panomaniac said:
It sounds like it would be. I think mine's just a single stage unit (was cheap by UK standards). It's a suction based gun, and the pot is larger than any amount of paint I've needed in a single job, so a smaller gravity fed unit would probably be better. It's served its purpose pretty well though.
I haven't read the whole thread so sorry if this has already been suggested, but another possibilty is polyester resin.
Cheaper than epoxy, don't have to measure two parts acurately, sands easier, less hydrophilic I think, and cure time is easily adjusted by amount of catalyst used.
Recoat time isn't an issue if you use laminating resin for the first coat (stays tacky) and add curing agent to the finish coat.
Cheaper than epoxy, don't have to measure two parts acurately, sands easier, less hydrophilic I think, and cure time is easily adjusted by amount of catalyst used.
Recoat time isn't an issue if you use laminating resin for the first coat (stays tacky) and add curing agent to the finish coat.
You better read the thread then 😉
Polyester resin does not bond to MDF was well as it could.
Also I think the epoxy isn't winning anyway, so anything kind of the same I would imagine won't be any better.
Polyester resin does not bond to MDF was well as it could.
Also I think the epoxy isn't winning anyway, so anything kind of the same I would imagine won't be any better.
sploo said:
Thanks for the sage words Gordon.
I've been trying the Iwata's out today but the compressor startup issue is driving me nuts. I'm certain it isn't doing the compressor motor nor the 3 phase converter any good either.
Can't justify a better and more expensive 3 phase converter so I think I'm going to have to put this down to experience, sell up and get a single phase unit.
I have seen a couple of 4hp 270ltr over on the 'bay. Looks like they need a 30amp line though... ouch. So I think practically speaking a 3hp (~10cfm FAD) machine is the only real sensible option for single phase.
There's also the dual compressor types that have twin 3hp piston compressor mounted to a single tank to effectively offer a 6hp machine but these are rare and always hold their price extremely well, which considering they sell for around £1k new isn't encouraging.
Best bet I think is to buy two 3hp machine, grab a T-junction, an inline regulator and wire the two machines together. This would provide around 18cfm(FAD) and cost around £300-400. Yep, think that's the route I'm going with this.
Gordon, why don't you grab a budget 3hp compressor and give compressed air a go? Your obviously very interested in sprayed finishes and I can assure you that you'll be suitably impressed over your existing single turbine HVLP setup.
Finally, despite the compressor issues I still got to test the Iwata's and
After using the Iwata I've been spoilt and I really don't know how I managed to get along with my faithful Kestrel gun for so long - there really is no reason to use that gun ever again. The atomisation of the Iwata's is just perfect and the spray pattern is incredibly uniform - this is even at the extreme ends of the fan width. It almost sprays by itself its that good. Before with the Kestrel I found that you had to have the gun at specific distances from the work to get the best results and no matter how routine and precise you made your passes you never quite got even coverage so you had to go back and do light drop coats or spot spray area's to even things up, these techniques were particularly important for metallics, micas and pearls. However and even after only a few minutes with the Iwata I found there's none of that, you just spray left to right with the recommend overlap and viola! Perfect uniform coverage.
You should see the way it lays clearcoats down too! Jesus its slick. I'm confident this gun will cut down on the final finishing work and specifically flatting out before polishing. There's very, very little orange peel such is the evenness of fan and uniformity of the material droplet size.
These guns are expensive but make a persuasive argument with your wallet. Consider me Iwata's bee-otch.
ShinOBIWAN said:
What about a better HVLP setup in the same price range? As he's already used to HVLP. Just thinking out loud really, there are pro's that swear by HVLP so it must be worth a second look?
richie00boy said:
I always find myself being a little more diplomatic on the forums because your speaking to a wide audience rather than a one-on-one private conversation where you get to speak your mind more.
You have to do this to make the answer universally appealing otherwise you risk offending people or can come across as pushing them in direction you have preference for or have adopted.
But in this case I'll be frank for a change. As far as I'm concerned HVLP turbines aren't much good for anything other than primers or painting a fence. HVLP guns that do not have to be used with turbines are a different matter altogether, some of them are very good. Two of the Iwata's I was talking about are HVLP and no these don't need gobs of air, 9cfm FAD is enough.
What do I base this opinion on? I've had an upper range 4 turbine HVLP and in few ways does it compare to compressed air.
Spraying with HVLP is painful because you have to move so slowly. Sure there's little overspray and thus material efficiency is high but compliant guns are only 3-5% behind here. There real killer is that a bee's fart would have better atomisation characteristics and these are required for the best base and clear finishes.
