# Sanding Sealer with Car Paint



## THRobinson (Jun 29, 2014)

I have a few guitar bodies to paint on my bench. I usually go to Napa and have paint made up since I don't have a spray booth yet. 

Normally I'd use an epoxy primer/filler paint (SprayMax 1K) and layer it up and sand it smooth then pain't them SprayMax 2K clear. Did a few guitars and worked quite well.

I have a couple now I stripped down to wood. Can I use a sanding sealer like Minwax water based poly?

I'm always lost when it comes to stuff like, don't paint acrylic over lacquer, or enamel over whatever... I understand why. some stuff takes more time to gas off than others but, keep forgetting which is which.

Is a water based poly sanding sealer ok to use? 

Plan is to build up a few layers, get stuff sanded out, then a light layer of primer because the colour I want is affected by base coat so, need a quick layer or primer on it. Plus the grey makes it easier to spot defects.

Also, I know there may be better brands (ie.Deft) but the local Home Hardware has the Minwax.


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## oldjoat (Apr 4, 2019)

no ... please don't do that , don't mix products .
water base with water base 
enamel with enamel. etc

best ... car primer over wood ... then sand with 400 , repeat till no marks show , sand with 600 or 800 ..

you can spray enamel over Laq , not the other way round ...
the thinner for enamel is "reducer" ( pretty mild stuff )
the thinner for Laq is toluene (AKA rocket fuel) , it will dissolve enamel paint ( or make it curdle ) or almost any other type of paint.

Laq "flashes" quickly for more coats , enamel must dry from the inside out (skin takes a long time to dry, so it breathes properly )

but, if you like to experiment and don't mind mistakes ... try it


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## THRobinson (Jun 29, 2014)

I need to make me a chart... one problem I had last year was that many brands of paint, ie Rustoleum, don't say what it is... poly, enamel, acrylic etc... even the datasheets some times dance around what it is. Makes it hard to know what goes with what. I wanted to do a satin metallic and finally gave up because couldn't find a decent clear that would go on the metallic paint I was using. 

For the one body I have, it's had the floyd cavity filled, and a les Paul type bridge installed in the wrong spot. Shame because was a Nuno signature series... but got it for $10. Thing is, first paint attempt you could see the lines where the two different woods met. Even after 3 or 4 coats of primer. Eventually sanded it all down and starting over, so wanted something that would build up quick and solid so I could hopefully be rid of the lines. 

Right now, I used Bondo Gold over it and sanded it down and a quick spray of primer to see trouble areas. Looks ok... but did the first time too.

Can says can be used with water or oil based poly after dries... but nothing about other stuff. Also need to recheck... will be testing out Duplicolor car paint off the shelf this time, and can't recall what it is...


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## knight_yyz (Mar 14, 2015)

You can always put a coat of shellac between coats of paint. Everything sticks to shellac and shellac sticks to everything


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## oldjoat (Apr 4, 2019)

any alcohol will lift shellac ( just bug juice ) fine for under house paint and hiding knots ... or french polishing ... or hiding water spots before repainting the ceiling.
Bondo , sand, car primer , spot putty (for small dings/ scratches, but let it fully dry ), sand finish smooth , Duplicolor is fine and they make a clear to go over it ( all car stuff and compatible )


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## THRobinson (Jun 29, 2014)

So stick with what I got.

My concern is, I did a Frankencaster for my nephew... numerous layers of epoxy primer, sanded smooth, painted with what I get mixed at Ideal Supply (Napa) which I believe was a quick flash urethane. Got a nice even coverage of that (many thin layers) then used the entire can of SprayMax 2K activated clear. Looking at the tech sheets, still not sure what it is... most I can find is "Two-component acrylate resins".

Basically, did a really heavy thick coat that I left for a week then wet sanded and polished it. Came out like glass it was so nice.

Year later, I saw the guitar a few weeks ago, and I swear I could see a few lines in the clear. Not cracks or scratches, but almost sunken indents. Very thin and small but, almost as if somehow the grain were trying to show through somehow.


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## oldjoat (Apr 4, 2019)

metal doesn't have pores that change or suck in coats to paint 
wood does, some worse than others ( oak is a big one ). They make wood filler for it ( bonds well and expands / contracts just like wood ).
Bondo is formulated for metal rates.

so yes, you could be seeing slight cracking under the hardened paint surface ( and the paint is stretching to cover it )


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## THRobinson (Jun 29, 2014)

Well... this is why asking about sanding sealers. I was just told to primer over wood, or bondo then primer over wood... but obviously there is a problem with that method. 

Right now, I have 3 guitars on the bench... 1 I don't see being an issue, the other 2 I suspect will have issues.

