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3 washes and a soak in acetone worked ok for me...but make no mistake, after the job is done, the brushes get tossed. Anyhow, I am not prescriptive, if it works I'd like to hear about it. I love 7008. But it can be a hassle to use.
On an earlier topic, I did once use it to refinish a pine table that we had out side on the verandah. It got lots of sun and a pot plant dripping on it for about 10-15 years. The wood cracked along some joins but the finish held up quite well.
Turps doesn't work by itself. Let us know if you find a combination that does.Quote:
Originally Posted by Tegmark
I know that for epoxy a mix of acetone and metho is effective and far cheaper than just using acetone - I have never tried with 7008. Also for epoxy, white vinegar works as epoxy is basic and the vinegar neutralises it. Again I haven't tried this with 7008 either.
I have found that the test pot Monarch brushes ($2.50 for a pack of 2) are good for detail work, so I just use these as consumables.
What brushes do you use that get tossed after a job? I was able to clean a thick varnish brush after 2pac & it seems no different cond than before, however cheapo brushes I would toss.Quote:
Originally Posted by q9
I was trying turps after about 3-5 cleans in thinners, the hope was that whatever diluted 2pac is left in the dense brush would came out by turps which would stay wet long enough to wash away with detergent. However I think after thinners, an hour or soak in a bit of acetone then detergent rinsing might be good enough.Quote:
Originally Posted by SPF
It seems that using a 3" china swan style brush with 7008 is alot worse & harder than just a small $3 1.2" bunnings varnish brush. The results were pretty bad with my swan. Unlike Oil based which I could lay a thick coat down like glass, it seems that this can't be done with 2pac.
Because, the thick dense brush just absorbs the clear making it very hard to get a thick wet glass like coat, second, the 2pac sets very quickly even at room temp unlike oil based, this results in the brush bristles being a bit hard holding in alot of clear & producing a dry coat with excessive pinholes. Compared to oil based the bristles stayed soft & smooth producing minimal pinholes. Also handling a large brush like this takes time. So any chance of an off the brush finish with this stuff is not gonna happen I think.
I didn't notice how quickly this stuff sets as I was using a small brush that enabled me to quickly lay down a thick coat before it sets.
But this stuff is amazing, how think you can lay it down & the next day its pretty much able to sand.
The 7008 isn't promoted as a self leveling paint, but it definitely has a tendency to flatten out quickly and evenly. I have found it impossible to get a thick coat down, even on horizontal surface; and I never use less than 3 coats as I just can't get a good even finish with less. I have had problems with pin holes - make sure you haven't got an open container of silicone sealant near where you are painting and you haven't used silicone spray or ptfe spray nearby. Using silicone based car polish to cut the paint will also be a problem. All these things will make your life very difficult.
2 pac is great for getting a job done quickly.
Are you saying it's impossible with just large areas? And because it sets quickly? I got a thick coat down no problems on a small a4 area with a cheap 50mm brush. But the pinholes I speak of are caused by the bristles (I'm not sure why exactly). Basically when the 2pac sets on my thick brush, the bristles start acting like a non smooth aggressive bristle, which is exactly what causes the excessive pinholes.Quote:
Originally Posted by SPF
I don't know for sure about silicone based products, I use meguiars M105 & M205 & they worked well on oil based. I will try 2pac once it fully cures. I beat it will come up mirror gloss like an auto paint job.
This stuff still looks pretty transparent after 6 thick coats. Love it.
When wet sanding with a large area block, you constantly need to clean away the rubbing water to prevent the huge friction encountered.
When applying thick coat, the clear at the edges right next to a 90degrees side of wood slightly bulge/rise up, making it more harder to sand as you have to sand those areas next to the edge first. I think maybe because 2pac has alot less solvent & more body?
Like in this illustration:
https://s32.postimg.org/9j6j2dtj5/wood.jpg
I was able to lay a thick coat down like glass, without a single pinhole, but after they start to form from most likely air trapped in the clear plus as I stated above the clear bulging at the sides when thick, there really seems to be no need or benefit at all using a large dense brush. The cost of solvent & gloves to clean one is huge too.
Interesting - thanks for posting that up. I have never got enough film thickness for that to happen with 7008. But it happens with just about all common 2 part resins. It is from a combination of the surface tension of the resin plus volumetric shrinkage due to the peak in temperature while the resin thermosets.Quote:
Originally Posted by Tegmark
If you leave an amount of 7008 in a jar and let it set, you will notice that the resin will appear to climb up the sides of the jar, and once the temperature peaks, and it starts to cool and harden, the resin will pull away from the edges of the jar as it shrinks. The force that this generates can be a real problem with unsupported veneers or thin material if only painted/applied on one side.
I got half way through responding to this and then lost the images I had to post up.Quote:
Originally Posted by Tegmark
Silicone based products and ptfe spray lubricants can cause problems with paint as they interfere with adhesion and create orange peel and other similar issues, including pinholes. Just to be helpful, you don't even have to use these products on the job, or have any direct contact from contaminated tools - having an open container in the same room can cause problems. So, if you are getting seemingly random problems and you have prep'd appropriately then keep this in mind.
Thanks SPF, good to know that from now on. Back to experimenting.Quote:
Originally Posted by SPF
:)
These pinholes are I think from air dissolved in the clear from the bristles working the clear, not that it matters in many cases as when thick the sides bulge up ruining any chance of an off the brush perfect finish.Quote:
Originally Posted by SPF
if I recall 7008 is designed to go on with a relatively thin wet film. The bulges yiu describe sound like a surface tension effect that might go away if the edges of your piece are "broken" or rounded
Tegmark how did you go sanding and polishing the 7008? The 7008 is pretty good straight off the brush for clarity and shine, but I haven't tried polishing it. I'm keen to see your results, especially if you are doing a broad flat surface.Quote:
Originally Posted by Tegmark
I'm looking at making a large American oak table in the next couple of months, and am considering either the epoxy and marine PU, or the 7008. I'd like to spray it for even finish, but if the 7008 can be polished, then that would be a quicker and simpler solution.