Fed up with acrylic clear coat

Started by rousejeremy, December 18, 2012, 01:56:08 PM

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rousejeremy

I've been using it for a few years now and in my experience it takes forever (more than a month) for it to harden. It says on the can it can be handled after an hour but it's still too soft. I sat an enclosure on my leg to put a couple jacks on it and my jeans were imprinted into the clear. I'm using Krylon.
Any suggestions for a better clear for an acrylic painted pedal? Something that won't react to the acrylic paints underneath?
Consistency is a worthy adversary

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Mark Hammer

The trick is to use thin coats and bake it at low temperature so that it cures fully, all the way through.  You need to use low temperature (I'd say 120F, and no higher) because too high a temperature will result in yellowing.  In view of your city of residence, that may well not be the sort of thing you can do during the winter with the windows closed....at least safely.

Of course getting thin coats is a whole other matter.  The stuff seems to come out of the can the way it wants to.  Sometimes it's a nice fine spray, sometimes it's thick, sometimes it comes out in spurts.  Partly it depends on the level within the can.  Plus, at least some of the spray pattern depends on the state of the nozzle.  The challenge is really more one of attaining a consistently fine spray by some means, so that you CAN lay down a couple of thin coats.

rousejeremy

Thanks Mark. Those are things I do NOT currently do. maybe I can get a little toaster oven as a Christmas present this year.
I read online somewhere that putting the acrylic in the fridge before use causes the spray to come out much finer. Not sure if this applies to a rattle can or the stuff I use.
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Vince_b

How many coats do you apply? If I remember correctly, there was someone on this forum who applied something like 20 coats of Krylon and he was wondering why it wouldn't dry  ::)

thelonious

+1 on the toaster oven. I got one at a salvation army store for $3.00, and it works great, other than smelling like onion bagels. ;D

I prime, bake for 20 minutes, spray 2 coats of color a few minutes apart, bake, spray 2-3 light coats of clear acrylic enamel, bake, spray another 2-3 light coats of enamel, bake again, and let sit overnight in a relatively warm and dry place. By the next morning I've never had a problem mounting hardware.

I've also used the process at http://www.beavisaudio.com/techpages/boxinaday.html with good success. He suggests brushing on polyurethane and baking. The only problem I had with that process was that the poly will yellow whatever color you start with (although maybe I was baking at too high a temperature, like Mark said). For instance, this pedal started white before the poly:

davent

To be able to work through what seems like an endless winter, i switched to using artist's acrylics and an airbrush. For clearcoat i've been getting really good results with Target 7000, a waterbased, waterclear spraying lacquer. Low VOC, spray indoors, year 'round, with an airbrush it takes a major effort to apply too thick coats, goes on thin and dries quickly, can be recoated within the hour, new coats burn into the undercoats when applied within a pretty generous time frame. So far so good, no negative issues yet.  StewMac sell it as their waterbased lacquer for finishing guitars but there is a Canadian distributor so crossboarder shipping can be avoided.

http://www.targetcoatings.com/shop/products/EM7000HBL_Clear_Semi_Gloss_1_Gal-86-0.html
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rousejeremy

Consistency is a worthy adversary

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Vince_b

Dave, where do you buy this product in Canada? I want to give it a try.

jymaze

#8
I always had bad results with anything Krylon. I would use Rustoleum lacquer, or even better, automotive stuff (Duplicolor). I never had to wait more than 5 days or so to have a surface hard enough to be usable.

davent

#9
Quote from: Vince_b on December 18, 2012, 03:25:49 PM
Dave, where do you buy this product in Canada? I want to give it a try.

Wood Essence, smallest size is a litre and they have four luster available. I went with the gloss but by spraying light and dry i can get a matt finish that i'm real happy with. I think i read somewhere that they ship in winter with a heat pack

http://www.woodessence.com/EM7000-Hi-Build-Lacquer-P212C22.aspx

I've also tried spraying Varathane waterbased polyurathane, doesn't go on as nice as sparaying lacquer and dries with a slightly milky cast to it.