You'll very rarely, if ever, see a HVLP turbine in a custom body shop - don't you watch Pimp my Ride, American Bodyshop and American Chopper? 😀
Thanks, it's good to be frank sometimes 🙂
I wasn't really clear (in my own head) on the distinction between turbine and non-turbine HVLP.
Let me know if you ever come across one of those Iwata guns cheap again. My dad has a compressor setup so it would actually be cheaper for me to get myself a gun like that and use his stuff than buy my own HVLP setup. But then again he is 200 miles away
If I were to spray here at my home I would for now until I get a new shed be spraying outside with just a gazebo for protection. So I guess even the best HVLP would be rubbish under these conditions anyway?
I wasn't really clear (in my own head) on the distinction between turbine and non-turbine HVLP.
Let me know if you ever come across one of those Iwata guns cheap again. My dad has a compressor setup so it would actually be cheaper for me to get myself a gun like that and use his stuff than buy my own HVLP setup. But then again he is 200 miles away
If I were to spray here at my home I would for now until I get a new shed be spraying outside with just a gazebo for protection. So I guess even the best HVLP would be rubbish under these conditions anyway?
Have to go along with you on this Ant. Compressed air is the way to go, especially for small stuff.
I have seen incredible results with expensive airless sprayers though. These will spray unthinned paint just as smooth as glass, no orange peel. Drawback is the price and cleanup.
You are finding a big difference with the new guns? I have a relatively cheap one ($150) that I use that I'm happy with (good atomization, spray pattern, easy to adjust and keep adjusted). I don't do enough spraying to justify a $500 gun. For me, it's about getting it on as smooth as possible, then it gets cleaned up anyway with the final sanding/polish.
Sploo,
I'm puzzled as to the results you are having with the urethane. Should be harder by now. My curved baffle speakers paint is pretty hard, too hard to dent with a fingernail, that's for sure.
Still, with that said, I believe I'll not be using the solvent based anymore. The waterbased version is what I'll use on my next project (whatever/whenever that will be).
I can only recommend you go that route also. There are 2K versions available that will not need fresh air supply, just a regular resperator. The 2K version of the waterbased urethane paint would have to be hard, hard,hard.
I have seen incredible results with expensive airless sprayers though. These will spray unthinned paint just as smooth as glass, no orange peel. Drawback is the price and cleanup.
You are finding a big difference with the new guns? I have a relatively cheap one ($150) that I use that I'm happy with (good atomization, spray pattern, easy to adjust and keep adjusted). I don't do enough spraying to justify a $500 gun. For me, it's about getting it on as smooth as possible, then it gets cleaned up anyway with the final sanding/polish.
Sploo,
I'm puzzled as to the results you are having with the urethane. Should be harder by now. My curved baffle speakers paint is pretty hard, too hard to dent with a fingernail, that's for sure.
Still, with that said, I believe I'll not be using the solvent based anymore. The waterbased version is what I'll use on my next project (whatever/whenever that will be).
I can only recommend you go that route also. There are 2K versions available that will not need fresh air supply, just a regular resperator. The 2K version of the waterbased urethane paint would have to be hard, hard,hard.
"Polyester resin does not bond to MDF was well as it could."
The resin penetrates the MDF (or a second coat wouldn't be needed); to separate them you have to break the MDF apart.
Why do you need any more than that?
The resin penetrates the MDF (or a second coat wouldn't be needed); to separate them you have to break the MDF apart.
Why do you need any more than that?
Hi Noah,
The problem with polyester resin is that it has styrene as it's solvent. The styrene is absorbed by the MDF, thereby weakening the resin, as it no longer has it's solvent to cure. As a straight primer, this is where it fails.
Without a doubt it has a strong bond with the MDF, but what's left on the surface is an incomplete mix (styrene is gone). Same problem with most automotive body fillers.
The problem with polyester resin is that it has styrene as it's solvent. The styrene is absorbed by the MDF, thereby weakening the resin, as it no longer has it's solvent to cure. As a straight primer, this is where it fails.
Without a doubt it has a strong bond with the MDF, but what's left on the surface is an incomplete mix (styrene is gone). Same problem with most automotive body fillers.
John,
Interesting, thanks.
What about using more catalyst and/or curing agent in the finish coat?
Is this particular to MDF? I've done test bonds of plywood and the wood failed, not the bond, when I broke them apart.
Interesting, thanks.
What about using more catalyst and/or curing agent in the finish coat?
Is this particular to MDF? I've done test bonds of plywood and the wood failed, not the bond, when I broke them apart.
I don't know the specifics of it, probably it's as John says, but I'm going off what Sploo has been told in his research for this thread. He spoke to the MDF Council (or whatever they are called) which is a trade body representing UK MDF users and manufacturers, and they said poly resin was not best to use with MDF, same as PVA glue.
noah katz said:
Using more hardener will not solve it.
