Fed up with acrylic clear coat

[Paul Marossy]

I tried using polyurethane once. Seems to work alright, expcet that if you spray it on anything white, in like 6 months or so, it will be yellow. 

[rousejeremy]

My oldest acrylic finished pedal has started to yellow and check a bit. I don't mind, it actually looks pretty cool.

[GGBB]

I tried using polyurethane once. Seems to work alright, expcet that if you spray it on anything white, in like 6 months or so, it will be yellow. 

Normal poly will do that because it's oil-based.  Water-based poly doesn't yellow with some exceptions.  There are some water-based polys that are designed to yellow like oil-based poly - Minwax makes one - http://www.minwax.ca/wood-products/interior-clear-protective-finishes/minwax-water-based-oilmodified-polyurethane.  The idea is low odor, water cleanup, fast dry with a traditional warm look.

[Paul Marossy]

I tried using polyurethane once. Seems to work alright, expcet that if you spray it on anything white, in like 6 months or so, it will be yellow. 

Normal poly will do that because it's oil-based.  Water-based poly doesn't yellow with some exceptions.  There are some water-based polys that are designed to yellow like oil-based poly - Minwax makes one - http://www.minwax.ca/wood-products/interior-clear-protective-finishes/minwax-water-based-oilmodified-polyurethane.  The idea is low odor, water cleanup, fast dry with a traditional warm look.

Good to know. If you want to intentionally make something white look aged and yellow, it works pretty good.

[davent]

I was using Armour Coat Lacquer, from Canadian Tire, over acrylic paints and found like you that after a year or so some of the clear finishes were all cracked and checked others perfectly fine. Could never figure out what would cause the inconsistency of the clearcoat/base interaction.

Switching to waterbased clearcoats over the acrylics, never had yellowing or cracking and checking of the finish. The first pedal i tried waterbased polyurethane on back in 2004, outside of all the chips and dings, still looks as good as the day it was completed.

[GGBB]

Good to know. If you want to intentionally make something white look aged and yellow, it works pretty good.

I refinished a maple headstock with oil poly a couple of years ago and after a couple of months it had a fantastic vintage tint to it - very nice.

[Paul Marossy]

Good to know. If you want to intentionally make something white look aged and yellow, it works pretty good.

I refinished a maple headstock with oil poly a couple of years ago and after a couple of months it had a fantastic vintage tint to it - very nice.

There's another instance of it being desirable. Otherwise, not so desirable. 

[davent]

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.

No secrets, no iron, no heat . All i'm doing is taking a mirror image, laser printed onto cheap printer paper and gluing it to the enclosure with Acrylic Medium. Let it dry, rough up the paper with some coarse sandpaper then spritz the paper with water and rub the paper away with my fingers. Never get all the paper off the first time so let it dry again then repeat the soak/rub/dry cycle as many times as needed to get all the paper off.

I mostly use Goldens brand acrylics so use their GAC200 as the transfer medium, dries water clear and hard enough to be very sandable.

More details here.  http://www.diystompboxes.com/smfforum/index.php?topic=36392.msg876642#msg876642

Again all the stuff i'm using is waterbased and am using indoors year 'round  no problem.

[davent]

How can you bring yourself to step on those???

Once they've had their "portraits" done... they're fair game.  Used but not abused.

dave

[GGBB]

no iron, no heat .

That was a secret to me until now.

All i'm doing is taking a mirror image, laser printed onto cheap printer paper and gluing it to the enclosure with Acrylic Medium. Let it dry, rough up the paper with some coarse sandpaper then spritz the paper with water and rub the paper away with my fingers. Never get all the paper off the first time so let it dry again then repeat the soak/rub/dry cycle as many times as needed to get all the paper off.

I wonder if that would work using waterslide decal paper - that would allow you to see through the decal for positioning while it's wet with the medium.  Any idea if that would work?

[davent]

Being able to see for positioning is not necessary, you can work blind and get pretty exacting placement, don't know how many waterslide decals i destroyed in trying to get them positioned just right. (The black legending on the Echo Base was the last time i used decals).

To work blind you just need to figure out a way to register your artwork to whatever you're applying it too. For the pedals i use the component holes.

Details of how i do that are spread down through this thread. http://www.diystompboxes.com/smfforum/index.php?topic=100194.msg880901#msg880901

For doing silkscreens i make a border slightly larger then the pcb artwork then just lay the pcb equadistant within that border when gluing it to the silkscreen artwork. Silkscreen pictures here. http://www.diystompboxes.com/smfforum/index.php?topic=36392.msg876642#msg876642

dave

[petey twofinger]

thin coats .

do not use too high temps , i would gofor 90 , i got a lil digi themometer for 6 bucks .

i ended up taking two old junk speaker , cutting plexgass windows in the bottom , and a 110 volt lamp socket on top . with the right bulb , it runs at 90 . i also alternate between the hot box and a cooler dry environment .

too much heat makes it cure wrong , then its rubbery / forever soft .

what a hassle , but i got it down now , i also had 3 bad cans of krylon . one was brown , i guess i shouldnt have garbage picked it . at least tested it first .

ymmv .

[p_wats]

Funnily enough I baked a few 1590As too quickly yesterday, so the paint began to bubble. It looked pretty cool though, so I blasted it with a bazillion layers of triple thick clear and now it looks intentional!

[Muthauzem]

Funnily enough I baked a few 1590As too quickly yesterday, so the paint began to bubble. It looked pretty cool though, so I blasted it with a bazillion layers of triple thick clear and now it looks intentional!

Post some photos. I'm curious now. Hahaha

[rousejeremy]

I took everyones advice.

Hopefully this makes my life a little easier.

[nobodysweasel]

For all you folks that use a toaster oven - how long do you bake between coats?

[GGBB]

I do about an hour or longer at 200 every third light coat and 10 minutes between each light coat.  Works well other than the clear coat softness.  The primer and paint coats don't seem to have the same problem.

[duck_arse]

I use estapol water-based satin finish, over water-based acrylic(?) interior paint. the estapol says "don't spray", but I do anyway, thinned with gallons of water (but not too much) and an airbrush. it goes on dry, just about, so I blow on a couple of coats, then bake it in a box with a 25 watt bulb overnight. recoat, rebake, finished.

nice and satin-y, doesn't take fingerprints, hasn't crapped out yet.

[jdub]

Dave, have you had any problems with lengthy cure times when using the Target 7000?  I'd love to switch to a low VOC finish... I've been using Krylon & it's actually worked pretty well, but man does that stuff stink...  

[Oatmeal]

I watched this yesterday so I'm thinking about buying my wife a new oven and putting the old one in the garage.

I don't think a toaster oven will get hot enough.