Help!! Spraying disaster!! Need advice!!

[boneyguy]

Well not quite a full blown disaster but it seems that way after posting yesterday about my phenominal success with heating the rattle can first and how great it turned out. Pride cometh before a fall, or something like that.

Anyway I let the neck dry over night and gave it a levelling today with 400 and then some 2000. Dry sanding.

Afterwards I gave it a good wipedown with methyl hydrate (wood alcohol) on a clean rag.

A few hours later I was ready to spray so I got my spray can into a bucket of hot water (feeling brave I used hotter water than yesterday) and headed down to the underground parking where I spray.

I gave it one medium thick coat and wound up with.......disastah...!!

The only things I can think of that I did differently from yesterday were...

1) Had the can in hotter water
2) Didn't shake the can before spraying for as long as I normally would.

It doesn't look to me like it's a problem with how close or far the can was from the neck.

It looks to me more like a contamination problem. Like there's something on the neck that's interacting with the finish. It's like that on the neck as well not just the headstock. It's like that on about What do you think.

Anyway I will just let it dry and sand it out and try again tomorrow!!

[brandt]

I feel your pain...

[boneyguy]

I've just had another look at it and it's smoothed out a little from what you see in the above photo but of course it will still need to be levelled again.

Is it possible that the can was too hot and the finish came out with too much force and caused the disturbance in the finish? Kinda like waves on the surface of a lake from a strong breeze.

It's like that too a lesser degree all over the neck.

[boneyguy]

Originally Posted by brandt

I feel your pain...

It was a little painful but having some experience with this stuff I didn't get too worked up about it. It's all repairable.

[jwells393]

If you're spraying lacquer and you want to start over from scratch it would be easier to wipe the finish off with acetone and paper towels........ a lot easier and faster than sanding.

You super-heated can just might have been too much of a good thing. Stick with what worked for you earlier.

[brandt]

It does seem that if its too warm then the propellant will spray it more aggressively than designed -too much air, too thin of product. I don't have a lot of experience but after my fun yesterday I'm getting more experience in repairs... ackk!!

[Burnjet]

How cold was it down in the garage last night? Looks like a temperature problem or reacting to an existing finish like nitro.

[boneyguy]

Originally Posted by jwells393

If you're spraying lacquer and you want to start over from scratch it would be easier to wipe the finish off with acetone and paper towels........ a lot easier and faster than sanding.

You super-heated can just might have been too much of a good thing. Stick with what worked for you earlier.

I'm spraying Krylon Interior/Exterior. Some sort of polyurethane. I'll just sand it out. And that's good advice Jack, I'll go back to repeating what worked yesterday. Thanks.

Originally Posted by brandt

It does seem that if its too warm then the propellant will spray it more aggressively than designed -too much air, too thin of product. I don't have a lot of experience but after my fun yesterday I'm getting more experience in repairs... ackk!!

That's how it kinda looks to me. It looks to me like it dried with the 'waves' in it caused by excess pressure blowing on the surface of the finish. The Krylon dries so incredibly fast to begin with and then when heated it dries even faster. I think it might be caused by a combination of the super fast drying and the excessive force out of the can. Maybe.

Originally Posted by Burnjet

How cold was it down in the garage last night? Looks like a temperature problem or reacting to an existing finish like nitro.

I sprayed it this afternoon. I'm pretty confident it's not a temperature/humidity thing. I sprayed over the same Krylon poly I applied last night.

[boneyguy]

I had a closer look at some areas towards the heel of the neck and the finish has what I would describe as 'wrinkles' in it.

Does this mean anything to anyone??

[Buckocaster51]

It sure looks to me like something didn't like something.

If I am reading things correctly, you are NOT spraying DEFT or a DEFT-like clear. You are putting some sort of polyurethane over KRYLON. Is that correct?

Did the wood alcohol react in ANY way with the finish when you wiped it down?

I don't use polyurethanes...can't give you much advice...but I would look into the recoating/sanding/wiping down...which is of course where the problem happened...so that wasn't much help...

Like I said, I don't know from poly...

[Ronkirn]

STOP!!

Ron Kirn

[Ronkirn]

OK... what has happened is a chemical reaction due to incompatibility... the solvents in the lacquer, while they do evaporate up and out, they also are absorbed down and in.... that can take a few minutes, or on old finishes, a day or more....

STOP... let it dry for several days... then lets see where we stand, DO NOT SQUIRT anything else on it... nothin'... nada, zip, zilch..... go do something else for a few days.

Ron Kirn

[Spunky99]

My experience with Polyurethane tells me you did the following wrong.
1. Too short a time in between sprays.
2. You used wood alcohol instead of rubbing alcohol.
3. The Poly was toooooo HOT and exothermed.
4. You sprayed too thick a coat.