What has to be clear here is that we are talking about extremely high quality finishes - similar to the finish on a custom car.
It is the rapid loss of solvent on any porous surface (especially the end grain of MDF) that causes a problem. Not just polyester resin, but also paint finishes. That's why it's important to use a suitable primer.
Primer is supposed to be stable enough to penetrate the substrate if it is porous, without breaking down and leaving the solids on the surface.
Once primed, the substrate will not absorb the solvent from the finish, making it suitable for any paint finish (or polyester resin, body filler).
For a good test for solvent stability, use a piece of brown cardboard. Put a small amount of the paint or whatever you want to use as primer on it. If after a few seconds it seems the there is a wet ring around where the paint is, it's solvent is separating. If this is the case, it's not suitable as a primer.
For now I use a dumb brute force method of just laying an uber thick layer of primer (around or slightly over 1mm thick) and it helps but doesn't solve the problem. Using this whilst simultaneously veneering the surface is very close to eliminating it. Infact I'd be confident with solid colours you'd be good to go but bright metallics are a PITA. After about 4 months I could see a very subtle change of metallic reflectivity around where the joints are beneath the veneer and primer. Crazy thing is the gloss reflection doesn't highlight it at all.
It very close to working but we want perfect and invisible, even with bright metallics.
It very close to working but we want perfect and invisible, even with bright metallics.
Wow... lots of posts recently. OK (takes deep breath)...
Hi Noah - yea poly resin was actually mentioned to me by an MDF manufacturer, but a fibreglass supplier recommended against it for the same reasons that John's stated.
I think epoxy probably is a solution - certainly when it's laid on really thick I have manged to get a glossy paint finish, with no MDF join lines showing (the CD rack I made a few weeks ago hasn't shown any such defects).
However, the epoxy is indeed fairly expensive, needs to be mixed, has a limited pot time, and is quite viscous. It makes it quite difficult to sand smooth, especially if laid on thick. I personally don't really like using it - especially in comparision with varnish or G4.
Bad luck. I'm afraid I can't think of anything else to suggest with that.
A 30 amp line shouldn't be a problem - my garage has a 30 amp feed from the house, and I put in a distribution box to supply 5 amp lighting lines, 20 amp line for the extractor and a 30 amp ring for the sockets. Your electrician uncle would be able to do that in his sleep.
I was thinking about this doubling of compressors. Why is it you need to join two machines together? Is it because one of the guns requires more CFM than a single 3hp unit can supply?
I'm still planning to go for one of those air fed masks, and a 3hp compressor. It had crossed my mind that I could/should get hold of a gun and try it using the compressor.
Sounds good. I guess you factor the (one off) cost of the guns against the cost of your time to sand back the problems you get with an inferior (but cheaper) unit.
I guess the turbine is just a convenience - you don't need a heavy compressor, don't get issues of the compressor motor kicking in and out to fill the tank, and don't need a moisture trap and/or oil filter with a turbine.
I've heard about conversion guns and kits to turn conventional systems into HVLP, but don't really know much about the differences (other than HVLP is High Volume Low Pressure).
Does this mean you could use either type of gun with the same compressor, and the conventional gun would use little volume but need loads of pressure, and the HVLP would need a high CFM, but not much pressure?
Yea, I am amazed by how soft it is. The test piece that only had a couple of coats is slightly translucent, but will still take a fingernail. The blocks that had several coats will show a fingerprint if I pick one up and squeeze it hard.
I am interested by the waterbased paint. The G4 coated block is now just showing the most subtle signs of lines, but it's still the best I've seen (apart from a really thick layer of epoxy). If that could be combined with the quick drying waterbased, it might be a good solution.
You know what we need; someone to make a product that is as cheap and dense as MDF, and cuts as easily, but doesn't move due to moisture changes. Perhaps some sort of plastic product?
noah katz said:
Hi Noah - yea poly resin was actually mentioned to me by an MDF manufacturer, but a fibreglass supplier recommended against it for the same reasons that John's stated.
richie00boy said:
I think epoxy probably is a solution - certainly when it's laid on really thick I have manged to get a glossy paint finish, with no MDF join lines showing (the CD rack I made a few weeks ago hasn't shown any such defects).
However, the epoxy is indeed fairly expensive, needs to be mixed, has a limited pot time, and is quite viscous. It makes it quite difficult to sand smooth, especially if laid on thick. I personally don't really like using it - especially in comparision with varnish or G4.
ShinOBIWAN said:
Bad luck. I'm afraid I can't think of anything else to suggest with that.
