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How do you know when the finish is ready?


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I'm using automotive paint from halfords, primer, colour and clear. I've read differing opinions from various places on how long to leave it, 3 days, 1 week, 2 weeks, a month, but i am itching to polish it up so i can fit my ferrules and play the damn thing!

I'm planning on leaving it for 2 weeks, but then how do i know it is definately hard enough, and for that matter, how hard is hard enough?

Is there a test i can do?

I'd hate to mess it up at this stage, but then i don't want to wait longer than i have to, its killing me!! :D

Cheers!

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What is the base of the paint. Poly, lacquer, etc..

Lacquer takes a long time to cure (cooler weather the longer it takes, hotter weather the sooner it is ready). Patience is your best friend if it is lacquer.

If it is polyurethane It should be ready in a couple of weeks.

I always spray a test piece to sand and polish to help me know when the finish on the guitar is ready.

I can generally feel when it is ready. It will be hard and not the slightest sticky.

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I can generally feel when it is ready. It will be hard and not the slightest sticky.

Not necessary, depending on how much paint you shoot with cans, you can color sand the very next day, in order to shoot another coat, I finished my guitar and 2 days later I color sanded and started polishing to only notice that the back sida was marked with the towel I set it over. It's being 1 week and still needs to dry a bit more. Just find a spot that nobody will see and push with your finger tip, hold for a second... then release and look in an angle, if you can see your finger print groves on the paint is not ready ( I don't mean like a smudge mark but like the paint took the for of your prints.) I will say atleast 3 weeks or more depending on weather and humidity...

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Sniff it.

If you smell ANY fumes at all, it's not ready yet, and I mean ANY, even the faintest whiff of chemical vapors, it's still curing.

A month is a pretty safe bet.

I know it can be hard to wait, but if you go at it too soon, you'll just get mad at yourself down the road for touching it when you really knew better and should have waited.

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What type of Automotive paint did you spray?

If it is a 2 part poly urethane like PPG, Dupont, or RM etc. you can sand and buff 18 hours after your first coat. I've been finding recently that if I sand and buff between 18 and 30 hours from my last coat I get the best results.

If it's a one part paint, laquer, urethane etc, then Drak is pretty much right, but typically 3 weeks is pretty safe with any paint.

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Sniff it.

If you smell ANY fumes at all, it's not ready yet, and I mean ANY, even the faintest whiff of chemical vapors, it's still curing.

A month is a pretty safe bet.

I know it can be hard to wait, but if you go at it too soon, you'll just get mad at yourself down the road for touching it when you really knew better and should have waited.

This is so true... I have the guitar inside a closet now, and I open the door and you can smell the fumes, in the last few days the smell have lessen some what, I will be waiting like Drak said, until I can't smell it any more... :D I cant' wait to play the thing...

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im a little bit worried when you guys say weeks and months, because the paint I have says "handle after 1 hour" and the clear coat says "handle after 24 hours" :D when i see days, weeks, and months, it scares me, are my paints correct?

btw, my paint is "Krylon Interior-Exterior Black" and my clear coat is "Krylon Triple-Thick Crystal Clear Glaze"

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Thanks for the replies guys,

I suppose i'll have to leave it at least another week and do the 'sniff' test! I recall reading that in melvyn hiscock's book. I can definately still smell the thinners.

Also, thanks for the soldering iron tip...i'm just hoping i drilled the holes large enough in the first place!

I used Solid Edge to produce the models, gave me something to do whilst waiting to start building and allowed me to iron out loads of issues before starting on the wood!

This is my first guitar, and i've definately learnt loads of lessons :D ! my top 6 are...

1) Don't lay the painted guitar on ANYTHING until its properly cured, hang it - i have the imprint of my bedsheet on the back (should finish sand out ok though)

2) Leave a VERY wide berth when jigsawing 1 3/4 in alder, especially on exterior curves - i had to 'modify' the bottom shape!

3) Thin the grain filler - the stuff i used set almost immediately, requiring loads of sanding

4) Use enough carpet tape to stick down templates - One went awol in the middle of routing a pickup cavity (luckily hidden under the pickup surround)

5) Don't use TOO MUCH carpet tape to stick down templates - the main body template was a pig to get off, there's no way to get underneath it without damaging the finish, and it sometimes rips grain out of the surface

6) Check your tape depth-stop for drilling after every couple of holes - when drilling out the excess in my neck pocket they got deeper and deeper!

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3) Thin the grain filler - the stuff i used set almost immediately, requiring loads of sanding

You can always go back and redissolve your grain filler by using it's thinning agent.

Water for waterbased, mineral spirits for oil based.

If you apply it way too thick, you can always redissolve it with a rag soaked in the proper solvent and 'wipe away' yer blues. :D

But if you do this, you might have to go back and fill in a few spots where you lifted the filler back out of the grain.

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