With Poly, you have to allow for proper drying time or subsequent coats will jelly the previous coat.
You should spray as thin a coat as possible.
There is no need to wipe it down with alcohol or any mineral spirits between coats.

The biggest problem is the exotherming of the Poly. It catalyzed so fast it took the soft previous coat and wrinkled up like it did. Poly has Xylene in it and that just flashed off in a heartbeat. Xylene is more volatile than Acetone and is a major degreaser. It'll take all the oil off your skin so fast you wouldn't believe. I use a respirator around Poly or any Isocyanates due to the extreme cancer danger. Xylene smells like banana oil...make you dizzy and a big headache later. I hope you are doing this in a well ventilated area.

Poly is a nice strong finish that has exceptional wear qualities for a fretboard.

I love the Sherwin Williams Hi-Build pre cat lacquer but you need a full face respirator and a moon suit to spray it. Thins with Tolulene or Xylene..NASTY!

Here is what is in Deft brush on and the aerosol lacquers.
ALIPHATIC HYDROCARBON
ISOBUTYL ISOBUTYRATE
VM & P NAPHTHA
METHYL n-AMYL KETONE
2-BUTOXYETHANOL
NITROCELLULOSE
n-BUTYL ALCOHOL
XYLENE
ISOPROPANOL ANHYDROUS
BUTYL CELLOSOLVE ACETATE
ETHYL BENZENE
ISOBUTYL ALCOHOL
ETHYL BENZENE

[Ronkirn]

I love the Sherwin Williams Hi-Build pre cat lacquer but you need a full face respirator and a moon suit to spray it. Thins with Tolulene or Xylene..NASTY!

This is important..... unless you have the equipment to protect yourself, and more importantly. . .. the disposition to actually use it, stay away from commercial grade chemicals that includes the paints, they are chemicals too.... They can kill you.... a band-aid won't fix that

Ron Kirn

[teleman1991]

erm i know nothing about this sort of thing i just hoppe it works out for u

[Spunky99]

Originally Posted by Ronkirn

This is important..... unless you have the equipment to protect yourself, and more importantly. . .. the disposition to actually use it, stay away from commercial grade chemicals that includes the paints, they are chemicals too.... They can kill you.... a band-aid won't fix that

Ron Kirn

Yeah,
Try spraying a cherry wood upper and lower set of kitchen cabinets that are already installed in the kitchen with a HVLP sprayer with the kitchen sealed off with plastic. No ventillation at all for fear of dust contamination on the clear coat and add summer weather in So Cal. You have a moon suit on, a full face respirator and heavy rubber gloves. You have taped the suit shut so nothing can penetrate to your skin and you have someone turn on the HVLP unit that is outside the room so it doesn't cause a flash fire and roast you and the kitchen with the electrical motor running at 25000 RPM. You have taped off everything that isn't going to be sprayed and you are spraying the nastiest stuff there is but also the most beautiful finish material there is. Your full face North mask is fogging up and the fresh cartridges you just paid $15.00 for are working like a charm but have to be tossed as the charcoal will release the nasties after 24 hours if you use them again the next day chocking you with toxics. Sweat is running down into your eyes and the vapor in the air is almost pure Xylene and is clouding your vision through the mask. In ten minutes your whole body is soaking wet with sweat and you still have another 10 to 20 minutes of work. The $25,000.00 set of cabinets are looking great and you just need to carefully control the spray while trying to see what you are doing in the dim light. It is surreal and you smell and taste nothing which is a very good sign that all is well.
Finally you are done for the day and can tear through the plastic at the outside kitchen doorway and escape the fog in the kitchen. You turn off the HVLP unit and quickly tape the plastic back into place, sealing the kitchen from dust.
You start with the gloves, then mask and then the head cover. You strip off the moon suit and rubber boots and sit down in the 95 to 100f heat and take a long pull on a cool one. You are proud of your work but worry about the dust and your health and whether the $5,000.00 you are going to get for all this is worth it.

Wear the gear and live long and healthy.......

[Flat357]

When is the movie coming out ?
I'm enthralled , and nails well bitten

[boneyguy]

Thanks. Lots of good replies so I'll take it from the top.

I sprayed Krylon Interior/Exterior Satin Poly over the very same finish which I had applied the day before.

The can says "Recoat: Apply multiple coats anytime"

This product also dries to the touch within probably 2 minutes or so depending on how thick it goes on of course.

On other Kyrlon products I have used they are very specific about recoating times, as in "recoat before 24 hrs or after 7 days"

So when they say I can recoat anytime I tend to take them at their word.