1 is the one mentioned before with the patch job, the other guitar is a Cort... got a neck/body cheap, and after a fret level/dress and fixing a broken abalone fret dot, that thing has a great neck on it. Never played a Cort before, heard of them, was surprised at the quality of the neck. The body, looks like it was dipped in poly. Literally almost 1/16" thick. I read some were made of a Mahogany like wood and looked reddish underneath the poly so spent hours sanding down to find out it was just white wood (basswood probably) with a reddish layer of something then 1/16" of poly. Sides and back are still a very thick poly, but the front was stripped to bare wood which I really regret doing. Debated the sander sealer for that as well because a poly and can get the thickness back. Not sure if poly that thick is especially great for tone/sustain but did add strength to the surface for the 5-way switch and screws.

Was actually debating taping that up and maybe resin coating? read somewhere something about the resin used on boats?

I added about 5 coats of poly, not a sander/sealer, to attempt to get the thickness built up... just worried about strength around the switches/pots now.


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## oldjoat (Apr 4, 2019)

if you have a lot of primer build up , you have to let it dry a long time (days) before the paint and clearcoat/topcoat.

resin will set at different temps ( usually more than 1 )
it goes plastic and soft , then re-hardens ... so if it sets at room temp and you leave it in the car / sun it will reset (sticky) and any paint on top will be FUBAR'd. ... reason why most composite aircraft are not left on the tarmac in the hot sun without supporting the plane. (wing droop)

regular resin will delam if submerged in water ( reason for the boat stuff).
most resins have a tint to them (very few dry clear ) look at the West System $$$$

not recommended for guitar work unless you have a bake oven.


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## knight_yyz (Mar 14, 2015)

If you want resin there is a company that makes a UV curable resin. Wipe it on and go outside for 1 minute and it is cured.


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## oldjoat (Apr 4, 2019)

so, only about $130 canadian a litre ?


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## THRobinson (Jun 29, 2014)

wow, $130... I'm good. 

For the Cort guitar I think my main concern is that missing 1/16" of poly. Added strength for the pots/5-way and the thickness allowed for countersinking the mounting screws on the switch.

Inside the cavity they routed a few mm out for that switch to fit. Maybe I'll just epoxy a thin maple strip there instead. 

... I don't have a countersink bit. Nice! I get to buy more tools! Tool shopping is like a mini Xmas. Speaking of, went to Lee Valley for the first time a few days ago. Didn't get much though, but did get a tiny wee toolmakers vise for nuts/saddles.


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## knight_yyz (Mar 14, 2015)

Wow, you guys did so much research. available in 4 oz , 1 pint, 1 quart, and 1 gallon starting at 19.95 US. 75 USD for a gallon is not 130 per liter. It's 98 per gallon. A quart is 32 bucks. Where the hell did you get your numbers from? A Hat? 

Polyester Gloss Resin | Solarez UV Resins


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## THRobinson (Jun 29, 2014)

Geez, someone needs his juice box.


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## oldjoat (Apr 4, 2019)

SOLAREZ EPOXY Econo KIT: Amazon.ca: Sports & Outdoors

Solarez Unisex 1 Litre Polyester Resin: Amazon.ca: Sports & Outdoors

https://www.amazon.ca/Solarez-Cure-Polyester-Ding-Resin/dp/B0007U7ZVA/ref=sr_1_4?qid=1561573927&refinements=p_4:Solarez&s=sports&sr=1-4


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## oldjoat (Apr 4, 2019)

THRobinson said:


> Lee Valley for the first time


 they have a nice set of 3 mini planes for luthiers.
and too many more "nice to have" tools. 

for that routered pocket , just some 5 min epoxy and some well matched popsicle sticks should work well.


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## THRobinson (Jun 29, 2014)

Ya, they had a few nice things for sure... that vise I got is identical to what StewMac had, got mine for about $25, after ship/duty/exchange etc... about $120 from StewMac.

Only difference though was that the StewMac had custom grips that were taller and had a 45 degree taper on either side so can file at low angles better. The grips come off the vise so can make custom ones. May need to find myself some metal an fab my own.


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## oldjoat (Apr 4, 2019)

nuther place to check for tools ... Busy Bee


now entering TAS as well as having GAS


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## THRobinson (Jun 29, 2014)

Busy Bee still around? Man... back in the day, that was my Dad's heaven.


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## THRobinson (Jun 29, 2014)

Busy weekend, painting bodies that have been waiting since the winter.

The trouble guitar, so far the primer isn't doing it... may have to experiment and go with the water based sander sealer.

The other guitar was a Cort body that I had sanded the front down only to find blah wood underneath. Sanded, primered, sanded, etc... and finally painted with waterborn paint I had made up from a car paint code I found.

Can we say Orange + Pearl? SO much pearl in it... Sadly, half the hardware is black and half satin aluminum. Not bad... originally guitar was gonna be metallic grey with racing stripes, bought the hardware, then changed my mind. Woulda been nicer all black hardware. Would only need to swap out the knobs and sadly the sating Schaller locking tuners with the 2-pins. Got them used super cheap and can use elsewhere, but for now, staying on this build.

Forgot to drill 1 small hole between the vol/tone for the mini 3-way toggle though... grrr.


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