the solvent in the second coat softend the first coat where it wasn't off allowing more solvent to penetrate into those portions pulling finish and stain up out of the timber giving the dark lumps result.

now
estipol make a sanding sealer which is good to use as a first coat & will give you a flatter base and is far easier to sand. it does also go off marginaly faster.

all this type of poly will blow out badly in drying time with reduction in temprture and increase in humidity.
I have had estipol still not sand cleanly after 36 hours.

Oh you are thinning the estipol arent you? it is easier to brush and will give you a beter result if you thin 5 to 10% with turps.
thinn too much and the finish will dry a little milky so don't overdo it.
you just want to make it flow a bit better.

cheers

[IRONxMortlock]

Quick update:

I sanded yesterday and managed to smooth out most of the chunk fairly easily. I just applied a third coat and it looks like it is going to come up nicely.

Thanks for your help everyone! I'll post some pics once it's complete.

In the meantime, here's a pic I made in sketchup. (http://sketchup.google.com/#utm_campaign=en&utm_source=en-ha-ww-google&utm_medium=ha&utm_term=sketchup)
http://img172.imageshack.us/img172/6155/bedonlysm5.jpg

P.S. Soundman, thanks for the tip about diluting the estapol with turps. It went on much more smoothly.

[IRONxMortlock]

I've finished the bed and it's come quite nicely even if I do say so myself. :;

Frame and bed head is solid tassy oak and the slats are made of pine. As promised here're a couple of pictures.

http://img501.imageshack.us/img501/1052/p3070004vl5.jpg

http://img443.imageshack.us/img443/5887/p3070005co0.jpg

Thanks for your help again everyone,

M

[munruben]

Nice work, looks great. glad it turned out okay for you