I have used quite a few of their products and they have always worked amazingly well. This is the first problem I have ever had.

Here's the process I followed:

1) I applied the finish on Sun. evening in the parking garage, approx. 5 coats.

2) Let it dry overnight

3) Levelled with 400 and then 2000.

4) Wiped down with methyl hydrate. (I have used this step before without problem. There is no obvious reaction with the finish while wiping down. The alcohol evaporates within seconds and appears to leave no residue.)

5) Approx. 2hrs after step 4 I took my stuff down to the parking garage. I put the can in a bucket of full on hot tap water. I sprayed on a medium heavy coat. I noticed immediatly a problem and didn't spray anymore.

6) Ran to the computer and began this thread.


As I stated earlier the only difference that I am aware of between the very successful spraying last evening and the very unsuccessful results today were...

1) I had the aerosol can in much hotter water today and

2) I shook the can only briefly before spraying whereas normally I would shake for a couple of minutes before hand.


Spunky99
I appreciate the information you have offered. It sounds like you've got lots of experience with spraying poly. Given what you've outlined it sounds to me like I may have overheated the can and the poly 'exothermed' as you have described.

Why is wiping with methyl hydrate a problem but rubbing alcohol isn't?
Now that I think about it this may be the first time I've used wood alcohol rather than isopropyl. How does this make a difference?
It all seems to evaporate very quickly with no residue left on the surface.


So what would you suggest I do next??


Thanks again everyone.

[Spunky99]

Boneyguy,

I race marathons on inline skates. I also modify my bearings so they are a lot faster than stock. Since I've shattered my fret wrist and broken my back, I think at my age I should slow down a bit but I keep wanting the wind in my face at speed......

So here goes...
Any alcohol I've ever used, left a residue that became gummy in my bearings after cleaning. I've tried all sorts of different alcohol products and all of them leave a residue!
Anything that could cloud or make a milky transparency in a clear coat is taboo.....
I use Coleman's white gas for the bearings with a couple of drops of 2 stroke oil but never would use it on a guitar finish.

So to make a long story short.....don't use any solvents, cleaners or any chemicals on a finish job.

[boneyguy]

Originally Posted by Spunky99

Boneyguy,

I race marathons on inline skates. I also modify my bearings so they are a lot faster than stock. Since I've shattered my fret wrist and broken my back, I think at my age I should slow down a bit but I keep wanting the wind in my face at speed......

So here goes...
Any alcohol I've ever used, left a residue that became gummy in my bearings after cleaning. I've tried all sorts of different alcohol products and all of them leave a residue!
Anything that could cloud or make a milky transparency in a clear coat is taboo.....
I use Coleman's white gas for the bearings with a couple of drops of 2 stroke oil but never would use it on a guitar finish.

So to make a long story short.....don't use any solvents, cleaners or any chemicals on a finish job.

Thanks for the help Spunky99.

Consider it done.

This Krylon product dries very quickly so I've already managed to level the surface. Tomorrow when I spray again I will do so without any chemical wipe down first. I will simply give it another wipe with a clean dry rag to get off any sanding debris. Hopefully between that and not overheating the can I'll be back in the saddle again.

The reason I wiped the surface with the alcohol was because I had read somewhere quite awhile ago that it was a good thing to do to remove any skin oil deposited from handling the piece you are finishing so the finger grease wouldn't cause problems with the finishing.

It occurs to me now however that I used to use mineral spirits to do the wipe down and for some reason over time had begun to use alcohol. I think I switched to alcohol because of it's lack of toxic odor.

Anyway I'll be back at it again tomorrow with a different approach.

[Nick JD]

Originally Posted by Spunky99

Wear the gear and live long and healthy.......

Good call, Spunky99.

I spent quite a few years blowing polyurethane surfboard foam for board blanks. Saw some stupid people pouring isocyanate without masks. The polyol is semi-safe, but that iso... proven carcinogen.

If you are spraying chemicalsthat aren't flyspray, you should be using a CARBON FILTER mask. I love watching people wear dust masks while spraying aerosols - a bit like wearing a fish-net condom.

[boneyguy]

Originally Posted by Nick JD

Good call, Spunky99.

I spent quite a few years blowing polyurethane surfboard foam for board blanks. Saw some stupid people pouring isocyanate without masks. The polyol is semi-safe, but that iso... proven carcinogen.

If you are spraying chemicalsthat aren't flyspray, you should be using a CARBON FILTER mask. I love watching people wear dust masks while spraying aerosols - a bit like wearing a fish-net condom.

What?!! So now you're telling me fish-net condoms aren't safe. Great. Will there be no end to this depressing day