Minwax Polycrylic dries nice and clear but doesn't spray great either, doesn't burn, very thin, just not as spray friendly as the lacquer.

dave

edit. Just noticed in the Wood Essence description that they say the lacquer is also brushable.
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GGBB

I'm frustrated by the same thing even though I bake.  My last pedal was Krylon and I don't think I'll be using it again - it's just like you say - almost forever soft.  The pedal before that was Valspray and it was better than Krylon as far as handling goes, but no better for overall hardness/resistance to scratching - both scratch quite easily.  When spring rolls around I will have to make up my mind as to whether or not to try Rustoleum or Tremclad next (foolishly hoping it will be better) or simply go the water-based poly route for the final clear coat.  The only problem with that is that I will still have to do an acrylic clear coat first since the waterslide decal paper needs an oil based top coat to make the decal transparent, so yet another finishing stage.  Enclosure finishing is both the most frustrating and most time consuming part of building pedals for me - it's like one big giant hurdle at the end of the steeplechase.
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deadastronaut

another +1 for a toaster oven.....especially at this cold time of year....with blooming from draughts etc...

i got one cheap second hand,  i clearcoat my boxes and stick em in the oven on a medium heat for just a few mins...they get very hot quick.

its enough to smooth out any orange peel, and comes out like glass (using car spray can clear laquer)  plus no dust /flies/cat hairs get on it.. ;)

they are ready to build in a couple of hours...if that. 8)

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chasm reverb/tremshifter/faze filter/abductor II delay/timestream reverb/dreamtime delay/skinwalker hi gain dist/black triangle OD/ nano drums/space patrol fuzz//

davent

#12
This one's Varathane waterbase polyurethane, satin finish, toner transfers, not decals. Brushed and sprayed, didn't like to be applied to vertical surfaces, would run and sag no matter what, remains slightly milky, even when used on wood you can notice this.



Polycrylic polyurethane, satin, dries much clearer then the Varathane but same application issues. Did produce a great matt finish.



This is StewMacs waterbased gloss lacquer (rubbed out) which they've since replaced with the Target 7000.



Top coats of this are Target 7000 gloss, spayed matt, big mess of various clears under it, again a toner transfer and no decals.


edit;spelling
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GGBB

Dave - you're convincing me.  What's your secret to doing toner transfer on paint?  I tried it once and it was such a disaster that I didn't even want to try a second time.
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Canucker

How can you bring yourself to step on those?????? Thriftshop/Yard Sale Toaster oven is the way to go! My mom just bought a toaster oven for my sister today for Christmas...I'm thinking she wouldn't appreciate me "borrowing" it for this purpose...but I'm still at the point where I'm obsessed with building the actual effects rather then stress over the enclosures.

Kesh

It's winter in the UK so I put mine on the radiator to bake, radiators are at about 50C = 122F, maybe a little hotter.

I do find it takes many many very thin coats to get a good result.

I use plastikote.

Arcane Analog

+1 on thin coats! It is absolutely crucial to getting a solid finish. I do not think you can get a good end result with thick coats and you will need to have it sit for months before it cures.

I have been using Krylon Crystal Clear and have had no issues as of yet.

rousejeremy

The verdict is in, I'm spraying too much and too thick. I visited another forum member here in Toronto last night and he uses the same lacquer I do but with baking between coats and his finishes are hard as a rock.
I checked Value Village for little toaster ovens but they are overpriced. I'm pretty sure I could find one for five dollars if I look hard enough.
Consistency is a worthy adversary

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Morocotopo

I´ve been using Rustoleum clear lacquer for a while now.

Easy to apply,  I apply three heavy coats at 10/15 minutes intervals. It takes about a week to really dry to the point of letting me do assembly, specially in winter.

Cons: It takes months to fully dry. Easily scratched. Reacts with some stuff in patch cables and some knobs, those that are a matt rubber, softens and gets marked.

The holy grail would be, I think, a clear epoxy in spray cans. Hardens not by evaporation but by chemical reaction, so once hardened it stays like that. I at one time used a water based two part clear epoxy. Was great, but had to apply it by brush, so the finish was always streaked.

I´ve been thinking of abandoning decals and paint and use engraved aluminum/plastic/acrylic plates on the top of the enclosure or something like that. More expensive, needs to be fastened/screwed down...
Morocotopo

p_wats

Quote from: rousejeremy on December 19, 2012, 09:46:32 AM
The verdict is in, I'm spraying too much and too thick. I visited another forum member here in Toronto last night and he uses the same lacquer I do but with baking between coats and his finishes are hard as a rock.
I checked Value Village for little toaster ovens but they are overpriced. I'm pretty sure I could find one for five dollars if I look hard enough.

That was me! Woo! Ha.

I started using Krylon's "Triple Thick" gloss spray and it's been working well. I don't bake as much as I used to, but I'm going to start with the next batch, as I've been having durability issues (don't trust those spray colours that say 'no primer needed on metal.' My mistake).

I also just bought some Tremclad clear coat to see if that's any better.