ShinOBIWAN said:
A 30 amp line shouldn't be a problem - my garage has a 30 amp feed from the house, and I put in a distribution box to supply 5 amp lighting lines, 20 amp line for the extractor and a 30 amp ring for the sockets. Your electrician uncle would be able to do that in his sleep.
I was thinking about this doubling of compressors. Why is it you need to join two machines together? Is it because one of the guns requires more CFM than a single 3hp unit can supply?
ShinOBIWAN said:
I'm still planning to go for one of those air fed masks, and a 3hp compressor. It had crossed my mind that I could/should get hold of a gun and try it using the compressor.
ShinOBIWAN said:Finally, despite the compressor issues I still got to test the Iwata's and
Sounds good. I guess you factor the (one off) cost of the guns against the cost of your time to sand back the problems you get with an inferior (but cheaper) unit.
ShinOBIWAN said:
richie00boy said:
I guess the turbine is just a convenience - you don't need a heavy compressor, don't get issues of the compressor motor kicking in and out to fill the tank, and don't need a moisture trap and/or oil filter with a turbine.
I've heard about conversion guns and kits to turn conventional systems into HVLP, but don't really know much about the differences (other than HVLP is High Volume Low Pressure).
Does this mean you could use either type of gun with the same compressor, and the conventional gun would use little volume but need loads of pressure, and the HVLP would need a high CFM, but not much pressure?
MJL21193 said:
Yea, I am amazed by how soft it is. The test piece that only had a couple of coats is slightly translucent, but will still take a fingernail. The blocks that had several coats will show a fingerprint if I pick one up and squeeze it hard.
I am interested by the waterbased paint. The G4 coated block is now just showing the most subtle signs of lines, but it's still the best I've seen (apart from a really thick layer of epoxy). If that could be combined with the quick drying waterbased, it might be a good solution.
ShinOBIWAN said:
You know what we need; someone to make a product that is as cheap and dense as MDF, and cuts as easily, but doesn't move due to moisture changes. Perhaps some sort of plastic product?
sploo said:
What about that Valchromat stuff we were discussing earlier in the thread?
http://www.avonplywood.co.uk/noframes/valchromat info.htm
I've handled some and it does feel plastic-like, although I've yet to have any practical experience spraying onto or cutting it.
Its more expensive than regular MDF but is also more dense and treated with something.
I'll be giving it a go on my next project but I wouldn't mind if someone beat me to it and could report back 😉
Excuse me for not reading the whole thread, guys, but as far as turbine HVLP goes, this seems to be close to nirvana for a lot of US guitar makers, spraying their nitro laquers....and some waterbased, too. I'll admit to not knowing too much about spray equipment, as I've always used veneer and brushing laquers.
For the sealing bit, -maybe it has been mentioned, but has anyone tried shellac, or vinyl sanding sealers, both quite common with guitar makers??
For the sealing bit, -maybe it has been mentioned, but has anyone tried shellac, or vinyl sanding sealers, both quite common with guitar makers??
AuroraB said:
Shellac is a good sealer, but will have issues with some topcoats (urethane).
Vinyl sanding sealer is a very good choice for sealing before priming, as it is very stable, and will not seperate.
Worth a try.
Sploo,
I believe your ultimate goal is commercial, is it not? Your best bet would be to contact a large paint manufacturer and ask for their recommendations.
I know PPG is worldwide and they have an automotive coating that is water based, dries fast, and obviously is very hard and durable:
http://www.ppg.com/refineurope/Tds/ShowImage.asp?ImageId=7960
Using my Mickey Mouse method is OK if you have eons to wait around for the finish to cure. Also if you are planning on doing a lot of spraying, the waterbased will make things simpler and safer.
As far as spray technology is concerned, compressed air seems to be the way to go. Besides, it's hard to hook a nail gun up to an HVLP rig.🙂
I have a portable 1.2 HP compressor that does it all for me. It's air delivery is only 3.2 cfm @ 100psi, but that seems fine for the small stuff.
I believe your ultimate goal is commercial, is it not? Your best bet would be to contact a large paint manufacturer and ask for their recommendations.
I know PPG is worldwide and they have an automotive coating that is water based, dries fast, and obviously is very hard and durable:
http://www.ppg.com/refineurope/Tds/ShowImage.asp?ImageId=7960
Using my Mickey Mouse method is OK if you have eons to wait around for the finish to cure. Also if you are planning on doing a lot of spraying, the waterbased will make things simpler and safer.
As far as spray technology is concerned, compressed air seems to be the way to go. Besides, it's hard to hook a nail gun up to an HVLP rig.🙂
I have a portable 1.2 HP compressor that does it all for me. It's air delivery is only 3.2 cfm @ 100psi, but that seems fine for the small stuff.
Attachments
- Status
- Not open for further replies.